Eco-friendly management of Colletotrichum gloeosporioides, incitant of fruit rot of guava (Psidium guajava)

Abstract

The present study was conducted at Tej Narayan Banaili College, T.M. Bhagalpur University, Bhagalpur, Bihar during 2015-2017 to evaluate the efficacy of 8 medicinal plants viz. Datura stramonium (datura), Curcuma longa (turmeric), Azadirachta indica (neem), Zingiber officinale (ginger), Allium sativum (garlic), Ocimum sanctum (tulsi), Nyctanthus arbortristis (harsringar) and Piper betle (betel/paan) and 4 bioagents viz. Trichoderma harzianum, T. viride, Gliocladium virens and Chaetomium globosum against Colletotrichum gloeosporioides (Penz.) Penz. & Sacc., an incitant of fruit rot disease of guava (Psidium guajava Linn.). A maximum inhibition of mycelial growth of pathogen was recorded in garlic clove extract (80%) followed by betel leaf extract (76%), turmeric rhizome extract (74%), neem leaf extract (70%) and ginger rhizome extract (64%). Harsringar leaf extract was found as the least effective (56%). In pre-and post-inoculation tests, all the phytoextracts were found significantly superior in reducing Colletotrichum rot severity on 7 days after treatments as compared to control. Garlic clove extract again proved highly effective in reducing fruit rot severity after 7 days after inoculation in both pre - and post - inoculation treatments. In vitro dual culture experiments, maximum growth inhibition was recorded with T. viride (76.5%) followed by G. virens (72.2%), T. harzianum (67.6%) and least inhibition by C. globosum (44.7%) In both pre - and post- inoculation treatments with antagonists, maximum DRI (disease reduction index) was noticed with C. globosum (69.2 and 62.4%) followed by T. harzianum (51.9 and 56.7%), G. virens (44.8 and 46.9%) and least with T. viride (38.1 and 35.4%). The rot incidence at 8 DAI (days after inoculation) was significantly higher than that at 4 DAI. The hot water fruit dip treatment at 50OC for 5 min was found best for controlling the rot without hampering the fruit quality.