Efektivitas Beberapa Isolat Cendawan Entomopatogen Verticillium lecanii Zimm. (Viegas) terhadap Telur Hama Pengisap Polong Kedelai

Abstract

The Effectiveness Entomopatogenic Fungi Verticillium lecanii, to Control Pod Sucking Bug (Riptortus linearis). V. lecanii have some advantages, in that it can infect at various developmental stages of R. linearis, i.e. at stage of: egg, nymph, and adult. The aim of the experiment was to evaluate the effectiveness of various V. lecanii isolates on egg of the insect. The treatments were arranged in Randomize complete design, using 37 V. lecanii isolates with four replicates. Isolates were cultured on Petridis (9.0 diam.) containing potato dextrose agar (PDA)media. To obtain 107/ml conidia densities, 21 days after inoculation (DAI) the developmental conidia on PDA were added with sterile water and counted using haemocytometer. These suspensions were applied on 100 of one day old eggs. The result showed that all fungi isolates effectively infected the eggs of R. linearis. The percentage of infected-eggs which failed to hatch was between 12 to 75%. Among the most effective isolates, four isolates, i.e. Vl-JTM11, Vl- JM12, and Vl-JTM15 was from East Java, and one isolate Vl-TB2 was from Lampung. The effective isolates was able to pressure eggs which failed to hatch over 70%. The shorter infection periode of effective fungi on egg, delayed the time of hatching of eggs for 3.3 to 4.5 days. The effective fungus was able to produce conidia over 7 x 106/failed hatch egg, and was able to pressure the life of nymph of R. linearis instar-II up to 20%. Nymphs of R. linearis were not able to develop into adult stage when they were infected by fungi. The research result indicated that, four effective isolates fungi V. lecanii can be used as biological agents in controlling soybean pod sucker.