Planococcus ficus (Signoret)
Common name: Vine mealybug, Mediterranean vine mealybug, Grapevine mealybug.
Geographical distribution: The vine mealybug of whose worldwide distribution. It was introduced to the Americas during the second half of the 20th century. Until the early 1980’s the pest was frequently misidentified as the citrus mealybug, Planococcus citri (Risso). Until the mid 1980’s mealybugs in vineyards were often identified as Planococcus vitis (Niedielski), whereas the name P. ficus was assigned only to those on figs.
Host plants: This mealybug was found on plants in 12 families, being most abundant on grapevines, figs and pomegranates.
Morphology: The adult female is mobile, with extended legs. Body 2-4 mm in length, depending on the host plant, the feeding site and the density of the infestation. It bears 18 pairs of short wax filaments (excreted from the cerarii) around the body’s margin; the anal pair is up to one quarter of body length, but usually becomes detached. The body is covered with white-grayish wax produced by different glandular organs and secreted through various pores. Antennae 8-segmented. The female larvae and the two early male instars resemble the female, but are smaller. The emerging dark-brown male is about 1.5 long and has only one pair of wings.
Life cycle: During autumn, as temperatures drop, the scales seek shelter, overwintering as adult females, hiding in stem cracks, under strips of dry bark and on the main upper roots. On fig trees they usually hide in old wounds on the trunk and at the bases of branches. In spring scales infesting grapevines begin to oviposit, migrating upwards on the vines, first colonizing the bark and later young canes, leaf bases, blossoms and new growth. Egg laying starts 1-3 days after mating, and lasts 5-15 days. A female lays 50-500 eggs, dependent on body size, host plant and temperatures (maximum at 20-22°C). The eggs are wrapped in wax filaments. In late spring the pests occur on the lower sides of leaves. Large populations that may harm grape bunches develop during the second half of summer. The early bunch colonization enables the pest to raise two successive generations on the green and early ripening grapes, resulting in dense populations. Intensive population growth ends on the mature grapes in autumn, but the pests can reproduce while feeding on the stem cortex and leaves. The pest raises up to 7 annual generations in warm areas, about 4-5 in cooler regions. Generation time in the laboratory lasts about 4-5 weeks. During development the female rarely changes its feeding site until adulthood, when it tends to leave that position. The male has two larval stages, as well as prepupal and pupal stages, during which it stops feeding. Male emergence coincides with the appearance of young females, who soon after emergence emit a sex pheromone. The males live only for 1-2 days. The pests may be found all over the plant; at moderate infestations the population has a clumped distribution. Density on the stem increases progressively from the ground level up, the scales preferring to settle on the shaded side of the stem. There is more crawler migration in mid-summer and many young scales scatter between vines.
Direct damage to grapes is mainly caused by scales that colonize the bunches, soiling them with honeydew and sootymold and the pest’s bodies, live and dead. Infested bunches become more susceptible to injury caused by fruit moths (Ectomyelois ceratoniae (Zeller) and Cryptoblabes gnidiella (Milliere)]) and fungal diseases. Table grapes are especially susceptible. Bunch colonization is intensified by ants that collect the honeydew. Heavily infested vines may be weakened. Vine mealybug infestation appears to be associated with the carpenterworm, Paropta paradoxa Schaffer, a pest that bores into vine stems and arms. The mealybug also transmits viral diseases, such as corky-bark disease and grapevine leafroll. Infected grapes contain less sugar and are more acidic. Reduced net photosynthesis in leaves affected by leafroll may result in less yield in the long term. Figs and pomegranates may also be damaged by this scale.
Monitoring: Pest occurrence, infestation levels and phenology can be followed with sex pheromones traps.
Horticultural control: In susceptible varieties (e.g. table grapes), removal of rhytidome strips from the stem improves chemical control by exposing the hiding scales. Old wood and loose bark often harbor overwintering mealybugs, grape bunches that touch old wood should therefore be thinned in order to avoid contact. Sticky materials may be smeared on trunks as barriers to keep ants, which hinder natural enemies, from the vine canopy could further the biological control of the pest.
Chemical control: Chemical control is problematic even with nonselective pesticidesa due to the cryptic habits of the pest and to its waxy body cover. Best results were obtained by applications of the organophosphate azinphos-methyl as a foliar spray. Application of neonicotinoids via the irrigation system is effective. In Egypt citric acid of plant origin, applied in May, initially had little effect, but it gradually increased to give the highest effectiveness after 18 days. Mineral oils are to be sprayed after the winter pruning process.
Biological control: Various encyrtids parasitoids attack P. ficus in the Middle East. The most common are Anagyrus pseudococci (Girault), Leptomastix dactylopii and Leptomastidea abnormis. In hilly fig groves L. abnormis and Neoplaticerus palestinensis (Rivnay) also occur. The predators include coccinellids like Hyperaspis and Scymnus, also Chrysoperla spp. (Chrysopidae) and Hemerobiidae. These enemies reach high densities only at the end of summer, thus playing only a partial role in reducing pest numbers in vineyards, because by that time most pests are protected under rhytidome strips. The attending ants further disrupt parasitization, but not coccinellid activity. On fig trees the pest is more accessible to parasitism. Insecticide treatments to control the fig fruit fly (Lonchaea aristella Becker) disrupt the activities of the natural enemies. Augmentative releases of the natural enemies in Turkish vineyards, aimed at the young adult pest stages, provided best results, despite much encapsulation.
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Karamaouna, F. (and 6 co-authors) 2013. Insecticidal activity of plant essential oils against the vine mealybug, Planococcus ficus. Journal of Insect Science 13: 142.
Mendel, Z., Gross, S., Blumberg, D. and Steinberg, S. 1995. Improvement of the biological control of mealybugs (Pseudococcidae) by inundative releases of natural enemies. Hassadeh 75 (8): 55-64 (in Hebrew with an English summary).
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Walton, V.M. and Pringle K. L. 2004. Vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), a key pest in South African vineyards. A review. Journal of Enology and Viticulture 25: 54-62.
Zada, A., Dunkelblum, E., Assael, F., Harel, M., Cojocaru, M. and Mendel, Z. 2003. Sex pheromone of the vine mealybug, Planococcus ficus in Israel: occurrence of a second component in a mass-reared population. Journal of Chemical Ecology 29: 977-988.
Zvi Mendel. E-mail: firstname.lastname@example.org, Tel: 972-3-9683636; Fax: 972-3-9683849. Agricultural Research Organization; The Volcani Center Department of Entomology; P.O. Box 6, Bet-Dagan, 50250, Israel
Daniel Blumberg. Email: email@example.com, Tel.: 972-3-9683518; Fax: +972-3-9604180, Agricultural Research Organization; The Volcani Center Department of Entomology; P. O. Box 6, Bet Dagan 50250, Israel