Effect of a commercial insecticidal soap on greenhouse whitefly (Hom: Aleyrod.) and its parasitoid, Encarsia formosa (Hym: Euloph.)

Safer’s Insecticidal Soap (IS) was topically applied at six concentrations to all growth stages of greenhouse whitefly as well as larvae and adults of the whitefly parasitoid, the eulophid wasp Encarsia formosa. IS at 0.5% ai caused more than 94% mortality of all whitefly larval stages and adults, and more than 82.5% mortalitv of whitefly pupae. Adults hatched from treated pupae occasionally showed altered development. E. formosa adults were more tolerant to IS than whitefly and 81.5% survived a 0.5% IS treatment. It was concluded that IS is an effective pesticide for greenhouse whitefly and should be integrated with E. formosa in greenhouse trials

Effects of some environmental conditions on the response of birch bark to wounding

A histological study was carried out on the process of wound-healing in the bark of Betula pendula after treatment at various temperatures and in the bark of B. pendula and B. pubescens after water stress. Low temperature inhibited phellogen restoration in B. pendula. Wound-healing was delayed in B. pendula when exposed to flooding and drought, and in B. pubescens under drought., The response of B. pendula was faster than that of B. pubescens