Pseudococcidae
Taxonomic placing: Insecta, Hemimetabola, Hemiptera, Sternorrhyncha, Coccomorpha, Coccoidea.
Common name: Mealybugs.
Geographical distribution: World-wide. The family consists of over 2,000 named species assigned to 270 genera.
Morphology: The elongated body of the female is fused, without clear separation between head, thorax and abdomen, but the segmentation of the latter is clearly defined. Two pairs of thoractic spiracles are present, the anterior pair behind legs I, the posterior pair between legs II and III. Various gland openings, which may have a single, three or five pores occur on the ventral and dorsal sides of the body. A median, round area, devoid of pores, the circulus, is often placed ventrally on segments IV or V of the abdomen. The ostiole, a unique, rounded dorsal opening occurs on each side near the margin of abdominal segment VII, and a setigerous anal ring is located between the two anal lobes. The dorsal margins of most body segments carry cerarii, groups of strong dorsal cone-like setae along with glands that secrete wax filaments of different lengths and shapes. The legs are usually developed and antennae bear 5-9 segments (except in leg-less genera, like Antonina, whose antennae are only two-segmented).The body may be yellow to grey to pink and covered by (usually) white waxy powder which imparts these insects their vernacular name. The males are insect-like, their bodies clearly separated into three parts. They bear two pairs of simple eyes, antennae, legs and a single pair of wings, and are short-lived.
Life cycle: In the Middle East mealybugs raise several annual generations. The eggs are deposited within filamentous ovisacs of different sizes that are usually left at the various feeding sites, because most females move around. Reproduction is usually sexual. Mealybugs feed on many annuals (especially grasses) and perennials, above and below ground, and often move between host plants. Many mealybugs are attended by protecting ants, which feed on the honeydew.
Economic importance: This family includes many pests, whose damage is due to sucking out plant sap, to injecting toxins into the hosts, to secreting large amounts of honeydew colonized by sootymold fungi, and, in a few cases, to transmitting virus diseases.
Management
Monitoring: Due to their cryptic habits it is difficult to follow changes in the numbers of these pests. Male sex pheromone traps provide the most reliable method of monitoring changes in their populations.
Chemical control: Due to their cryptic habits and waxy body covers, mealybugs are often difficult to control by cover sprays. However, good results can be obtained with organophosphates that have high vapor pressure or when applied as soil drenches. Control may also be achieved with systemic insecticides like imidacloprid, applied (when feasible) through the irrigation system. Insect growth regulators (IGRs) are ineffective due to their low vapor pressure. Ant control by ground sprays or through blocking their path to the canopy, or by dusting an insecticide around the base of the crop-tree, reduces pest numbers and damage.
Biological control: Various endoparasitoids, especially in the family Encyrtidae, control mealybugs in the Middle East. Predatory insects that prey and sometimes control these pests include the (Coccinellidae) Hyperaspis and Scymnus, lacewings such as Chrysoperla spp. (Chrysopidae) and Sympherobius spp. (Hemerobiidae), as well as larvae of Dicrodiplosis spp. (Cecidomyiidae). Augmentative releases of parasitoids and of the coccinellid Cryptolaemus montrouziei Mulsant may reduce pest populations in some habitats and can be obtained in commerce.
Mealybug pests included in this compendium
Antonina graminis (Maskell) (Rhodes-grass mealybug).
Maconellicoccus hirsutus (Green) (Pink hibiscus mealybug, hibiscus mealybug).
Dysmicoccus brevipes (Cockerell) (Pineapple mealybug).
Ferrisia virgata (Cockerell) (Stripped mealybug).
Nipaecoccus viridis (Newstead) (Sphereical mealybug).
Phenacoccus solenopsis Tinsley (Cotton mealybug).
Planococcus citri (Risso) (Citrus mealybug).
Planococcus ficus Signoret (Sphereical mealybug).
Planococcus vovae (Nasonov) (Cypress mealybug).
Pseudococcus cryptus Hempel (Citriculus mealybug).
Pseudococcus longispinus (Targioni Tozzetti) (Long-tailed mealybug).
Saccharicoccus sacchari (Cockerell) (Sugarcane mealybug).
References
Attia, A.R. 2012. Hymenptrous parasitoids as a bioagents for controlling maybugs (Hemiptera: Pseudococcidae) in Egypt Egypt. Academy Journal of Biological Scienes 5: 183-192.
Ben-Dov, Y. 1994. A systematic Catalogue of the Mealybugs of the World (Insecta: Homoptera: Coccoidea: Pseudococcidae and Putoidae) with Data on Their Geographical Distribution, Host Plants, Biology and Economic Imprtance. Intercept, Andover.
Downie, D. A. and Gullan, P. J. 2004. Phylogenetic analysis of mealybugs (Hemiptera: Coccoidea: Pseudococcidae) based on DNA sequences from three nuclear genes, and a review of the higher classification. Systematic Entomology 29: 238-260.
Franco, C., Suma, P., Borges da Silva, E., Blumberg, D. and Mendel, Z. 2004. Management strategies of mealybug pests of citrus in Mediterranean countries. Phytoparasitica 32: 507-522.
Hardy, N.B., Gullan, P.J. and Hodgson, C.J. 2008. A subfamily-level classification of mealybugs (Hemiptera: Pseudococcidae) based on integrated molecular and morphological data. Systematic Entomology 33: 51-71.
Mohammad, Z.K. and Moharum, F.A. 2012. Key to the genus of Family Pseudococcidae in Egypt (Hemiptera: Coccoidea). Egyptian Academy Journal of Biological Sciences 5: 1-5.
Swirski, E., Izhar, Y., Wysoki, M., Gurevitz, E. and Greenberg, s. 1980. Biological control of the longtailed mealybug Pseudococcus longispinus (Coccoidea, Pseudococcidae) in the avocado plantations of Israel. Entomophaga 25: 415-426.