Boarmia selenaria (Denis and Schiffermüller)
Common name: Giant looper.
Taxonomic placing: Insecta, Holometabola, Lepidoptera, Geometridae.
Geographical distribution: Mediterranean Region, Far East, East and South Africa.
Host plants: Many fruit trees, especially avocado.
Morphology: The larvae (caterpillars) are green, yellow/green or brown, resembling twigs, and they move with a looping motion (therefore “looper”). They may be up to 55 mm long. The wingspan of the adults is 40-50 mm, the forewings are pale-yellow and bear numerous dark markings, as well as distinctive moon shaped spots, which are also on the hindwings.
Life cycle: The pest has five annual generations. The female lives for 5-6 days, during which it lays up to 3000 eggs, placed on all parts of the host trees. After a few days the larvae hatch, feed on the hosts, reaching up to 6 mm in length within 4 weeks and pupating in the upper soil parts.
Economic importance: A pest of many crops, such as alfalfa, citrus, coffee, mulberry, peanuts and tea in different parts of the world. In the Middle East it is mainly a pest of avocado.
Management
Monitoring: Traps baited with virgin females are employed to monitoring changes in the male population. In Israel the first peak of males occurs in March, with additional peaks in June-July and September-October. Some individuals may overwinter as adults or emerge later from pupae when the temperatures were suitable. When 5-10 males per tree are found, they will be usually be located on avocado leaves and fruits and the trees should be sprayed with a Bacillus thuringiensis (Bt) preparation. The sex pheromone of B. selenaria has been identified, synthesized and may be used for monitoring.
Chemical control: The B. thuringiensis preparations can only be used against young caterpillars, up to 1.5 cm in length, as larger larvae are not susceptible to these compounds.
Biological control: Several parasitoids assignable to the orders Hymenoptera and Diptera, as well as some predators, attack the pest, but their overall effect is unclear.
References
Cossé, A.A., Cyjon, R., Moore, I., Wysoki, M., and Becker, D. 1992. Sex pheromone components of the giant looper, Boarmia selenaria Schiff. (Lepidoptera: Geometridae): identification, synthesis, electrophysiological evaluation, and behavioral activity. Journal of Chemical Ecology 18: 165-181.
Izhar, Y. and Wysoki, M. 1995. Control of the giant looper Boarmia Selenaria (Ascotis). Proceedings of the World Avocado Congress III, 440–441.
Swirski, E., Wysoki, M. and Izhar, Y. 2002. Subtropical Fruits Pests in Israel. Fruit Board of Israel, pp. 285 (in Hebrew).
Wysoki, M.1982. A bibliography of then giant looper, Boarmia (Ascotis) selenaria Schiffermüller, 1775 (Lepidoptera: Geometridae) for the years 1913-1981. Phytoparasitica 10: 65-70.