Effect of Trichoderma harzianum and fungicides on plant growth and intensity of collar rot of elephant foot yam (Amorphophallus paeoniifolius).

摘要

The effects of fungicides and T. harzianum on the performance of A. paeoniifolius (cv. Gajendra) and on the incidence of collar rot (caused by Sclerotium rolfsii [Corticium rolfsii]) were studied in Jorhat, Assam, India, during 1999 and 2000. Before planting, corms were treated with T. harzianum conidial suspension (109 conidia/ml) overnight and dried in the shade. For the fungicide treatment, corms were treated with 0.2% solutions of captan and carbendazim for 30 minutes. T. harzianum on wheat bran was also applied to soil at 20 g per plant during planting, and at 30 and 45 days after planting (DAP). Captan (0.1%) and carbendazim (0.1%) were also applied as soil drench at 500 ml per plant. The population densities of T. harzianum and S. rolfsii in the rhizosphere of A. paeoniifolius were evaluated at 30, 45, 60 and 75 DAP. Observations on plant growth and yield parameters were recorded from 30 to 75 DAP at 15-day intervals. Soil treatment was more effective than corm treatment in the enhancement of plant height, canopy size and yield, and in the reduction of disease intensity, but the combination between both application methods was the most effective. A negative correlation between the population of S. rolfsii and the population of T. harzianum was observed except at 30 DAP. All the treatments were superior to the control in reducing the disease intensity. The combination of corm and soil treatment with T. harzianum recorded the lowest relative disease intensity (9.43) and the highest yield (35.67 t/ha).