Efficiency of the entomopathogenic fungus Verticillium lecanii in the ...

probitprobitprobit2438 Afr. J. Microbiol. Res.Figure 4. Germination of V. lecanii spores after 24 h of incubation at 24°C and at a RH of 100%. G 40X0.75.Table 1. Probit analysis of egg treatment.No. of insects (n) Slope ± SE LC (95%) Chi-square LD50788 0.69±0.10 (13.060-86.134)10 6 12.709 4.2x10 7788 0.73±0.09 (93.573-37.621)10 6 15.929 2.1x10 7788 1.02±0.10 (41.553-79.95)10 6 23.169 0.59x10 764a86b86c20-22 4 6 8 10Log dose of spores/ml420-22 4 6 8 10log dose of spores/ml420-22 4 6 8 10log dose of spores/mlFigure 5. Effect of V. lecanii on T. vaporariorum eggs. Day 5 (a), day 6 (b) and day 7 (c) after treatment.day 5 was 7 folds higher than that found in day 7(Figure 5a, b and c). Microscopic examination showedthat the infected T. vaporariorum egg was surroundedwith V. lecanii mycelium (Figure 6a and b).Effect on larvaeAs seen in Figure 7, the percentage of mortalityincreased according to contact time, whatever wasthe dose of spores used. LD 50 were: 11x10 3 , 3.4x10 3and 0.5x10 3 spores/ml for the three incubation times(Table 2). Figure 8 showed T. vaporariorum larvaewith an abnormal shape surrounded with V. lecaniimycelium.Effect on adultsAfter 7 days of incubation of 120 adult insects, only 81