Thursday, November 26, 2009

Increase 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 moths resemble a wasp, with a red abdomen surrounded with black bands at each segment; their front wings are covered with metallic brown scales and their back wings are clear with a brown band. Adult females lay eggs on the leaves and stems of primarily 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.

Some Control Suggestions:

Some Non-Chemical Controls:
Keep natural enemies in the garden such as parasitic wasps that will attack squash vine borer eggs and larvae. Also adult ground beetles (Family Carabidae) will attack squash vine borer larvae. Split vines should be covered with soil immediately after the larvae have been removed. Also remove vines soon after harvest to destroy any larvae still inside stems.

Some Chemical Controls:

Some 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.

Southwestern squash vine borer, Melittia calabaza (Lepidoptera: Sessidae), adult. Photo by G. McIlveen, Jr,

Friday, November 20, 2009

Abundance of Hackberry Gall Nipple Makers

Many residents that live in neighborhoods with hackberry trees have been noticing many 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. In the fall, these insects invade indoors looking for an overwintering site. Normally, they will overwinter under the bark of trees, but will also come indoors through any cracks and crevices such as around windows and doors usually at night since they are attracted to indoor lights. However, those that come inside are going to die.
In the spring, the adult psyillds will emerge and lay eggs in the leaves of hackberry trees. When the egg hatches, the developing psyilld begins feeding and the leaf begins to form a small pocket around the psyilld as the insect develops, forming a gall. The galls that are produced vary in size from 1/8 to ¼ inch and are found on the leaves and petioles. The adult gall will then emerge in the fall. Even though the galls can be unsightly on the leaves and sometimes cause premature leaf drop, they do not appear to affect tree health. This means no chemical treatments are recommended.
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 psyilld population!

Photo of hackberry gall psyllids, Pachypsylla sp. (Homoptera: Psyllidae), adults. Photo by C.L. Cole, Texas A&M University.

Thursday, November 12, 2009

Argentine Ants Not Crazy Rasberry Ants

Argentine ants seem to be causing alarm to some homeowners. Many people are confusing them with the Rasberry crazy ant (recently in the news); since they form dense foraging trails and often invade homes and other structures. Argentine worker ants are all the same size, about 1/8-inches in length and are dull brown in color. These ants have multiple queen colonies allowing workers to move freely between colonies. Populations sometimes appear to be a giant super colony. Even though, argentine ants do not bite or sting, their colony size can be in the hundreds of thousands.
These ants usually nest in cavities in soil, under rocks, in flower beds and in branches or cavities of trees. They eat sweets, fresh fruit, and buds of some plants and tend honeydew-producing insects, such as scales and aphids. These ants travel in distinctive trails along sidewalks, up the sides of buildings, along branches of trees and shrubs, along baseboards, and under edges of carpets.

Some Control Options:
Some Non-Chemical Control Options:

Trim tree branches and other plants so they do not touch structures, since argentine ants can use these branches to get into structures.
Caulk and seal any cracks or little openings around the structure.
Do not stack firewood and building materials next to structures, since these ants can build nests in these materials.
Reduce moisture sources such as leaky plumbing and free-standing water in and around structures.
Clean window sills to remove dead insects, since these ants will feed on dead insects.
Check potted plants for ants before bringing the plants indoors by watering to check for ants moving within the soil.

Some Chemical Control Options:
Spot treatments at points of entry into structures such as around window sills and door thresholds may be effective. Insecticides used for these treatments should be a wettable powder or microencapsulated formulation labeled for this type of application. If colonies cannot be located, bait insecticides can be used. Argentine ants are mostly attracted to sweet baits. Such baits containing boric acid, hydramethylnon and sulfluramid are suggested for control.

Photo of argentine ant worker. Photo by Elizabeth “Wizzie” Brown, Program Specialist-IPM, Texas AgriLife Extension.