Tomatoes

Over the last 4-5 years I have received calls and emails from growers about insect pests that they cannot seem to control as well as they had in the past. This presentation is going to look at some of the top vegetable pests that growers in the mid-Atlantic have had problems with and some ways to mitigate those problems.

Normally at this time of year when I talk about any insect problems in crucifers I talk about harlequin bugs that feed by sucking out plant juices and inject toxins into the plant. But I have seen several fields and even some high tunnels with blister beetles feeding and defoliating several different vegetables such as tomato (including the fruit), leafy greens, crucifers, spinach and especially swiss chard (fig. 1). Blister beetles begin feeding on the edges of leaves eventually leaving only stems (fig. 1). The presence of blister beetles now is not unusual as they are often found in large clusters in late summer-early fall. They can arrive in large groups, seemingly overnight and can do a great deal of damage in a short period of time.

I have seen and have gotten reports of stinkbug damage in tomatoes over the past few days. 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 part into the fruit and removes material from a large number of cells.

Fruit and Vegetable News, Volume 12, Issue 4 (July 15, 2021)

In figure 1 you can see tomato plants that look a bit squirrely. I thought it was possibly herbicide or virus or nutrient problems. After eliminating the first and third we had the plants tested for a battery of viruses. There were 3 viruses found in the plants. The most unusual one was the Pepino mosaic virus, which belongs to the Potexviruses. This virus is very easily transmitted mechanically and has a low seed transmission rate. Seed transmission occurs at rates of less than one in a thousand when seed is not properly cleaned. The virus is external, contaminating the seed coat and not the embryo or endosperm.

A couple of high tunnels and even a field of tomatoes have been found with tomato spotted wilt virus in Maryland. The high tunnel finds were not too suprising but the field was a bit as we usually do not see field infections until later in the season.

In the last week or so high tunnel tomato plants have been reported that look a bit squirrely. I thought it was possibly herbicide or virus or nutrient problems. After eliminating the first and third possibilities we had the plants tested for a battery of vi-ruses. There were 3 viruses found.

The recent discovery of Tomato Spotted Wilt Virus (TSWV) in a resistant tomato cultivar has raised concerns about the emergence of resistance-breaking variants. It is important for growers to closely monitor the situation while continuing to use resistant cultivars.

As this growing season winds down and for the next few weeks it is a good time to examine vegetable roots for root knot nematode (RKN). I would be suspicious of having RKN if my vegetables seemed to need more water than normal or wilted during the heat of the day and recovered later or plants had nutrient deficiency symptoms rarely seen in your fields and the addition of fertilizers did not seem to alleviate the deficiency symptoms.

Fruit and Vegetable News, Volume 13, Issue 1 (April, 2022). Topic in this issue are: Check for Allium leaf miner in onions and leeks over the next few weeks, Edema problem in high tunnel tomatoes, Using Plant Growth Regulators to Improve Apple Return Bloom, Botryis Fruit Rot (Gray Mold) and Crown Rot in Strawberries, Spring Pest Scouting in Strawberries, and Early Spring Vegetable Insect Scouting Tips.