|Crop Knowledge Master|
Abgrallaspis cyanophylli (Signoret)
|An Armored Scale|
Jayma L. Martin Kessing, Educational Specialist
Ronald F.L. Mau, Extension Entomologist
Department of Entomology
Updated by: J.M. Diez April 2007
This scale attacks several fruits and ornamental plants including Annona, avocado, banana, guava, macadamia, mango and palms.
This scale is prominent throughout the Tropical South Pacific and common as a greenhouse pest in cooler areas.
This scale is present on the leaves, bark and fruit of its hosts. Although it has never been a major pest in ornamental nurseries it is often a serious pest of palms.
Abgrallaspis cyanophylli is classified as an armored scale. Unlike other scales, armored scales do not produce honeydew (Beardsley and Gonzalez, 1975). Armored scales feed on plant juices. Feeding sites are usually associated with discolorations, depressions and other host tissue distortions (Beardsley and Gonzalez, 1975).
Scale insects belong to one of two types, the armored scales or the soft scales. This scale is classified as an armored scale. These scales are protected by a distinct, hard, separable shell or scale over their delicate bodies (Metcalf, 1962). The shell is made of entangled threads of wax exuded from the body wall of the scale and discarded cast skins (the old skin shed during molts). Armored scales lose their legs and antennae after the first molt. Females are always wingless and remain under their scale their entire life. Males have one pair of membranous wings, move about actively in search of females and do not feed during the adult stage. Except for a few species that birth live young, most armored scale species lay eggs. Abgrallaspis cyanophylli is an egg laying species. Eggs are protected underneath the scale or shell of the mother insect until they hatch. All armored scales have essentially the same life history (Metcalf, 1962).
The small eggs are yellow or greenish-yellow (Newstead, 1900).
Immature stages are yellow or greenish-yellow (Newstead, 1900). Their overall shape is similar to the adult form. The exuviae, or discarded skins from moltings, are located subcentrally on the protective scale of the insect.
Females are oval or triangular with points bluntly rounded when situated at a fold or along a vein on the under surface of the leaf. They are slightly convex to flat, thin, whitish and semitransparent with the yellow body of the insect showing through. The greatest diameter, or longest dimension when triangular, varies from 1/25 - 1/12 inch (1-2.25 mm). The discarded skin is centrally located, yellow, and covered with a light colored secretion. Males are smaller and elongated. Refer to Komosinska (1969) for a detailed description for identification under a microscope and Davidson (1964) for a key to the Abgrallaspis genus.
Scales often disperse with infested plant material. Infestations can sometimes be avoided by thoroughly inspecting new plant material for scales and other insects (Copland and Ibrahim, 1985). In Florida, this scale is usually kept under control by parasitic wasps.
Chemicals used on scales are usually the same as those used on mealybugs and may include diazinon, dimethoate, formothion, malathion and nicotine (Copland and Ibrahim, 1985). As in the use of all chemicals, consult the label, or a pesticide database to see what chemicals may be used on specific crops.
There is no listing for malathion, diazinon and dimethoate are not labelled as of April 2007.
Sprays are effective on the crawler stage of scales. However, control is difficult on other life stages. Adults are firmly attached to the plant and remain so after their death (Copland and Ibrahim, 1985). Infestations should be carefully examined before treatment is made. It is also important to know whether the pesticide is safe to use on the plant species.
Beardsley, J. W. and R. H. Gonzalez. 1975. The Biology and Ecology of Armored Scales. Ann. Rev. Ent. 20: 47-73.
Copland, M. J. W. and A. G. Ibrahim. 1985. Chapter 2.10 Biology of Glasshouse Scale Insects and Their Parasitoids. pp. 87-90. In: Biological Pest Control The Glasshouse Experience. Eds. Hussey, N.W. and N. Scopes. Cornell University Press; Ithaca, New York.
Davidson, J. A. 1964. The Genus Abgrallaspis in North America (Homoptera: Diaspididae). Ann. Entomol. Soc. Am. 57: 638-643.
Dekle, G. W. 1976. Abgrallaspis cyanophylli (Signoret). pp. 22. In: Florida Armored Scale Insects. Florida Dept. of Agric. and Consumer Ser. Division of Plant Industry.
Elmer, H. S. and O. L. Brawner. 1975. Control of Brown Soft Scale in Central Valley. Citrograph. 60(11): 402-403.
Komosinska, H. 1969, Abgrallaspis cyanophylli (Signoret). Acta. Zool. Cracoviensia. 14: 43-85.
Metcalf, R. L. 1962. Destructive and Useful Insects Their Habits and Control. McGraw-Hill Book Company; New York, San Francisco, Toronto, London. 1087 pages.
Newstead, R. 1900. Monograph of the Coccidae of the British Isles Volume 1. The Ray Society: London. 220 pages 34 plates.
Williams, D .J. and G. W. Watson. 1988. Abgrallaspis cyanophylli (Signoret). pp. 22-24. In: The Scale Insects of (Signoret). pp. 22-24. In: The Scale Insects of the Tropical South Pacific Region Part I the Armored Scales (Diaspidae). The Cambrian News Ltd. 290 pages.