Swirski, E., Div. of Entomology, The Volcani Center, ARO, Bet Dagan, Israel
Izhar, Y., Extension Service, Ministry of Agriculture, Akko, Israel
Wysoki, M., Div. of Entomology, The Volcani Center, ARO, Bet Dagan, Israel
Gurevitz, E., Div. of Entomology, The Volcani Center, ARO, Bet Dagan, Israel
Greenberg, S., Div. of Entomology, The Volcani Center, ARO, Bet Dagan, Israel

Avocado plantations in Israel neighbouring cotton fields were heavily infested with and damaged by the long-tailed mealybug Pseudococcus longispinusTargioni Tozzetti. Drift of pesticides from the aerial sprays of those cotton fields upset the biological equilibrium and resulted in outbreaks of the mealybug population. The honeydew moth, Cryptoblabes gnidiellaMill. is attracted to the honeydew and its larvae gnaw the fruit. Avocado plantations in the vicinity of deciduous fruit trees, vines and citrus orchards treated with non-selective pesticides were also damaged, but to a lesser degree. The annual peak of the long-tailed mealybug population occurs in late spring and early summer, declines from autumn to winter, and is at an ebb usually in April. The parasitic wasp Hungariella peregrinaCompere, the most important natural enemy in Israel of the long-tailed mealybug, was released in the striken areas. Anagyrus fusciventrisGirault was introduced from Australia and well established in citrus and avocado plantations. The lady beetle Cryptolaemus montrouzieriMuls. did not become established in avocado plantations. Lacewings were less important than parasites as biocontrol agents. Control of ants did not affect markedly the fluctuations in the mealybug populations. As a result of limitations of aerial sprays of cotton near avocado, as well as of release of natural enemies in afflicted plantations, the long-tailed mealybug population and its damage were reduced greatly. © 1980 Le François.