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Extension Entomology

Category: Greenhouse

Gorgone Checkerspot

–by Dr. Raymond Cloyd

Have you noticed the leaves of your sunflower (Helianthus annuus) plants being fed upon by caterpillars (Figure 1)? If so, the caterpillar in question is the gorgone checkerspot (Chlosyne gorgone). The caterpillar ranges in color from black to orange, with a black head and spines or barbs covering the body (Figure 2). The caterpillars feed on sunflowers and other related plants. The young caterpillars feed in groups (Figure 3) whereas the mature caterpillars, which are approximately 1.0 inch in length, feed individually (Figure 4). Third instar larvae will eventually search for a place to overwinter.

Figure 1. Gorgone Checkerspot Caterpillars Feeding On Sunflower Leaf (Raymond Cloyd, KSU)

Figure 2. Gorgone Checkerspot Caterpillar (Raymond Cloyd, KSU)

 

 

Figure 3. Young Gorgone Checkerspot Caterpillars Feeding In A Group (Raymond Cloyd, KSU)

Figure 4. Mature Gorgone Caterpillar (Raymond Cloyd, KSU)

If you see the caterpillars feeding on sunflower leaves and your plants can tolerate some feeding damage, then just leave them alone as the caterpillars will eventually develop, by means of complete metamorphosis, into beautiful butterflies.

 

Green June Beetle Adult

–by Dr. Raymond Cloyd

Green June beetle, Cotinis nitida, adults are flying around in massive numbers near managed and/or unmanaged grassy areas, and occasionally ‘bumping’ into people and objects. Adults are 3/4 to 1.0 inch long, velvety-green, and tinged with yellow-brown coloration (Figures 1 and 2).

Figure 1. Green June Beetle Adult (Raymond Cloyd, KSU)

 

Figure 2. Green June Beetle Adult (Raymond Cloyd, KSU)

Green stripes with yellow-orange margins extend lengthwise on the front wings. The underside of the body is distinctly shiny and metallic green or gold. Adults resemble ‘dive bombers’ flying around for several weeks in July. Green June beetle adults are sometimes confused with Japanese beetle (Popilla japonica) adults; however, they really do not look alike (Figures 3 and 4).

 

 

Figure 3. Green June Beetle Adult (Raymond Cloyd, KSU)

 

Figure 4. Japanese Beetle Adult (Raymond Cloyd, KSU)

Green June beetle has a one-year life cycle, and overwinters as a mature larva or grub. Adults generally emerge in late-June and are active during the day, resting at night on plants, in thatch, or in compost. Adults produce a sound similar to that of bumble bees. Adults feed on ripening fruits (Figure 5) and corn tassels, and may feed on the leaves of oak and maple trees. Male beetles swarm in the morning, ‘dive bombing’ to-and-fro just above managed and/or unmanaged grassy areas where females are located. Females emit a pheromone that attracts the males. Clusters of beetles may be seen on the surface of the soil or in grassy areas with several males attempting to mate with a single female, resulting in an ‘insect orgy.’ Mated females that survive the ‘experience’ will lay clusters of 10 to 30 eggs in moist soil that contains high amount of organic matter.

Figure 5. Green June Beetle Adults Feeding On Fruit (Raymond Cloyd, KSU)

 

Mimosa Webworm

–by Dr. Raymond Cloyd

Damage associated with mimosa webworm (Homadaula anisocentra) larvae/caterpillars is now quite prevalent on honeylocust (Gleditsia triacanthos) and mimosa (Albizia julibrissin) trees throughout regions of Kansas. The larvae/caterpillars are 1/2 inch long when fully-grown (Figure 1) and rapidly move backward when disturbed. Caterpillars’ web leaves together on the ends of branches (Figure 2).

Figure 1. Mimosa Webworm Caterpillars Feeding On Leaves (Raymond Cloyd, KSU)

Figure 2. Mimosa Webworm Webbing On End Of Branch (Raymond Cloyd, KSU)

Webbing, in general, starts at the tops of trees and protects caterpillars from natural enemies (parasitoids and predators) and insecticide spray applications. Heavily infested trees are brown or scorched in appearance (Figures 3 and 4) as the caterpillars skeletonize the leaf tissue. Caterpillars eventually fall from trees on a silken strand before pupating. Mimosa webworm pupates in bark crevices or pupae are attached to structures (e.g. buildings). There are two generations per year in Kansas.

Figure 3. Mimosa Webworm Caterpillar Feeding Damage (Raymond Cloyd, KSU)

Figure 4. Extensive Feeding Damage Caused By Mimosa Webworm Caterpillars (Raymond Cloyd, KSU)

Regarding management of mimosa webworm, it is too late to apply an insecticide if trees are already heavily infested with webbing because caterpillars are protected from spray applications of insecticides inside the leaf webbing. However, next year (2021), you can manage mimosa webworm caterpillar populations by applying an insecticide when the caterpillars are initially present and exposed to insecticide spray applications. Insecticides that contain the following active ingredients can be used: Bacillus thuringiensis subsp. kurstaki, spinosad, bifenthrin, cyfluthrin, and permethrin. Read the label of each product to ensure that “webworms” are listed. High-volume spray applications are required to contact the caterpillars. If possible, selective pruning can quickly remove isolated or localized infestations of mimosa webworm.