|Crop Knowledge Master|
Dysmicoccus neobrevipes (Beardsley)
|Gray Pineapple Mealybug|
Jayma L. Martin Kessing, Educational Specialist
Ronald F.L. Mau, Extension Entomologist
Department of Entomology
Updated by: J.M. Diez April 2007
Reported hosts of the gray pineapple mealybug include: Acacia farnesiana, Achras zapota fruit, Agave sisalana, Annona reticulata, banana, Barringtonia speciosa, coconut caps, coffee, Cresentia alata, custard apple fruit, Garcinia mangostana, Guettarda, Banana, Musa paradisiaca sapientum, Opuntia megacantha, Pandanas, pineapple, Pipturus argentea, Piscidia piscipula, Samanea saman (monkeypod), sisal, Theobroma cacao and tuberose. This species has not been found on grasses.
This pest has a pantropical distribution, with a few records from subtropical localities. Essentially it is found wherever pineapple is grown such as Fiji, Jamaica, Malaysia, Mexico, Micronesia, Philippines and Taiwan. It is present on all of the major Hawaiian Islands.
The gray pineapple mealybug was described from specimens collected in Hawaii (Beardsley, 1959).
On pineapple this mealybug has been implicated as a vector of mealybug wilt and with green spot disease. Because of its involvement in pineapple wilt, the gray pineapple mealybug is one of the most economically important mealybug pests in Hawaii.
Pineapple wilt, or mealybug wilt, is the most serious type of damage and is the principal cause of crop failure in Hawaii. There are two types of wilt, "quick wilt" and "slow wilt". Both types cause the collapse of roots by the invasion of saprophytic organisms or by drying up. "Quick wilt" is produced by a short period of feeding by a large colony of mealybugs and is characterized by discoloration of leaves to yellows or reds and the loss of rigidity in leaves. "Slow wilt" occurs after the development of a large colony of mealybugs and shows fewer color changes. Leaves will be covered with mealybug feeding sites, leaf tips are browned, outer leaves droop and the leaf will be flaccid to the touch. Pineapple wilt has also been called "edge wilt" because the margins of the field would be effected first and the infection would move inward as the mealybug infestation dispersed. Fortunately this disease has been controlled for the last 3 decades by routine ant control. However, it may once again become prevalent if mealybugs are not continually suppressed by limiting ant populations.
Green spotting is characterized by the production of welt-like simulations of galls. The galls are produced by a secretion of this mealybug that reacts with the plant tissues.
The life cycle of this insect was extensively studied by Ito (1938). The "gray form" mentioned in his paper is presently known as the gray pineapple mealybug. This insect goes through three larval stages before becoming an adult. The life span (first instar to death as an adult) varies from 59 to 117 days, averaging at 90 days.
This species does not lay eggs. Instead they are ovoviviparous, meaning the eggs hatch within the female. Thus, births live young (nymphs).
Larvae, called "crawlers", are the primary dispersal stage in all mealybug species. They have flattened bodies with long hairs which aid in their dispersal by wind.
Female larvae molt three times before reaching adult maturity. The first, second and third larval instars or stages last for 11 to 23 days, 6 to 20 days and 7 to 28 days respectfully. Thus, the total larval period varies from 26 to 52 days, averaging at about 35 days.
Males, however, molt four times before becoming winged adults. The first, second, third and fourth larval instars or stages last for 11 to 19 days, 7 to 19 days, 2 to 7 days and 2 to 8 days respectfully. Thus, the total larval period varies from 22 to 53 days.
Larvae only feed during the first instar and the early part of the second instar.
Adults appear predominantly gray in color as their common name implies. In actuality their bodies are brown to grayish-orange, but take on a grayish appearance in combination with the waxy exudation that covers them. The body is broadly oval and measures about 1/17 inch long by 1/25 inch wide. The back is heavily coated with tiny tufts of white mealy wax. Short filaments of wax extend from around the margin of the entire body. Lateral wax filaments are usually less than one fourth as long as the breadth of the body and those towards the back of the insect are one-half as long as the body. Refer to Beardsley (1959) for a detailed description of the gray pineapple mealybug.
Adult females start birthing larvae about 26 days into adulthood. They continue birthing larvae for 30 days. Each female produces about 350 larvae, but there are some that produce up to 1000 young. Females die about four days after they cease to produce young. Duration of adult life varies from 48-72 days, averaging at about 61 days.
Compared with females, the males are short lived. The winged males live from 2 to 7 days.
The gray pineapple mealybug is normally found on the aerial parts of its hosts such as leaves, stems, aerial roots, and flower and fruit clusters. These sites of attack differ from that of the pineapple mealybug, Dysmicoccus brevipes (Cockerell), which inhabits the base of their host plants such as the lower portions of stems and exposed roots of grasses and herbaceous plants, the butts of pineapple plants and the lower stalks of sugar cane.
Mealybug control often focuses on the control of caretaking ants that are essential for the proper development of pineapple mealybugs. They provide the mealybugs shelter, protection from predators and parasites and keep them clean from detritus that may accumulate in the secreted honeydew and be deleterious to the colony. Because of the essential role of the ants, management practices often include the control of tending ant species. Without the ants, mealybug populations are small and slow to invade new areas and the field would be free of a serious mealybug infestation.
Three ant species are responsible for maintaining mealybug populations on Hawaiian pineapple: 1) the big headed ant, Pheidole megacephala, the primary ant caretaker, which is found at elevations less than 2300 feet; 2) the Argentine ant, Iridomyrmex humilis (Mayr), at elevations above 1968 feet; and 3) the fire ant, Solenopsis germinata Fab. var. rufa, which is found under very dry conditions on the lowlands.
There are many natural enemies for this mealybug in Hawaii. Parasites include Aenasius cariocus Compere, Aenasius colombiensis Compere, Anagyrus ananatis Gahan, Euryhopauus propinquus Kerrich, Hambletonia pseudococcina Compere and Ptomastidae abnormis (Girault). Predators include Cryptolaemus montrouzieri Mulsant, Lobodiplosis pseudococci Felt, Nephus bilucernarius Mulsant, Scymnus (Pullus) unicatus Sicard and Scymnus pictus Gorham. Although many natural enemies to the pineapple mealybug are present, they exhibit minimal control if protective ants are tending the mealybug colony.
When ants encounter a fence or wall they are likely to travel the course of the fence rather than up and over the fence to forage on the other side. Physical barriers such as ant fences running parallel to the field periphery are partially successful in keeping ants out of the field, and subsequently controlling mealybug populations.
Previously infested fields should plowed and crop residue removed or burned. Crop residues and grass roots left in the field can harbor mealybug populations and often provide an in field source of insects that will infest the new crop.
Field borders should be kept clean of weeds and debris that may support mealybugs between plantings. Weeds also provide alternative food sources that maintain ant populations between periods where mealybug infestations are small.
The chemical control of tending ant species has shown to be effective in the control of mealybug populations on pineapple. In the past, chemicals such as heptachlor and mirex have been used to control ant populations and subsequently mealybug wilt in pineapple. Unfortunately, these chemicals have detrimental effects on the environment because of their slow degradation and have been banned for use by the Environmental Protection Agency. Alternative chemicals are being evaluated. AMDRO, an effective ant-bait, has been given a special local needs permit for use on pineapple the past few years. It is currently being evaluated for labeling on crop use.
Big-headed ant colonies are destroyed during land preparation and planting procedures because their nests are located near the soil surface. Reinvasion by colonies from adjacent infested fields, fallow or uncultivated areas is slow. Establishment of ant populations in new plantings may therefore be prevented by the use of suitable ant bait or broadcast spray applied to the margins of new plantings (100 feet from margin) and adjacent areas. Some colonies within the field may survive through land preparation but are unable to survive until suitable food may be found and usually die out. If necessary, they may be controlled by ant-baits and spraying throughout the entire planting.
AMDRO is not labelled for the crops of Anonna and Banana as of April 2007.
Beardsley, J. W. 1959. On the Taxonomy of Pineapple Mealybugs in Hawaii, with a Description of a Previously Unnamed Species (Homoptera: Pseudococcidae). Proc. Hawaiian Entomol. Soc. 17(1): 29-37.
Beardsley, J. W. 1960. A Preliminary Study of the Males of Some Hawaiian Mealybugs (Homoptera: Pseudococcidae). Proc. Hawaiian Entomol. Soc. 17(2): 217-218.
Beardsley, J. W. 1965. Notes on the Pineapple Mealybug Complex, With Descriptions of Two New Species (Homoptera: Pseudococcidae). Proc. Hawaiian Entomol. Soc. 19(1): 55-68.
Beardsley, J. W., T. H. Su, F. L. McEwen, D. Gerling. 1982. Field Investigations on the Interrelationships of the Big-Headed Ant, the Gray Pineapple Mealybug, and the Pineapple Mealybug Wilt Disease in Hawaii. Proc. Hawaiian Entomol. Soc. 24(1): 51-68.
Carter, W. 1932. Studies of Populations of Pseudococcus brevipes (Ckl.) Occurring on Pineapple Plants. Ecology. 13: 296-304.
Fullaway, D. T. 1924. Pineapple Insects. Annual Short Course of Pineapple Production. 3: 57-66.
Ghose, S. K. 1983. Biology of Parthenogenetic Race of Dysmicoccus brevipes (Cockerell) [Pseudococcidae, Hemiptera]. Indian J. Agric. Sci. 53(11): 939-942.
Hill, D. S. 1983. Dysmicoccus brevipes (Ckll.) pp. 214. In Agricultural Insect Pests of the Tropics and Their Control, 2nd Edition. Cambridge University Press. 746 pages.
Illingworth, J. F. 1931. Preliminary Report on Evidence that Mealy Bugs are an Important Factor in Pineapple Wilt. J. Econ. Entomol. 24(4): 877-889.
Ito, K. 1938. Studies on the Life Histories of the Pineapple Mealybug, Pseudococcus brevipes (Ckll.). J. Econ. Ent. 31(2): 291-198.
LePelley, R. H. 1968. Dysmicoccus brevipes. pp. 346. Pests of Coffee. Longmans, Green and Co., Ltd. London. 590 pages.
Rohrbach, K. G., J. W. Beardsley, T. L. German, N. J. Reimer and W. G. Sanford. 1988. Mealybug Wilt, Mealybugs, and Ants on Pineapple. Plant Disease. 72(7): 558-565.
Zimmerman, E. C. 1948. Pseudococcus brevipes (Cockerell). pp. 189-201. In Insects of Hawaii. A Manual of the Insects of the Hawaiian Islands, including Enumeration of the Species and Notes on Their Origin, Distribution, Hosts, Parasites, etc. Volume 5. Homoptera: Sternorhyncha. 464 pages.