In vitro Studies on Efficacy of Some Plant Extracts and Biocontrol Agents against Lasiodiplodia theobromae and Lasiodiplodia pseudotheobromae

Abstract

Stem-end rot of mango caused by Lasiodiplodia theobromae and Lasiodiplodia pseudotheobromae is a major post-harvest problem in Manipur and reduces yield. An experiment on antifungal efficacy of three plant extracts viz., Garlic (Allium sativum), Neem (Azadirachta indica) and Ginger (Zingiber officinale) was done through poisoned food technique by taking three concentrations in in vitro conditions against the pathogens and eight Trichoderma isolates viz., T. ovalisporum (KU904456), T. koningiopsis (KU904460), T. harzianum (KU904458), T. atroviride (KU933472), T. harzianum (KU933474), T. asperellum (KU933475), T. asperellum KU933476) and T. hypocrea (KX0113223) were evaluated against the pathogens through production of non-volatile (Dennis and Webster, 1971a) and volatile Dennis and Webster, 1971b) compounds The results revealed that among plant extracts, the highest inhibition for Lasiodiplodia theobromae was shown by garlic at 1.25, 2.5 and 5 per cent of 100 per cent and for Lasiodiplodia pseudotheobromae, the highest inhibition was showed by garlic at 5 per cent of 81.17 per cent. Effect of volatile compounds produced by Trichoderma spp against Lasiodiplodia theobromae showed maximum percentage inhibition with isolate T. asperellum (KU933476) of 95.24 per cent and T. hypocrea (KX0113223) least by 68.52 per cent. Effect of volatile compounds produced by Trichoderma spp against Lasiodiplodia pseudotheobromae showed maximum percentage inhibition with isolate T. ovalisporum (KU904456) of 12.39 per cent and no inhibition was observed by T. asperellum (KU933475), T. atroviride (KU933472), T. harzianum (KU933474), T. harzianum (KU933458), T. koningiopsis (KU904460), and T. hypocrea (KX0113223) against the pathogen. Effect on non-volatile compounds produced by Trichoderma spp. at two different concentrations viz., 7.5% (volume/volume) and 15% (volume/volume) against Lasiodiplodia theobromae showed 42.36 to 82.40 per cent at 7.5% volume/volume concentration and 53.70 to 100.00 per cent at 15% volume/volume concentration, In Lasiodiplodia pseudotheobromae, results showed 3.59 to 56.31 per cent at 7.5% volume/volume concentration and 44.47 to 100.00 per cent at 15% volume/volume concentration Present study suggests that Garlic and Trichoderma spp. could be tried for the eco-friendly management of the diseases.