End of Season Practices to Reduce Vegetable Diseases Next Year

Emmalea Ernest, Extension Fruit & Vegetable Specialist; emmalea@udel.edu

Harvest in some of this season’s vegetable fields is done and others will finish up very soon. End of season sanitation in these fields can help prevent next year’s disease problems. When harvest is complete, it is best to mow and incorporate (disc, plow, till) crop residue as soon as possible.

One way that this helps control plant diseases is that disease organisms will continue to increase on the abandoned crop – especially after disease management sprays stop. With more of the disease present in the field there is a greater chance that some of it will overwinter and survive until next year. When you terminate the host crop, the disease organism can’t keep buying raffle tickets (figuratively, of course) to win a trip to your next growing season.

The second way that sanitation will help to manage vegetable diseases is that many disease organisms survive best on intact plant residue. Decomposition of crop residue reduces the survival of many diseases that affect vegetable fruit, leaves and stems. It may seem like exposing residue to winter conditions above soil would be most detrimental to survival, but actually the breakdown of crop residue by soil microbes is more effective at reducing disease. Incorporation of plant residue is especially recommended for managing certain diseases including gummy stem blight of watermelon, anthracnose of pepper/tomato/eggplant and Alternaria leafspot of brassicas.