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.
Suppression of Heliothis spp. on Cotton by using Bacillus thuringiensis, Baculovirus heliothis, and Two Feeding Adjuvants
The application of Bacillus thuringiensis Berliner and Baculovirus heliothis to cotton suppressed Heliothis spp. populations an average of 28% compared with the untreated check during field tests in 1980. The addition of the feeding adjuvants Coax® and Gustol® to the microbial insecticides increased the control by reducing the number of larvae by 46% in 1979 and 54% in 1980. The two feeding adjuvants Gustol® and Coax® improved efficacy of the microbial insecticides, but neither proved better than the other. In addition, spray combinations of B. heliothis + B. thuringiensis + feeding adjuvants did not prove to be superior to either pathogen alone + feeding adjuvants. For full-season use, the Heliothis spp. control in cotton using the microbials plus feeding adjuvants was not adequate compared with the insecticide standard permethrin. Significantly higher yields and lower Heliothis spp. populations were found With permethrin.
Inhibition of Root Growth and Polyamine Metabolism in Sunflower (Helianthus annuus) Seedlings Under Cadmium and Copper Stress
Although sunflower is usually regarded as a highly tolerant crop, impairment of root growth at initial stages of plant development may result in poor crop establishment and higher susceptibility to pathogen attack. In order to evaluate if Cd2+ and Cu2+ may impact on sunflower germination and initial root development, a pot experiment under controlled conditions was carried out. Possible involvement of polyamine metabolism in sunflower response to these stressors was also investigated. Although Cd2+ and Cu2+ treatments affect neither seed germination nor radicle emergence, sunflower seedlings grown in the presence of these heavy metals showed significant inhibition of root growth, being this inhibition greater for Cd2+. Both metals caused significant increases in proline contents at the highest concentrations tested (0.5 and 1 mM), and these increments were more pronounced for Cd2+ treatments, especially between days 3 and 10. Metals also increased putrescine (Put) contents at all concentrations assayed from the seventh day onward, causing no variations on this polyamine time-course pattern. Spermine and spermidine contents, however, were increased only by 1 mM Cd2+. Arginine decarboxylase seems to have been the enzyme responsible for Put increases under both metal treatments. This work demonstrates that initial root growth of sunflower seedlings may be significantly impaired in Cd2+ or Cu2+ contaminated soils. It also shows that polyamines are key biological compounds, which are probably involved in signaling pathways triggered under stress environmental conditions.