THE CONTROL OF THE GREENHOUSE WHITE FLY (ASTEROCHITON VAPORARIORUM) WITH NOTES ON ITS BIOLOGY1

Abstract

SUMMARY.The insect exhibits partial adaptation to a temperate climate, the egg and adult being resistant to considerable cold.The wide range of its food plants is indicated.The adults are gregarious and show marked colour reactions. The life is long and the fecundity great. Parthenogenesis occurs and only male offspring result from this; mating is the rule and produces offspring of both sexes.The incubation period of the egg varied from 8 to 117 days according to temperature, and the duration of the scale stage from 17 to 43 days.The occurrence of A. sonchi Kotinsky in England was noted.The attacks of the pest on tomatoes mainly make it of great economic importance. Specialisation in tomato growing to the exclusion of other crops is a useful precaution and other precautionary measures are indicated.Fumigation is the only effective method of treating infested plants. Naphthalene and tobacco preparations give little relief. Tetrachlor‐ethane is a good fumigant, but is too costly for trade growers.Cyaniding is the best method of treatment. The dose of sodium cyanide varies from one‐quarter to one‐tenth ounce per thousand cubic feet of greenhouse space, according to the type of greenhouse and the condition of the plants. Long fumigations with these small doses are more effective than short fumigations with larger quantities.The precautions necessary to avoid damage to the plants are given, avoiding daylight during fumigation and having the roots of the plants dry being the most important.