Nematode pests of maize and other cereal crops

Abstract

Maize is the most important cereal crop grown in South Africa, followed by wheat and grain sorghum. Yields of grain crops usually vary considerably between years, mainly due to highly variable rainfall. The most widespread and frequently encountered nematode pests of maize are root-knot nematodes, with Meloidogyne incognita and M. javanica dominating. Lesion nematodes follow, with Pratylenchus zeae generally being the predominant of a range of species from this genus. However, other plant-parasitic nematodes of the families Criconematidae, Dolichodoridae and Hoplolaimidae and species of Longidorus, Nanidorus, Paratrichodorus and Xiphinema have also been recorded from maize-producing areas. The response to treatment with nematicides in field experiments generally has not given consistent results, due in part to fluctuating rainfall. As a result, nematodes are not considered by maize farmers as a primary yield constraint. In contrast with an extensive body of information being available for maize nematodes, limited nematology research has been done on other cereal crops. The most commonly occurring nematode pests associated with barley, grain sorghum, millet, wheat and rice are also referred to in this chapter