Tuesday, June 16, 2015

Meet the Tomato Bug!

Tomato bug adult. Note the beak tucked underneath the head.
This beak is inserted into plant tissue for feeding.
Photo by Debbie Roos.
By Debbie Roos, Extension Agent
Agriculture - Sustainable/Organic Production
Chatham County
Damage caused by tomato bug feeding.
They seem to only feed on the top half of the plants.
Photo by Debbie Roos.

I got a call from a Chatham County greenhouse tomato grower recently about an insect flying around that they had never seen. I visited the greenhouse and saw many tiny insects moving around the plant canopy. They were quite active so we brushed a few of them onto a yellow sticky card just to get a good look at them. Although it was something I had never seen I knew it was some type of Hemipteran, or true bug, by looking at the mouthparts. I sent a sample off to North Carolina State University’s Plant Disease and Insect Clinic for identification.

Our NCSU entomologist Dr. Bob Blinn identified the insect as a tomato bug, Engytatus modestus, in the family
Miridae along with tarnished plant bugs and many others. I have never heard of this insect, much less seen one! It turns out there is very little information about it but it can cause significant damage to a tomato crop (see photos below).

Both adults and nymphs feed on plants by inserting their piercing, sucking mouthparts into leaves and stems. They move quickly and the adults are good fliers. The nymphs resemble aphids but move fast. Tomato bug feeding causes leaves to shrivel and die.

I came across some references in the literature to the tomato bug being a biological control agent. I asked Dr. Blinn about this and he said the tomato bug was likely a facultative predator,
meaning it can feed on both insects and plants. There are some similar species of Mirids (e.g. Dicyphus hersperus) used as beneficial insects in tomato greenhouses to control thrips and whiteflies. What an interesting insect!

Now that you have learned a little about the tomato bug, keep your eye out for it in the field and greenhouse. Growers are advised to scout early for it. Fortunately for the greenhouse tomato grower the pest showed up towards the end of the tomato season so negative impacts from feeding damage were minimal. Since so little is known about this insect we have not been able to find any research on organic control options. NCSU entomologist Dr. Jim Walgenbach suggested that organic pesticides effective against stink bugs would likely also be effective against tomato bugs. Research has shown that neem, spinosad, and pyrethrum provide the best control of nymphs but very little control of adults. Make sure and read the labels carefully and if toxic to bees avoid spraying when they are actively foraging.


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