Starting to see some watermelon, cucumber and other cucurbit crops that are looking a bit pale green or even yellow (fig. 1). Sometimes the plants have brown speckles or spots on them that may look like a foliar disease has started (fig. 2). But it has not. Most of the time if you look at the underside of the leaf with spots you do not see the same browning of the tissue or it is much reduced (fig. 3). Also as in this field of watermelon that these photos came from, much of the field looked like the plant in figure one. When the damage appears on one side of the leaf or is in much of the field it is usually an abiotic problem-- one that is not caused by an insect, fungus bacteria, or other living pest, but is caused by a non-living factor such as weather. This is what seems to be popping up in some vegetable fields now, but especially in cucurbits in the last few days. The unusually cloudy, cool weather we had most of last week and this past holiday weekend along with some heavy rains have stressed the cucurbit crop and slowed its overall growth (foliar and root). Plants should recover and grow out of it with warmer weather.
This article appears on June 10, 2021, Volume 12, Issue 3 of the Vegetable and Fruit News
Vegetable and Fruit News is a statewide publication for the commercial vegetable and fruit industries and is published monthly during the growing season (April through October). Subscribers will receive an email with the latest edition.