Kansas State University

–by Dr. Raymond Cloyd

The threestriped blister beetle, Epicauta lemniscata, is an insect pest that feeds on a wide-range of vegetable crops including: bean, beet, carrot, cabbage, corn, eggplant, melon, mustard, pea, pepper, potato, radish, spinach, squash, tomato, and turnip. Adults are slender, brown to yellow-gray, 1/2 to 3/4 (12.7 to 19.0 mm) inches long, with approximately five black stripes extending lengthwise on the wing covers or abdomen (Figure 1). In addition, there are two spots on the head and two black stripes on the thorax (middle section of body). The thorax is narrower than the head and abdomen, which is a distinguishing morphological characteristic used for identification of blister beetles.

Figure 1. Threestriped Blister Beetle Adult (Raymond Cloyd, KSU)

In general, adults are present from May through October. The adults are active in the morning and late afternoon, and seek shelter during mid-day to minimize exposure to sunlight. Females lay clusters of 100 to 2,000 eggs in the soil. Larvae emerge (eclose) from eggs and feed on grasshopper eggs. Eventually, the larvae transition into pupae. The threestriped blister beetle overwinters as a late-instar larva in the soil. In spring, adults emerge from the soil and feed on vegetable plants causing damage by consuming leaf tissue with their chewing mouthparts. They tend to aggregate in groups when feeding (Figure 2). There are two generations per year in Kansas.

Figure 2. Threestriped Blister Beetle Adults Feeding (Raymond Cloyd, KSU)

Management of threestriped blister beetle adult populations involves placing floating row covers over susceptible vegetable crops ensuring that the sides are fastened down to prevent adults from crawling underneath the floating row cover. Physical removal by hand-picking may be effective; however, be sure to wear leather gloves because adults emit a substance called cantharidin, which protects them from attack by predators, but can cause blisters to form on the skin of humans. Removing weeds within the vegetable garden will eliminate potential alternative food sources; especially pigweed, Amaranthus spp., which is highly susceptible to adult feeding. Foliar applications of insecticides will kill threestriped blister beetle adults; however, multiple applications will be required during the growing season to prevent plant damage.

–by Frannie Miller

ID from last week’s bug

Brown Lacewing: The brown lacewing is similar to the green lacewing except they are brown in color and have smaller wings that are more rounded. Females attach eggs directly to the leaf. Both the adults and larvae are predacious

–by Frannie Miller

–by Frannie Miller

Tiger Beetle: This Punctured Tiger beetle is attracted to ultraviolet light, so I was able to capture this image under the lights of a tennis match. This species tends to be dull colored with a few small spots. Tiger beetles tend to be extremely quick in their movements making it challenging to get pictures. The feeding habits of the adult and larvae stage make them somewhat beneficial.

–by Dr. Raymond Cloyd

This is the time of year when we see the golden garden spider, Argiope aurantia, in landscapes, gardens, and in unmanaged areas. Golden garden spiders are 1.0 inch (25.4 mm) long, with black and yellow markings on the abdomen, and a silvery cephalothorax (combination of head and thorax) (Figure 1). The spider typically hangs with the head positioned downward in the center of a web that has vertical crossed zigzag bands (Figure 2).

Figure 1. Golden garden spider (Raymond Cloyd, KSU)

Figure 2. Golden garden spider in web. Note the vertical zigzag bands in the web (Raymond Cloyd, KSU)

Golden garden spiders find prey in their webs by sensing vibrations as prey try to escape. Spiders capture grasshoppers in their webs and then wrap them in fine silk (Figure 3). Golden garden spiders typically build webs in open areas instead of inside the canopy of trees and shrubs or inside shelters. The other species in Kansas is the banded argiope spider, Argiope trifasciata, that does not have distinct black markings on the top of the abdomen. However, thin black transverse lines may be present.

Figure 3. Golden garden spider wrapping a grasshopper in silk (Raymond Cloyd, KSU)

–by Frannie Miller

–by Frannie Miller

Red milkweed beetle – The red milkweed beetle comes by its name due to the fact it is generally host specific to milkweed plants. The antennal base of these beetles bisects the eyes creating the appearance of four eyes. If these beetles are startled, they will make a shrill noise.

–by Raymond Cloyd

Now is the time of year when we start noticing the leaves of the Eastern redbud, Cercis canadensis, turning brown and folded on top of each other. This is caused by the caterpillar stage of the redbud leaffolder, Fascista cercerisella. Adults are 1/4 inch in length, black to dark brown with an orange head, and there are approximately 10 white spots on the wings. They are very active when disturbed. Adult females lay oval, white eggs near the leaf veins.

Caterpillars emerge (eclose) from eggs and feed on the leaves of Eastern redbud. Early-instar caterpillars are 1/4 inches long, initially white (Figure 1), and then become light-green. Later-instar caterpillars are 1/2 inches in length with alternating bands of white and black on the body (Figure 2). Caterpillars fold the edges of leaves onto the upper side (Figure 3); fastening the leaves together with white strands of silk (Figure 4). The caterpillars feed within the folds on the upper leaf surface, which protects them from natural enemies (e.g. parasitoids and predators). If you pull the leaves apart, the caterpillars will move vigorously and fall off the leaves. Redbud leaffolder overwinters as a pupa in the folds of fallen leaves. There are three generations per year in Kansas.

Figure 1. Early-instar caterpillar of redbud leaffolder (Raymond Cloyd, KSU)

Figure 2. Later-instar caterpillar of redbud leaffolder (Raymond Cloyd, KSU)

Figure 3. Edges of leaves folded onto the leaf upper side (Raymond Cloyd, KSU)

Figure 4. White silken strands that hold leaves together (Raymond Cloyd, KSU)

Eastern redbud trees or shrubs may be disfigured and leaves distorted when leaf margins fold over each other. Heavily infested Eastern redbud trees or shrubs may drop their leaves prematurely.

Redbud leaffolder caterpillars are difficult to manage with spray applications of insecticides once the leaves are fastened together because the caterpillars are protected from exposure inside the folded leaves. However, folded leaves can be physically removed and placed into a container of soapy water that will kill redbud leaffolder caterpillars.

–by Frannie Miller