|
Southwestern squash vine borer, Melittia calabaza (Lepidoptera: Sessidae), adult. Photo by G. McIlveen, Jr.
|
Invasion of Squash Vine Borers
Squash vine borers are the most common and most damaging pests of squash. The larvae are borers, so they will cause damage as they tunnel into the stems. They usually feed on squash and related wild plants, but also can feed on melons and cucumbers.
The adult moth resembles a wasp, with a red abdomen surrounded with black bands at each segment; the front wings are covered with metallic brown scales, and the back wings are clear with a brown band. Adult females lay eggs on the leaves and stems primarily of squash. The larvae hatch and begin burrowing into host plant stems. The larva is white in color with a brown head and grows to be an inch in length. The larvae will produce sawdust-like frass near the base of the plant, which may cause the stems to wilt and die. The larvae then climb from the stems to pupate in the soil.
Non-Chemical Controls
Keep natural enemies in the garden, such as parasitic wasps that will attack squash vine borer eggs and larvae. Adult ground beetles (Family Carabidae) also will attack squash vine borer larvae. Split vines should be covered with soil immediately after the larvae have been removed. Remove vines soon after harvest to destroy any larvae still inside stems.
Chemical Controls
Chemical suggestions include such active ingredients as pyrethrins, permethrin, or carbaryl. Apply the chemicals to the base of the plant, underneath the foliage and underneath the stems of the plant.
Aggregating Lady Beetles
|
Multi-colored Asian ladybeetle. Photo by Mike Merchant, professor and Extension entomologist, Texas A&M University.
|
Multi-colored Asian ladybeetles are introduced insects from Asia that have established themselves in many areas of the U.S., where they reduce populations of aphids and scale insects. However, these lady beetles likes to congregate in large numbers around buildings when they overwinter. This causes them to sometimes move indoors in the cooler months. They will exude a yellowish liquid when disturbed (reflux bleeding), which can stain fabric and can cause skin irritation. They can also bite, since they have chewing mouthparts.
Exclusion practices should be used to prevent these ladybeetles from entering buildings. All cracks and crevices, such as around windows, doors, air conditioners, and utility pipes should be sealed in late summer and fall. If beetles are spotted inside the home, then a vacuum should be used to remove them. Remember to dispose of the vacuum bag outside, so the beetles do not escape and re-invade the building.
Other Insect Sightings
Hackberry gall nipple makers
Many residents who live in neighborhoods with hackberry trees have been noticing small cicada-looking insects, about 3/16 inches in length with spotted wings, on their window screens and doors. These insects are adult hackberry gall psyllids or also called hackberry nipple gall makers. Hackberry psyllids are not harmful to people or pets and will not attack indoor plants or furnishings. Since they are a seasonal annoyance, residents can vacuum them to remove them as needed. As the temperatures fall, so will the hackberry gall psyllid population!
Chilli Thrips
Chilli thrips, Scirtothrips dorsalis (Hood), have been documented in eight counties across Texas and are believed to be in other counties. The adult thrips are extremely small, 2 mm in length, pale with dark wings. The immature chilli thrips are also pale in color. Since these thrips are smaller than western flower thrips, we usually do not notice them, but we can detect their presence by their damage. They are foliage feeders, causing the leaves to brown and curl and sometimes detach from the stem at the petioles. Their feeding may also cause buds to become brittle and drop. If you are currently spraying for western flower thrips, then you will probably not have a problem with chilli thrips. For more information, please visit http://chillithrips.tamu.edu.
About the author: Kimberly Schofield is a program specialist in the field of urban integrated pest management at the Texas A&M Research Center in Dallas.
Mention of commercial products is for educational purposes only and does not represent endorsement by Texas AgriLife Extension or The Texas A&M University System. Insecticide label registrations are subject to change, and changes may have occurred since this article was written. The pesticide user is always responsible for applying products in accordance with label directions. Always read and carefully follow the instructions on the container label.
|
