Molecular Mechanisms of Fungicide Resistance in Sclerotinia homeocarpa

Multiple fungicides are applied to control dollar spot, however, the repeated use of fungicides has led to the development of resistance in S. homoeocarpa to different fungicide classes. Resistance to benzimidazole and dicarboximide classes and reduced sensitivity to DMI fungicides have been reported in field populations. Benzimidazole and dicarboximide resistance is governed by non-synonymous polymorphisms in the respective target genes, which reduce fungicide-binding affinity to the target site. Fungicide efflux via overexpression of an ABC-G transporter(s) is one of the mechanisms for reduced S. homoeocarpa sensitivity to multiple fungicides including DMIs. We investigate other factors that detoxify fungicide molecules using molecular and genomic techniques to a better understanding of fungicide resistance mechanisms in S. homoeocarpa.

Impact of  Soil Microbes and Nematodes on Turf Quality and Disease Suppression

Soil ecology has an impact on plant health, including turf grass.  Not only are pathogenic microbes and nematodes found underground, but also beneficial organisms that can influence plant health by reducing the number of pathogens or priming plant immune systems.  There is a lot of interest in using beneficial organisms to control turf diseases to reduce pesticide usage.   More and more products are being released with the aim of adding specific bacteria, fungi, and nematodes with potential turf health benefits to golf courses.  However, more research is needed to determine ways to sustain these populations.  

Organic management practices are believed to promote beneficial bacteria and result in more balanced populations of beneficial and pathogenic species.  In order to determine how organic management practices affect the microbe and nematode populations on turfgrass we are comparing conventionally and organically managed golf courses.  We are using Next-Generation pyrosequencing to characterize bacterial and fungal populations and morphological taxonomy to identify and count nematode trophic (feeding) groups on all management areas (roughs, fairways, and putting greens) of these golf courses.  This study should provide more information on how different management techniques change soil communities and how these communities differ in ecological processes and their affect on plant health. 

Turfgrass Disease Control and Management

Our lab is continually testing new means for disease control on turfgrass.  Each year we conduct field trials to evaluate new and industry standard products for control of anthracnose, brown patch, dollar spot and snow mold.  We are also one of the few labs that evaluate products on locations that contain fungicide resistant Sclerotinia homoeocarpa populations.  We also seek methods to manage fungicide resistant Sclerotinia homoeocarpa populations through fungicide rotation strategies and site-specific resistance monitoring.  Our results are disseminated to turfgrass practitioners through extension publications and educational conferences to give practitioners non-biased disease control information.

Tomato Breeding

We are working to develop a tomato breeding model and protocol for varieties adapted specifically for New England vegetable production. Using high tech, natural breeding platforms we aim to assist local food production with highly efficient plants and production.    

Also, in cooperation with  Dr. Young Hoon Park at Pusan National University in South Korea, we are evaluating multiple experimental tomato rootstock varieties by grafting on to commercially desired tomato plants. Grafting is a great way to transfer disease resistance and plant vigor to susceptible varieties that produce high quality fruit. 

© UMass Turf Pathology 2015