Integrated management of Fusarium wilt of chickpea (Cicer arietinum L.) caused by Fusarium oxysporum f. sp. ciceris with microbial antagonist, botanical extract sp. ciceris with microbial antagonist, botanical extract

The present study was carried out to assess the efficacy of an integrated management strategy for Fusarium wilt of chickpea that combined the use of microbial antagonist, botanical extract and fungicide. Before setting the experiment in field micro plots, a series of in vitro and in vivo experiments were conducted to select a virulent isolate of F. oxysporum f. sp. ciceris, an effective antagonistic isolate of Trichoderma harzianum, a fungitoxic botanical extract and an appropriate fungicide. The isolate FS1 of F. oxysporum f. sp. ciceris appeared to be most virulent to chickpea cultivar BU-Chola-1 and selected as test pathogen. Among the 20 isolates screened, T. harzianum isolate T-75 showed the highest (75.89%) inhibition of the radial growth of F. oxysporum f. sp. ciceris in dual culture assay on PDA. Absolute inhibition (100.00%) of colony growth of F. oxysporum f. sp. ciceris was observed where fungicide Provax-200 at 100 ppm was used. Azadirachta indica leaf extract gave maximum inhibition (55.19%) of radial growth of F. oxysporum f. sp. ciceris at all concentrations. The integration of soil treatment with T. harzianum isolate T-75 and Az. indica leaf extract and seed treatment with Provax-200 appeared to be significantly superior in reducing Fusarium wilt and in improving seed yield of chickpea compared to any single or dual application of them in the field. The results of this study exhibit the importance of integrating selective microbial antagonist, botanical extract and fungicide to achieve appropriate management of Fusarium wilt and increase of seed yield in chickpea in Bangladesh.Keywords: Integrated management, Fusarium wilt, Fusarium oxysporum f. sp. ciceris, chickpea (Cicer arietinum L.), antagonists, botanicals, fungicides.African Journal of Biotechnology Vol. 12(29), pp. 4699-470

Biocontrol efficiency of microencapsulated Trichoderma harzianum coupled with organic additives against potato stem rot caused by Sclerotium rolfsii

Potato (Solanum tuberosum L.), world's fourth most carbohydrate supplying crop is often challenged by numerous pathogens among which Sclerotium rolfsii remains one of the most damaging during both growth and storage. As biocontrol is being preferred for their safety and sustainability, the present experiment was conducted for testing the biocontrol effectiveness of microencapsulated Trichoderma harzianum application in combination with organic additives against S. rolfsii. Five combinations (no T. harzianum+no organic additive [control]; T. harzianum+no organic additive; T. harzianum+rice husk biochar; T. harzianum+mustard oil cake; and T. harzianum+tea waste) were tested against two levels of S. rolfsii (absence [control] and presence) under a polyhouse environment. Prior to that, hyper-parasitism of T. harzianum against S. rolfsii was tested in vitro which showed 63.2% growth inhibition for the later. Polyhouse study revealed 16%, 25%, 19%, 21%, 38%, 27%, 9%, 13%, 28%, 20% and 9% average increase in plant height, branch number plant–1, leaf number plant–1, shoot dry matter, root dry matter, healthy tuber, total tuber yield, leaf greenness, net photosynthetic rate, total phenolic content and total antioxidant activity respectively with a subsequent reduction of 49% unhealthy tuber and 32% disease severity index due to T. harzianum+organic additive treatments. Disease suppression and growth recovery of S. rolfsii inoculated potato plants were found significantly better when T. harzianum was applied with organic additives compared to solitary application. The results of this study would provide useful information in strategizing T. harzianum formulation preparation for effective biocontrol of potato stem rot caused by S. rolfsii