Control ofAgrotis ypsilon (Hufn.) (Lep., Noctuidae) on some vegetable crops in Egypt using the microbial agentBacillus thuringiensis
The effective threshold rate of application of Dipel 2X was 250g/f. Incorporation of some chemical additives such as calcium sulphate (CaSO4) or calcium oxide (CaO) significantly potentiated the effectiveness of Dipel 2X on larval population. The addition of calcium carbonate (CaCO3) and zinc sulphate (ZnSO4) to Dipel 2X greatly reduced the larval population and led to a significant increase in the yield of some vegetable crops. Dipel 2X baits at 250g/f were almost as effective as the chemical insecticide Hostathion when used at 1.5l/f in controllingA. ypsilon larvae attacking vegetable crops.Control of the greasy cutwormAgrotis ypsilon population was better achieved when the biological control agent Dipel 2X was used as baits.ZusammenfassungDie Wirksamkeits-Schwelle desBac. thuringiensis-Präparats Dipel 2X betrug 250g/f(eddan). Eine Hinzugabe von CaSO4 oder CaO erhöhte die Wirkung von Dipel 2X auf die Raupen signifikant. Die Hinzugabe von CaCO3 und ZnSO4 zu Dipel 2X führte zu starker Reduzierung der Raupenpopulation und zu signifikanter Steigerung der Ernte bei einigen Gemüse-Arten. Dipel 2X-Köder in einer Dosierung von 250g/f waren fast so wirksam wie das chemische Insektizid Hostathion (1,5l/f). Die Bekämpfung der Raupen vonAgrotis ypsilon ist somit in biologischer Form mittels Gebrauchs von Dipel 2X-Ködern sehr gut möglich.
The potential of the predatorOrius albidepennis onAgrotis ypsilon as affected byBacillus thuringiensis
The relation between the pathogenBacillus thuringiensis and the predatorOrius albidepennis (Hem.: Anthocoridae) associated with the greasy cutwormAgrotis ypsilon (Lep.) has been investigated.The biology of the predator showed to be affected in terms of nymphal duration, rate of food consumption and egg production when the predator larvae were fed on treated eggs or neonate larvae of the host (A. ypsilon). The effect of B-exotoxin (thuringiensin) on the predator has been also demonstrated.
The Host-Parasite Relationship of the European Corn Borer, Ostrinia nubilalis, and the Protozoan, Perezia pyraustae, in Delaware1
A high incidence of Perezia pyraustae was found in European corn borer larvae collected in the Autumn of 1959. Four hundred additional larvae were collected in April 1960 and subjected to controlled laboratory studies of the host-parasite relationship.

Of the 114 adults that emerged from these larvae, P. pyraustae was found in 85%. Eighty per cent of a sample of 50 dead larvae examined contained spores of this pathogen.

P. pyraustae significantly reduced adult longevity in both males and females. The fecundity of infected females was greatly lowered as compared with no infected females. The number of viable eggs laid by infected females was somewhat lower, suggesting that the pathogen may also have adversely infuenced embryonic development.

The results of this investigation, coupled with recent findings of workers in other areas of the country, suggest that P. pyraustae may be an important biotic factor in the regulation of the population density of the European corn borer in Delaware.