Effect of soil solarization on population dynamics and disease causing potential of Fusarium oxysporum f.sp. dianthi, the incitant of Fusarium wilt of carnation

摘要

Carnation wilt caused by Fusarium oxysporum f.sp. dianthi is the most damaging disease resulting upto 79 per cent incidence of plant mortality in Himachal Pradesh. The present study was conducted in two sets of experiments. In one set, nylon sieve bags containing the mass culture of wilt pathogen buried in the soil were subjected to solarization for different durations of 20, 30 and 40 days at different depths (5 and 15 cm) under transparent polyethylene sheet and unsolarized conditions. Soil solarization with transparent polyethylene sheet for 40 days resulted in increase of 8.2°C and 6.7°C in average maximum soil temperature at 5 and 15cm during the period of solarization. Soil solarization of the culture of wilt pathogen with transparent polyethylene sheet at 5 cm soil depth for 40 days was found most effective and resulted in 83.76 per cent reduction in viable propagules of the wilt pathogen in comparison to unsolarized beds at same depth. In second set, the retrieved culture of wilt pathogenof different durations and soil depths were mixed in sterilized soil in the earthen pots planted with rooted carnation cuttings. SS of the culture of wilt pathogen retrieved from different soil depth after 20, 30 and 40 days resulted in 16.66,40.01 and66.67 per cent reduction in the wilt incidence in comparison to unsolarized plots. In general, soil solarization had a significant effect on delaying the average incubation period, which was delayed to 85.19 days, respectively in comparison to 61.60 daysin the pots containing culture of wilt pathogen retrieved from unsolarized pots.