Population dynamics of reniform and root-knot nematodes on tomato, cowpea, squash, sweet pepper, and watermelon
1995
Castillo, M.B. | Pamorntip, A. (Philippines Univ. Los Banos, College, Laguna (Philippines). Dept. of Plant Pathology)
Fortnightly recoveries of Rotylenchulus reniformis and Meloidogyne incognita starting at 2 weeks until the 18th week of cropping in field soil showed that tomato, cowpea and squash were susceptible to both nematodes, while sweet pepper and watermelon were resistant. Much higher populations were obtained from the susceptible than the resistant crops. Populations on the latter remained low throughout the sampling periods. On susceptible crops, initial populations remained relatively low and changed only slightly during the first 6 weeks, then drastically increased starting from the 8th for R. reniformis and the 10th week for M. incognita. These increases could be attributable to more root developments and nematode reproduction. The first life cycle of R. reniformis on tomato and cowpea appeared to be completed within the 6th to 8th week; that of M. incognita, within the 8th to 10th week. Except on cowpea, where M. incognita density peaked on the 14th week, the peak periods of both nematodes occurred on the 12th week. The drastic decline in populations from the peak periods until the 16th week could be related to food competition and crop senescence. The marked increase in populations of both nematodes from the 16th to the 18th week was probably due to the unusual heavy rains that occurred during these periods, which could have stimulated egg hatching
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