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.
Role of Some Additives in Enhancing the Formulation of Bacteria Bacillus thuringiensis Against Phthorimaea operculella and Helicoverpa armigera : 2-Chemical additives
Some Chemical additives have been adopted to improve the potency of the formulation of Bacillus thuringiensis var. Kurstaki (HD-234) against Phthorimaea operculella and Helicoverpa armigera. Results showed that after the addition of boric acid the percentage of the corrected mortality was 89 ± 2.55 and 90 ± 2.12% for P. operculella and H. armigera, respectively. Also results showed that when sodium dodecyle were added to the B.t. (HD-234) the means% of the corrected mortality recoded 88±2.47 and 91± 1.58 for the same corresponding pests. When urea were tested alone at 0.1% the means% of the corrected mortality recoded 4.0 ±2.41 and 8 ± 2.3 for P. operculella and H. armigera, which increased to 51 ±4.05 and 54 ±2.72, respectively. When urea was tested as protein solublizing agent, data showed that, there was no significance difference after the combination of urea at 0.1, 0.05 and 0.01% concentrations with B. thuringiensis (HD-234), it was not enhancer for B. thuringiensis. Larval mortality of P. operculella were 49 and 50%, respectively, when B. thuringiensis (HD-234) tested alone at LC50 and they increased to be 88 and 80% after the incorporation of Larginine and L-serine at 0.1% concentration, respectively; the efficiency of B. thuringiensis (HD-234) increased by factor of 1.80 and 1.60, respectively. After the incorporation of acetamide at 0.1% concentration to B. thuringiensis (HD-234) at LC50, larval mortality of P. operculella and H. armigera highly increased to be 82 and 88%, respectively, as compared to 47 and 51% when B. thuringiensis (HD-234) tested alone at LC50. The efficiency of B. thuringiensis (HD-234) increased by factor of 1.74 and 1.73 after the combination of calcium acetate at 0.1 and 0.05% concentrations with B. thuringiensis (HD-234) enhancing the activity of B. thuringiensis measured by the increase in mortality percentage. Larval mortality highly increased from 46 and 49% for B. thuringiensis alone at LC50 against P. operculella and H. armigera larvae, respectively, to 68 and 70% after the incorporation of 0.1% calcium acetate with B. thuringiensis, causing 1.48 and 1.43 fold increase in the efficiency. When B. thuringiensis (HD-234) tested alone at LC50. the larval mortality of P. operculella and H. armigera was 47 and 51%, respectively; it decreased to reach 39 and 39%, respectively, after the incorporation of sorbic acid at 0.1% concentration larval mortality caused by B. thuringiensis (HD-234) alone was 50 and 52% at LC50 against 1 instar larvae of P. operculella and H. armigera, respectively, while larval mortality increased to 68 and 76% after the addition of 0.1% of dimethyle sulfoxide, respectively.
Gill diseases of cultured salmonids in Ontario.
Between 1977 and 1981, the Fish Pathology Laboratory of the Ontario Veterinary College received 239 cases from trout farms of southern Ontario, 51 (21.3%) of which had diseased gills. Branchial lesions in 86.3% of these 51 cases were characterized by marked lamellar epithelial hyperplasia with epithelial hypertrophy and lamellar fusion. Filamentous bacteria were seen on the surface of the branchial filaments and lamellae in 68.6% of the cases. Our observations highlight the importance of gill diseases as a production problem of farmed salmonids in southern Ontario.