AKTIVITAS LARVISIDAL EKSTRAK ETIL ASETAT DAN HEKSANA DARI FILTRAT Beauveria bassiana TERHADAP Aedes aegypti

Beauveria bassiana produces several metabolites that are toxic to insects so that it can be used as a biological insect control agent as an alternative to synthetic pesticides. The aim of this study was to determine the larvicidal activity of ethyl acetate and hexane extract from B. bassiana filtrate culture against Aedes aegypti 2nd instar larvae. This research was it cooked by determining the optimum age of spore inoculum of B. bassiana on the Potato Dextrose Agar (PDA) based on the number of spores and its viability. Afterwards, we determine the incubation time of B. bassiana in the Potato Dextrose Broth (PDB) in order to obtain filtrate culture which have highest mortality effects against Ae. aegypti 2nd instar larvae. B. bassiana filtrate culture was extracted with hexane and ethyl acetate and tested aegypti for larvicidal activity with a concentration range of 50, 100, 200, 300 ppm. The LC50 value was carried out by probit analysis. The results showed that ninth day old culture in the PDA was the optimum age of spore inoculum with the spore number and viability were 2.54 x 107 spore/mL and 93.46% respectively. The filtrate of sixth day old culture in PDB medium gave 100% mortality against 2nd instar Ae. Aegypti larvae. LC50 values of ethyl acetate and hexane extract were 117.28 dan 287.09 ppm. These results showed that the ethyl acetate and hexane extract of B. bassiana filtrate culture have biopesticide potential against 2nd instar Ae. aegypti larvae.

Biological insect control using Metarhizium anisopliae: morphological, molecular, and ecological aspects

Microbial control of insects is based on the rational use of pathogens to maintain environmentally balanced pest population levels, and Metarhizium anisopliae has been the most studied and most utilized fungal species for that purpose. The natural genetic variability of entomopathogenic fungi is considered one of the principal advantages of microbial insect control. The inter- and intraspecific variability and the genetic diversity and population structures of Metarhizium and other entomopathogenic fungi have been examined using ITS-RFLP, ISSR, and ISSP molecular markers. The persistence of M. anisopliae in the soil and its possible effects on the structures of resident microbial communities must be considered when selecting isolates for biological insect control.

The Influence of Host Plants on Herbivore Community Composition on Brassica Crops in Western Siberia

Experiments on three varieties of Brassica oleracea (white cabbage, red cabbage, and cauliflower) were conducted during the years 2008–2011 in Western Siberia (Russia) to study the influence of host plant on herbivore infestation. The results revealed the evidence of different infestation of white cabbage, red cabbage, and cauliflower by the common herbivores in Western Siberia. Flea beetles as the earliest herbivores preferred to infest white cabbage. Contrary to those herbivores, M. brassicae and P. xylostella larvae infested red cabbage most of all. The latest herbivore of all plants studied, P. brassicae, preferred cauliflower but not red cabbage. The possible contribution of some factors in summary effects observed in the study was discussed. Further studies are being planned in which tritrophic interaction including B. oleracea plant, herbivore, and microbial insecticides should be investigated. These studies will help to develop biological insect control on Brassica oleracea crops in order to supply ecologically safe plant protection.

V-ATPase-energized epithelia and biological insect control.

Background is provided for the experimentally detailed contributions concerning the structure, distribution and function of V-ATPase-based ion pumps in insect epithelia. The mode of action of an insecticidal bacterial protein, which is dependent upon the V-ATPase-energized state in larval lepidopteran midgut for activity, is discussed.