Effect of temperature, relative humidity and aphid developmental stage on the efficacy of the mycoinsecticide Mycotal® against Myzus persicae

The green peach aphid, Myzus persicae, is a major pest worldwide. An examination of the impact of temperature, relative humidity and developmental stages of M. persicae on the efficacy of the whitefly mycoinsecticide Mycotal®, based on Lecanicillium muscarium and the effects of infection on aphid fecundity was evaluated under controlled conditions. Although this fungus can be grown at a broad range of temperatures (15-30oC), the optimum temperature for control of M. persicae ranged between 20 and 30oC. L. muscarium had high efficacy as a microbial control against M. persicae between 55 and 90% relative humidity. Total mortality of aphids treated with different spore dosages of L. muscarium varied according to the developmental stage: adults, fourth and third instar nymphs of proved more susceptible than first instar nymphs. Although the fungus did not affect the rate of nymph production, the reproductive period of aphids significantly decreased with increasing the spore dosage. Thus, total fecundity of treated aphids was 22.6 ± 1.1 and 31.6 ± 2.4 offspring per adult at the medium (644 ± viable spore/mm2) and low (330 ± 40 viable spore/mm2) dosages, compared with 45.7 ± 4.3 offspring per untreated aphid. The results suggest that L. muscarium has the potential as a biological control agent of M. persicae. However, fungal infection appears to have no sub-lethal effects on the fitness of the host’s progeny

EFFECT OF VARIOUS INSECTICIDES FOR THE CONTROL OF POTATO CUTWORM (Agrotis ipsilon Huf., NOCTUIDAE: LEPIDOPTERA) AT KALAM SWAT

ABSTRACT Studies were carried out on the management of potato cut worm, Agrotis ipsilon, through chemical insecticides; Steward (Indoxycarb), Linnate (Methomyl) and Poison Bait (Dipterex +Sugar + Rice husk) on permanent plots of potato crop at Kalam Swat, NWFP on private farm during 2002. The insecticides were applied at recommended doses, before the appearance of adult moths of black cut worm (Agrotis ipsilon) and then subsequent symptoms of the cutworm larvae in the potato plots. The data were collected by counting the number of damage plants or plant parts by potato cutworm at the interval of 2-days, 3days, 5 days and 12 days after treatment. The results showed that insecticides were non significant to each other but significantly different from control. Seasonal mean infestation was the highest (11.5%) in the check plot, while the lowest (1.3%) in poison bait followed by Lannate (1.6%) and then by steward (1.8%). Poison bait application is laborious but still effective and comparatively safe, it is, there for, suggested it could be incorporated in the IPM of potato for minimum and target use of pesticide