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In the present investigation, hyperparasitic interaction between B. bassiana, TM (MH590235) and P. xylostella was studied through scanning electron microscopy and chromatographic techniques. Dose–mortality responses showed an increase in mortality of larva with an increase in spore concentration. The LC50 value for B. bassiana isolate TM (MH590235) was 2.4 × 107 spores mL−1. The ditrophic interaction between B. bassiana and P. xylostella after 24 h revealed the adherence of conidia on stemmata, sensory setae, maxillary palpi and legs. After 48 h post-infection (hpi), germination of the conidia and appressorium formation was observed. Formation of hyphae and initiation of fungal networking was observed at 72 hpi. Complete ramification by mycelia and conidiogenesis of B. bassiana was observed over the mycosed cadaver after 168 hpi. Subsequently, typical sympodial conidiophores of B. bassiana bearing secondary spores were also observed. The metabolome profile of healthy larvae of P. xylostella revealed the presence of non-volatile organic compounds (NVOCs) like docosene, nonadecene, palmitic acid and heneicosane. However, the NVOC profile was different in the P. xylostella larvae hyperparasitized by B. bassiana. The metabolites present in the infected cadaver were phthalate esters, hydroxyquebrachamine and lactones. [ABSTRACT FROM AUTHOR]

Bio efficacy of virulent isolate of entomopathogenic fungi, Beauveria bassiana (MK918495) was evaluated against two spotted spider mite, Tetranychus urticae on tuberose under pot culture condition at Insectary, Department of Agricultural Entomology, TNAU, Coimbatore. For effective working of any insect pathogen, it is mandatory to develop an effective formulation. Keeping this point in view, in the present study, compatibility of the fungal isolate with two different oils, viz., ground nut and sunflower were tested at different concentrations, viz., 1, 3, 5 and 10%. The results revealed that the groundnut oil was compatible with B. bassiana at all concentrations with respect to colony growth and spore yield compared to sunflower oil which was compatible only at one percent. Based on the results, oil in water and oil based formulations were prepared. At higher concentration of 10%, groundnut oil recorded the radial colony growth of 36.90 mm diameter and spore yield of 1.2 x 108 spores mL-1. Among the seven formulations (A-G) tested, formulation D which contained surfactant mixture having HLB value of 10.00 (53.33% Tween 80 and 46.67% Span 80) formed a better suspension with less flocculation layer and dispersion of conidia in spray fluid and was found to be better as it formed a good emulsion with water by mere shaking. Results of pot culture studies revealed that groundnut oil based fungal formulation was effective with a cumulative mean mite population reduction of 64.98% followed by crude fungal spore suspension (62.16%) and both were statistically on par with each other. Standard chemical check, Fenazaquin 10% EC @ 1.5 mL L-1 recorded significantly highest population reduction of mites (77.20%). [ABSTRACT FROM AUTHOR]

Entomopathogenic fungi are known to produce a multitude of low molecular weight secondary metabolites involved in different biological processes including fungal development, intercellular communication and interaction with other organisms in complex niches. In the present investigation, heterogeneity in metabolome profile of three isolates of Beauveria bassiana viz., MH590235 (TM), MK918495 (BR) and KX263275 (BbI8) were analyzed through GC-MS. Distinct differences in metabolite profile of the isolates were observed. A total of 63 metabolites were detected from all the isolates combined. Metabolites, 5-Oxotetrahydrofuran-2-carboxylic acid and undecane were found to be specific to BR isolate. Macrocyclic gamma lactones were detected in culture filtrates of BR and BbI8, oleic acid and hexadecanoic acid in TM and BR. An insecticidal compound, levoglucos an was detected in all the fungal isolates. Among the isolates, TM revealed higher variability in the metabolite production through PCA analysis. The metabolome of TM isolate contained compounds having several biological functions, viz., insecticidal and antimicrobial activity, lipid and fatty acid metabolisms and virulence enhancing factors. [ABSTRACT FROM AUTHOR]