Chemo-profiling of Purpureocillium lilacinum and Paecilomyces variotii isolates using GC-MS analysis, and evaluation of their metabolites against M. incognita.

Nematophagous fungi are the best alternatives to chemical nematicides for managing nematodes considering environmental health. In the current study, activity of metabolites from ten isolates of Purpureocillium lilacinum (Thom) Luangsa-ard (Hypocreales: Ophiocordycipitaceae) and two isolates of Paecilomyces variotii Bainier (Eurotiales: Trichocomaceae), were examined to inhibit the hatching of Meloidogyne incognita (Kofoid & White) Chitwood (Tylenchida: Heteroderidae) eggs. At 100%, 50%, and 25% concentrations, respectively, the culture filtrate of the isolate P. lilacinum 6887 prevented 97.55%, 90.52%, and 62.97% of egg hatching. Out of all the isolates, Pl 6887, Pl 6553, and Pl 2362 showed the greatest results in the hatching inhibition experiment.Gas chromatography-mass spectrometry (GC-MS) analysis revealed a variety of nematicidal compounds from different isolates. A total of seven nematicidal compounds, including four very potent nematicidal fatty acids were found in the isolate Pl 6553. Secondary metabolites of the same isolate possess the highest M. incognita juvenile mortality, i.e., 43.33% and 92% after 48 hrs of treatment at 100 and 200 ppm concentrations, respectively. Significant difference was observed in juvenile mortality percentage among the isolate having highest and lowest nematicidal compounds. Nematicidal fatty acids like myristic and lauric acid were found for the first time in P. lilacinum. Multiple vacuole-like droplets were found inside the unhatched eggs inoculated with the culture filtrate of isolate Pl 6887, and also in the juveniles that perished in the ethyl acetate extract of isolate Pl 6553.

Destructive Phytophthora on orchids: current knowledge and future perspectives.

Anton de Bary first coined the genus, Phytophthora, which means "plant destroyer", viewing its devastating nature on potatoes. Globally plants have faced enormous threat from Phytophthora since its occurrence. In fact, a century ago, Phytophthorapalmivora was first reported on Dendrobium maccarthiae in Sri Lanka. Since then, members of beautiful flowering crops of the family Orchidaceae facing the destructive threat of Phytophthora. Several Phytophthora species have been recorded to infect orchids with economic loss worldwide. To date, orchids are attacked by 12 species of Phytophthora. Five Phytophthora species (P. palmivora, P. nicotianae, P. cactorum, P. multivesiculata, P. meadii) are the major pathogenic Oomycetous Chromista" rather than true fungi frequently occurred on Orchidaceae. Phytophthora palmivora (having ~32 orchid host genera in 15 countries), Phytophthora nicotianae (having ~15 orchid host genera in 16 countries), Phytophthora cactorum (having ~43 orchid host genera in 6 countries), Phytophthora multivesiculata (having 2 orchid host genera in 5 countries) and Phytophthora capsici (having 2 orchid host genera in all Vanilla growing countries) are potential destroyers of Orchidaceae. Most of them are water loving Oomycetes cause disease in moist environments (> 80% RH) at 16-28°C. In artificially constructed orchidaria, anthropogenic factors are mostly contributed to the dissemination Phytophthora diseases in addition to many other factors. Water management, clean cultivation, and agro-chemicals are the major options for effective management of orchid Phytophthora, as the eco-friendly management options like development of resistant hybrids/cultivars, biological disease management, transgenic approaches, RNAi technology remained in the infant stage. In this review, we intended to highlight the insight of Phytophthora diseases associated with the orchid disease with reference to the historical aspect of the diseases, symptoms and signs, the pathogens, taxonomy, geographic distribution, host range within the Orchidaceae, pathogen identification, molecular diagnostics, mating types and races, management options and strategies and future perspectives.

Performance appraisal of Trichoderma viride based novel tablet and powder formulations for management of Fusarium wilt disease in chickpea.

In developing a Trichoderma viride-based biocontrol program for Fusarium wilt disease in chickpea, the choice of the quality formulation is imperative. In the present study, two types of formulations i.e. powder for seed treatment (TvP) and tablet for direct application (TvT), employing T. viride as the biocontrol agent, were evaluated for their ability to control chickpea wilt under field conditions at three dosages i.e. recommended (RD), double of recommended (DD) and half of recommended (1/2 RD). A screening study for the antagonistic fungi strains based on volatile and non-volatile bioassays revealed that T. viride ITCC 7764 has the most potential among the five strains tested (ITCC 6889, ITCC 7204, ITCC 7764, ITCC 7847, ITCC 8276), which was then used to develop the TvP and TvT formulations. Gas Chromatography-Mass Spectrometry (GC-MS) analysis of volatile organic compounds (VOCs) of T. viride strain confirmed the highest abundance of compositions comprising octan-3-one (13.92%), 3-octanol (10.57%), and 1-octen-3-ol (9.40%) in the most potential T. viride 7764. Further Physico-chemical characterization by standard Collaborative International Pesticides Analytical Council (CIPAC) methods revealed the optimized TvP formulation to be free flowing at pH 6.50, with a density of 0.732 g cm-3. The TvT formulation showed a pH value of 7.16 and density of 0.0017 g cm-3 for a complete disintegration time of 22.5 min. The biocontrol potential of TvP formulation was found to be superior to that of TvT formulation in terms of both seed germination and wilt incidence in chickpea under field conditions. However, both the developed formulations (TvP and TvT) expressed greater bioefficacy compared to the synthetic fungicide (Carbendazim 50% WP) and the conventional talc-based formulation. Further research should be carried out on the compatibility of the developed products with other agrochemicals of synthetic or natural origin to develop an integrated disease management (IDM) schedule in chickpea.