Tomatoes

Vegetable and Fruit Newsletter, Volume 15: Issue 3, May 2024. Topics include: Preemergence Herbicides for Common Weeds in Vegetables, Greasiness in Apples: Why it Happens and How to Prevent it, Insect Scouting Tips, Beginning Farmer FAQ –Soil Testing, Upcoming UME and UMES Events

IPM Threshold Guide for Vegetable Crops

Insect Pests of Tomato

In the past, field trials I have conducted on gold flecking were inconclusive as to its causes as they showed more problems caused by environmental concerns than by thrips or mites. However, upon several visits to growers’ fields over the last 4 years that were having mite or thrips outbreaks there were almost always greater rates of gold flecking in the most heavily infested areas of the tomato field.

It is unusual that I see or hear about broad mites (Polyphagotarsonemus latus) being a problem in our tomato high tunnels. A grower was having symptoms of twisted growth and browning/bronzing of their tomato leaves this spring and guessed they might have broad mites. They did, with some plants severely damaged while others were fine. The grower had a late fall crop of cherry tomatoes that they kept into December but did not clean up their high tunnel until 2 weeks before they planted their spring crop of tomatoes. Unfortunately, the grower had a small infestation of broad mites in the fall crop of tomatoes that was able to overwinter.

Tomato Ripening Problems and Cucumber Beetles

Several growers have complained that their second set of tomatoes is catfaced or are deformed and ripening poorly. Their first set of tomatoes looked good, but the second set is having problems in scattered areas throughout the field.

I have seen and have gotten reports of (and some really nice pictures of) stinkbug damage in tomatoes over the past few weeks from all over Maryland including the Eastern Shore. Stinkbug feeding damage is called cloudy spot in tomato fruit (fig. 1). It occurs when the adult or immature stinkbug puts its needle-like mouth parts into the fruit and removes material from a large number of cells. On green fruit the damage appears as whitish areas with a black dot in the center and indistinct borders (fig. 2) on ripe fruit the spots are golden yellow (fig. 1).

This has been a bad year for stink bug damage in tomatoes. Just about every field I walk into has at least some damage while others have moderate to heavy damage (>20% tomatoes not marketable). Cloudy spot of tomato fruit is caused by the feeding of various species of stink bug (SB). On green fruit the damage appears as whitish areas with indistinct borders (Fig. 1).

The Brown marmorated stink bug (BMSB) Halyomorpha halys (Figs. 1 and 1a) was accidentally introduced into the United States in shipping containers arriving from Asia. The first confirmed specimen was collected in Allentown, PA in October 2001, although there is evidence that it was collected from black light traps in New Jersey as early as 2000.