Biology and control of cereal cyst nematode in northern New South Wales

Abstract

Cereal cyst nematode, Heterodera avenae Woll., has been found on four farms in the northern, summer-dominant rainfall, region of New South Wales. Studies on the relationship of its life cycle to season indicate a pattern similar to that in southern, winter-dominant rainfall regions. Eggs collected from the field in January hatched best at low temperatures (5, 10¦C). We suggest that this low temperature requirement prevents wasteful hatching after rain in summer in the north. Fungal parasitism of eggs and larvae was observed in the field but its significance in the ecology of the nematode in the north remains to be investigated. Five wheat and a barley cultivar resistant to H. avenae in the south resist the northern population; this suggests that the pathotype is the same as that in the south. The nematode produces large numbers of cysts on all wheats grown widely in the region; two of five barleys, and all of three oat cultivars showed some resistance. Control of H. avenae in a nematicide trial on one of the region's main soil types (black earth) increased yield of wheat (cv. Kite) by 45-68%. The nematode's potential effect on wheat production in northern Australia is discussed.