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.
Field evaluation of the potency ofBacillus thuringiensis on lepidopterous insects infesting some field crops in Egypt
Agrotis ypsilon andSpodoptera littoralis can be successfully controlled on various field crops usingBacillus thuringiensis (Dipel 2X) baits and sprays. Baits based on the pathogen at 200–250 g/Feddan, scored the best efficacy againstA. ypsilon in clover fields followed by potato, tomato, and cotton cultivations. Addition of some chemical additives (inorganic salts) toB. thuringiensis bait formulations greatly enhanced its potency. This was associated with an obvious increase in the yield of clover, potato and tomato crops; calcium oxide showed to be highly afficient in this respect. Sprays of Dipel 2X were also found as affective as lannate in controllingS. littoralis on clover cultivations.ZusammenfassungDie Untersuchungen ergaben, daßAgrotis ypsilon undSpodoptera littoralis an verschiedenen Feldfrüchten erfolgreich mitBacillus thuringiensis (Dipel 2X) als Köder oder Sprühmittel bekämpft werden können. Die Köder auf der Grundlage von 200–250 gBacillus/Feddan erzielten die besten Ergebnisse gegenA. ypsilon auf Kleefeldern, gefolgt von Kartoffel, Tomate und Baumwolle. Die Beimengung von chemischen Zusatzmitteln (anorganische Salze) zu denBacillus-Ködern erhöhte die Wirksamkeit beträchtlich. Daraus resultierte eine auffallende Steigerung der Klee-, Kartoffel- und Tomatenernte. Dabei war Kaliumoxid das wirksamste Zusatzmittel. Das Sprühen mit Dipel 2X erwies sich in Kleefeldern als ebenso wirksam wie die Anwendung des chemischen Pestizids Lannate.
Insecticidal activity of HD-1, a new isolate of Bacillus thuringiensis var. alesti.
Abstract Preparations from fermentation beers of HD-1, a new isolate of Bacillus thuringiensis var. alesti , were 200 times more active in laboratory tests against the pink bollworm, Pectinophora gossypiella , the tobacco budworm, Heliothis virescens , and the cabbage looper, Trichoplusia ni , than a typical commercial formulation, and were 20 times more active than an improved commercial product now undergoing tests. The activity of two preparations of HD-1 and the commercial products in the three test species was also compared against the proposed international standard, E-61, produced by the Institut Pasteur, Paris, France. One lot of HD-1, coded HD-1-PL-1, was adopted as a secondary standard; it had a potency of 16,000 IU/mg. The homology of the international standard to the four test materials was considered.