Interactive effects of leaf pulling and non-toxic chemical interventions on rot management in north central region vineyards

Commodities

Practices

Grape production is a growing industry in the North Central region, which includes juice, wine, and table grape production. Successful grape production relies on high quality fruit to make excellent juice and wine, but growers in this region face high risk of cluster rots in vineyards, mainly caused by fungal and bacterial infections such as botrytis bunch rot and sour rot. The vinegar fly Drosophila melanogaster is often associated with sour rot. These rots are favored by the humid microenvironment around the cluster. The cultural practice of leaf pulling to reduce humidity is effective against cluster rots, but that must be done early in the season, and it reduces yield. Another approach is to use antimicrobials and insecticides near harvest to manage sour rots, but resistance developing in D. melanogaster necessitates exploring non-toxic alternatives. Here, I aim to investigate the effect of non-toxic chemical alternatives on Drosophila species, by assessing attraction, fecundity, survival, and larval development. The most effective treatments will be tested in two commercial vineyards in a factorial experiment in combination with leaf pulling for 2 seasons. The objectives are to:

1. Determine the effects of non-toxic chemical alternatives on the behavior and life-table components of Drosophila melanogaster in the laboratory
2. Determine sour rot control and economics from combining effective cultural and chemical treatments

I hypothesize that Drosophila melanogaster will be less successful on grapes in response to the non-toxic chemical alternatives compared to control. I also expect these effects will vary among the different treatments. I also hypothesize that sour rot infestation will be lower when effective non-pesticide treatments are combined with leaf pulling treatment.

My project will include an educational component, introducing farmers to the insect’s role in cluster rot and the available non-toxic chemical interventions. I will share my results through farmer field days, a grower-oriented newsletter article and a scientific publication. The impact of my study will be determined by farmer responses to pre-and post-study evaluations of their approaches to cluster rots, the role of insects and their management, and from metrics such as visits to the online extension article and farmer adoption after project completion.

As a learning outcome, growers will learn about the insect and pathogen causal agents of cluster rots and the importance of insects. They will also acquire knowledge on non-toxic chemical alternatives to address resistance issues in vineyards. Growers will gain practical knowledge and skills of integrating leaf pulling with chemical interventions through a grower-oriented article and field days. My research will offer an alternative, eco-friendly option for cluster rot management, improving the end product quality in commercial and organic vineyards. Growers will advance their knowledge on alternative options to toxic chemical interventions for cluster rot management, leading to better-quality end products. Researchers and educators will identify new non-toxic interventions and can extend recommendation options to growers. As an action outcome, growers can substitute or integrate these products and practices into their rot management strategies, allowing expansion of sustainable practices. Researchers will leverage new studies based on our findings from this project.