Evaluation of different fungicides, bioagents and botanicals against Alternaria blight caused by Alternaria helianthi (Hansf) of sunflower

Abstract

Alternaria blight (Alternaria helianthi Hansf) is one of the major diseases of sunflower during Kharif season in Maharashtra. Present Lab study was conducted at Department of Plant Pathology and field experiment at Oilseed Research Station, College of Agriculture, Latur, VNMKV, Parbhani, Maharashtra, India. Here, six fungicides were evaluated at 500, 1000, 2000 and 2500 ppm; five botanicals each at 10 and 20%) by poisoned food technique and readymade formulations of four bioagents; three fungal antagonists were evaluated in vitro and in vivo against A. helianthi- an incitant of Alternaria blight; in sunflower all the treatments were found fungistatic and significantly inhibited mycelial growth and disease intensity of the test pathogen over untreated control. Among the fungicides, maximum inhibition was observed in treatment with SAAF at 2000 ppm (90.36%), followed by Mancozeb at 2500 ppm (88.88%). Among botanicals, maximum inhibition was recorded with Neem (63.05 and 68.88%) in addition to Karanj (56.38 and 63.60%) at 10 and 20% concentrations. Fungal bioagents, T. harzianum was found most effective and recorded maximum mycelial growth inhibition (72.22%), followed by T. viride (70.27%). Bacterial antagonist P. fluorescens was found comparatively least effective with 48.60% inhibition of the test pathogen. After lab study, effective treatments was tested on field condition; results revealed that fungicide seed treatment with SAAF at 3 g/kg seed + two sprays of SAAF at 0.2% at 30 and 45 DAS recorded highest disease control (82.82%) and highest seed yield (1686 kg/ha) followed by seed treatment with SAAF 12% at 3 g/kg seed + two sprays of Mancozeb at 0.25% at 30 and 45 DAS recorded disease control (78.50%) and seed yield (1595 kg/ha) over untreated control (00.00) (792 kg/ha). Minimum disease control (45.25%) was recorded in seed treatment with Neem seed powder at 10 g/kg + two sprays of Neem extract at 10% at 30 and 45 DAS with 908 kg/ha yield.   Key words: Alternaria helianthi, sunflower, fungicides, bioagents, botanicals, management.