Crop-induced bio-ecological variations in Rotylenchulus reniformis

The effect of nine different crops (okra var. Pusa Sawani, bottle gourd var. Pusa Summer Prolific Long, chilli var. Pusa Jwala, cotton var. H-777, cowpea var. Pusa Komal, maize var. Ganga-5, soybean var. Pusa-24 and castor) on the various bio-ecological features of single egg-mass progeny of Rotylenchulus reniformis was studied. Population development, sex-ratio and fecundity of this nematode varied greatly from crop to crop. The maximum increase in population was recorded on bottle-gourd (12.6 times) followed by castor and okra while the decline in population was observed on chilli, cotton and maize. Most of the good host crops shifted the initial male-female ratio of 1:2 towards the higher number of females ie. 1:5.1 to 1:6.9, whereas the reverse trend was observed on poor host crops. Fecundity was maximum (112 eggs/egg-mass) on bottle gourd and minimum on cotton (19 eggs/egg-mass). The studies indicated large crop-induced intra-specific bio-ecological variability in R. reniformis.