Worldwide distribution. On cucurbits: gourds, melons, pumpkins, squash, zucchini, and others.
There are a number of reasons for the warts. (i) there are heirloom varieties or varieties that are selected or bred for warts; they are popular for historical reasons and sought for Halloween, Thanksgiving, and for traditional foods; (ii) oedema occurs in cool, cloudy and wet weather. It occurs when there is a build-up of water and cells burst, but later heal; (iii) virus infections cause knobbly fruit; (iv) insects chew the fruit.
Oedema warts on pumpkin can affect marketability; and viruses can cause high (>50%) losses.
Cultural control: (oedema) control irrigation practices, check drainage; (viruses) avoid overlapping crops, rogue, virus resistant varieties (Cucumber mosaic virus); weed. If insects are a problem, use soaps or oils; possibly, synthetic pyrethroids.