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UC Pest Management Guidelines


Female longtailed mealybug, Pseudococcus longispinus.

Avocado

Longtailed Mealybug

Scientific name: Pseudococcus longispinus

(Reviewed 1/07, updated 1/07)

In this Guideline:


DESCRIPTION OF THE PEST

Nymphs and adult female mealybugs (order Pseudococcidae) are soft, oval, white powder- or wax-covered insects. Adult males are tiny, two‑winged insects with two long tail filaments, but are rarely seen. In many mealybug species the female lays tiny yellow eggs in an ovisac, a mass of eggs intermixed with white wax. Longtailed mealybug produces no external egg sacs; it gives live birth to nymphs. Longtailed has two to four overlapping generations a year. All stages can occur throughout the year.

Longtailed mealybug is the only species common in California avocado. Other species to look out for because they infest avocado elsewhere include citrus mealybug (Planococcus citri), pink hibiscus mealybug (Maconellicoccus hirsutus), and vine mealybug (Planococcus ficus), none of which are reported pests of avocado in California.

The citrus, longtailed, and vine mealybugs have distinct, well-developed wax filaments around their body margin. Female longtailed mealybugs have tail filaments almost as long as the body length. Citrus and vine mealybug filaments are relatively short. Pink hibiscus mealybug lacks distinct waxy filaments.

Have unfamiliar mealybug species identified by an expert. For example, the introduced vine mealybug has not been found in California groves, but it infests avocado elsewhere. Pink hibiscus mealybug in California has been limited to Imperial county. Introduced parasites, especially Anagyrus kamali (Encyrtidae), are providing good biological control. If pink hibiscus mealybug is discovered elsewhere in California, notify agricultural officials as prompt management action may be warranted.

DAMAGE

Mealybugs suck phloem sap. When abundant, they can reduce tree vigor, foul plants with sticky honeydew, and promote growth of blackish sooty mold that fouls fruit. Mealybug populations are usually very low. They occasionally are pests of young trees. New scion grafts on old (top-worked) trees have sometimes been damaged by longtailed mealybugs abundant during late winter to early spring.

MANAGEMENT

Conserve natural enemies that control most mealybug populations. Selectively controlling ants causes longtailed mealybug populations to decline and can prevent outbreaks. Reduce dust, which interferes with natural enemies. Whenever possible, apply only selective or short-residual pesticides when treating other pests. Pesticide application is not recommended for mealybugs in avocado.

Biological Control
Mealybug predators include green lacewing (Chrysoperla spp.) larvae, pirate bugs, predaceous fly larvae, and lady beetles, such as the mealybug destroyer (Cryptolaemus montrouzieri). Parasitic wasps are especially important in controlling outbreaks because the wasps specialize on mealybugs and reproduce rapidly. Acerophagus notativentris, Arhopoideus peregrinus, and Anarhopus sydneyensis (family Encyrtidae) parasitize longtailed mealybug.

Organically Acceptable Methods
Biological control is organically acceptable.

PUBLICATION

[UC Peer Reviewed]

UC IPM Pest Management Guidelines: Avocado
UC ANR Publication 3436
Invertebrates
B. A. Faber, UC Cooperative Extension, Santa Barbara/Ventura counties
J. G. Morse, Entomology, UC Riverside
M. S. Hoddle, Entomology, UC Riverside
Acknowledgment for contributions to Invertebrates:
P. A. Phillips, UC IPM Program, UC Cooperative Extension, Ventura County
M. Blua, Entomology, UC Riverside
P. Oevering, UC Cooperative Extension, Ventura County
D. Machlitt, Consulting Entomology Services, Moorpark, CA
T. Roberts, Integrated Consulting Entomology, Ventura, CA
B. B. Westerdahl, Nematology, UC Davis

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