Pest Management Guidelines |
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Introduction to Managing Fruit Flies in Hawai'i | ||
By: Laurel Dekker (1) and Dr. Russell Messing
(2)
(1) Hawai'i Diversified Technologies, lnc., HCR1 Box 4115,
Kea'au, HI 96749 and (2) University of Hawai'i, College of
Tropical Agriculture and Human Resources, Department of
Entomology, 7370 A Kuamo'o Road, Kapa'a, HI 96746
HITAR Brief No. 114
The purpose of this paper is to provide identification and
pre-harvest information to farmers, gardeners, and extension
agents about four distinct species of pest fruit flies (oriental,
melon, Mediterranean, and solanaceous).
INTRODUCTION
Introduction to Managing Fruit Flies in Hawaii points out simple
but essential management tools that each grower should consider
whenever planting crops that are hosts to fruit flies in Hawai'i.
However, it does not provide a single, "one-answer"
solution to the fruit fly problem, nor does it cover postharvest
treatments for export.
BACKGROUND
Fruit fly pests in Hawaii are members of the Family Tephritidae
in the Order Diptera. They came from as far away as Africa, as
long ago as 1895, and feed on hundreds of host plants. Many of
these plants are shared by more than one fly. The flies are
widespread from sea level to mountainous areas (over 7,000 ft.).
The melon fly is commonly found in low areas in commercial and
backyard vegetable gardens. The Mediterranean fruit fly (medfly)
moved away from most of the lowlands when the oriental fruit fly
arrived in 1945. The , medflv is now thriving in the upper
elevations and in lower elevation coffee fields . The oriental
fruit fly is found in most climates. The solanaceous fruit fly
survives in both cool and hot climates and, as of this printing,
has only been found in Hawai'i in areas with an average of less
than 100 inches of rain per year.
DAMAGE
Plant Injury: Fruit fly adults most often lay their eggs in the
fresh flesh of fruits and vegetables. Fruit is a term that refers
to the fertilized embryo of fruit and vegetable flowers. The eggs
hatch into larvae (maggots) which most often feed on the inside
of the fruit, resulting in a soft, mushy mess. Look for wiggling
white larvae the next time you pick a very ripe guava or other
fruit.
Economic Injury: Fruit flies can often be present at low levels
without causing significant economic problems, so control may not
be necessary. If high fly populations are causing severe fruit
damage, management practices may need to be implemented.
STEPS, TO MANAGING FRUIT FLIES
1. Prevention. Practice sanitation techniques (see Minimizing
Risks
from Fruit Fly Damage for Details).
2. Monitor your local pests; determine if you have economic
injury;
evaluate and use your best strategies.
3. Identify the pest fruit fly and familiarize yourself with its
life cycle and
hosts (see Life Cycles and Rearing for Identification).
4. Determine which other plants in your area are fruit fly hosts,
and
determine when these plants are fruiting.
5. If possible, rotate your crops to fruit at times other than
peak host
(and peak pest) population times.
6. Harvest under-ripe fruits when possible (e.g., papayas are
usually
fruit-fly-free if picked less than l/4 ripe)
7. If fruit flies exceed economic injury, reduce your pest
populations or
apply controls (see Minimizing Risks from Fruit Fly Damage and
Controls).
8. Divert pests with poisoned border plants, baits or lures.
9. Monitor your pests again and re-evaluate your strategies.
LIFE CYCLES
Fruit fly development (life cycle) is dependent on temperature.
Cool temperatures will slow the development cycle. Warmer
temperatures will speed up development. Information below is
listed for growth at 77° F at 50% relative humidity, except for
B. Iatifrons (80° F at 60% RH). Note also that data have been
generated from laboratory flies; wild flies will most likely be
different.
Traits Common to All Four Species
1. Eggs white, up to 1/16 of an inch long.
2. Larvae range in length from 1/16-3/8 of an inch. Just before
pupating, the larvae often pop and flip to leave the fruit.
3. Pupation normally occurs 1-2 inches under the soil.
4. Adults usually rest in shady locations unless feeding, mating
or
laying eggs. Most feed at dawn and mate at dusk.
5. Wing pattern is easiest and most distinguishing
characteristic; color
is inconsistent and, therefore, unreliable.
Melon Fly
Scientific name: Bactrocera cucurbitae.
Native to: Malayan region. Detected in Hawai'i around 1907.
Key characteristics: Wing pattern has tiger-like stripes and
large black spot at the wing tip. Abdomen usually brown with gold
to brown horizontal band and faint black "T".
Ovipositor (egg-laying tube) has plump, straight sheath (the
outer covering of the ovipositor) and is about 1/16 inch long.
Distribution: Africa, Burma, Ceylon, China, Guam, Hawai'i, New
Guinea, Rota, Commonwealth of the Northern Marianas, Southeast
Asia, and South Asia. Sea level to 4500 feet.
Hosts: Over 100 known hosts. Preferred hosts are Cucurbitaceae
(squash and melon etc.). Other hosts include Solanaceae (tomato,
eggplant, pepper, etc.) and Caricaceae (papaya).
Life cycle: One generation takes around 37 days. Egg to adult in
15-18 days. Eggs hatch in about 30 hrs. Larvae develop in 7-8
days. Adults emerge in 9-10 days. Pre-oviposition period is 7-8
days. Females lay an average of 15 eggs /day, singly or in
clusters.
Special notes: Known to feed on stem shoots and buds of squashes
and melons.
Mediterranean Fruit Fly
Scientific name: Ceratitis capitata
Native to: Africa. First reported in Hawai'i in 1895.
Key characteristics: Wing pattern is very complex and
multi-colored (gold and black) with black tiger-like stripes and
detailed markings. Black spots on back or thorax. Abdomen usually
brown. Adult is about 2/3 the size of the other fruit flies.
Distribution: Mediterranean countries, South Pacific, Hawai'i,
Australia, Central, and South America. Dominant pest in Hawaii
over 3000 ft. and in low-elevation coffee; prefers dry regions.
Hosts: Over 300 hosts. Preferred hosts include Rubiaceae
(coffee), Rosaceae (peach, plum, and loquat), Rutaceae (orange),
Myrtaceae (guava and rose apple), Solanaceae (pepper, Jerusalem
cherry), and Sapotaceae, among others.
Life cycle: One generation takes around 18-31 days. Egg to adult
in 19 days. Eggs hatch in about 2-3 days. Larvae develop in 7-8
days. Adults emerge in 9-10 days. Pre-oviposition period is about
3 days. Females lay an average of 10 eggs/day, singly, or in
clusters up to 10.
Oriental Fruit Fly
Scientific name: Bactrocera dorsalis.
Native to: Asia. Introduced to Hawai'i in 1945.
Key characteristics: Wing pattern has 2 solid black lines
stemming from the point of attachment, without a black spot at
the tip as in B. latifrons. Abdomen gold to brown with gold to
brown horizontal band and prominent black "T".
Ovipositor has slender, straight sheath.
Distribution: Asia, Africa, Australia, and islands of the
Pacific. The major pest in Hawai'i at low elevations, except for
coffee fields.
Hosts: Over 200 wild and cultivated hosts. Preferred hosts
include guava, mango, papaya, starfruit, passion fruit, citrus,
fig, rose apple, tomato, and many more.
Life cycle: One generation takes around 37 days. Egg to adult in
19 days. Eggs hatch in about 38 hrs. Larvae develop in 7-8 days.
Adults emerge in 10-11 days. Pre-oviposition period is 6-7 days.
Females lay over 130 eggs /day, usually in groups of 10, but can
be as many as 100 or more.
Solanaceous Fruit Fly
Scientific name: Bactrocera latifrons, also known as Malaysian
fruit fly.
Native to: South and Southeast Asia. First detected in Hawaii in
1983.
Key characteristics: Wing pattern has 2 solid black lines
stemming from the point of attachment plus a black spot at the
wing tip that easily differentiates it from B. dorsalis. Abdomen
usually brown, no "T". Ovipositor tri-lobed, as long as
1/16 inch.
Distribution: China, Taiwan, Malaysia, Thailand, Laos, India,
Pakistan, and Hawai'i.
Hosts: 33 reported hosts, mostly Solanaceae (pepper, tomato,
eggplant, apple of sodom) and Cucurbitaceae (on an incidental
basis).
Life cycle: One generation takes around 48 days. Egg to adult in
21 days. Eggs hatch in about 2 days. Larvae develop in 8-9 days.
Adults emerge in 10 days. Pre-oviposition period is 10-11 days.
Females lay an average of 10 eggs /day, one at a time.
Special notes: Generally low-level populations, patchy
distribution.
PREVENTION STRATEGIES
Healthy Ecosystem
Healthy plants, soils, and ecosystems are the foundation of plant
defenses. Plan your cropping system to maximize populations of
beneficial organisms and minimize potential pests.
Research on pests (other than fruit flies) has shown that plant
stress is usually followed by pest damage. Stress can be caused
by extreme changes in soil moisture, temperature, pH or
fertilizer. More information on these effects in Hawai'i is
needed.
Exclosure
There are several ways to prevent fruit fly damage by exclosure
(keeping the fruits out of reach of the females). A screen house
is a good way to produce fruit-fly-free crops. Local research has
found that an economical structure ($1.20/sq. ft.) was cost
effective within the first harvest for tomato production. Netting
(floating row covers or lightweight netting from the fabric
store) can be placed directly over plants like zucchini or over
PVC tubes for temporary cover. Tomatoes and self-pollinating
cucumbers are pollinated by the wind. Some other crops may need
hand pollination if plants are covered by screen. A possibility
that has not been fully explored is to add bee hives to large
screenhouses to provide ample pollination. Note: secondary insect
or weed problems may arise from reduced air circulation and lack
of beneficial insect populations in exclosure areas.
Another method of exclosure is bagging individual fruits with
paper bags or other barriers. Wooden clothespins work well to
keep the bag closed. This method works very well, but it is
labor-intensive.
Minimizing Risks From Fruit Fly Damage
Practice sanitation: Remove fruits as they ripen. If they fall to
the ground, be sure to kill any larvae in the fruits. Bury deep
or put in air- tight container for four days,or until no movement
is found. Check for pupae (and destroy) before adding to compost
pile. Note that burying fruit can also kill parasites. Sanitation
by itself will not be effective in many situations; fruit flies
can still fly in from outside areas.
Regarding burial: Melon fly pupae buried as deep as 2 feet have
managed to emerge as adults from dry sand, wet sand, and soil. If
burying infested fruit, soil must be tamped thoroughly. If mixed
with compost, the pile must achieve internal temperatures of at
least 120° F.
Mowing or shredding ground fruit can provide sanitation by
killing the larvae or exposing them to other predators.
Harvest at early ripening stage: By harvesting early, you can
sometimes prevent infestation (e.g. fruit flies do not usually
sting papayas or 'Sharwil' avocados that are less than l/4 ripe).
However, some fruits lose flavor when harvested too early, as
they will not fully ripen.
Reduce populations: If fruit flies are present in your field
prior to your crop ripening, reduce their population by baiting
the adults to a poisoned area. This can be done by spraying a
protein bait/insecticide mixture onto nearby plants or
wind-breaks, or onto a planted corn crop border (flies gather on
the silks). Farmers and researchers have observed reduction of
melon flies in zucchini, cucumber, and watermelon fields using
bait sprays on border crops. Suppression sprays have also been
used in Australia, Israel, Mexico, Florida, and California. Mass
trapping with protein baits (for males and females) or with lures
(for males) is being researched for potential fruit fly
reduction.
Create an "isolated" area: Planting between other crops
or rotating to opposite ends of a field has been tried for a few
crops (melon fly hosts). Often, fruit flies do not find the crop
during the first half of the harvest. Note: this should not be
repeated in consecutive plantings in the same place.
About plant resistance: High amounts of citrus oil in immature
citrus peels are toxic to larval growth. Giberellic acid is being
studied to delay peel-ripening on oranges and reduce
susceptibility to fruit flies. Mango cultivars are being
developed to keep fruits hard and crisp, even when ripe. Contrary
to popular belief, small tomatoes (Roma and cherry) can be
infested by fruit flies; however, many growers have found that
small varieties can be harvested with less infestation than
larger varieties.
Integrated Pest Management
1. Monitor pests.
2. Remove ripe fruits from area (sanitation).
3. Harvest early.
4. Control with bait and insecticide sprays.
5. Enhance or conserve beneficial wasps.
Don't be confused: Note that the fresh-fruit eating fruit flies
discussed here (Tephritidae Family) are not the same as the tiny
"fruit flies" that feed on yeasts of decaying fruit.
These tiny flies are called vinegar flies (Drosophilidae Family)
and can often be found on soggy fruits on the ground or overripe
(fermenting) fruits. Control: Use vinegar and yeast attractant.
Mix 11.2 oz. (dry) sugar (11/3 packed cups of raw sugar), 1 3/4
oz. (fluid) vinegar, I packet yeast, and 1 gallon water. Then add
1 drop soap. Mix again. Solution is ready to trap these tiny
nuisances (see page 6 for more information on protein traps).
CONTROLS
Cultural and Chemical Controls
Bait spray: In fruit fly infested areas, a protein hydrolysate
compound, such as Nu-lure or Staley's fly bait, can be combined
with insecticide and applied to plants that are associated with
the resting and feeding areas of the adults rather than on the
crop to be protected. Bait sprays use small amounts of chemical
and are not attractive to parasites. To apply with a knapsack
sprayer, find a malathion wettable powder (25% WP) product
cleared for use on the target site. Following the directions for
fruit fly control on the pesticide label, mix the appropriate
amount of malathion 25% WP with 1 quart Nu-lure and 3 gal. water.
Or mix 1 part malathion (57% EC) with 3 parts Nu-lure. For
conventional power sprayers of 20-100 gallons, mix 1 quart
Nu-lure with the appropriate amount of malathion. Agitate during
application. Spray with concentrated coarse droplets on border
plants that are listed on the pesticide label. Apply weekly (high
populations) to bi-weekly (low populations). Small gardens may
have a higher amount of immigrant flies and may need to be
sprayed more often. Reapply after rain. Researchers and farmers
have observed good control of melon flies with this technique.
The Hawai'i Department of Agriculture's Pesticides Branch has
allowed application of pesticide bait sprays to other border
plants and windbreaks under certain conditions. You should
contact your Pesticides Branch District Office for more
information. Please note that this policy may change. Note also
that the above mixture has a pH of 4.7; recent research indicates
that a pH of 9.2 is more attractive to the flies, so researchers
are looking at ways to raise the pH.
Spot treatment: Workers in Mexico have applied bait spray to
orchard tree trunks with good results. Israeli producers also
have found spot treatments of mix effective for medflies in or
around the fields (2 oz. per spot, spaced at 40-80 spots per
acre, 16-33 feet between spots). Insecticide sprays: Chemicals
should be used only as a last resort and only on approved crops.
At least 40 chemicals have been found to be toxic to fruit flies,
including malathion and naled. Pyrethrum is not as toxic to fruit
flies as malathion, and permethrin is more toxic to parasites
than fruit flies. In fact, most pesticides are more toxic to
parasites and other beneficials than fruit flies.
NOTE ON USING CHEMICALS: Read the pesticide
label completely and apply according to manufacturer's
recommendations with chemicals registered for your crop. If in
doubt, contact your local CES office.
Approved Organic Controls
Neem: In research tests, neem-treated sand was found to be toxic
to oriental and medflies but not to several parasites. This may
provide a good potential for soil treatment to reduce fly
development in the field; however, adult flies may still invade
from outside areas. Azatin is a registered neem product in
Hawai'i that can be used as a soil treatment against larvae.
Follow the directions on the label. Note: the National Organic
Standards Board has approved use of neem in certified fields;
however, the inert ingredients in Azatin are being investigated.
Biological Controls
Fowl: Chickens and guinea hens are good at controlling larvae
found at the top of the soil . Wild birds have also been seen
digging through infested ground fruits for larvae. The fowl might
also help with sanitation of the fruits.
Other Predators: Ants are known to feed on most life stages of
fruit flies (research reports up to 40% kill), while earwigs have
been reported to feed on fruit fly larvae and other insects.
Nematodes: Some soil-borne organisms feed on pests in the soil.
Nematodes are microscopic round worms that have a broad host
range, including fruit fly larvae. Currently, commercial use of
Steinernema carpocapsae is not permitted in Hawai'i. These
nematodes may be a viable control in the future for areas heavily
infested with fruit flies.
Parasites: Fruit fly parasites are tiny wasps that attack only
fruit flies. Parasites can lay their eggs in the egg, larva or
pupa of a developing fruit fly. The parasite develops within the
immature stages until the fruit fly pupa is consumed and the
adult parasite emerges from the soil. To recover parasites from
infested fruits, rear out the same as fruit flies (see info on
Rearing). Parasites are more effective in controlling fruit flies
than people realize (e.g., reports have indicated up to 90% kill
on oriental fruit flies in unsprayed guava).
Plants generally known to attract beneficial wasps include
yarrow, white sweetclover, tansy, sweet fennel, sweet alyssum,
spearmint, cowpea, knotweed, and caraway, among others. These
floral nectar sources or household honey might enhance parasite
populations. There are 6 primary and 3 minor Tephritid fruit fly
parasite species established in the state of Hawai'i that were
introduced for biological control. Many additional parasites
exist in Africa, Asia, and South America. CTAHR is researching
the possibility of bringing in more parasites for biocontrol in
Hawai'i, with precautions being taken not to impact native
ecosystems. Do not attempt to bring in parasites; there are
stringent import regulations to protect Hawai'i from alien
species.
Rearing for Identification - (Get to Know Your Pests)
Raising larvae to adulthood is the best way to identify the fruit
fly attacking your crops. An easy home method uses a wide-mouth
plastic container with lid. Make some air holes in the top. Place
a small amount of infested fruit with wriggling larvae inside the
clean container. Observe regularly, making sure there is no
liquid collecting on the bottom. Soil or sand can be added to
prevent drowning. As the larvae age, they will leave the fruit to
pupate. You can remove the fruit after the pupae are formed. The
adults will emerge after 9-11 days. Compare them with the
pictures and descriptions in this paper.
You can rear out beneficial wasps (parasites) in the same way.
Because they are smaller, be sure that the holes in the top are
smaller than 1/16 of an inch, or put a tissue or small-mesh
screen between the top and bottom of the cup. Adults emerge in
2-10 days from ripe fruit.
TRAPPING STRATEGIES
Monitoring with Traps
Monitoring is important to identify pests and to keep track of
changes in population levels of fruit fly pests in order to
indicate when or whether to implement controls. However, fruit
infestation is the best indicator for presence of pests or
evaluation of pest controls.
Liquid traps with food bait: Liquid traps with food bait mixes
attract males and females. Put 1-2 inches of mix into the trap.
Check weekly. Yeast tablets: Mix five Torula Yeast Tablets in
2-21/2 cups water. Stir to dissolve tablets. Protein hydrolysate:
Mix 11 fluid oz. Nu-lure or Staley's bait, 7 fluid oz. of borax,
and 31/2 qts. water. Cucumber: Blend cucumber or other primary
host with water. Place small amount in trap. Change often.
Parapheromone lure traps: Parapheromone lure traps use highly
volatile lures which attract many male flies; these traps will
need to be checked frequently. Amount of lure will determine how
volatile and long-lasting these traps will be. Note: lures catch
only males, leaving the females to remain in the field to infest
the fruit. Presently, only methyl eugenol for oriental fruit fly
is available locally.
To catch male fruit flies, use 3-5 drops of lure in a trap
initially. Addition of an insecticide to the lure provides better
catch than traps
without insecticide. Use I drop of insecticide approved for use
on your crop for every 20 drops of lure used. Replenish lure as
needed, using more lure to catch males over longer distances and
over longer time periods. No insecticides may be used for pest
control unless they are EPA-registered and labeled for use on
that crop at that intended site. The Hawaii Department of
Agriculture Pesticides Branch has agreed that parapheromone lures
with insecticide may also be used in fields with non-approved
crops to collect fruit flies for survey purposes only in properly
labeled traps. Please note that this policy may change.
Yellow sticky panels are also used to monitor in-field flies.
Check regularly; change when trapping surface is full or becomes
dusty.
Mass Trapping
High-density trapping is being explored to reduce or suppress
populations of fruit flies. USDA researchers have not produced
evidence that small-scale trapping helps reduce infestation.
However, mass trapping is used in other areas. Mass trapping in
Crete resulted in substantial reduction of insecticides used
against a similar fruit fly. A local fruit grower reported fruit
fly-free harvests of mango when applying 3 drops of methyl
eugenol lure to sticky fly tapes, which were placed 12-45 feet
from host plants. Tapes were in the open, between plants. Local
research is needed to determine if small-scale suppression of
fruit flies can be effective.
TYPES OF ATTRACTANTS
Food Baits
Food baits are effective, mild attractants for males and females
of all four species. They are not very volatile, so bait traps
typically have lower catches than the parapheromone lure traps,
but they can be used directly in the field. Torula Yeast tablets
are more effective than Nu-lure over time, as the pH is stable at
9.2. The level of pH in the mix plays an important role in
attracting fruit flies. Fewer fruit flies are attracted to the
mix as the pH becomes more acidic. USDA researchers are working
on a combination of dyes commonly used in cosmetics and drugs
with Torula to attain substantial population reductions in medfly
and oriental trials. Nu-lure (yeast extract) and Staley's Fly
Bait (corn extract) are hydrolyzed proteins. They are not
effective over time as the pH drops from its initial state of
8.5. Promar (experimental hydrolyzed protein) developed by
Australians has been very effective in Malaysia against a species
similar to the oriental fly. Starfruit orchards with Promar spray
applications rather than insecticidal cover sprays have doubled
yields (mostly due to more bees being available for pollination).
Other food baits: Reports from farmers indicate that homemade
mixes (cucumber or zucchini with water) or vinegar and yeast have
attracted both males and females of the melon fly.
Lures
Parapheromone lures attract only the males, and each fruit fly
species in Hawaii is attracted to a different lure. Most are very
volatile and longer-lasting than protein baits. The amount of
lure necessary is determined by the purpose of the trapping
(i.e., monitoring versus mass trapping). A few drops may be
effective but not long-lasting. To understand the strength of the
lures, note that detection traps in California with trimedlure
and methyl eugenol are used at the rate of 10 per square mile and
2 per square mile, respectively (6 ml. dosage each). Reports in
Hawai'i have indicated that 3-5 drops of methyl eugenol have been
used on traps within a field. Currently, only methyl eugenol for
oriental fruit fly is available in local garden shops.
Parapheromone Lures for Male Fruit Flies
Type of lure Strength Fly attracted
Methyl eugenol very volatile & persistent Oriental
Cue-lure moderately persistent Melon
Ceralure persistent Medfly
Trimedlure moderately persistent Medfly
Latilure mildly persistent Solanaceous
Color, Shape or Size
Yellow is the most attractive color to males and females of
oriental fruit fly, melon fly, and medfly. They are attracted to
yellow and white flat panels as well as spheres. In field tests,
researchers collected as many or more females than males on the
colored traps.
TYPES OF TRAPS
USDA-ARS is currently working on a comprehensive review of all
traps
used in the market and in research.
Commercial
Protein bait: Glass or plastic McPhail traps can be used. Flies
enter from below and cannot get out.
Lure: A popular lure trap is a waxed cardboard Jackson trap, or
tent trap, that has a sticky insert floor to catch flies and a
cotton wick for lures.
Yellow sticky board: Rectangular yellow boards covered with
stick'em are used with or without other attractants.
Double yellow Panels: Two panels sandwiching a wick-soaked lure
(without insecticide) are being tested with medflies and
ceralure. This has been found to be very long-lasting and
effective.
Homemade
Homemade Protein bait: Use a clear plastic bottle and make
several 1 inch holes around the sides. Add liquid bait mix.
Lure: Use a clear plastic bottle and make a few 1/4 inch holes
around the sides. Put cotton inside for lures.
Harris trap: Harris trap can be used for any attractant. Use a
tall container with a clear wide cover. Make 1" dia. holes.
Easier to use than traps with stick'em, but when used with lures,
must have insecticide to kill the flies so flies don't escape.
Sticky panels: Paint cardboard or wood panel bright yellow. Cover
with Tanglefoot.
Labels
All traps used for catching fruit flies must be properly labeled.
Include bait or lure and date trap was set. Keep out of reach of
children.
PLACEMENT OF TRAPS
Location
Placement of monitoring traps may be more critical for medflies
than the other flies . Some research has shown that trap response
for medflies is greater in mating areas. Medfly mating takes
place in the crown of the tree with some light, on the upwind
side. Traps for the other flies should be placed in resting or
feeding areas.
Protein traps and other mild attractants should be placed close
to host plants, in a shady area. Place lure traps at borders,
comers, and outside areas of the field, before flies move into
your field. Color attractants should be placed in the open for
effectiveness.
Distance
Trap density or spacing is based on amount and type of attractant
used. Monitoring traps do not need to cover the entire area.
Protein bait traps have been used at 15-30 feet spacing in-field
and lure traps have been spaced at 100 feet outside the field.
Visual range for fruit flies is about 15-20 feet. Yellow traps
should be placed within that distance from the host plants at
greater densities than the lure traps.
Mainland programs recommend monitoring traps to be 4-6 feet from
ground level. More information on specific densities and
placement of monitoring traps under Hawai'i conditions is needed.
GLOSSARY
Bait: An attractant and food source (sometimes mixed
with insecticide) for treating fruit fly infested areas.
Beneficial organisms: Birds, parasites, nematodes or
other organisms that aid in controlling pests.
Development: Growth through life stages or life cycle.
Fruit flies have 4 life stages: eggs, larvae, pupae, and adults.
Generation: The period of time it takes to complete all
stages of development, including pre-oviposition period.
Host: A plant or animal that provides food for larval
growth and development.
Infestation: Presence of a fruit fly in a host.
Integrated pest management: Control strategy that
integrates cultural, biological, and chemical techniques to
manage pests.
Larva: Maggot. Juvenile stage of fly development.
Nu-lure: Commercial formulation of corn protein that
acts as a broad-spectrum food attractant for male and female
fruit flies.
Ovipositor: Egg-laying tube.
Parapheromone lure: Mild to very strong attractants that
attract only male fruit flies. Many are produced by plants.
Persistent: Relates to how long-lasting a lure is.
Pre-oviposition period: Time period after adults emerge,
before egg- Iaying begins.
Protein hydrolysate: Extracts of yeasts or grains that
act as a broad- spectrum food attractant for male and female
fruit flies (and many other protein-feeding insects).
Pupa: Transformation stage of fly development, after
larva and before and adult. Hard, brittle case covers the pupa.
Plural form is pupae; pupation refers to the act of
transformation.
Sheath: Outer covering of ovipositor.
Staley's fly bait No. 7: Commercial formulation of corn
protein that acts as a broad-spectrum food attractant to male and
female fruit flies.
Thorax: Back or top of the mid-body.
Torula yeast tablets: Commercial formulation of yeast
protein that acts as a broad-spectrum food attractant for male
and female fruit flies. Volatile: Readily vaporized [lures]. Can
carry on the wind.
REFERENCES
A complete list of references is available upon request.
Liquido,N. 1993. Reduction of oriental fruit fly (Diptera:
Tephritidae) populations in papaya orchards by field sanitation.
J. Agric. Entomol.10(2): 163-170.
Liquido, N., E. Harris and L. Dekker. 1994. Ecology of Bactrocera
latifrons (Diptera: Tephritidae) populations: host plants,
natural enemies, distnbution, and abundance. Ann. Entomol. Soc.
Am. 87 (1): 071-084.
Mau, R. F. L. 1983. Watermelon insecticide guide for commercial
producers. Univ. of Hawai'i, HITAHR Brief No. 044.
Robinson, A. S., and G. Hooper, ed. 1989. World crop pests: Fruit
flies- their biology, natural enemies and control. Vol.3A and 3B.
Steiner, L., W. C. Mitchell and K. Ohinata. 1959. USDA recommends
poisoned-bait sprays for fruit flies. Hawaii Agriculture. March:
25-30.
United States Department of Agriculture, Animal and Plant Health
Inspection Service. Emergency programs manuals. (Mediterranean
fruit fly action plan. 1982. Melon fly action plan. 1984.
Oriental fruit fly action plan. l989. Malaysian fruit fly action
plan. 1993).
Trap Sources: Great Lakes IPM, 10220 Church Rd., NE,
Vestaburg, MI 48891; and Pest Management Supply Inc., 311 River
Dnve, MA 01035.
ACKNOWLEDGMENTS
We are grateful to the following for information and assistance
with the Brief: Deborah Ward, Terry Sekioka, Vince lones and Ken
Kaneshiro of UH Manoa; RobertBoesch, Lance Kobashigawa and Pat
Conant of HDOA; Norman Makio; Tane Datta; Michael Rassa; Joe
Rosenova; Bart Jones; Kert Hamamoto; Jack Banks; and Jim Frazier.
We are extremely grateful for the support from LISA for Hawai'i
Project; Hawaii County Research & Development Department;
Hawaiti Fruit Fly Committee; and Big Island Resource,
Conservation and Development Council.
DISCLAIMER
Reference to a company or product name does not imply approval or
recommendation of the product by the College of Tropical
Agriculture and Human Resources, University of Hawai'i, United
States Department of Agriculture, or Hawai'i Diversified
Technologies, Inc. and does not imply its approval to the
exclusion of other products that may be suitable. All materials
should be used in accordance with label instructions or
manufacturers' directions.