Description
Spined stilt bugs are small, slender insects in the family Berytidae. Typically brown or bronze in color, these insects have slim bodies with long and thin legs (Figure 1). The antennae of stilt bugs bend at very sharp angles and frequently have obvious swelling at the tip. Occasionally, some stilt bug species will also have slight swelling at the joints and ends of their legs. Stilt bugs are omnivores and, in the context of vegetable production, feed mainly on the sap of tomatoes, though they may feed on different crops like corn, peaches, and okra. They will also supplement this plant food with other insects as a source of protein. When left unmanaged, they can cause significant damage.
Figure 1. Stilt bug on flower (Photo by Laura Ingwell).
Life cycle
Like all Hemiptera insects, stilt bugs go through incomplete metamorphosis. They overwinter as adults under grasses and emerge in the spring to lay eggs on weeds and other herbaceous plants (Figure 2). Their eggs are typically about 1 mm long, usually yellow to white, and are oval. Upon hatching, they go through five immature “instar” stages before becoming adults. While growing, they require food from both plants and other insects. They will feed on many crop species, as well as hornworm caterpillars, aphids, and budworms, to supplement their diet.
When born on tobacco, stilt bugs can benefit the farmer. Though they will occasionally take “drinks” of sap from the tobacco, they are much more inclined to feed on the insect pests present instead. Stilt bug nymphs can consume, on average, 12 hornworm eggs and 80 budworm eggs during their development, while adults will consume roughly two hornworm eggs and ten budworm eggs a day. Over their roughly 80-day lifespan, stilt bugs have the potential to provide an extremely significant amount of pest control.
Figure 2. Stilt bug mating on snapdragon (Photo by John Obermeyer).
Damage
Stilt bugs are occasional pests of fruiting plants, most often tomatoes, especially in climate-controlled areas like greenhouses and high tunnels. Nymphs and adults feed on the stems, flowers, and fruit of the plant, causing flowers to blacken and die, reducing yield. When stilt bugs feed on unripened tomatoes, they cause the tomatoes to become malformed and develop white blotches beneath the skin, much like the damage caused by stink bugs and other hemipterans, damaging the fruit quality (Figure 3).
Figure 3. Stilt bug damage to tomato (Photo by Kacie Athey).
Management
Because stilt bugs are significant biocontrol agents in tobacco and only occasional pests in tomatoes, the control of their populations has not been researched extensively, and few studies have been done specifically on tomatoes. The only situation in which we have encountered this insect at potentially damaging levels is on high tunnel tomato crops. Unfortunately, we cannot make any insecticide recommendations at this time. Crop rotation has been found to have some effect on stilt bug populations, and controlling the population of prey insects can also assist in controlling stilt bug populations.
Other management practices can influence stilt bug populations in agricultural fields. Delayed tobacco planting dates showed increased populations later in the season, and when non-crop plants like alyssum were planted alongside tomato plants, higher densities of stilt bugs were found on both plants.