Distribution of lesion nematodes associated with maize in Kenya and susceptibility of maize cultivars to pratylenchus zeae

Abstract

The distribution and impact of lesion nematodes (Pratylenchus spp.) in Kenyan maize producing areas were evaluated. Soil and root samples were taken from 120 farms in three districts of Kenya, namely Kakamega, Machakos and Trans Nzoia. Mean populations of Pratylenchus spp. (P. zeae and P. brachyurus) in 5 g roots were 280, 131, and 6 in Kakamega, Machakos and Trans Nzoia districts, respectively. Lesion nematodes were recovered from 73.3% of the samples. P. zeae and P. brachyurus had overall incidences of 72.5 and 6.7%, respectively. Greenhouse tests were conducted to determine the effects of P. zeae on growth of seven maize genotypes used in Kenya, Dryland composite 1, Katumani composite, and hybrids 511, 512, 614, 625 and Pwani. Numbers of P. zeae extracted from 5 g roots were significantly (P< 0.05) different and ranged between 6230 in hybrid 614 and 10970 in Katumani composite. The nematode caused significant (P < 0.05) reduction in root weight of Katumani composite, Dryland composite 1, hybrid 511 and hybrid 512. Nematode infection significantly (P < 0.05) reduced shoot weight of Pwani hybrid and height of Dryland composite 1.