Adaption of potato late blight prediction models for New Zealand

Abstract

Current management of potato late blight (caused by Phytophthora infestans) in the Pukekohe district is by frequent application of fungicides but consumer concerns over chemical use may require more accurate targeting of spray applications to times of greatest disease risk Decision support systems incorporating potato late blight infection models have the potential to assist growers in modifying management practices Outputs of two overseas models and one developed locally were compared using data from two weather stations at Pukekohe (severe late blight area) and Lincoln (low disease risk) over the 2003/04 growing season Two of the models were too sensitive for Pukekohe conditions but the Smith model developed in the United Kingdom gave usable results No attempt was made to verify the performance of the models under field conditions