INTEGRATED MANAGEMENT OF LATE BLIGHT IN TOMATO USING GENETIC RESISTANCE AND REDUCED RISK FUNGICIDES AND BLITECAST

Tomato is the most popular and second most economically important vegetable crop in the world, the most economically important vegetable crop in the U.S., and the third most economically important vegetable crop in Pennsylvania. Late blight (LB), caused by oomycete Phytophthora infestans, is one of the most devastating diseases of tomato as it can destroy the crop in as few as 5-7 days when conditions are favorable. LB management currently relies on planting disease-free transplants, frequent scouting for early disease detection, use of a protectant fungicide spray program initiated prior to disease onset and subsequent use of LB specific systemic fungicides once the disease is detected in the field or region. The selection and use of resistant cultivars is often considered the first line of defense against plant diseases. For many diseases, the use of resistant cultivars can delay disease development until later in the season thus potentially reducing the number of in-season fungicide applications. Genetic resistance to tomato LB has been of interest for many years and three major resistance genes were previously identified. Recently several breeding lines and cultivars of tomato containing these resistance genes have been developed and released. Research at Penn State has resulted in the identification of two additional resistance genes in a new accession of the tomato wild species Solanum pimpinellifolium. At Penn State, we also have developed several fresh-market and processing tomato lines with LB resistance conferred by one or a combination resistance genes. The objective of this project is to evaluate and compare the response of LB-resistant breeding lines and cultivars of tomato when coupled with different fungicide/ biopesticide programs applied using the LB fungicide scheduling program BLITECAST, delivered through the Pennsylvania Pest Information Platform for Extension and Education (PA-PIPE). BLITECAST uses information on pathogen biology and environmental conditions to assess the potential risk of disease development and therefore determine whether or not a fungicide application is recommended. The PA-PIPE provides the cyber-infrastructure necessary to provide this information at a 6 km grid scale across the state rather than based on individual weather stations. We anticipate that host resistance alone will reduce the LB and that the resistant breeding lines and cultivars containing multiple resistance genes will perform better in the field than currently available commercial cultivars. In turn, these resistant lines/cultivars will also require fewer fungicide applications, thus reducing input costs for the grower and the potential impact of pesticides on the environment. The use of BLITECAST to schedule fungicide/biopesticide applications will facilitate their application on an as-needed basis. In a dry and hot season fewer fungicide applications would be needed compared to a cool wet season that favors disease progress. Delivery of BLITECAST via the PA-PIPE will provide all growers access to this model independent of whether or not they have access to an on-farm weather station.