Melons, Pumpkins, Cantaloupes

Last week I was in a pumpkin field that had foliar symptoms of a Potyvirus (Fig. 1), but also had some other strange foliar symptoms (Fig. 2). Foliar samples were sent off to Agdia, Inc. (Elkhart, IN) for virus testing. All samples tested positive for a potyvirus (most likely watermelon mosaic virus), while one field tested positive for a virus called Melon necrotic spot virus (MNSV). MNSV is in a family of viruses called carmoviruses, which have been reported worldwide, primarily in hydroponic and greenhouse cucurbit production.

At times growers may be surprised to find a fairly large number (10-15 adults and 7-10 immatures/leaf) of thrips on the leaves of cantaloupe, watermelon and potato early in the season. However, no thrips feeding dam age was visible on the leaves.

There have been problems in our vegetable fields with three pests, which include striped cucumber beetles, leafhoppers and twospotted spider mites. I think most of the problems we are having with these three comes from our mild winter as each has had an outbreak population after a mild winter sometime in the last 12 years.

I have gotten several emails and calls from growers in different areas of the state reporting they are seeing the beginnings of squash vine borer problems in their pumpkins or squash crops. IF you rotated at least 1/2 mile from your squash/pumpkin fields of last year you should be OK, however, I know some growers either cannot rotate or they cannot rotate very far from last year’s crop.

Cantaloupe (Cucumis melo) is a warmseason crop that generated $319 million in sales in the U.S. in 2013 (1). Most commercial production occurs in California and Arizona, but historically production has centered in Maryland, Delaware and New Jersey (14). Cantaloupe grows best in well drained silty or sandy loam soils with a pH of 6.0-6.5. This vegetable is well-suited to growers with small-scale cultivation of 5 acres or less (14), as production doesn’t require a lot of specialized equipment, and fruit are highly marketable.

IPM Threshold Guide for Vegetable Crops

Field evaluation of triploid cultivars for resistance to Fusarium wilt of watermelon in Maryland, 2014

Evaluation of fungicides for management of foliar diseases on watermelon, 2014

Field evaluation of pollenizers for resistance to Fusarium wilt of watermelon in Maryland, 2014

Evaluation of fungicides and Melcast forecasting program for watermelon disease management, 2014