Kate Everts, Vegetable Pathologist, University of Delaware and University of Maryland; keverts@umd.edu
Basil Downy Mildew
Basil downy mildew has been confirmed in Howard County Maryland in a home garden. Excellent information is available from Dr. Meg McGrath at Cornell. Her website, http://vegetablemdonline.ppath.cornell.edu/NewsArticles/BasilDowny.html, includes information on both conventional and organic management options.
Bacterial Spot in Tomato
Bacteria spot in tomato is a perennial problem on the crop. A new tool has just been registered for conventional tomato production. Quintec, which was previously registered for bacterial spot on pepper, is now available for tomato bacterial spot. More information is available at
Watermelon
I continue to see lots of gummy stem blight on watermelon. Regular fungicide applications should slow the spread of lesions from the leaves onto the petioles or stems, where yield damage will occur. Our weather has been highly conducive to gummy stem blight. Continue regular fungicide sprays.
Downy mildew on watermelon is also present in Delaware. Effective products for this disease should be added to management programs.
Downy mildew on watermelon.
Powdery Mildew on Summer Squash
Yellow squash fields have powdery mildew, now. For conventional squash, continue applying a protectant fungicide and mix with a targeted products such as Torino, Procure, tebuconazole, Proline, Inspire super, Fontelis, Pristine, or Rally. Rotate materials with different modes of action. Organic producers can use copper and sulfur as well as biorational material such as Regalia, Cease, Sonata, Serenade, Oxidate, and others.