Cultural Practices and their Effects on Heterodera avenae and Grain Yields of Wheat in Victoria, Australia1

Abstract

The effects of various cultural practices on cereal cyst nematode (Heterodera avenae) populations, and the subsequent yield of wheat, have been studied over many seasons in Victoria, Australia. Crop rotations which include periods of fallow, or of non‐host crop reduce population levels and improve yields. The inclusion of a legume has the additional advantage of improving soil nitrogen levels. Early sown crops (April/May) are less severely damaged, and produce better yields, than late sown crops (June/July). The resowing of damaged wheat crops with either wheat or barley is not effective in improving yields, although cyst numbers are lower on resown crops. Nitrogenous fertilisers are not generally applied to cereals, and although small increases in yield are sometimes obtained, they are rarely economic. Sulphate of ammonia applications increase cyst numbers, especially when applied at seeding, but urea has only a marginal effect on cyst numbers.