Field efficacy of different combinations of Trichoderma harzianum, Pseudomonas fluorescens, and arbuscular mycorrhiza fungus against the major diseases of tomato in Uttarakhand (India)

Abstract

Tomato is one of the major cash crops in the Golapar area of district Nainital in Uttarakhand (India), where farmers are facing the problem of diseases in tomato cultivation. In the present investigation, a survey of tomato fields in the Golapar area of Haldwani block was conducted. The survey revealed the occurrence of late blight, early blight, stem rot, and wilt diseases causing an average loss of 80% to tomato. To counter the above diseases, Trichoderma harzianum (Th43), Pseudomonas fluorescens (Pf173), Jas mycorrhiza (AMF), and the fungicide (Mancozeb) in different combinations applyed through soil application (SA), seedling treatment (ST), and foliar spray (FA) were evaluated for growth promotion and disease control in tomato at experimental and farmers’ fields. The results of the study revealed that in experimental field, the maximum plant height (43.67 cm), highest number of branches (7.33) per plant, highest weight of fruit (47 g), highest number of fruits (39) per plant, minimum plant mortality (4% at 30 DAT and 3.2% at 30–60 DAT), minimum plant disease index (6.85), maximum total yield (256.00 q/ha), and marketable yield (246.67 q/ha) were observed in Th+Pf+JM (SA) + Th+Pf (ST) + Mancozeb (FS). At farmer’s field, minimum plant mortality (7.31%) at 30 days after transplanting (DAT) (5.73%) in 30–60 DAT, minimum plant disease index (11.47), and maximum yield 249.91 q/ha were observed in Th+Pf+JM (SA) + Th+Pf (ST) + Mancozeb (FS) combination. So, it can be concluded that among all the treatments, integrated treatment comprising of soil application of T. harzianum , P. fluorescens , Jas mycorrhiza (AMF) + seedling treatment with T. harzianum and P. fluorescens + three foliar sprays of Mancozeb was found very effective in reducing the plant mortality, promoting the plant growth, and increasing the yield at experimental field as well as at farmers’ fields.