Efficacy of talc-based formulation of Beauveria bassiana (Bals.) Vuill. (MZ749636) against two spotted spider mite, Tetranychus urticae Koch

Tetranychus urticae is one of the most important and destructive mite species infesting the vegetable crops, which is very important to control because of its wide host range. The damage caused by the two spotted spider mite can be eliminated by using entomopathogenic fungi, as the acaricidal control causes various problems such as resistance, resurgence and residue problems. Therefore, the present study was carried out with a view to evaluate the efficacy of the talc-based formulation of Beauveria bassiana (MZ749636) under pot-culture conditions against two spotted spider mite (TSSM), T. urticae in potted bhendi (Abelmoschus esculentus) plants, in comparison with fenazaquin 10 EC @ 1.5ml/l, azadirachtin 3000 ppm @ 2ml/l and crude formulation of B. bassiana, MZ749636 @ 1 x 108 conidia/ml. After two rounds of spraying at fortnight intervals, the talc- formulation of B. bassiana, MZ749636 resulted in 62.83 per cent cumulative reduction of TSSM over the control. However, fenazaquin 10 EC @1.5 ml/l recorded the maximum cumulative mortality of 80.07 per cent, followed by azadirachtin 3000 ppm @ 2ml/l, which recorded a cumulative mortality per cent of 71.06 per cent. Crude formulation of B. bassiana recorded 58.12 per cent reduction of TSSM over the control after two rounds of spraying. This was the first study that attempted to evaluate the efficacy of the talc formulation of the B. bassiana (MZ749636) isolate against TSSM

Isolation, Identification and Pathogenicity Assay of Fungal Species on Horse Purslane (Trianthema portulacastrum L.,)

A field survey was carried out in Tamil Nadu agricultural university, Coimbatore, to locate Horse purslane (Trianthema portulacastrum) infected with fungal pathogens. Heavily infested areas were recognized and symptomatic leaves were collected. Fungal species account for leaf spot disease of Horse purslane were Isolated from infected leaves on PDA medium. Based on morphological characteristics two foliar pathogens of Horse purslane were identified as Gibbago trianthemae Simmons and Curvularia tuberculata Sivan. Pathogenicity of two isolates was tested by applying spore treatment to Horse purslane (test plants). Leaves of test plants showed naturally occurring symptoms after inoculation with pathogens. Among the two isolates, Gibbago trianthemae was shown to be more effective against Horse purslane than Curvularia tuberculata

Pathogenicity of Beauveria bassiana (Balsamo) Vuillemin Isolate (TNAU ENT BB1) Against Rice Leaf Folder, Cnaphalocrocis medinalis (Guenee) in In-vitro (Laboratory) Conditions

Rice productivity is impaired by sucking, leaf feeding and borer insect pests. Among the leaf feeders, rice leaf folder Cnaphalocrocis medinalis (Guenee) cause significant yield loss. The non-chemical insect pest management is gaining momentum among farmers, and biocontrol management is one of the essential components. The efficacy of entomopathogenic fungi Beauveria bassiana (Balsamo) Vuillemin isolate against C. medinalis was studied using the laboratory culture maintained in rice leaves. Different concentrations of B. bassiana were applied topically on the second instar C. medinalis larvae. The mortality observations were recorded at 48 hrs intervals from the third day and continued up to 11 days. The highest mortality of 78.33% was observed at concentration 1×108 conidia/ml, and the lowest mortality of 36.67% was observed at concentration 1×103 conidia/ml. The determined median lethal concentration (LC50) of B. bassiana (Balsamo) Vuillemin isolate against C. medinalis is 5.44 x 105 conidia/ml