Effect of preceding and intercropping crops on suppression of lentil damping-off and root rot disease in New Valley - Egypt

Rhizoctonia solani and Fusarium solani were isolated from diseased lentil roots showing damping-off and root rot collected from different locations of New Valley governorate. R. solani isolate R-1 and F. solani isolate FS-9 were the highest virulent isolates. The influence of some agricultural factors on severity of damping-off and root rot disease was studied under greenhouse and field conditions. Intercropping cumin, anise, onion and garlic significantly decreased damping-off and root rot disease and increased seed yield. Anise has the greater effect than other crops, while intercropping onion showed the lowest effect. All tested preceding crops planted before lentil decreased disease severity and population of the tested fungi except in case of soybean and groundnut which increased percentage of disease severity as well as populations of the tested fungi in soil. Cowpea and gaur cultivated before lentil gave the highest decrease in disease severity. On the other hand, lentil cultivated after cowpea produced the highest seed yield followed by gaur and millet. Lowest seed yield production was recorded when plants were cultivated after soybean followed by sesame and groundnut. The lowest population of R. solani was recorded when cowpea cultivated before lentil, while, cultivating sorghum before lentil resulted in the lowest population of F. solani. Root exudates of intercropping and preceding crops reduced mycelial dry weight of the tested fungi in vitro except groundnut and soybean. Crown Copyright (C) 2011 Published by Elsevier Ltd. All rights reserved.