Kansas State University

search

Extension Entomology

Protecting your home from wasps

Posted on by Department of Entomology
Adult mud dauber getting mud for nest building.

By K-State Research And Extension News Service.

A common problem many homeowners encounter is wasps taking up residence outside their homes. Kansas State University entomologist Raymond Cloyd says, however, not all wasps are harmful.

“Wasps are beneficial and they are part of the ecosystem,” Cloyd said. “They are predators of many caterpillar pests and are docile overall. They will usually only sting if disturbed or agitated.”

Mud daubers and paper wasps are commonly seen around homes and will generally not attack people. However, yellow jackets will actually attack people.

Despite the beneficial role of wasps, many people may want to remove wasp nests to avoid the possibility of getting stung when outdoors. When considering removing wasp nests, Cloyd advises determining whether the nest is new or mature.

“If the home has a history of wasps building nests, such as in late spring or early summer, physically remove the nest when you see the nest being initially built,” Cloyd said.

New nests can be removed with minimal risk of being stung because there are usually fewer wasps present inside the new nest. Wasps generally do not rebuild nests in the same location, so physically removing the nest will avoid having to deal with nests in the future.

Spraying nests with an insecticide should be done at night when the wasps are inside the nest, Cloyd said.

If the nest is large, mature, and has been around for some time, Cloyd recommends contacting a pest management professional.

“To avoid getting stung, contact a pest management professional,” he said.

Cloyd said that it is important to correctly identify the wasp that is creating the nest. He recommends contacting your local K-State Research and Extension office and either describing the insect over the phone or sending pictures via email.

More information: Raymond Cloyd, 785-532-4750, rcloyd@ksu.edu

Related: Household Pests of Kansas

Western Bean Cutworms Active in Western Kansas

Posted on by Department of Entomology

Western bean cutworms (Figure 1) are primarily a pest of corn in Kansas and activity is generally isolated to the western part of the state.  This pest overwinters as prepupa in the soil in earthen cells about 3 to 9 inches deep.

Figure 1. Adult western bean cutworm moth (Adam Sisson, Iowa State Univ., Bugwood.org).

The moths begin emerging in southwestern Kansas in mid-June and in early July for northwestern Kansas, usually around the time that corn is close to tasseling.  White eggs are laid in masses on the upper surface of leaves and gradually turn purple as they get closer to hatching (Figure 2).  After about a week, the eggs hatch and caterpillars (Figure 3) enter corn ears to feed on the developing kernels.  Mature caterpillars exit the corn ears and enter the soil to overwinter.  There is a single generation of this pest each year.  Pheromone trap counts of western bean cutworm moths are not a metric for determining losses in corn, but can be utilized to help detect when moths start to emerge from the soil in order to properly time scouting efforts.  Early detection of egg masses is important, as any chemical control, if warranted, needs to happen before larvae enter corn ears.  When the field is almost fully tasseled, an average of 6-8 % of plants with eggs or small caterpillars justifies control measures. Control will be reduced if applications are delayed until all silks have emerged or if larvae have already entered the ear tips.

Figure 2. Maturing western bean cutworm eggs. Photo credit- Marlin Rice.
Figure 2. Maturing western bean cutworm eggs (Marlin Rice).
Figure 3. Western bean cutworm caterpillar. Photo credit- KSU Entomology
Figure 3. Western bean cutworm caterpillar (KSU Entomology).

Currently, trap counts indicate that the western bean cutworm flight is light in southwest Kansas and began slightly later than in 2024. In northwest Kansas, trap counts of adult moths have been increasing over the last several weeks. The moth flight should conclude in early August. Until then, any at risk fields should continue to be scouted.

Control options and additional information on western bean cutworm can be found in the 2025 Corn Insect Pest Management Guide.

Fall Armyworm Season Approaches

Posted on by Department of Entomology

Fall Armyworm, Spodoptera frugiperda, can damage several important Kansas crops as well as pasture, turf and home landscaping.  This insect does not overwinter in Kansas.  Rather, it is native to the tropical regions of the western hemisphere and is active year-round along the gulf coast and southern Florida, migrating in from these locations each year.  Two full generations are possible in Kansas with defoliation and grain damage being the biggest concerns.  Each generation’s abundance and distribution across the landscape are usually different; the first generation does not necessarily impact the abundance of the second generation.  Feeding damage from fall armyworm during the vegetative stage in corn and sorghum causes chewed up and ragged looking leaves.  In fact, one of the common names used for fall armyworm during this stage is “ragworm”.  Sorghum is particularly at-risk during grain fill as fall armyworm will completely consume berries as they develop.  This caterpillar has been causing increased concern in eastern Kansas brome fields the last couple of seasons.  Brome fields can rapidly decline from fall armyworm feeding (Figure 1) as large numbers of caterpillars can be present consuming leaf material; often larger caterpillars are found along with younger ones.

Figure 1. Brome field damaged by caterpillars (Tina Sullivan).

Fall armyworm tends to begin arriving in Kansas towards the end of June, so scouting should start for this pest in at risk crops and on a weekly basis for the remainder of the growing season.  Caterpillars increase in size at an exponential rate and most of the feeding occurs during the later stage of development.  It is critical to scout early and treat, if needed, when the caterpillars are less than an inch long.  Larger caterpillars are harder to control and do the most damage.  Often, infestations are discovered after it is too late to treat. Recommended thresholds can be found below.

Fall Armyworm Thresholds

  • Alfalfa:  1-2 caterpillars per square foot can destroy seedling alfalfa.  10-15 per square foot can destroy 12” tall plants.
  • Corn:  damage to whorl stage in early summer is typically not a concern and will not impact yield.  Bt corn may prevent ear damage.
  • Sorghum:  damage to whorl stage in early summer is typically not a concern. 1-2 larvae/head during flowering to soft dough reduces yield 5-10%.
  • Wheat:  Larval “window-paning” in early planted wheat can be a concern. Very late second generation fall armyworm will be the biggest concern for wheat.  If 25-30% of plants show damage, examine field frequently.  Treat at 2-3 active larvae/ft.

Pasture/Brome: If damage is notable or there is window-paning, treatment may be warranted with 4 to 5 caterpillars per square foot.

Figure 2.  Caterpillars found damaging a brome field. Infestations can often include multiple species and multiple life stages (Tina Sullivan).

Since fall armyworm is present for several months of the growing season, it is possible that sometimes mixed infestations of different caterpillar species can occur (Figure 2).  As with any pest, proper identification is important to ensure that the right control recommendations are followed.  A species often confused with fall armyworm is true armyworm, Pseudaletia unipuncta.  The two species can be told apart with a couple of easily seen characteristics.  Fall armyworm has a noticeable inverted “Y” on its head (Figure 3), while true armyworm does not.  Additionally, the thickest stripe on the side of the fall armyworm caterpillar will be dark, while on true armyworm the thickest stripe is tan to orange (Figure 4).

The fall armyworm is depicted in a c-shape, with one thick black strip on its lateral sides.
Figure 3. Fall armyworm. Notice the thickest stripe is black (K-State Entomology).
Figure 4. True armyworm. Notice the thickest stripe is a light color (K-State Entomology).

For more information regarding fall armyworm management, take a look at the following Insect Pest Management Guides:

Anthony Zukoff – Extension Entomology, Western Kansas Research and Extension
Tina Sullivan – Northeast Region Extension Agronomist

 

Insect and Mite Pests of Greenhouse Grown Tomatoes

Posted on by Department of Entomology

Tomato, Solanum lycopersicum, is a vegetable grown outdoors under field conditions and in greenhouses. Managing insect and mite pests in a greenhouse environment is challenging. Tomatoes are susceptible to insects and mites that feed on leaves, fruits, and/or flowers, causing damage that can lead to a reduction in yield. Read our new publication Insect and Mite Pests of Greenhouse Grown Tomatoes available in the K-State Research and Extension bookstore. This publication provides information on the major insect and mite pests and strategies to manage their populations on greenhouse grown tomatoes.

Dr. Raymond Cloyd’s research and extension program involves pest management and plant protection in greenhouses, nurseries, landscapes, turfgrass, conservatories, interiorscapes, Christmas trees, and vegetables and fruits. To read more publications by him, you can view his author’s page on the K-State Research and Extension bookstore.

More information: Raymond A. Cloyd, Professor and Extension Specialist in Horticultural Entomology/Plant Protection

Turf & Ornamental Insect Update

Posted on by Department of Entomology
Ray at the Kansas Turf & Ornamental Field Day.

Registration is open for Kansas Turf & Ornamentals Field Day at Rocky Ford Research Center in Manhattan on Thursday, August 7, 2025. This program is designed for all segments of the turf and ornamentals industry – lawn care, athletic fields, golf courses, landscape, nursery, and grounds maintenance. 

During the program, Dr. Raymond Cloyd will be giving an update on insect and mite pests of ornamentals and turfgrass. This will include new insecticides and miticides and the common insect and mite pests of 2025. There will be lots of “bug” samples for everyone to see! Be sure to bring your own “bug” samples if you have any. 

Kansas Turf and Ornamentals Field Day highlight with the schedule, time and date of the event.

You can find more information about each tour and how to register on the Turf Events page.

If you are interested in serving as a lunch sponsor or vendor for the event, contact Christy Dipman at 785-532-6173 or cdipman@ksu.edu.