Ceroplastes floridensis Comstock

Taxonomic placing: Insecta, Hemimetabola, Hemiptera, Sternorrhyncha, Coccoidea, Coccidae

Common name: Florida wax scale.

Geographical distribution: World-wide in tropical and subtropical regions; mostly in the eastern part of the Mediterranean Basin. CABI Pest Map #440 (2010).

Host plants: Citrus and many ornamentals. In the Middle East found on plants that belong to more than 40 families.

Morphology: The dark-red body (3-4 mm in length) of the female is covered by whitish wax, which consists of a large median block and eight surrounding small plates that are separate only in young females. Body with about 60 marginal spiracular setae with pointed apices on each side. Venter with numerous tubular ducts, arranged in a submarginal band. The anal plates are heavily sclerotized, irregularly rounded.

Life history: The crawlers may be dispersed by winds for long distances. They settle on leaves along the veins and on thin branches and begin to feed and to excrete honeydew, rarely leaving that site. There are two annual generations, those infesting citrus trees that grow on sandy soil appearing in April-May and in July. Those infesting trees grown in loam appear during June-July and September to November. The scales of the latter generation overwinter as nymphs, ovipositing in the next spring. The threshold of development is at 10ºC and about 1,700 day-degrees are required to complete a generation. Reproduction is by parthenogenesis, each female depositing about 300 eggs, the number being related to the size of the mothers, which in turn appears to correspond to the duration of development. The pest and its natural enemies may be mass-reared on potted Myrtum communis L. (Myrtaceae), provided they are grown under sufficient light conditions.

Economic importance: Damage is due to secreting large amounts of honeydew that is colonized by sootymold fungi, which covers the fruits and leaves by a thick black mass. As a result photosynthesis is reduced, leaves may drop and branches dry up. Thick mats of sooty mold inhibit the fruit (especially grapefruits) from changing their color, reducing their commercial value. Avocado and mango may occasionally also be damaged.

Management:

Sampling: Regression of mean scale age over time (of both generations on both soils), from settled crawlers to adults, usually yields a straight line, despite temperature fluctuations. This enables the forecasting of the development of a given generation when it is still in its early development, and could help in timing spray applications.

Chemical control: The pest can be controlled with organophosphates, applied with best results during the emergence of the susceptible juveniles. A carbamate was applied for some years but the pest became resistant to this compound, which also killed natural enemies. Other options include treatments with potassium nitrate or IGRs, which, being less toxic, do not harm the natural enemies.

Biological control: Florida wax scale is attacked by many hymenopterous endoparasitoids, of which Aprostocetus ceroplastae are the most important, comprising 84% of all emerged parasitoids The coccinellid Chilocorus bipustulatus and spiders prey on young scales in summer.

References

Argov, Y., Podoler, H., Bar-Shalom, O. and Rosen, D. 1987. Mass rearing of the Floridae wax scale, Ceroplastes floridensis, for production of natural enemies. Phytoparasitica 15: 277-287.

Ben-Dov, Y. 1976. Phenology of the Florida wax scale, Ceroplastes floridensis Comstock (Homoptera: Coccidae) on citrus in Israel. Phytoparasitica 4: 3-7.

Mansour, F. and Whitcomb, W.H. 1986. The spiders of a citrus grove in Israel and their role as biocontrol agents of Ceroplastes floridensis (Homoptera: Coccidae). Entomophaga 31: 269-276.

Peleg, B.A. 1987. Resistance of adult Florida wax scale to commercial formulations of carbaryl. Alon Ha’Notea 41: 601-603 (in Hebrew).

Peleg, B.A. Gothilf, S. 1981. Effect of the insect growth regulators Diflubenzuron and Methoprene on scale insects. Journal of Economic Entomology 874: 124-126.

Pelizzari, G. and Camporese, P. 1994. The Ceroplastes species (Homoptera: Coccoidea) of the Mediterranean basin with emphasis on C. japonicus Green. Annales de Société Entomologique France (N.S.) 30: 175-192.

Schneider, B., Podolet, H. and Rosen, D. 1987. Popuation dynamics of the Florida wax scale, Ceroplastes floridensis (Homoptera: Coccidae), on citrus in Israel. 3. Development rate and progression of mean age. _Acta Oecologica _8: 95-103.

Yardeni, A. 1987. Evaluation of wind dispersal of soft scale crawlers (Homoptera: Coccoidea) in the infestation of a citrus grove in Israel. Israel Journal of Entomology 21: 25-31.

Yardeni, A. and Rosen, D. 1995. Crawler phenology and generation development of the Florida wax scale, Ceroplastes floridensis, on citrus planted in two soil types. Phytoparasitica 23: 307-313.

Websites: http://www.weedimages.org/browse/subthumb.cfm?sub=8272