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Extension Entomology

Month: September 2022

Goldenrod Soldier Beetles

Posted on by Sharon Schroll

–by Raymond Cloyd — Horticultural Entomologist

Goldenrod soldier beetle, Chauliognathus pennsylvanicus, adults are feeding on goldenrod (Solidago spp.) (Figure 1) as well as other flowering plants. Adults can be seen feeding and mating simultaneously. The goldenrod soldier beetle is common throughout most of Kansas.

Figure 1. Goldenrod soldier beetle adults feeding goldenrod flowers (Raymond Cloyd, KSU)

Adults are about 1/2 of an inch long, elongated, and orange with two dark bands on the base of the forewings (elytra) and thorax (middle section) (Figure 2). In general, adults are present from August through September. Adult soldier beetles feed on the pollen and nectar of flowers. In addition, they are predators and will consume insects such as aphids and caterpillars. Flowers are a great place for the male and female soldier beetle adults to meet and then mate (Figure 3). Soldier beetle adults do not cause plant damage. Adults may occasionally enter homes, but they are rarely a concern. The best way to deal with adults in the home is to sweep, hand-pick, or vacuum.

Figure 2. Goldenrod soldier beetle adult (Raymond Cloyd, KSU)

Figure 3. Goldenrod soldier beetle adults mating (Raymond Cloyd, KSU)

 

Adult females lay clusters of eggs in the soil. The larva that emerges (eclose) from eggs are dark-colored, slender, and covered with small dense hairs or bristles, which gives the larva a velvety appearance. The larva resides in soil feeding on grasshopper eggs. Sometimes, the larva will emerge from the soil and feed on soft-bodied insects and small caterpillars.

 

Roberts joins the Extension Integrated Pest Management Team

Posted on by Sharon Schroll

–by Frannie Miller, Pesticide Safety and IPM Coordinator

 

The Departments of Entomology, Horticulture and Natural Resources, and Plant Pathology would like to welcome Terry Roberts, Training Support Specialist to the Extension Integrated Pest Management Team. She will serve as a vital team member on the Extension Implementation grant and help to us to achieve our project objectives. She will be helping with Extension Master Gardener training, K-State Garden Hour, and Commercial Applicator Training. The team is excited to have her join us!

Terry most recently served as a Program Coordinator for Kansas 4-H Youth Development, where she provided programmatic support for a grant from the Kansas Department of Education. Before this, Roberts managed the Kansas 4-H Online system and provided leadership to various projects within the State 4-H Office. Terry has a passion for serving others, building relationships, and enjoys spending time with her family.

 

Fall brings horse bot flies

Posted on by Sharon Schroll

–by Cassandra Olds, Livestock and Veterinary Entomology

 

 

Horse owners may be noticing the appearance of small yellow eggs laid on the legs of their horses. All four legs can be targeted but higher egg numbers are normally observed on the front legs (Figure 1). These eggs are laid by the horse bot fly, Gasterophilus intestinalis (DeGeer) with each female laying between 150 and 1000 eggs! Eggs are glued to the hair shaft and multiple eggs can be laid on a single hair strand (Figure 2).

 

Figure 1: Horse bot fly eggs laid in batches attached to hair on the hind (A) and front (B and C) legs of a horse. This horse had well over 700 eggs in total.

 

Figure 2: Removed horse bot fly eggs still attached to horse hair. Multiple eggs can be laid on a single hair strand. These eggs were removed prior to hatching as the egg casing remains intact and closed.

 

Eggs hatch within 10 days, stimulated by horse licking and increased humidity. Larvae enter the horse mouth and imbed in the tissue where they remain for roughly 28 days. After molting, second stage larvae exit mouth tissues and are swallowed, thereby moving the stomach. The larva can remain in the stomach for 9-12 months where it molts into the third and final larval stage. After maturing the third instar detaches from the digestive tract and is passed out in the feces. The larva will burrow into the soil and pupate where it will remain for 1-2 months. As horses tend to create manure piles, the number of flies pupating in an area can become significant. Adult flies can cause significant fly worry, adverse reactions to flies can result in horses injuring themselves trying to escape from attack. Under high numbers, reduced grazing can result in weight loss.  Significant mouth irritation can occur when first instar larvae burrow into oral tissue and although horses can tolerate low levels of stomach parasitism, large numbers can cause blockages, colic and reduced nutrient uptake.

 

Control can be achieved through a combination of sanitation, egg removal and correctly timed oral dewormer. Removing eggs immediately will significantly reduce the risk of a horse consuming larvae and initiating the infestation cycle. A simple and inexpensive ($3-7) bot egg knife (Figure 3) can be used to physically remove eggs from the legs.

 

Figure 3: A bot fly knife can be used to remove bot fly eggs from horse hair by scraping downwards with the direction of hair growth.

 

Deworming one month after eggs were noticed will kill any second instar larvae that may have been consumed and now reside in the stomach. A second round of dewormer can be administered 6 months after the first dose to remove any third instar larvae. Removing manure piles from the site can reduce the number of adult flies emerging.

 

Elm Leaf Beetle

Posted on by Sharon Schroll

–by Raymond Cloyd, Horticultural Entomology

Elm leaf beetle, Pyrrhalta luteola, larvae and adults are prevalent throughout Kansas feeding on elm trees (e.g. Siberian and American). The larvae and adults are typically present simultaneously. Extensive feeding damage can ruin the aesthetic quality of elms in landscapes, parks, and other areas where elms are grown.

Elm leaf beetle adults are 1/5 to 1/4 of an inch long, yellow to dull-green, with a black stripe on each side of the wing cover that extends the entire length of the abdomen (last section). In addition, there are two black spots on both sides of the thorax (middle section) (Figure 1). Adults feed between the major veins, which results in leaves having a ‘shot hole’ (similar to ‘buckshot’) appearance (Figure 2).

Figure 1. Elm leaf beetle adult (Raymond Cloyd, KSU)

 

Figure 2. Feeding damage associated with elm leaf beetle adults (Raymond Cloyd, KSU)

Elm leaf beetle larvae are 1/3 to 1/2 of an inch long when mature and dull-yellow with two black lines extending the length of the body (Figure 3). The larvae cause the most damage feeding for about three weeks. The larvae feed on the underside of leaves causing the leaves to appear skeletonized and eventually turning brown (Figure 4). The larvae will migrate down the trunk of elm trees and tunnel into or reside on the soil surface to pupate (Figure 5). Adults emerge later on and migrate upward on the tree trunk. In late summer through fall, elm leaf beetle adults will leave elm trees and seek sites to overwinter. Adults overwinter in buildings, homes, and in protected places outdoors such as the bark of elm trees. Adults can be a nuisance pest inside homes when they enter in the fall or leave in the spring. There are two generations per year in Kansas.

Figure 3. Elm leaf beetle larvae feeding on leaf underside (Raymond Cloyd, KSU)

 

Figure 4. Feeding damage associated with elm leaf beetle larvae (Raymond Cloyd, KSU)

Figure 5. Elm leaf beetle larvae and pupae on the soil surface at the base of an elm tree (Raymond Cloyd, KSU)

A contact insecticide should be applied in spring to manage elm leaf beetle larvae and adult populations feeding on leaves. Thorough coverage of leaf undersides is important because the leaf undersides are where larvae and adults primarily feed. However, if elm trees are exhibiting ≥50% feeding damage then do not spray. Mature elm trees can usually sustain damage associated with elm leaf beetle larvae and adults feeding without direct harm. However, be sure to implement cultural practices such as providing sufficient water and mulching the base of elm trees to ensure that elm trees produce leaves for next year.

Systemic insecticides can be applied to the soil or injected directly into elm trees in early spring before new growth emerges. The systemic insecticide active ingredient will translocate throughout the elm tree and accumulate in the leaves. Elm leaf beetle larvae and adults are killed when they ingest a lethal concentration of the systemic insecticide active ingredient after feeding on leaves.

 

For more information on how to manage elm leaf beetle populations please refer to the following extension publication:

 

Elm Leaf Beetle: Insect Pest of Elm Trees (MF3537 July 2020)

https://www.bookstore.ksre.ksu.edu/pubs/MF3537.pdf

 

Chiggers: small bites, big itch!

Posted on by Sharon Schroll

–by Cassandra Olds, Livestock and Veterinary Entomology

Chiggers, also commonly known as harvest mites are a prevalent problem in Kansas as well as much of the United States. Nymph and adult stages are free-living predators that feed off other arthropods and their eggs but the six-legged larval stage are parasitic. Chiggers do not feed on blood, instead they secrete digestive enzymes from their salivary glands which liquefy skin cells at the attachment site. They consume the liquefied cells together with lymph secreted by the body in response to the induced damage. In many people the result of this feeding is an intensely itchy local reaction. Chigger eggs are laid in batches in plant litter on the ground or directly on the soil surface. People and animals often happen across groups of larvae when walking across or sitting on the grass surface with multiple bites occurring at the same time often in a localized area. Chiggers often chose areas where the skin is thin such as ankles (Figure 1 and Figure 2).

 

Figure 1: Local reaction on ankle to five chigger bites 24 hours after being bitten. The white itchy bumps are similar to those seen with insect bites like mosquitoes but usually occur in groups.

Figure 2: One week after chigger bites, itching has resolved and the red marks begin to fade.

 

Keeping grass cut short and avoiding walking through areas of taller grass can limit exposure to chiggers. Insect repellants can also be useful in deterring these itch-inducing critters. Removing clothing and washing the skin surface can remove any chigger larvae before they have the chance to attach and feed. If you have already been bitten, the intense itching can be relieved (at least for a while) with topical itch creams and usually resolves by itself within a week to 10 days. Try as much as possible to resist the intense urge to scratch at the bites as this can introduce bacteria which can cause a secondary infection!

Correction to Sorghum Pests Article in Aug. 26, 2022 Newsletter

Posted on by Sharon Schroll

–by Jeff Whitworth – Field Crop Entomologist

Figure 1 should have been:

Figure 1: Sorghum (Sugarcane) aphids

Aphids are rapidly increasing around South Central and North Central KS., both corn leaf aphids (as seen in the Fig 2 in last week’s newsletter) which was miss labeled as sorghum (formerly sugarcane) aphids! These sorghum (sugarcane) aphids are rapidly increasing as seen in Fig 1 here (which was only a 2-week-old infestation) as are corn leaf aphids (again-seen in Fig 2 from last week’s Newsletter).

Figure 2:  Corn leaf aphids

Thus, monitoring should continue for these aphid populations, especially since, as yet, there do not seem to be many beneficials, see Fig 3 (ladybeetle larva decimating aphid nymphs) in most fields monitored.

 

Figure 3: Ladybeetle larva feeding on aphid nymphs