Plant parasitic nematodes associated with cabbages in Kenya.

Abstract

A survey was conducted in 22 farms in Kiambu and Kajiado districts to study the nematode associated with cabbage. Roots were rated for galls using a scale of 0 – 10. Roots were stained in Phyloxine B and in NaOCl-acid fuchsin for egg mass and endoparasite detection. Some roots were macerated for nematodes assays. A 200g soil sample per farm was assayed for nematodes. The study revealed that cabbage is a poor host of root knot nematodes (RKN) with 0 – 40% of the root systems galled and very few egg masses. The roots were predominantly infected by lesion nematodes (Pratylenchus spp.), having a 56% frequency of occurrence. The species detected included Pratylenchus brachyurus, P. zeae, P. scribneri, P. neglectus and P. loosi. The lesion nematodes were also detected in soils with a frequency of occurrence of 64%. Meloidogyne spp were detected in both the roots and soil at a frequency of occurrence of 26 and 14%, respectively. Tylenchorhynchus and Belonolaimus spp, potentially serious nematodes of vegetables were also recovered in significant numbers. The spiral nematodes; Scutellonema, Helicotylenchus and Hoplolaimus spp. were detected in soil with a frequency of occurrence of up to 77%. The stubby root nematodes (Trichodorus and Paratrichodorus spp) were present in 65% of the farms. Other nematodes detected included Xiphinema, Longidorus, Criconemoides, Hemicriconemoides and Hemicycliophora, Tylenchus, Coslenchus, quinisulcus, Polenchus and Paratylenchus spp. Although Filenchus spp. were detected in about 73% of the farms, it has not been reported as a serious pest of cabbage.