Influence of crop growth and weather conditions on speckled leaf blotch in winter wheat

Abstract

Speckled leaf blotch (SLB) a foliar disease of winter wheat caused by Septoria tritici (teleomorph Mycosphaerella graminicola) can cause significant yield losses Wheat crops are at greatest risk during stem extension when the final three leaves emerge in close proximity to infected leaves lower in the canopy Winter wheat cv Consort was sown in May 2002 to test a model that links development of SLB in the field to weather events and to compare disease severity between plots treated with fungicide applied at three different crop growth stages Generally quite low disease levels were experienced associated with a small number of likely infection events This meant that the top three leaves were infected after they were fully emerged and SLB severity was low as there was little time for secondary cycles to occur before the leaves senesced Despite low disease severity there was a significant yield response to applied fungicide increasing with the number of applications The model requires some improvement