Jerry Brust, IPM Vegetable Specialist, University of Maryland; jbrust@umd.edu
This has been a strange spring weather pattern we have been having. It has been cloudy and wet for the last 10 days or so and on top of all that we have had isolated down pours with hail. In some fields growers were not aware of the hail that had passed through and wonder now what could have caused the type of damage they are seeing in their crop. The damage on tomatoes and onions that I saw was from pea-size hail (Figures 1 and 2). The damage to tomatoes was always one-sided or even a quarter of a side of the tomato that was not covered by foliage. There was some tomato foliar damage, but not much. The noticeable and important damage was to the developing fruit. Developing vegetable fruit is often more sensitive to damage from hail than the stems and even leaves which are more durable and can take some small hail damage. Onion leaves were more beat up, but the bulbs all looked good in the fields I visited. In cucurbit fields the damage again was usually on only one side of the fruit with much lighter damage to stems and leaves (Fig. 3). If you have not had a chance to check out your vegetables or fruit, be sure to do so in the next few days to get an idea of how much, if any, damage occurred.
If you do have hail damage be sure your fungicide spray coverage is thorough and that plants are at least sufficient if not better in nutrient levels. This may be a good time to try some biostimulants that are purported to help plants overcome stressful conditions. Be sure to treat only some or half of your damaged plants to see if the biostimulant worked or not. Damaged fruit should be removed from plants as it will be unmarketable, but will continue to drain the plant’s resources until it is removed.
Figure 1. Hail damage to tomato on only one side of fruit by pea-size hail
Figure 2. Hail damage to onions
Figure 3. Hail damage to zucchini on only one side of fruit and light damage to stems