Pest Management Guidelines

     
Management of Turf Pests  
     

By: Dr. Wallace Mitchell, Emeritus Professor, Dept. of Entomology

University of Hawaii at Manoa

MANAGEMENT OF TURFGRASS INSECT AND MITE PESTS
Hawaii has fewer pests of turfgrasses than the mainland United States. Experience on various crops from the mainland U. S. has shown that the use of chemical pesticides has been reduced between 25-50% with an IPM program. Brief discussions of the insect and mite pests of turfgrasses in Hawaii are presented.
Both federal and state laws and regulations concerning the sale and use of pesticides are continually changing. Pesticides mentioned in the various sections of this document were registered in Hawaii for application to turfgrass when this report was prepared. The mention of trade names does not constitute an endorsement. It is the responsibility of the user to make sure label directions are followed precisely.
Insects and mites are soft-bodied, invertebrate organisms that have lived on earth for more than 300 million years. They are better adapted than humans to exist on earth. Insects vary in size from 0.01 inch to over 10 inches in length. they can be found from below sea level (Death Valley) to the top of the highest mountains and in the air to 6,000 feet or more. Most insects are not harmful to man and in fact are very beneficial. Less than one percent of the insects known to man are considered pests. Being cold blooded organisms, activity of insects and mites is controlled by temperature and humidity. Cool temperatures slow down all activities, including feeding, reproduction, etc. Activities of mites and insects increase with increasing temperatures up to a certain point. Extremely high or low temperatures are lethal. Each insect and mite species has an optimum range of temperatures for their biological activities. Turfgrass insect and mite pests occupy a specific part of the turfgrass environment, namely leaves, stems, thatch and soil. The mild temperatures in Hawaii allow insects and mites to be active throughout the year although there may be some seasonal variation in population size.
A turfgrass manager should familiarize himself with the basic biological and ecological knowledge of the insect and mite pests. Good pest management depends upon correct identification of pests and the injury they produce. The manager should know about their behavior, growth and development, life stages causing damage, and food preference. In addition, he must understand environmental factors, such as humidity, temperature, soil type, location etc. that affect pest populations growth.

GENERAL BIOLOGY OF INSECTS AND MITES
Adult insects may be recognized by being segmented and having a body divided into three sections, the head, thorax and abdomen. The head contains structures to monitor the environment, antennae (1 pair that contains sensory hairs, cells, etc.), compound eyes, simple eyes, and mouthparts that are adapted for sucking plant juices or chewing plant tissue. The thorax contains appendages for locomotion, 3 pairs of legs, and may be wingless or have one or two pairs of wings. The abdomen is the terminal end of the insects body and the last segment contains structures for reproduction, ovipositor in the female and claspers in the male. Insects possess structures for the five senses common with man, sight, touch, smell, taste, and hearing. Adult moths and butterflies do not damage turfgrass while adult billbugs, chinch bugs and mealy bugs will feed on turfgrasses.
Mites are relatives of insects but differ greatly. They have only one body region that is sac-like. Antennae and wings are lacking. Adult forms usually have simple eyes and four pairs of legs. Mouthparts are called chelicerae, not mandibles, and are adapted for sucking plant juices.
All insects and mites develop from eggs that are deposited by the female on or in plant tissue or near a food source and conditions suitable for development. This stage of the life cycle is resistant to most pesticides. Size, color, ornamentation, and placement of eggs differs greatly and is characteristic for each species. Eggs do not damage turfgrasses.
Upon hatching from the egg, growth and development of insects and mites are accomplished in distinct steps or a series of molts, in which the exoskeleton (outer shell) is shed and renewed. They change in form and size as they grow. The amount of change varies from group to group. This change is called metamorphosis. Two basic types, simple and complete, are found in insects. Stages between molts are called instars. Growth ceases with the adult stage.
Immature forms that hatch from eggs of insects with simple metamorphosis are called nymphs. Nymphs resemble the adults except in size, body proportions, and the development of wings. Wings are developed externally during the early instars (stages) and compound eyes are present. There is no prolonged non-feeding stage prior to the last molt. Nymphs generally live in the same habitat and feed on the same food as adults. Chinch bugs, mealybugs, grasshoppers, cockroaches, stink bugs, termites, etc. all develop with simple metamorphosis.
Eggs of insects with complete metamorphosis hatch into a worm-like stage, the larva. Larvae of insects vary in form, some have legs or are legless, some lack a well developed head. Mouthparts of larvae may be different than the adult (caterpillars have chewing types while the adult butterflies and moths have sucking mouthparts). Food habits of the immature forms may be similar (bill bugs or snout beetles) or different than the adults. Larvae do not have compound eyes. Wing development is internal. Larvae molt and pass through several instars, increasing in size and often changing in color. The larva is the most damaging stage in the development of insects having complete metamorphosis and is the primary target of a pest management program. After the last larval instar, the insect changes into a pupa. Pupae do not move about, are inactive and do not feed. The pupa may be enclosed in a special cell or protective covering, which may be a hibernaculum, cocoon, or formed by the last larval skin, the puparium. The pupal stage is highly active, biologically for all larval tissues are broken down and reconstructed into adult tissues. Wings develop externally. The pupal stage is difficult to kill with pesticides for it does not feed or come in contact with pesticidal sprays. Moths, butterflies, beetles, flies, wasps, and bees develop through complete metamorphosis.
Turfgrass problems can result from causes other than insects. Careful observation should be made of areas exhibiting injury. Other causes of turf injury may be improper irrigation, improper fertilizer practices, excess accumulation of thatch, poor root system, detrimental weather conditions, improper mowing height, improper selection of turfgrass cultivar, oil or fuel spills, pesticide injury and acid or basic soil reaction. Many of these conditions are discussed in more detail in the section on turfgrass management.
When examining turfgrass, look for signs of insect or mite injury such as; thin grass stands, discolored, twisted or withered leaf blades, dying or dead patches, chewed or frayed leaf blades, and the presence of webbing or frass (fecal pellets) in the grass. The presence of large numbers of bufo toad or bird droppings indicate feeding on insects and a turfgrass problem may be developing. Small mounds or burrows also indicate the presence of turfgrass pests or predators in the damaged area. Inspect the zone between the healthy and damaged turfgrass.
In IPM we encourage the use of all pest control tactics in an integrated unified program. Pesticides are not eliminated as a tactic, but are used in a precise manner only when needed. There are many alternatives to chemical pesticides and all should be considered.
Damage to turfgrass is done by feeding of adult and/or immature forms. The type of injury is closely associated with the type of mouthparts. Insects with chewing mouthparts have laterally moving mandibles that tear off pieces of plant tissue and those with sucking mouthparts have the parts modified into a beak through which the plant sap is sucked. Mites also suck juices from the plant. Some pests feed only at night. Unless special effort is made to find the pest they may go undetected for some time.
Most turfgrass injury from mites or insects can be prevented by regular inspections of the areas and immediate remedial action. Insects and mites damage may be recognized by defoliation, yellowing, twisted growth, shortening of the internodes, stunting, browning and bleaching of leaves or dieback of the turfgrass. Early detection of such symptoms may prevent rapid buildup of insect pest populations when conditions are optimum.

PESTS
In Hawaii there are ten arthropod invertebrate pests of turfgrasses. Five are larvae of moths or butterflies (Order: Lepidoptera). One is a snout beetle or bill bug (Order: Coleoptera). One is a mealybug (Order: Homoptera). Early workers have erroneously called the mealybugs scale insects (i.e. Rhodesgrass scale). One is a scale insect (Homoptera). One new pest of St. Augustinegrass which has only recently (August 1990) been reported in the state is a chinch bug (Order:Hemiptera). One species of mite (Order:Acarina) is a pest of bermudagrass. Each of these will be covered separately.

MOTHS AND BUTTERFLIES
Order: Lepidoptera

KEY PESTS GRASS WEBWORM (GWW)

Herpetogramma licarsisalis (Walker) (Family: Pyralidae) is the most serious pest of turfgrasses in Hawaii. It was first reported in 1967 feeding on Kikuyu grass, Pennisetum clandestinumHchst. ex Chiov., (Davis, 1969). It was infesting pasture grasses and then spread to turfgrasses.

DAMAGE
Larvae damage turf by feeding on grass blades and crowns. Their presence is noticed by the feeding injury (ragged blades), green fecal pellets, and the conspicuous amounts of webbing on the surface leading to holes into the thatch. Feeding occurs at night. During the day larvae may be found near the base of the grass curled up. When disturbed, they become active and move rapidly away. Larvae are usually shiny green when feeding and brownish when unfed. The larvae live in silken tunnels near the soil line. The first indication of damage is usually the ragged appearance of turfgrass, although it is still green. After a period of time, with continued feeding, large brown patches appear. These patches may coalesce into larger areas.

HOST RANGE
Larvae of the GWW will damage pasture grasses and are considered serious pests of Sunturf bermudagrass, Cynodon magennisii Hurcombe. Davis (1968) reported larvae feeding on 13 other grasses in Hawaii (Table 1), including all the important bermudagrasses. Host preference studies by Murdoch and Tashiro (1976) with Sunturf bermudagrass; common bermudagrass, C. dactylon (L.) Pers.; Tifway bermudagrass, C. dactylon x C. transvaalensis Burtt-Davey; Tifway bermudagrass C. dactylon x C. transvaalensis Burtt-Davey; FB-137 bermudagrass, C. sp. showed the least feeding injury on common and Tifway bermudagrasses. Feeding injury spread more rapidly on the fine textured grasses than on coarse textured ones. Reinert and Busey (1983) reported on resistance of several bermudagrass selections to the tropical sod webworm, Herpetogramma phaeopteralis Guenee, not found in Hawaii, but closely related to the GWW. In their studies common bermudagrass and the FB-119 selection had less feeding injury.

DESCRIPTION OF THE LIFE STAGES
Reports on the biology of the GWW have been published by Champ (1955), Davis (1969), Tashiro (1976, 1977,1987) and Marsden. (1979a.)

Adult
Moths are gregarious and often found clustered on vegetation. They are attracted to lights and may be a nuisance around the home when populations are high. The moth is nearly a uniformly light brown in color with small dark dots scattered about the wings. Wing span is about 0.75 inches when at rest in the field. Fully expanded wings reach 0.94 inches and the body is about 0.5 inches long. When at rest, the insect is triangular in shape. Preovipositional period varied from 3 to 6 days. Egg production averaged 249 per female with a maximum of 557. Mating and oviposition occurs at night. Adult longevity averaged 13.1 and 13.5 days for male and female moths, respectively.

Egg
Females usually deposit their eggs on the upper surface of a leaf, along the midrib near the base of the blade. Eggs are flat, elliptical and laid singly or in masses overlapping each other like shingles. Newly deposited eggs are creamy white and as

Table 1. Host range of Herpetogramma licarsisalis in Hawaii.

Host common name

Host scientific name

   

Narrow-leaved carpetgrass

Axonopus affinis Chase

Californiagrass (paragrass)

Brachiaria mutica (Forsk)

Stargrass

Chloris divaricata R. Br.

Bermudagrasses

Cynodon spp. Rich

Henry's crabgrass

Digitaria adscendens H. B. K.

Pangolagrass

Digitaria decumbens Stent

Goosegrass (wiregrass)

Eleusine indica (L.) Gaertn.

Centipedegrass

Eremochloa ophiuroides (Munro) Hack

Torpedograss (Wainakugrass)

Panicum repens L.

Hilograss

Paspalum conjugatum Berg.

Panama paspalum

Paspalum fimbriatum H. B. K.

Seashore paspalum

Paspalum vaginatum Sw.

Kikuyugrass

Penniseturn clandestinum Hochst ex Choiv.

Rattailgrass

Sporobolus africanus (Poir.)

St. Augustinegrass (buffalograss) Stenotaphrum secundatum (Walt.) Kuntz

development of the embryo progresses, change in color from light yellow to orange. Just prior to hatching, the black head of the larva is visible through the chorion (egg shell). Egg development ranges from 4 to 6 days. Hatching of the egg takes place at night. Eggs have been collected on grasses up to 4000 feet elevation.

Larva
There are 5 larval instars in the development of the GWW. The first instar, with a black head capsule, does not eat the chorion. It is translucent and amber colored until feeding begins. It then changes to light green as a result of the ingested plant material. All other instars have brown head capsules. Larger larvae are various shades of color from brown to green, depending upon the quantity of fresh food ingested. The body of larger non-feeding larvae are mostly brown and may have a rose tint over most of the body. The prothoracic shield (above the first pair of legs) is lighter brown than the head capsule and each segment of the body has a ring of dark brown spots. Many of the brown spots bear 1 to 3 conspicuous setae (hairs). First instar larvae are about 0.04 inch long and the mature larvae (5th instar) are nearly one inch. Larvae feed at night and hide in the thatch near the surface of the soil during daylight. First and second instar larvae feed on the upper surface of the blades leaving the lower surface intact. Third to fifth instars notch and eat entire leaves and spin large quantities of silk webbing. Larval development averages 14.3 days. Prior to pupation, the fifth instar larva becomes quiescent, slightly shorter in length, and constructs a silken sheath (hibernaculum), covered with insect excrement and plant debris. Pest management tactics are applied against the larval stage.

Pupa
GWW pupation takes place within the hibernaculum. Pupae at first are creamy white color, then change to light brown and finally dark brown. Sex of the pupae can be determined. The average length of the pupae is about 0.4 inch. Duration of the pupal stage averages 7.3 days. Adults emerge from the pupal stage at night. Pesticides are ineffective against this stage of development. Natural control factors affect this stage of development.
At 24. 5 C (76.1 F) the total duration from egg hatching to adult emergence averaged 21.7 days. If the temperature was 30 C (86 F), the period was shortened to 16 days. Tashiro (1976) estimated that the optimum temperature for development of the GWW was slightly above 31 C (87.8 F).

MONITORING METHODS
A simple, rapid, accurate method of measuring the population of GWW larvae in turfgrass is essential for a pest management program. Several techniques have been tried. One of the earliest was a sprinkling can application of one gallon of water containing either pyrethrins or a detergent over an area of one sq. yd. The number of larvae rising to the surface within a ten minute period were counted (Anon., 1981; Niemczyk, 1981). Plywood boards 0.5 x 12 x 24 inches were placed on the turfgrass in the late afternoon, left overnight, and GWW larval counts taken the following morning. Nocturnal feeding larvae came to the surface to feed and remained, since the board excluded light (Mitchell and Murdoch, 1974). Visual ratings of larval feeding within a randomly selected area (2 sq. ft.), replicated 4 or 5 times, have been used to estimate GWW damage. Researchers' visual ratings of GWW feeding in the turfgrass plots were averaged.
Tashiro et al. (1983) made comparisons of the boards, sprinkling can and submergence of an area with water alone and water containing either pyrethrins or a detergent. For submergence tests, three metal rings (each 8 in. in diameter and 8 in high) were compared to a rectangular metal frame 3 x 12 x 24 in. The metal forms, with the bottom edge tapered to a cutting edge, were forced through the turfgrass into the soil at randomly selected areas. Four liters of liquid were applied to each frame, allowed to stand for 10 minutes with continuous counting of the larvae coming to the surface. Number of larvae surfacing was compared with larval counts under the boards. Research indicated more than one gallon of liquid irritant per treated area may be needed to completely saturate the turf.
Liquid irritants tested were water alone, water with 0.0002% (v/v) pyrethrins and water with 0.25% (v/v) liquid detergent. The detergent used was a mixture of anionic and nonionic surfactant plus ethyl alcohol (Joy, Procter and Gamble Co.).
Use of liquid irritants resulted in higher counts per unit area of turf. Approximately 3 times more larvae were forced to the surface within the 10 min. period than were found under plywood boards left overnight on the same turfgrass plots. Boards were 31% as efficient as pyrethrins and 25% as efficient as detergent Complete submergence with standing water for 10 min. was more effective than sprinkling solutions over the surface or utilizing boards.
To obtain accurate counts, continuous observation of the treated area for 10 min. was necessary. Not all larvae were forced to the surface within a 5 min. period but some larvae forced to the surface early reenter the turf before 10 min. period is up. It is recommended that a metal form, circular in shape (6 in. high and 20 in. diameter), be used as a sampling frame. Four liters of water containing either 0.0015% pyrethrins or 0.25% detergent is poured within the frame and the number of larvae coming to the surface within ten minutes counted. The process is replicated 3 to 5 times. The Lawn armyworm (LAW), fiery skipper (FS), and black cutworm (BCW) larvae responded to liquid irritants in the same manner as the GWW. Short (1990) recommended mixing one fluid ounce of detergent in two gallons of water and drenching a 4 sq. ft. area with the solution. If no larvae are observed coming to the surface, examine other suspect areas and repeat.

ACTION (THRESHOLD) LEVELS
The action or threshold level is when the pest population or turfgrass damage level has reached the point that a decision must be made whether or not to treat with an insecticide. The decision will depend upon the population of pest per unit area, the vigor and condition of the turf, and the intended use of the turf. Decision to treat is purely subjective, as pest populations are so dependent upon available moisture, temperature and vigor of turfgrass. Pests in Hawaii are active throughout the year, but become inactive if the temperature goes below 61 F. Threshold levels for more valuable greens and tees will be lower than for fairway and rough areas.
A visual rating of 10% or greater damage to bermudagrass turf, with the presence of lepidopterous larvae, is considered the level at which a pest management control tactic (insecticide) must be applied (Mitchell and Murdoch, 1974). Grass webworm larval counts of 5 per 2 sq. ft. plot indicated that more frequent observations were needed to determine the impact. An average of 10 GWW larvae per 2 sq. ft. is considered the action level at which a pest management tactic must be considered. These action levels are a beginning and can be finely tuned with experience.
Bowen (1980) in California recommended control measures be initiated if pest populations exceeded 5 cutworms, 10 skipper larvae, 15 sod webworms, or 9 billbug larvae per square yard of turfgrass.

BIOLOGICAL CONTROL
A number of parasites and predators attack various stages of the GWW in Hawaii. Several of these beneficial organisms were purposely introduced for other lepidopterous pests, others arrived accidentally. Pathogenic organisms attacking the GWW have not been reported to date in Hawaii.

Egg Parasite
Davis (1969) reported an accidentally introduced small wasp, Trichogramma sp., parasitized up to 96% of the GWW eggs from sea level to 2,000 feet (610 meters) elevation. An average of two parasites emerged from each GWW egg. The parasite was mis-identified as T. semifumatum.

Larval Parasites
Three parasitic wasps and one fly have been recorded attacking GWW larvae (Table 2). Adult tachinid flies, Eucalatoria armigera, have been observed, in a wide range of field conditions, to be an effective parasite. The ichneumonid wasp, Cremastus flavo-orbitalis also ranked high in parasite emergences.
A single Chalcid wasp was reported parasitizing the GWW pupa. Data on the impact of the larval and pupal parasites is meager.
Both invertebrate and vertebrate predators have been recorded feeding on GWW larvae. The bigheaded ant, Pheidole megacephala (Fab.) (Family: Formicidae) was the most common insect. Avian predators included the cattle egret, Bubulcus ibis L.; the
mynah bird, Acridothermes tristis tristis (L); the Brazilian cardinal, Paroaria coronata (Latham) and the Pacific golden plover, Pluvialis dominica fulva (Gmelin). Head capsules of the GWW have been found in the droppings of the giant toad, Bufo marinus (L.). The impact of these predators on GWW populations is not known.

Table 2. Grass webworm larval and pupal parasites.

Scientific name   Order   Family
         
Larval Parasites        
Casinaria infesta (Cress)   Hymenoptera   Ichneumonidae
Cremastus (= trathala ) flavo-orbitalis Cam.   Hymenoptera   Ichneumonidae
Meteorus laphygmae Viereck   Hymenoptera   Braconidae
Eucelatoria armigera (Coq.)   Diptera   Tachinidae
         
Pupal Parasites        
Brackymeria sp.   Hymenoptera   Chalcidae

Biocontrol agents are effective in some situations. Accurate observations on the impact of beneficial organisms are essential in making the decision whether or not to apply additional pest management tactics on the GWW population.

CULTURAL CONTROL
Some of the cultivars of bermudagrass have shown differences in feeding injury by GWW larvae (Murdoch and Tashiro, 1976, Tashiro, 1976 and Reinert and Busey, 1983a) . Future genetic selections of bermudagrass may show resistance to GWW feeding. Good management practices, fertilization, irrigation, aeration, etc., which produces healthy turfgrass, allows the turf a better chance of recovery from GWW damage. Mowing at 1.5 inches and reduced use of nitrogen fertilizer has been recommended in Florida (Short, 1990). Short recommended using water insoluble (slow release) N and controlling thatch.

CHEMICAL CONTROL
Insecticidal control is the first line of defense when there is a sudden widespread increase of defoliation by GWW or other turfgrass pests. There is no alternative but to depend upon a recommended insecticide. A number of insecticides for application to turfgrasses have been registered by the EPA and the Hawaii Department of Agriculture for use in Hawaii (Table 3). Even though a pesticide may be registered for turfgrass on the mainland U. S., it may not be used in Hawaii unless it is registered in Hawaii.
Insecticides are compounds that kill insects through their chemical action. All insecticides must be considered hazardous chemicals in handling, storage, application and post-application use. Pesticide users must understand the label to be sure that the pesticide is registered for use in Hawaii for turfgrass and for the particular site and pest in question. Directions for use, clean up, safety, precautions, storage, disposal, and symptoms of poisoning and emergency procedures should be clearly understood. For example, diazinon, and organic phosphate insecticide, CANNOT BE USED ON GOLF COURSES AND SOD FARMS, but may be used by homeowners on their lawns. The federal and state regulations change frequently and one must follow directions on the latest label. Information on the insecticides may be obtained from the basic manufacturer or his representative in Hawaii, University of Hawaii Extension Service, and Hawaii Department of Agriculture, Pesticide Division. Any problems with spills or accidents should be reported to the State Departments of Agriculture and Health, Occupational Safety and Health (OSHA).
Proper timing of a pesticide application directed against the most vulnerable stage is necessary for effective GWW control and may reduce the number of applications necessary per season. The most commonly used formulations are emulsifiable concentrates (EC), wettable powders (WP), soluble powders (SP), and granules (G). Granular formulations were more effective in reaching the crown of the grasses at the soil level and lasted longer than emulsifiable concentrates. Soluble powders and emulsifiable concentrates were easier to mix, apply, and in some instances more effective than the WP formulations. Pesticides selected should be biodegradable, nonphytotoxic, have a low leaching potential and a low mammalian toxicity. Extreme care should be taken in the selection of a pesticide to be applied to turf or pasture grasses for grazing cattle, horses or pets in order to reduce pesticide residue hazard.
Insecticides registered in Hawaii for control of turfgrass pests are listed in Table 3. Registrations for use are changing daily, so one should read and understand the label before applying the material to turfgrass. The insecticide selected must be registered for application to turfgrass in golf courses. If there is any question as to whether it can or cannot be used, check with the DOA, basic manufacturer or their representative. New materials may be added and present registrations may be withdrawn at any time by EPA, DOA, and the basic manufacturer.

Table 3. Insecticides registered for turfgrass insect control on golf courses in Hawaii.

Common name Trade name(s)

Use*

Classification**

     

Biorational:

   

Bacillus thuringiensis Dipel, Thuricide

I

G

Carbamates:

   

Bendiocarb Turcam

I

G

Carbaryl Sevin 80S

I

G

Organic Phosphates:

   

Acephate

Orthene Turf, Tree and

 
 

Ornamantal spray I

G

Chlorpyrifos

Dursban 50W I

G

Ethion

Ethion 8 EC I, A

R

Isofhenfos

Oftanol 2 I

G

Methomyl

Lannate I

R

Trichlorfon

Dylox 80 I

G

     

Synthetic Pyrethoids:

   

Fluvalinate MavrikAquaflow

I. A

G

*Use: I = insecticide, A = acaricide, N = nematocide:
**Classification: G = general use, R = restricted use
BE SURE TO READ THE LABEL BEFORE APPLYING PESTICIDES

Other insecticides that have been suggested for sod webworms and army worms in Florida are acephate, bendiocarb, Bacillus thuringiensis var. kurstaki, ethion, methomyl and trichlorfon (Short 1990, Reinert 1976, 1983a). These materials have not been tested against lepidopterous pests in Hawaii.
For the GWW and other lepidopterous larvae, chlorpyrifos (Dursban) emulsifiable concentrate or granular formulations and carbaryl (Sevin) soluble powders, wettable powders, and granular formulations have been very effective. Check the label for the rate of application. Treatments should be applied in the evening or late afternoon and not watered in. Repeat the treatment if necessary. Chlorpyrifos is normally tightly sorbed onto the organic matter in the thatch and in the soil so that leaching is not a problem.


OCCASIONAL PESTS LAWN ARMYWORM (LAW) Spodoptera mauritia (Boisduval) [Family: Noctuidae]

The LAW was first discovered in Hawaii in 1953 (Pemberton, 1953) and like the GWW is established on all islands. LAW is not known to occur in the continental United States. During the sixties it was the most important pest of turfgrass and in recent years the populations have stabilized, apparently due to actions of parasites and predators. Information on the biology and ecology of the LAW have been published by Tanada and Beardsley (1958), Marsden (1979b) and Tashiro (1987).

DAMAGE
The larval stage or caterpillar damages the turfgrass by feeding on the blade, crowns and stems. Young larvae may feed on the blades during daylight hours and the grass shows a silvering at the tips. Watch for this sign of feeding damage. As the larvae increase in size they eat all the leaves and stems in their path and greener portions of the crown leaving only the tough old runners. Damaged areas take on a brown, dried up appearance. Active infestations are characterized by having a sharply defined advancing front between defoliated and green undamaged turf. With large active populations the front may move as much as one foot each night. Normally the denuded area spreads out from around the bases of buildings or trees and shrubs where eggs have been deposited. Older larvae feed at night and hide in the grass during the day.

HOST RANGE
In Hawaii LAW damage was most severe to bermudagrass lawns. Tanada and Beardsley (1958) believed the large recorded host range may have been confusion in larval identification of other species of Spodoptera. They conducted host range and preference studies. LAW larvae have been reported to feed on sedges (Firnbristylis tenera Roemer and Schultes), two week old sugarcane seedlings and several grass species (Table 4). In the Orient the insect sometimes caused injury to rice. Survival of LAW larvae on these hosts ranged from 72 to 100 per cent in various tests.

DESCRIPTION OF THE LIFE STAGES
Descriptions of the life stages and the biology of the LAW have been published by Fletcher (1956), Marsden (1979a), Tanada and Beardsley (1958) and Tashiro (1987).

Adult
Moths are nocturnal and commonly attracted to lights. Adults are common grayish brown with a wingspan of 1.2 to 1.6 inches. Males are slightly smaller (1.31.5 inch wingspan) and more vividly marked than the females. The forewing of the male has a white diagonal mark in the anterior median area of the upper surface of the wing between the whitish or buff-colored orbicular spot and the dark bean-shaped spot. The female is slightly larger (1.4-1.6 inch wingspan) than the male and this area is dull grayish-brown and not much different from adjacent areas of the forewing. The dark bean-shaped spot is well defined. The hind wings of both sexes

Table 4. Host Range of Spodoptera mauritia in Hawaii

Common Name

Scientific Name

   

Bermudagrass

Cynodon spp.

McCoy grass

Cyperus gracilis R. Br.

Kyllinga

Cyperus kyllingia Endl.

Nutgrass

Cyperus rotundus L.

Henry's Crabgrass

Digitaria adscendens H.B.K.

Wiregrass

Eleusine indica (L.) Gaertn.

Dallisgrass

Paspalum dilatatum Poir.

Napiergrass

Pennisetum purpurem Schumach.

Bristly Foxtail

Setaria verticillata (L.)

Buffalograss,St.Augustine Grass

Stenotaphrum secundatum (Walt.) Ktze.

Manilagrass

Zoysia matrella (L.) Merr.

are pale with darker areas along the outer margins. The dorsum of the thorax is covered with greyish to reddish brown scales.
Adults mate within a day after emergence from the pupa and start to lay eggs about 4 days later. Oviposition begins shortly after dusk and is usually completed before midnight When fed sugared water adults lived for 9-14 days.

Egg
Females usually deposit their eggs on the foliage of shrubs and small trees. Females rarely deposited their eggs on grass. Wooden and concrete structures, especially near outdoor lights allowed to burn in the evening or near a window from which light emanated, were used as ovipositional sites.
Eggs are deposited in flat, felt-like masses, elongate-oval in outline, covered with light brown hairs from the tip of the females abdomen. The eggs are not visible unless the female is old and her abdominal hairs are exhausted, the last egg masses may be nearly naked. Each egg mass consists of several layers and may contain 600, 700 or more eggs. Eggs are light tan or greenish with a pearly luster and as development progresses turn to grey or dark tan prior to hatching. Eggs are circular, flattened and sculptured with fine lines. Eggs hatch within 3-5 days.

Larva
Caterpillars of the LAW have 7 or 8 instars in their development. First instar larvae are pale green, about 0.05 inch long, emerge from the eggs and spin a silken thread to reach the ground. First to third instar larvae remain predominantly green as soon as feeding begins. As the larvae continue to grow, they become brownish with a pair of pale stripes down their backs. Patterns and stripes are present in the fifth to seventh or eighth instars. Mature larvae are 1.5 inches long with a pair of prominent jet black marks on each body segment, with exception of the first thoracic and terminal segments, toward the center of the body inside the longitudinal yellow stripes. Spiracles are black. Development takes approximately 28 days.

Pupa
Pupation occurs in a loosely formed silken cocoon containing dirt, plant material and larval webbing. The pupa is normally found in the soil or grass debris at the base of the turf. It is reddish brown when fully hardened. Pupal period lasts from 10-14 days.
The entire life cycle takes approximately 42 days depending upon the temperature and humidity. Adult moths have a preovipositional period of nearly 4 days, eggs hatch in 3 days, larval period lasts 28 days and the pupal period averages 11 days.

MONITORING METHODS
Methods for monitoring LAW populations are the same as described for the GWW. The use of liquid irritants or flooding the sample area with water forced the larvae to come to the surface. The liquid irritants were more efficient than the boards left overnight.

ACTION LEVELS
Larval populations of LAW have been low probably due to the impact of predators, parasites and pathogenic organisms. A general level of 5 LAW larvae per square yard indicates an increasing population and a pest management tactic should be considered. With more experience the action level may be fine tuned and more accurate.

BIOLOGICAL CONTROL
In Hawaii a number of natural enemies have made an impact on populations of LAW. Several of these beneficial organisms were introduced for other lepidopterous pests and others arrived accidentally with the host.

Microorganisms
A polyhedrosis virus attacking LAW was reported by Bianchi (1957). The virus has been observed in both young (second to fourth instar) and older larvae. The viral infection was most likely introduced by the insect. Tanada and Beardsley (1957) and Tanada (1960) described the virus as Borrelinavirus sp. The virus could infect all larval stages but was more pathogenic to the younger than older larvae.
A microsporidian, Nosema spp., was found in LAW eggs. The microsporidian was highly infectious but its impact on LAW populations has not been determined. A fungus and bacterial disease of LAW has been reported in Australia (Smith 1933) and Sri Lanka (Hudson 1920). Neither of these two microorganisms has been reported in Hawaii. Some of the microorganisms may show promise in microbial control of the LAW.

Egg Parasites
Two species of parasitic wasps, (Telenomus nawai Ashmead [Family: Scelionidae] and Trichogramma minutum Riley [Family: Trichogrammatidae]) attack LAW eggs. Parasitism of eggs ranged from 20 to 80 per cent. The heavy covering of hair and several layers of eggs appeared to hinder the egg parasites.

Egg-larval Parasites
The braconid wasp, Chelonus texanus (Cresson) was observed ovipositing in LAW eggs. The parasitoid was introduced into Hawaii from Texas to control Laphygma exempta (Walk.) (Bianchi 1944). The wasp larva emerges from fifth or sixth instar LAW larvae and pupates in a silken cocoon in ground litter. Thirty days are needed for completion of development from oviposition to emergence of the adult wasp.

Larval Parasites
LAW caterpillars attacked by braconid wasps are killed usually before they are half grown. One of the most important parasites of LAW larvae is Apantales marginiventris (Cress.). It was reared from early instar LAW larvae. The parasitoid larvae emerges from the hosts fourth instar caterpillar and forms a white cocoon, usually found on a grass blade. The life cycle of A. marginiventrus is completed is 12-18 days.
Three species of tachinid flies, Chaetogaedia monticola (Bigot), Achaetoneura archippivora (Williston) and Eucelatoria armigera (Coq.) have been found parasitizing LAW larvae. When parasitized by one of these flies the host is killed in the pupal or last larval stage. The emergence of the parasitoid in the later instars allows the larvae to do contribute materially to the damage of turfgrass before they die.

Predators
Both invertebrate and vertebrate predators have been observed in Hawaii feeding on LAW larvae or pupae. Two species of ants, Monomorium floricola Jordan and Pheidole megacephala (Fab.) attack LAW egg masses. The big-headed ant, P. megacephala has also attacked LAW larvae. Three species of coccinellid (ladybird) beetles, Orcus chalybeus (Boisd.) larvae and adults, and only adults of Cryptolaemus montrouzieri Mulsant and Scymnus roepkei Fluiter were feeding on eggs of LAW. Although data is lacking, other insects, such as lacewings larvae and wasps may also attack LAW larvae in the grass.
The major vertebrate predators of LAW larvae are the giant toad, Bufo marinus (L.), and the Indian mynah bird, Acridotheres tristis (L.). The toad is believed to be a valuable predator because its nocturnal feeding habits coincide with those of mature LAW larvae. In other parts of the world ducks, storks, cranes, herons, egrets, chickens and crows have been reported to be effective predators of the LAW.
The biocontrol agents are effective in some situations. Accurate observations on the impact of these natural control agents is essential in making the decision whether or not to apply an insecticide on the LAW population.

CULTURAL CONTROL
One of the simplest methods is to brush off egg masses on ceilings and walls of buildings. Mow grass properly. Avoid the buildup of thatch and remove it when it is excessive. Larvae tend to hide in the thatch. Fertilize turfgrass properly for the increase in succulence of grass encourages an increase in insect attack

CHEMICAL CONTROL
The insecticides suggested for GWW control are also effective in controlling LAW. The biorational, Bacillus thuringiensis var. kurstaki spores, is an effective larvicide. It is harmless to humans and safe to the environment. Its activity decreases with exposure to strong sunlight and extreme temperatures. Refer to the label for instructions on dosage rates, application information and precautions. An area treated with granular formulations should be watered down following application. Evening treatments are preferred and repeat applications may be necessary.


POTENTIAL PEST FIERY SKIPPER (FS) Hylephila phyleus (Drury) [Family: Hesperiidae]

The skipper butterfly was first discovered in Hawaii in 1970 (Kawamura and Funasaki 1971), has the potential to cause significant damage to turfgrass during warm periods. It is found on all islands with the exception of Lanai. The common name, fiery skipper, is due to the bright orange and brownish color and erratic, skipping flight pattern of the adults.

DAMAGE
Larvae are seldom seen and the first evidence of damage are small isolated round spots where single larvae have devoured the grass blades. The circular spots are 1-2 inches in diameter. These spots may coalesce into larger areas.

HOST RANGE
Larvae will feed on all common lawn grasses but appears to prefer bermudagrasses (Cynodon spp.), bentgrasses (Agrostis spp.), crabgrasses (Digitaria adscendens) and St. Augustine grass (Stenotaphrum secundatum).

DESCRIPTION OF LIFE STAGES
Biology of the fiery skipper in Hawaii has been published by Tashiro and Mitchell (1985) and Tashiro (1987).

Adult
Adults are more commonly seen flying about visiting flowers of lantana, honeysuckle, clover and other plants to feed on nectar. The FS has a wingspan of 1.0 inch or slightly larger. Males are predominantly bright orange-yellow above and pale yellow with black spots on the underside of front and hind wings. Females are predominantly dark brown with orange-yellow spots on the upper wing surface and similar coloration of the males on the undersurface of the wings.

Egg
Hemispherical eggs are deposited singly on the upper surface of the grass blades. Freshly deposited eggs are pearly white and as development continues change to powdery blue, then greenish blue within 1-2 days. Just prior to hatching the egg becomes nearly white again and the black head of the larva is visible through the chorion. Egg development may take 3-5 days.

Larva
Larvae are seldom seen since they remain concealed in lightly woven silken tubes in the thatch area. There are five larval instars in the development of FS. First instar larvae are pale greenish in color with a granular appearing surface over the body. The first two body segments behind the head are smaller than the rest, appearing as a strongly constricted neck. The "neck" is a distinguishing characteristic for all FS larval instars. The head is strongly constricted in the neck area and a black narrow shield over the prothorax is evident. The head is black and mottled or striped with brown and the body is covered with short setae for all five instars. Later instars the body becomes yellowish-brown to grayish-brown with a faint median longitudinal stripe. FS larvae are approximately 1.0 inch in length. Just prior to pupation the body becomes rigidly straight (prepupa). First instar larvae notch the edges of the blade and later instars consume the whole leaf. Third to the fifth instar larvae spin large quantities of strong silk webbing. Larval development at 81-84 F is completed in about 15.5 days

Pupa
Pupation often occurs in grass near the surface of the soil in a loosely woven cocoon covered with leaf litter debris. If debris is not available the pupa may be free in the grass-root zone. Young pupae have a light green head and thorax, and a light tan abdomen. As development progresses the pupa turns brownish-yellow with a conspicuous black dorsal line and is covered with rather thick bristly hairs. Pupae of FS are about 0.7 inch long. Pupal development at 81-84F is completed within 7.6 days.
Development from egg to adult takes 48 days when reared at 75F and fed bermudagrass. When reared at 81-84F it took only 23 days.

MONITORING METHODS
Methods for monitoring FS populations are the same as described for the GWW. Larvae have been observed under boards as well as being forced to the surface with the use of irritating liquids.

ACTION LEVELS
Larval populations of FS have been low and present in few situations. We do not know the reason for such low populations but believe it must be due to environmental conditions and the impact of parasites or predators. Because of the low populations in Hawaii, action levels have not been developed for FS. Ten FS larvae per square yard as suggested by Bowen (1990) in California may be a starting point.

BIOLOGICAL CONTROL
Information on natural enemies of FS is lacking for Hawaii. In California a braconid wasp, Apanteles spp., and an ichneumonid wasp, Amblyteles sp., attack the larvae and pupae, respectfully.

CULTURAL CONTROLS
Mow, fertilize and manage the turfgrass properly. Avoid the build up of thatch and remove it when it is excessive. Thatch provides a haven for the larvae to hide in and their populations may increase. Good management practices for good healthy turf requires fewer insecticide applications.

CHEMICAL CONTROL
Insecticide treatments may not be needed if the FS populations continue to remain low. The insecticides suggested for GWW and LAW are also effective in controlling FS. Refer to the label for rates of application, precautions and directions for use. Granular formulations should be watered down to move the toxicant down into the thatch and grass at the surface of the soil. Apply the pesticides in the evening or late afternoon. Repeat treatments may be necessary.


POTENTIAL PEST BLACK CUTWORM (BCW): Agrotis ipsilon (Hufnagel) [Family: Noctuidae]

Occasionally a larva of this noctuid moth will come to the surface of the turfgrass when monitoring for the key pests. Although the insect has been recorded in Hawaii since 1879, it has not developed into a serious pest of turfgrass but has the potential for serious outbreaks. It is also called the greasy cutworm.

DAMAGE
The common name describes the larval habits. Larvae feed at night on the leaves and crown of the turfgrass and may cut off plants near the soil surface. They may cut off one plant, not feed, move to an adjacent plant and repeat the process. During daylight the larvae hide in the thatch, ground litter or burrow into the soil.

HOST RANGE
In Hawaii is has been a serious pest of many garden vegetable crops by cutting the seedlings off at or below the ground level. It has damaged sugarcane and corn. It was recorded feeding on Sunturf bermudagrass, Cynodon magennissii Hurcombe experimental plots at Waimanalo. In particular situations it probably will attack other bermudagrass cultivars as well as other lawn grasses. They also feed on some weeds i.e. purslane, Portulaca oleracea L.. In California it feeds on dicondra and white clover.

DESCRIPTION OF LIFE STAGES
Descriptions of the developmental stages are published by Zimmerman (1958), Rings (1977) and Tashiro (1987).

Adult
Moths are dark grey to black or brown. Antenna of the male is pectinate and filiform for the female. In the forewing is a black reniform spot and a black bar extending toward the tip of the wing. The hind wings are nearly white, veins prominent without a medial band. Adults are active at night. Wingspan of the adults is about 1.0 inch. Adults are attracted to lights, especially black light. Adults may live 30 days.

Egg
Freshly laid eggs are naked, creamy white in color, dome shaped with a small circular depression at the upper pole from which radiate ridges down the sides to the base. As development progresses the eggs darken to tan, gray, dark brown and black before hatching. Eggs are deposited on the surfaces of leaves or stems near the soil surface. Eggs may be deposited singly or close together in a batch. Development takes 2-4 days.

Larva
Like other lepidopterous pests, IPM programs are directed against the worm stage. The larvae are nearly a uniform dark greasy gray to black in color and paler underneath. Spiracles are black. The head and dorsal part of the segment behind the head is brown. Conspicuous tubercles appear as rows of brown dots. The larva molts five times in its development. Mature larvae are 1.75 inches long. The larvae actively feed at night and hide during the day in the thatch or beneath the soil or plant debris at the surface of the soil. Young larvae feed on the grass blades and later instars tunnel under the soil, cutting off the plants and pulling them down into the burrow. With crowded conditions the larvae are cannibalistic. Larval development takes 28-30 days.

Pupa
Pupation takes place in an earthen cell below the surface of the soil. It is about 0.75 inch long, medium brown color, with a dark dorsal band at the apex of abdominal segments 4 to 7. At the tip of the abdomen are two large tapering spines. The spines are black at the base and pale at the tip. Pupal development takes 10-14 days.
The entire life cycle from egg to adult may take from 40-48 days.

MONITORING METHODS
Methods for monitoring BCW populations are the same as described for the GWW. Liquid irritants or flooding the area forced the larvae to the surface to be counted.

ACTION LEVELS
Larval populations of the BCW have been low in our turfgrass experiments probably due to the impact of parasites and predators and environmental conditions. Because of the low populations action levels for BCW have not been ascertained. As a starting point an artificial control measure may be necessary if the larval population reaches 5 per square yard.

BIOLOGICAL CONTROL
A number of parasites and predators of the BCW have been recorded for Hawaii (Zimmerman 1958). Invertebrate parasites and predators of BCW are presented in Table 5. The invertebrate organisms attack both the larvae and pupae. Information on vertebrate predators is lacking. The mynah and other birds, the giant toad probably consume BCW larvae when feeding in the turfgrass. Data on the impact of these beneficial organisms is lacking.

Table 5. Invertebrate parasites and predators of BCW in Hawaii

Parasites

   
     

Diptera

Tachinidae

Archytas cirphis Curran

   

Chaetogaedia monticola

   

(Bigot)

   

Eucelatoria armigera (Coq)

Hymenoptera

Braconidae

Chelonus texanus Cresson

   

Meteorus laphygmae Viereck

 

Eulophidae

Euplectrus plathypenae

   

Howard

 

Ichneumonidae

Hyposoter exiguae (Viereck)

   

Pseudamblyteleskoebeli

   

(Swezey)

   

Pterocormusrufiventris

   

(Bruelle)

     

Predator

   
     

Coleopteraa

Carabidae

Calosoma blaptoides

   

tehuacanum (Lapouge)



CULTURAL CONTROLS
Mow the grass properly. Avoid the buildup of thatch and remove it when it becomes excessive. Larvae will hide in the thatch.

CHEMICAL CONTROL
The insecticides suggested for GWW and LAW are also effective for the BCW. Products containing Bacillus thuringiensis var. kurstaki, carbaryl, chlorpyrifos or trichlorfon are suggested for BCW application. Refer to the label instructions on proper application, dosage rates, and precautions. The biorational compound B. thuringiensis is a larvicide.


POTENTIAL PEST BAGWORM (BW): Brarachycyttarus possibly griseus de Joannis

The bagworm was found in Kaneohe, Oahu in 1984. The common name "bagworm" is due to the bag-like silken case covered with pieces of grass in which the larva and adult female live (Heu et al. 1984).

DAMAGE
Similar to other lepidopterous pests, the larva is the damaging stage. The larvae chew off the blades of grass. Ragged appearance of the grass may be noticeable but the first evidence will most likely be the conical silken case hanging from branches of shrubs, buildings, or other structures. Large numbers of bags are often noticeable.

HOST RANGE
This is a new pest to Hawaii, and the host range is not well known. The larvae have been recorded feeding on bermudagrass, Hilograss (Paspalum conjugatum), foxtail (Setaria spp.), Natal redtop (Rhynchelytrum repens (Wild.) C. E. Hubb.), Desmodium sp., sensitive plant, (Mimosa pudica L.), green kyllinga (Kyllinga brevifolia Rottb.), and purple nutsedge (Cyperus rotundus L.). It has also been able to complete its life cycle on Citrus spp., Nishiki juniper, lima beans and Spanish needle (Bidens pilosa L.).

DESCRIPTION OF LIFE STAGES

Adult
Male bagworm moths have well developed, grey colored wings and are about 0.2 inch long. Females are slightly longer than the male, wingless, legless, lacking eyes, antennae, and mouthparts. The females remain in the silken case made while it was a larva. The female attracts the male, probably with a pheremone, mating takes place without leaving the bag. Shortly after mating she lays several hundred eggs within the silken case and then dies.

Egg
The eggs are deposited within the silken case. They hatch and the young larvae crawl out of the bag, construct their own conical silken case that is carried upright.

Larva
The bagworm larva carries the silken case with it as it moves about. The bag protects the larva. As the larva matures, the surrounding bag increases in size and is positioned beneath the body while the larva clings to a surface with its thoracic legs. A mature larva case may be nearly 0.5 inch long.

Pupa
Pupation takes place within the silken case.
The life cycle is completed in approximately 11 weeks.

MONITORING METHODS
Monitoring methods have not been developed. First evidence of a population is usually the silken bags hanging form the grass stems, vegetation, or buildings surrounding the turfgrass area.

ACTION LEVELS
Action levels have not been developed. The populations have not been sufficiently damaging to turfgrasses to warrant a research program.

BIOLOGICAL CONTROL
No information is known about beneficial organisms attacking this insect.

CULTURAL CONTROLS
Brushing the silken cases from buildings may provide a measure of control.

CHEMICAL CONTROLS
With the present population pressures, control with chemicals has not been researched. The insecticides suggested for GWW should be effective against bagworm larvae.


BEETLES
Order: Coleoptera

OCCASIONAL PEST HUNTING BILLBUG (HBB). Sphenophorus venatus vestitusChittenden [Family: Cucurlionidae]

This snout beetle was first reported in Hawaii in 1960 infesting zoysiagrass. It has been reported from all islands with the exception of Lanai.

DAMAGE
First symptoms of hunting billbug damage are regular elongated or round areas of brown dead or dying grass. The turf can easily be pulled by hand and the root system appears to be cut off. Presence of the legless, white grub of the billbug near the border of dead and healthy grass will confirm the diagnosis. Young larvae feed on the stolons, crowns and new leaf buds. Older larvae attack the roots and runners to a depth of 3 inches or more. Adults and larvae damage turfgrass.

HOST RANGE
Billbug damage has been observed in lawns, turfgrasses and pasture grasses in Hawaii. Serious infestations have been in bermudagrasses of greens and tees. The list of hosts for Hawaii are presented in Table 6. Kikuyugrass pastures at 2,500-3,500 feet elevation on the island of Hawaii were damaged by the HBB (La Plante, 1967). Weevils were also damaging sugarcane and corn seedlings. Literature reports St. Augustinegrass, centipedegrass, crabgrass, signal grass, barnyardgrass (Echinochloa crusgalli (L.) Beauv.), leatherleaf fern and Pensacola bahiagrass (Paspalum notatum Flugge) as hosts. In Hawaii, zoysiagrass and bermudagrass cultivars were most seriously damaged.
The host range of the HBB is given in Table 6 below.

Table 6. Host range of the hunting billbug in Hawaii.

Common name

Scientific name

   

Bermudagrass

Cynodon spp.

Manieniegrass (Common bermuda)

Cynodon dactylon (L.) Pers.

Yellow nutsedge

Cyperus esculentus (L.)

Kikuyugrass

Pennisetum clandestinum Hochst ex Chiov.

Sugarcane

Saccharum officinarum L.

Corn

Zea mays L.

Manilagrass

Zoysia matrella (L.) Merr.

Japanese lawngrass

Zoysia japonica Steud.


Biologies and descriptions of the HBB have been published by Woodruff (1966), Marsden (1979c), Tashiro (1987) and Johnson-Cicalese (1990).

DESCRIPTION OF LIFE STAGES

Adult
The adult weevil is dark reddish brown in color about 0.4 inch long. A slightly curved beak at the front of the head bears a pair of stout mandibles for chewing grass stems and blades. When disturbed, the adults will feign death for short periods of time. Adults can fly and may live 6 months or longer.

Egg
Females bite a small hole in the stem, leaf or crown of the grass and then deposit a small, white elongate egg in the slit. Eggs are deposited singly and hatch in 3-7 days depending upon temperature.

Larva
The larva or grub is legless, dirty white in color with a brown head. Mature grubs are about 0.4 inch in length. Upon hatching, the young grubs hollow out the stem and fill the space with frass. As the larva increases in size, the stem can no longer conceal it, and the grub feeds on the crown and moves to the roots. Mature larvae may be found in the crown, just below the thatch or just below the soil surface to a depth of 3 inches. Larval development takes from 3-5 weeks.

Pupa
Pupation takes place in an earthern cell in the soil. Development to the adult stage takes from 7-10 days.
The entire life cycle may take from 27-55 days depending upon the temperature.

MONITORING METHODS
A standard monitoring method has not been developed for the HBB because of its secretive habits. Turfgrass should be examined for irregular or circular brown spots of dying grass. These spots should be examined more closely for the presence of adult or larval HBB. First instar larvae are concealed inside the stem and easily missed. Frequent examination of suspect areas would find the later larval instars that are outside the stems. The use of irritating liquids forces a few adults to the surface but the legless grubs do not respond like the GWW, LAW and BCW larvae. If adult HBB are noticed crawling along walkways, curbs or paved areas, they are indicative of a potential problem.

ACTION LEVELS
Because of the cryptic habits of HBB, if 1 or more grubs per square foot are found, the turfgrass should be treated. Spot treatment may be all that is necessary.

BIOLOGICAL CONTROL
In Hawaii the billbugs appear to be free from many of the beneficial organisms. Mitchell (1966) reported adults killed by the fungus, Beauvaria bassiana (Bals.) Vuill. This disease attacks many insect species if conditions are optimum. A braconid parasite, Bracon sp. nr. sphenophori Mues. was released in 1968 (Chong, 1968). A mymarid egg parasite, Patassion calendrae (Gahan) had multiple releases in 1929, 1963, and 1967 (Bianchi, 1968). Neither one has been recovered to confirm establishment. Scats of the giant toad, Bufo marinus, have contained large numbers of HBB adults (Habeck, 1962). Some HBB were alive in the fecal droppings. The toad feeds at night on HBB, GWW, LAW, and BCW.

CHEMICAL CONTROL
Insecticide applications are suggested because the HBB is free of effective parasites or predators. For effective control, the chemical must reach the larvae which are located in or below the thatch or under the surface of the soil. Most researchers suggest pretreatment irrigation of the area to soak the thatch layer and the upper surface of the soil. The wetting of the area will insure better penetration of the toxicants to the depth of the roots and the zone where adult and larval HBB exist. Post treatment irrigation is recommended when granular formulations are applied. Products containing chlorpyrifos, carbaryl, ethoprop, isofenphos, propoxur or trichlorfon have been suggested for HBB control in Florida (Short, 1982). Refer to the label to be sure the chemical is registered for the site and HBB control


MEALYBUGS
Order: Hemiptera Suborder: Homoptera

Mealybugs are small elongate, oval, soft-bodied insects with well developed legs. They damage plants by sucking the juices from them. Their bodies are often covered with waxy secretions. Mealybugs produce honeydew which is attractive as food for other insects.

OCCASIONAL PESTS:
RHODESGRASS MEALYBUG: (RGMB): Antonina graminis (Maskell) [Family: Pseudococcidae] .

The Rhodesgrass mealybug has been misnamed Rhodesgrass scale. The insect has been in Hawaii since 1910 and occasionally develops troublesome infestations in turfgrasses. It is found on all islands.

DAMAGE
Rhodesgrass mealybug damage to grasses is difficult to see because the insects are small and located at the bases of the grass stems and under old leaf sheaths. Active infestations produce large quantities of honeydew, a sweet sticky secretion that is highly attractive to honeybees, ants and other insects. Bee activity in the grass or being stung while walking barefoot in the grass are often the first indications of the development of a mealybug population. Closer examination of the turfgrass will reveal small, reddish, globular insects enclosed in white felt-like waxy masses, near the bases of the stems and under old leaf sheaths. Larger populations of RGMB cause the infested grass to become unsightly and weak in appearance. The bases of the infested plants, including crowns, leaf axils, etc., appear to be covered with tufts of cotton. Injury is most severe during extended hot, dry periods.

HOST RANGE
The insect has a worldwide distribution and has been reported infesting over 100 species of grasses. In Hawaii, it has been recorded on sugarcane, bermudagrasses, caribgrass (Eriochloa polystachaya (H. B. K.) Hitch), torrid panicgrass (Panicum torridum Guad.), Paspalum spp., rhodesgrass (Chloris gayana (Kunth.)) and pineapple roots (Zimmerman, 1948).

DESCRIPTION OF THE LIFE STAGES

Adult
The small mealybug adults are inside the white, cottony, waxy secretion that the insect produces. All adults are females. Reproduction is by parthenogenesis, and males are unknown. The adult is a globular, dark purplish, reddish-brown, saclike body about 0.125 inch diameter. Mealybugs are found clustered about the bases of the plants. Mealybug feed by sucking plant sap through a long, hair-like proboscis which is inserted into the tissue of the grass plant.

Egg
Females give birth to living young (nymphs or crawlers). Elongate, cream colored eggs can be seen if dissected from a female.

Nymph or Crawler
Young, larvae, nymphs or crawlers, are produced in large numbers by the female. They are minute, flat, brownish insects with well-developed legs and antennae. The infestation is spread in the turfgrass by these tiny crawlers moving from plant-to-plant. Crawler and adult feeding cause cells to collapse and reduce vigor of the plant. Once the crawlers have started to feed they become sessile, loose their appendages, become saclike and look like adult females but are smaller in
size.
The life cycle from crawler to reproductive adult may take as much as 45-50 days depending upon the temperature.

MONITORING METHODS
A standardized monitoring method for RGMB has not been developed. If white cottony masses are observed in the turfgrass and there is considerable activity of honeybees and ants feeding on the honeydew there is most likely an infestation developing. Further close inspection of the turfgrass is suggested.

ACTION LEVELS
We do not have an action level for RGMB. If people are being stung, by bees feeding on the honeydew, as they walk across the turf a pest management tactic is suggested.

BIOLOGICAL CONTROL
In Hawaii one encyrtid parasite, Anagyrus antoninae Timberlake, has been recorded attacking RGMB. The parasite has effectively controlled RGMB populations in some situations. Failures have probably been due to parasite mortalities from insecticide applications.

CULTURAL CONTROLS
Grass mowed at l.5 inches or more is less prone to injury than grass that has been cut shorter. Proper irrigation and fertilization aides in preventing damage Do not spread grass clippings from an infested area to uninfested areas.

CHEMICAL CONTROL
Insecticidal control has not been very effective because of the waxy secretions protecting the mealybug. In Florida malathion in combination with volck oil has been reported to give satisfactory control. In Hawaii the insecticides suggested for GWW control have also prevented population increases of RGMB. Timing of the insecticide application is important to contact the crawler stages.


SCALE INSECTS
Order: Hemiptera Suborder: Homoptera

The pest of turfgrass is an armored scale. They are generally small, flat disc like organisms without legs and antennae. They live under a scale (armor) formed of wax secretions of the insect and cast skins of immatures. The scales vary in shape, size and color. Scale insects also produce honeydew.

POTENTIAL PEST
BERMUDAGRASS SCALE (BGS). Odonaspis ruthae Kotinsky [Family: Diaspididae]

This insect was first discovered in Hawaii in 1910 (Zimmerman 1948). It is also called Ruth's scale. It may be found wherever bermudagrass is found.

DAMAGE
In Hawaii, the scale seldom causes serious damage to bermudagrass but is most injurious when the turf is under stress. Adults and immatures suck plant juices from the plant and may reduce vitality and growth of turf. Heavily infested turfgrass takes on a brown, dry appearance and new growth is retarded. The scale does well in shade and heavily thatched turf.

HOST RANGE
As the common name implies, the host range is limited to bermudagrass and its hybrids.

DESCRIPTION OF THE LIFE STAGES

Adult
The adult scale (0.06 inch long) is oyster or clam-shaped and chalky white found beneath the leaf sheaths, clustered around the nodes and occasionally on the leaves. Scales have not been reported on the roots.

Egg
Eggs are deposited by females under their oyster-shaped scale.

Nymphs or Crawlers
These are the active mobile stage in the life cycle. Crawlers move out from beneath the scale and spread the infestation. They soon settle down, loose their legs, insert their piercing sucking mouthparts into the grass, start to feed and become sessile. In molting they loose their appendages, secrete the waxy covering and remain there for several months before producing eggs and repeating the life cycle.

MONITORING METHODS
Methods for monitoring have not been developed. Close examination of the turf for the white oyster or clam-shaped scales will indicate the presence of the scale.

ACTION LEVEL
The scale has not developed into sufficient populations to determine an action level.

BIOLOGICAL CONTROL
As with the mealybug only a single encyrtid wasp, Adelencyrtus odonaspidis Fullaway, has been recorded parasitizing BGS. Data on its effectiveness is lacking.

CULTURAL CONTROL
Keep the turfgrass in a healthy condition. Do not spread grass clippings from an infested area into uninfested areas.

CHEMICAL CONTROL
Infestations in Hawaii have not required pesticide applications. The insecticides suggested for GWW control should also be effective for control of this pest. Timing of the application is important so that the crawlers come in contact with the insecticide. The waxy covering protects the scale from the sprays, therefore an adjuvant or volck oil may be incorporated into the spray to overcome this problem.


SOUTHERN CHINCH BUG
Order: Hemiptera Suborder: Heteroptera

OCCASIONAL PEST
SOUTHERN CHINCH BUG (SCB). Blissus insularis Barber [Family: Lygaeidae]

The southern chinch bug is an recent arrival in Hawaii. If was found infesting St. Augustinegrass in Nuuanu Valley in August 1990. Under certain conditions this insect may be a limiting factor in the culture of St. Augustinegrass and its cultivars.

DAMAGE
Both adults and nymphs suck juices from the turfgrass. They insert their needle-like mouthparts, suck sap and in the process inject saliva that interferes with water conducting system of the plant. Damage begins as patches of yellowing grass which later turn brown. If the grass is under stress and the yellowing continues to spread the grass may be killed. Activity is greatest in hot, open areas. Shaded areas are not usually damaged unless the SCB populations are very large. By parting the grass runners, adults and nymphs can be seen crawling through the loose debris on the surface of the soil.

HOST RANGE
Its major host is St. Augustinegrass, Stenotaphrum secundatum. Other grasses in close proximity to St. Augustinegrass that have been slightly damaged by SCB are zoysiagrass, centipedegrass, bahiagrass, and bermudagrass. Some selections of St. Augustine grass are resistant to SCB.

DESCRIPTION OF THE LIFE STAGES:

Adult
Adults are 0.2 inch long, black with shiny wings that are held flat over the back. The white wing covers are marked with a black triangular patch at the middle of their outer margin. Legs are reddish to reddish yellow. Fully winged (macropterous) and short winged (brachypterous) adults may be found in the population.

Egg
Eggs are deposited in the leaf sheaths and in the ground on roots. The eggs are nearly cylindrical, are three or four times longer than broad, whitish when freshly deposited. As development progresses the color changes to yellow and a deep red prior to hatching. Egg development takes about 2 weeks.

Nymph
There are five wingless instars in the development of SCB. The first two instars are red in color, with a white band on the first two abdominal segments. The basic color changes from red to orange in the third instar, orange brown in the fourth and black in the fifth instar. Wing pads are visible in the fifth instar. Nymphal development takes 30 days or longer depending upon temperature. The complete life cycle from egg to reproductive adult may take 6-8 weeks.

MONITORING METHODS
Sampling methods described for sampling the GWW are effective for SCB. Flooding of an area with water or irritating liquids will force the adults and nymphs to the surface to be counted. Ten minutes of continuous counting is advised.

ACTION LEVELS
Action levels for the SCB have not been developed for Hawaii. Populations have been scarce and limited to the island of Oahu. Reinert (1982) recommended treatment if 22-28 SCB were observed per square foot.

BIOLOGICAL CONTROL
The infestation is so recent in Hawaii, no information is available on beneficial organisms here. One biorational, Beauvaria bassiana, and a number of parasites and predators have been recorded elsewhere (Tashiro 1987).

CULTURAL CONTROL
St Augustinegrass is the preferred host for the SCB. A number of varieties have shown resistance to chinch bug feeding. Publications by Busey and Coy (1988), Busey and Center (1987), Busey (1990), discuss the vulnerability of St. Augustinegrass and the genetics of resistance. Floratam and accessions FA 108 and TX 33 have exhibited resistance to SCB feeding. We do not know if the cultivars of St. Augustine grass being sold commercially in Hawaii are tolerant to SCB feeding. Control of thatch will reduce SCB numbers. Reduced amounts of nitrogen should result in less chinch bug problems.

CHEMICAL CONTROL
To preserve any beneficial organisms spot treatment of the damaged area and a ten foot swath surrounding it is suggested. Refer to the label for directions on dosage rates, application methods, precautions etc. Insecticides containing chlorpyrifos, ethion, ethoprop, isofenphos or propoxur are suggested. Irrigation of the turf prior to application will allow the pesticide to reach the SCB below the thatch and at the surface of the soil. In some area phosphate resistance has developed in the SCB (Reinert and Portier, 1983). We do not know if a phosphate resistant population of chinch bugs is present in Hawaii. Resistant cultivars is the best control of SCB.


BERMUDAGRASS MITE
Order Acarina

OCCASIONAL PEST
BERMUDAGRASS MITE (BGM).Eriophyes cynodoniensis Sayed [Family: Eriophyidae]

This eriophyid mite, also called the bermudagrass stunt mite, was first detected in Hawaii in 1966. It has spread to all islands. It can be a serious pest of bermudagrasses under certain conditions. It is a more frequent problem in grasses under stress and in new plantings.

DAMAGE
Damage is characterized by a yellowing of the tips of the leaves, a turning upward and inward of the leaves and shortening of the internodes and a rosetting or tufting of the grass (Kerr and Brogdon, 1968). When rosettes are numerous the area looks clumped without internodes. Walking over the area the turf feels lumpy. With heavy infestations the grass turns brown and dies. Adults and immatures suck plant juices.

HOST RANGE
As the name implies, the host range is limited to bermudagrasses and the cultivars or hybrids. Cultivars have varying degrees of resistance to feeding by the mite.

DESCRIPTION OF THE LIFE STAGES

Adult
Adults of the mite are extremely small and with difficulty can be seen with a 10X hand lens magnifier. They are worm like, creamy white to yellow in color and have four legs near the head end. They are found behind the leaf sheath sucking plant sap.

Eggs
Eggs are spherical, transparent to opaque white and deposited singly or in groups behind the leaf sheaths.

Nymphs
Nymphs resemble the adults in being microscopic in size, about twothirds the size of the adults, longer than broad with two pair of legs at the head end. The nymphs may be observed behind the leaf sheath sucking plant sap. Upon hatching the nymphs molt twice (2 instars) and molt again into a sexually mature adult. All stages of development may be found behind the leaf sheath. Major means of dispersal are by wind, grass clippings and riding on other insects or birds. During warm weather the life cycle of the BGM may only take 5-10 days.

MONITORING METHODS
Look for tufted or rosetted plants. With the aide of a dissecting microscope pull away the leaf sheath from the stem and examine the inside of the sheath for eggs, nymphs and adults.

ACTION LEVELS
An action level has not been developed for BGM in Hawaii. If damage continues to increase and the turf show evidence of decline, thinning etc. a pest management tactic must be considered.

BIOLOGICAL CONTROL
Information on parasites or predators of BGM in Hawaii is nil. Two predacious mites, Neocunoxoides andrei (Baker and Hoffman) [Family: Cunaxidae] and Stenotarsonemus spirifex (Marchal) [Family: Tarsonemidae] have been reported reducing BGM populations in Florida and Arizona, respectively (Butler 1963. Johnson 1975).

CULTURAL CONTROL
Several cultivars, Midiron, Tifdwarf, Tifgreen 328, Tifway 419 exhibited degrees of resistance to BGM (Reinert 1982, 1985). New selections are currently being developed. The normal maintenance operation, mowing, may spread the mite on clippings to uninfested areas. Reduce mowing height.

CHEMICAL CONTROL
Insecticidal control of the mite with chlorpyrifos has been erratic in Hawaii. The insecticide-miticide, fluvalinate is recommended in Florida. Reinert and Cromroy (1981), Reinert (1985) and Butler (1963) have reported on BGM resistant cultivars and the effectiveness of various miticides.