On the feasibility of chemical control of diseases of barley and wheat varieties grown at several environments
1985
Hadjichristodoulou, A. | Kari, A. (Agricultural Research Inst., Nicosia (Cyprus))
Disease control through foliar application or seed treatment with chemicals was studied in a number of trials during 1968-84, using several barley and wheat varieties. The most important diseases were: leaf rust, net blotch, powdery mildew and scald for barley, and leaf rusts for wheat. Disease incidence in wheat was lower than in barley. In general, disease incidence was low, except under irrigation or high rainfall conditions. In barley, leaf rust, powdery mildew and scald were controlled by foliar applications of Dithane Z-78 (zineb) and Bayleton 25WP but their effect varied with variety, location and year. Seed treatment with Baytan Universal was not effective in most cases. Disease incidence and yield losses were higher in barley than in wheat. Spraying increased yield of barley by up to 56%, depending on variety and environment, but in most dryland trials there was no significant difference in yield between sprayed and control plots. Control of diseases increased yield more in some varieties than others, indicating variation in tolerance levels among varieties. Athenais appeared tolerant to leaf rust. Sheaf weight, volume weight and 1000-grain weight were also affected by diseases, but number of tillers, and number of grains per spike were not affected. It is concluded that under rainfed conditions in Cyprus it is not economically justifiable to control cereal diseases chemically. However, breeding, cultural practices and other strategies should be used to control diseases in order to achieve high and stable yields under both low and high rainfall conditions
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