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University
of California Cooperative Extension
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| Identification Biology Damage Return to main page |
Four mealybug species cause economic damage to North American vineyards. |
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Three closely related species: grape mealybug, Pseudococcus maritimus (Ehrhorn), obscure mealybug, Pseudococcus viburni (Signoret), and longtailed mealybug, Pseudococcus longispinus (Targioni-Tozzeti), have been in California since the early 1900s. Together, they make up the "grape mealybug complex." There are generally good chemical, cultural and biological controls for these mealybug species, although problems can flare up.
The fourth mealybug species is the vine mealybug, Planococcus ficus Signoret. This invasive pest was first found in California in 1994 in the Coachella Valley. Its range expanded and, 1998, it was found in a few vineyards the southern San Joaquin Valley (near Del Rey and Arvin, CA). By 2003, small populations of the vine mealybug were found in vineyards in El Dorado, Madera, Monterey, Napa, Sacramento, San Luis Obispo, Sonoma, and Stanislaus Counties - where it is the target of eradication programs. Because the vine mealybug is a much more serious pest, measures to remove it from infested vineyards should be taken immediately (see VMB section). (Return to top) |
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Vine Mealybug
Identification key
Most of the vineyard mealybugs look similar and a thorough ID requires an adult that has been "cleared," "stained" and mounted on a slide. Below is a field guide to help with ID with mature mealybugs (immatures are very difficult to ID). 1. Wax filaments around body margin well-developed? Yes. Grape, obscure, longtailed, citrus or vine mealybug ... GO TO 2 No. GO TO 5 2. Caudal (or tail) filaments >¾ of body length, well defined dorsal stripe? Yes. Stop here - Longtailed mealybug. Found in Central Coast regions. No. GO TO 3 3. Caudal filaments between ¼ to ¾ of body length, poorly defined dorsal stripe? Yes. Stop here - Grape and obscure mealybugs. Separation of these species is difficult. The grape mealybug is found in most regions, the obscure mealybug is most common in the Central Coast. When poked with a sharp object, a ball of fluid will be secreted from ostiolar pores near the front of the back. The grape mealybug fluid is reddish, while the obscure is clear or white. Secretion of ostiolar fluid can be seen on the lacewing video. No. GO TO 4 4. Caudal filaments <¼ of body length Yes. Stop here - Vine and citrus mealybugs. These species are difficult to separate. The vine mealybug is a very damaging pest, the citrus maelybug is rarely found on grapes. See Vine Mealybug for a field description. 5. Wax filaments are not well developed around the body margin. Yes. Stop here - Pink hibiscus mealybug. This species has not yet been found in vineyards. If suspect, submit a sample to the local UCCE office or County Agricultural Commissioner.
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Each species has slightly different biological attributes, geographic and host ranges, and natural enemy complexes that can change the amount of damage and control options. There are, however, some basic biological similarities. Mealybugs are Pseudococcidae, a family in the order Hompotera - a group that includes many other insect pests such as scales and aphids.
The four vineyard mealybugs have an elongate-oval body, covered with wax secretions on the dorsal and lateral sides. The wax secretions give the appearance of cottony, spine-like projections. While these waxy secretions are not part of the mealybug’s body and will be lost with each molt, they can be helpful to separate some mealybug species. For example, mealybugs in the "grape mealybug complex" have the forked caudal tail, while the vine mealybug does not have a long caudal tail.
Typically, seven development stages can be recognized: (1) egg, (2) bright-orange to yellow-orange colored “crawlers” or rapidly moving 1st instars emerge, (3) the settled 1st instar begins to secrete wax, which gives the body a whitish appearance, (4) a 2nd and 3rd instar mealybugs begin to develop distinctive lateral and caudal spines, an increase in body size, and being to produce large amounts of honeydew excretion, (5) the immature female, and (7) the adult female. Adult grape, obscure and vine mealybugs deposit eggs in the protective “ovisac,” which is covered with wax filaments to protect the eggs or from predators and the environment. The longtailed mealybug is “viviparous,” and deposits live crawlers rather than eggs.
Male mealybugs look like females from the egg to the 3rd instar stages. After which, a non-feeding pupal stage forms. The male pupa is more slender and elongate than the female. From the pupa, a winged adult male emerges. Adult males have a single pair of wings halters, at the end of the abdomen there is a single pair of cerci that look like the waxy, anal filaments of the female.
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Mealybugs feed on plant phloem, using its needle-like mouth parts to suck out plant content and excreting the unused plant material, the carbohydrate rich “honeydew” on to the vine and grape bunches. The honeydew can cover leaves, canes, and fruit. The end result is layers of sticky, wet honeydew; dried, white honeydew-deposits; and thick, black sooty mold. An infested crop is unmarketable for table grapes.
Mealybugs feed on the vine’s trunk, canes, leaves, or fruit.
For mealybugs in the "grape mealybug complex" damage to the vine from feeding is of minor importance compared with the accumulation of live and dead mealybugs and their excretion (honeydew) that can foul the fruit and promote sooty molds and even defoliation. Damage is described separately for each of the four species.
Some of the mealybug species transmit viral pathogens.
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