Prays citri (Millière)
Taxonomic placing: Insecta, Holometabola, Lepidoptera, Yponomeutidae.
Common name: Citrus flower moth.
Geographical distribution: Mediterranean basin, Southern Asia to the Philippines. CIE Map #443, 1982.
Host plants: Lemons, citrons and pealed citrus varieties; rare on oranges.
Morphology: The adult is brown-grey, about 5 mm long, both pairs of wings are heavily fringed and with many darker spots. The larva is yellow-greenish, with a brown head, up to 6 mm long.
Life cycle: The females move from flower to flower (or bud to bud) and place 1-3 eggs on each, laying about 100 or more eggs. The emerging larvae bore into these organs, wherein they feed and produce abundant webbing that ties the flowers together. The pest completes 4-5 annual cycles, with much overlap of generations during summer and autumn. Females attract males by a pheromone that is produced during the dark hours. The moths, which are poor fliers, tend to remain in the same area. They may be reared in the laboratory on a cell culture consisting of citrus callus induced from lemon flower parts supplemented by malt extract and sucrose.
Economic importance: The larvae feed on the flowers and bind the adjacent plant parts together. Affected buds and flowers wilt and drop; heavy attacks may result in almost total yield loss. Young shoots and even small fruit (especially citron) can be damaged. The larvae invade graft wounds and bore therein, killing the graft.
Monitoring: Pheromone traps placed on the trees during spring may serve as an early warning system.
Mass trapping: Applying this method by placing 120 traps/hectare in a citrus grove was more efficient, and cheaper, than 3-6 organophosphate applications.
Chemical control: Repeated organophosphate applications can control the pest but are harmful to the natural enemies of other citrus pests. In addition, the pest is becoming resistant to these chemicals.
Biological control: The egg parasitoid Trichogramma evanescens (Westwood) (Trichogrammatidae) is very effective. Several bacteria of the genus Bacillus infected the pest in Egypt and an application of a commercial product of Bacillus thuringiensis reduced larval infestations by about 60-75%.
Abo-Sheaesha, M.A. and Agamy, E.A. 2004. Use of the egg parasitoid Trichogramma evanescens (West.) and (Agerin) Bacillus thuringiensis compared to ethion (organophosphorus insecticide) for suppressing infestation of Prays citri ( Mill.) in lime orchards. The First Arab Conference on Applications of Biological Control of Pests in Arab Countries.
Carimi, F., Caleca, V., Mineo, G., De Pasquale, F. and Crescimanno, F.G. 2000. Rearing of Prays citri on callus derived from lemon stigma and style culture. Entomologia Experimentalis et Applicata 95: 251-257.
Drishpoun, Y. 2000. A Guide to the Control of Citrus Pests. Ministry of Agriculture and Rural Development, Extension Service, pp. 97 (in Hebrew).
El-Metwally, M.M., Ghanim, N.M. and El-Kady, S.M.L. 2010. Local bacterial isolates as entomopathogenic agents against the citrus flower moth, Prays citri Miller (Lepidoptera, Hyponomeutidae) in lime orchards at north Delta region, Egypt. Bulletin of The Entomology Society of Egypt 36: 171-184.
Shetata, W.A. and NASR, F.N. 1998. Laboratory evaluation and field application of bacterial and fungal insecticides on the citrus flower moth, Prays citri Miller (Lep,, Hyponomeutidae) in lime orchards in Egypt. Anzeiger fur Schadlingskunde, Pflanzenschutz Umweltschutz 71: 57-60.
Sternlicht, M., Barzakay, I. and Tamim, M. 1990. Management of Prays citri in lemon orchards by mass trapping of males. Entomologia Experimentalis et Applicata 55: 59-67.