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.
Possible extension of the activity spectrum of Bacillus thuringiensis strains through chemical additives
Some chemical procedures have been developed to extend the activity spectrum of δ‐endotoxin of Bacillus thuringiensis var. kurstaki HD‐1; so as to include Spodoptera littoralis (Boisd.) normally known as being weakly susceptible to this variety. These procedures were based on the incorporation of some selected essentially non toxic compounds with different modes of action with the endotoxin resulting in its potentiation. Experiments were made using artificial diet and natural host plants. Among the compounds tested, some inorganic salts, amino acids and amides, aromatic compounds, protein solubilizing agents, sodium borate and tannic acid showed a remarkable potentiation in the endotoxin activity of B. thuringiensis var. kurstaki HD‐1; vs. S. littoralis. These findings confirm the possible extension of the activity spectrum of the tested endotoxin and may be used to fill the gaps now existing with respect to the spectra of different B. thuringiensis strains, their host ranges and biological specificities. The mode of action of these compounds has been discussed in the light of the results obtained and the results are analysed in correlation with their application feasibilities.
Toxicological Studies on the Egyptian Cotton Leaf worm, Prodenia litura. VI. Potentiation and Antagonism of Organophosphorus and Carbamate Insecticides
The toxicity of 11 organophosphorus and 2 carbamate insecticides was determined by topical application to 3rd instar larvae of the Egyptian cotton leafworm, Prodenia litura F. Several organophosphorus insecticides were potentiated when pairs were applied jointly. Most of the potentiated pairs contained 1 strong and another weak insecticide. There were also antagonistic pairs as well as other pairs producing only additive effect when jointly applied. Most pairs that showed potentiation by contact showed it also when applied as stomach poisons.

Several pairs of 1 organophosphorus and 1 carbamate insecticide, either carbaryl or UC 10854® ( m -isopropylphenyl methyl carbamate), were potentiated as well.