MANHATTAN, Kan. – Many people view spiders as pests, and the fear of spiders is one of the most common phobias among Americans. However, spiders are predators that feed on insect pests in gardens and landscapes.
Kansas State University entomology expert Raymond Cloyd says that spiders feed on insects that may damage ornamental and vegetable crops. Consequently, they should be left alone and encouraged to take up residence in gardens and landscapes.
“There are two common species of garden spiders in Kansas that are active during the day,” Cloyd said. “They are the yellow garden spider and banded garden spider.”
The yellow garden spider has a black abdomen with yellow markings and black legs with a yellow or red band, Cloyd said. The banded garden spider has continuous bands across the abdomen and legs, alternating white and dark with orange and black bands on the legs. Both spiders create large webs in gardens and landscapes.
Garden spiders rely on vibrations that move through the web to indicate that prey have been captured.
Cloyd recommends leaving garden spiders alone because they are beneficial and are not harmful to humans.
Cloyd and his colleagues in K-State’s Department of Entomology produce a weekly Extension Entomology Newsletter with information on managing insect and mite pests of landscapes and gardens.
By Raymond Cloyd, K-State extension horticultural and plant protection entomologist.
The catalpa caterpillar or catalpa sphinx, Ceratomia catalpae, is an insect pest native to the eastern USA that only feeds on catalpa trees, including Catalpa bignonioides and C. speciosa. This article describes the biology, damage, and management of the catalpa caterpillar.
Figure 1. Catalpa sphinx adult (Ken Childs).
Biology
Adults are brown (Figure 1) and have a 2.5 to 3.7 inch (6.3 to 9.3 centimeter) wingspan. Adults are present from spring through fall. After mating, females lay clusters of up to 1,000 eggs on the underside of leaves. Young catalpa caterpillars that emerge (eclose) from eggs are white with black spots on the body (Figure 2). Older caterpillars are approximately 3.0 inches (7.6 centimeters) long, with a black head and black stripe that extends the length of the back (Figure 3).
Figure 2. Young catalpa caterpillars (Andy Reago and Chrissy McClarren).Figure 3. Older catalpa caterpillars.
There are also yellow stripes, with black vertical bands, that extend along both sides of the body (Figure 4). Some caterpillars will have a row of black spots along the back but will not have a black stripe. There are five instars (stages between each molt). Caterpillars are present from spring to late fall. Caterpillars eventually move to the base of a catalpa tree and enter the soil to pupate. They overwinter as pupae in the soil at a depth of 2 to 3 inches (5.0 to 7.6 centimeters). There may be up to three generations per year in Kansas.
Catalpa trees contain iridoid glycosides, which are compounds that serve as antifeedants for generalist insect species or attractants for specialist insect species. The presence of iridoid glycosides, also called catalposides, may be why the catalpa caterpillar only feeds on catalpa trees. The iridoid glycosides, which are stored in the hemolymph, are sequestered by catalpa caterpillars, resulting in their being unpalatable to predators.
Damage
Young caterpillars feed initially in groups and then disperse among a tree. Caterpillars remove leaf tissue, except for the main veins. Extensive populations of older caterpillars can completely defoliate a catalpa tree (Figures 5 and 6).
Figure 5. Catalpa tree feb upon by catalpa caterpillars (Raymond Cloyd).Figure 6. Catalpa tree fed upon by catalpa caterpilars (Raymond Cloyd).
Management
Remove leaves with eggs and caterpillars from trees and place them into a bucket with soapy water.
Ensure that catalpa trees are properly watered and fertilized so they can withstand feeding by catalpa caterpillars and produce new leaves later in the growing season.
Apply a contact or stomach poison insecticide when young caterpillars are present in the spring.
Replace young catalpa trees that are completely defoliated with a different type of tree.
Caterpillars are susceptible to attack by a parasitoid, Cotesia congregata. A catalpa caterpillar that has been attacked by the parasitoid will be covered with white cocoons (Figure 7).
Figure 7. Catalpa caterpillar with white cocoons on the body (Bill Duncan)
Kansas State University Research and Extension Bookstore recently released three new and updated publications to assist growers and gardeners. The publications cover topics ranging from agricultural pests to new wheat varieties and are available for download.
The new Kansas Wheat Variety Guide (MF991), authored by Kelsey Andersen Onofre and others, is an annually updated resource for selecting wheat varieties. The 2025 guide features new variety profiles and additional information on varieties with herbicide-tolerance traits, providing a valuable tool for farmers making planting decisions.
In addition to the wheat guide, two new publications by Raymond A. Cloyd address common insect-related issues in landscapes and gardens. The guide titled Lace Bugs: Insect Pests of Horticultural Plants (MF3703) offers detailed information on the biology, damage, and management of lace bugs, which are known to feed on a variety of horticultural plants.
The second publication, Cicada Killer (MF3704), focuses on the solitary wasp known as the cicada killer. The guide provides insights into the insect’s biology and behavior, as well as management strategies for those dealing with them in their yards or gardens.
All three publications are available for free download from the K-State Research and Extension Bookstore website.
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 Tomatoesavailable 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
The time is approaching when the 1/8 to 1/4 of an inch bag of the bagworm, Thyridopteryx ephemeraeformus, caterpillar (larva) will be present on broadleaf and evergreen trees and shrubs. Hence, you should be ready to “take action” against bagworms when they are observed on plants. Bagworm caterpillars (larvae) feed on conifers, but they also feed on a wide range of broadleaf plants, including: elm, flowering plum, hackberry, honey locust, linden, maple, oak, rose, sycamore, and wild cherry. Apply insecticides when bagworms are 1/4 of an inch long or less (Figure 1) to maximize effectiveness of insecticide applications and reduce plant damage.
Figure 1. Young bagworm caterpillar (larva) feeding on plant foliage (Raymond Cloyd).
There are several insecticides labeled for use against bagworms; however, the insecticides commonly recommended to manage bagworm populations early in the season are Bacillus thuringiensis subsp. kurstaki and spinosad. These active ingredients are commercially available and sold under various trade names.
Figure 2. Product containing Bacillus thuringiensis subsp. kurstaki as the active ingredient (Raymond Cloyd).
The bacterium, Bacillus thuringiensis subsp. kurstaki (Figure 2), kills young bagworm caterpillars after they have consumed or ingested the bacterium. The insecticide is sensitive to ultraviolet light degradation and rainfall, which reduces residual activity (persistence). Consequently, repeat applications may be required. Spinosad is the active ingredient in several homeowner products, including Captain Jack’s DeadBug Brew (Figure 3) and Monterey Garden Insect Spray. Spinosad works through contact and ingestion but is most effective when ingested by young bagworm caterpillars. Managing bagworms with these insecticides involves applying the insecticides early in the growing season and making frequent applications to kill the young caterpillars feeding on plant foliage. Apply the insecticides weekly for three to four weeks when bagworms are first noticed to avoid problems later in the growing season.
Figure 3. Product containing spinosad as the active ingredient (Raymond Cloyd).Figure 4. Arborvitae (Thuja) defoliated by bagworm caterpillars (Raymond Cloyd).
Bagworms typically start feeding on the tops of trees and shrubs. Therefore, thorough coverage of all plant parts and frequent applications are important in managing bagworm populations. Multiple applications are usually required because bagworm caterpillars do not emerge (eclose) from eggs simultaneously. Instead, they emerge over time depending on temperature. In addition, young bagworms may be ‘blown in’ (called ‘ballooning’) from neighboring plants on silken threads. If left unchecked, bagworms can cause substantial plant damage, thus ruining the aesthetic quality of plants (Figure 4). In addition, bagworms can kill plants (especially newly transplanted small evergreens) because evergreens usually do not produce another flush of growth after being fed upon or defoliated by bagworms. For small plantings with minimal bagworm infestations, you can hand remove the 1/8 to 1/4 of an inch bags containing the caterpillars and squish them between your fingers.
For more information on bagworms, you can access and read the following extension publication:
Cloyd, R. A. 2019. Bagworm: insect pest of trees and shrubs. Kansas State University Agricultural Experiment Station and Cooperative Extension Service. Kansas State University; Manhattan, KS. MF3474. 4 pages. http://www.bookstore.ksre.ksu.edu/pubs/MF3474.pdf
By Raymond A. Cloyd, Professor and Extension Specialist in Horticultural Entomology/Plant Protection
