Evaluation of In Vitro Efficacy of Commercial Fungicides Against Alternaria Alternata Isolates Causing Leaf Spot on Populus Deltoides

Abstract

Poplar is the one of the domesticated forest trees in India and has better synergy with agriculture system than forestry operations. Populus deltoides have shown great promise in north-western part of India. Many a times, single clone of poplars have been propagated extensively. Ninety per cent of the total planted poplar comprises of clones G-48, WSL-22, WSL-39, Udai, WSL-32, Wimco81 and S7C15 in the states of Punjab, Haryana, Uttarakhand and Uttar Pradesh. High incidence of Alternaria leaf spot was noticed on different commercial clones of P. deltoides (G-48, Udai, WSL-22 and WSL-39) during surveys in poplar nurseries (2009-11). The most common method of managing plant diseases is use of fungicides. In vitro efficacy of two fungicides, namely, propiconazole (systemic) and chlorothalonil (non-systemic) was tested against Alternaria alternata isolates using poisoned food technique. It was observed that propiconazole was more effective in suppressing the growth of the fungus than chlorothalonil as cent per cent inhibition was achieved for all the isolates at 40ppm. On the other hand, cent per cent inhibition of growth was achieved for only four isolates, no. A15, A24, A41 and A47 at highest concentration of 400ppm of chlorothalonil. The study indicated that propiconazole proved to be effective at a very low concentration of 40ppm against A. alternata under in vitro conditions.