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.
Shoot and fruit borer, Earias vittella (Fab.) is commonly encountered and economically important insect pest on okra (bhendi). Experiments were carried out to investigate the antifeedent and mortality activities of panchagavya alone and in combination with plant extracts against E. vittella in the laboratory and to evaluate the effectiveness in the field during rabi and kharif 2017 at C. Mutlur, Chidambaram. This study assessed five binary botanical extracts mixture with panchagavya used in vitro which included extracts containing panchagavya, neem leaf extract (NLE) 5%, Prosophis leaf extract 5%, Calotropis leaf extract 5%, Pungam oil 3% and NSKE 5%. Fruit disc no-choice methods were performed in a laboratory using bhendi fruit to determine the antifeedant activity and per cent mortality. Results indicated that all binary mixtures showed antifeedant activity and highest recorded was in NLE (5%) + panchagavya (3%) (65.11%) and was on par with NSKE (5%) (64.84%) and the highest mortality was recorded in panchagavya (3%) + NSKE (5%) (83.33%) followed by pungam oil 3% + panchagavya 3% (66.67%) and NLE 5% + panchagavya 3% (53.33%). Field studies indicated that highest per cent reduction of E. vittella was recorded in panchagavya (3%) + Neem Seed Kernel Extract (NSKE) (5%) treated plot followed by pungam oil 3% + panchagavya 3% and Neem Leaf Extract (NLE) 5% + panchagavya 3%. The field studies demonstrated that NSKE 5% in combination with panchagavya were effective in the management of E. vittella and could be an efective alternative to synthetic pesticides.
Abundance of natural enemies in mango ecosystem was studied through survey and surveillance. In order to record the natural enemies associated with mango ecosystem surveys were conducted in mango orchards in and around Malihabad block of Lucknow for two years. During the study period ten species of coccinellids and two species of chrysopid predators were recorded. The activity of lady bird beetles was noticed in mango orchard during first week of March to last week of March (10 to 13th Standard Meteorological Week (SMW) of 2016). Lady bird beetles, Coccinella septempunctata, C. transversalis, and Menochilus sexmaculata, were found in abundance and their population counts were taken. Peak populations of coccinellids were observed during 12th SMW with 3.3 adult beetles/panicle. Six species of parasitoids were collected from the mango ecosystem, among them; the most abundant parasitoid was Brachymeria lasus, parasitizing mango leaf webber. It was evident that wherever indiscriminate use of insecticides was undertaken, natural enemy population was very low. In unprotected orchards abundant natural enemies were recorded. In order to achieve natural control of the pest it is advised that the orchardists adopt minimal spray may be taken up.
Chilli (Capsicum annum L.) an important economic crop worldwide is severely infected by fruit rot disease which may cause yield losses of up to 100%. Although different chemical fungicides are being recommended and used for the management of the disease, biocontrol-based strategy attracts considerable attention and offers great potential of novel biocontrol agents. Further, biological control methods for chilli fruit rot/anthracnose disease have not received much attention. Therefore, an investigation was carried out to assess the efficacy of different biological control agents against chilli fruit rot/anthracnose disease. Antagonistic yeast isolates Pichia guillermondii (Y-12), Hanseniaspora uvarum (Y-73) and Trichoderma asperellum (Th-3), Pseudomonas fluorescens (Pf-1) were tested through seed treatment, seedling dip and foliar spray at concentration of 2 × 108 cfu/g. The pathogens viz., Colletotrichum capsici, Alternaria alternata and Periconia byssoides were found associated with fruit rot during the study. Lowest mean disease intensity (MDI), highest disease control (DC) over untreated control was recorded in the treatment <i>P. guillermondii</i> (Y-12) (5.39% MDI, 64.72% DC) and this was found at par with the treatment <i>P. fluorescens</i> (Pf-1) (5.92% MDI, 65.52% DC). However, <i>T. asperellum</i> (Th-3) showed satisfactory results. The present study highlights the efficacy of antagonistic yeast species against chilli fruit rot pathogens and these findings serve as base for further exploration and exploitation of yeast species for eco-friendly management of crop diseases.