Sunday, November 21, 2010

Squash Vine Borers are Active in Gardens

Squash vine borers are the most common and can be the most damaging pests of squash. The larvae tunnel into the stems of squash and other plants, including melons and cucumbers. This causes the stems to wilt and die. 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 larvae are white in color with a brown head and they grow to be an inch in length. The larvae will produce sawdust like frass near the base of the plant as they tunnel and then climb from the stem 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.
When wilting is noticed, a sharp knife can be used to cut a slit into the stem so the larva can be removed. New roots may grow along the cut stem, allowing the plant to survive. Split vines should be covered with soil immediately after the larvae have been removed.
Also remove vines soon after harvest to destroy any larvae that still might be inside the stems.

Some Chemical Controls:

Some chemical suggestions include using such active ingredients as pyrethrins, permethrin, or carbaryl. Apply the dusts or sprays to the base of the plant.

Photo of a southwestern squash vine borer, Melittia calabaza (Lepidoptera: Sessidae), larva. Photo by Bart Drees, Professor and Extension Entomologist, Texas A&M University.

Tuesday, November 9, 2010

Boxelder Bug Sightings

Boxelder trees are sometimes planted in landscapes, since they grow quickly, reaching heights of 30 to 50 feet. However, they are prone to attack by boxelder bugs. These bugs feed primarily on the female seed-bearing boxelder trees by sucking sap from the leaves, twigs and developing seeds. They will also feed on other trees such as ash, maple, plum and apple, causing scarring of fruits.
Adult boxelder bugs are ½ inches in length, brownish-black in color with three lengthwise red stripes near their heads. Under their wings, their abdomen is red. The immature boxelder bugs resemble the adults in shape, except they are smaller, wingless and bright red in color.
During the fall months, adults and immature boxelder bugs tend to congregate on the female boxelder trees and then begin migrating to a place to overwinter. Only adults overwinter by moving to hibernation sites either by crawling or flying. These bugs tend to cluster in large numbers on the sides of trees and structures, so they can easily enter structures under windows sills or through open doors or vents. If they do invade structures, their feces can stain curtains, paper and other home furnishings. Also their mouthparts can penetrate human skin, so beware when touching them.
The boxelder bugs that happen to enter indoors, will not live more than a few days indoors, do not breed inside, and are essentially harmless.

Some Options for Control:

Some Non-Chemical Control Options:
Removal of the female boxelder trees from the landscape would decrease this insect’s population.
Eliminate hiding places such as piles of boards, rocks, leaves, grass and other debris close to the house.
Caulk and close openings where boxelder bugs can enter the house such as around light fixtures, doors and windows, utility pipes and air conditioners.
Screen all windows, doors, crawl spaces, roof vents, since boxelder bugs are attracted to light and can fly in through doors and windows.

Some Chemical Control Options:
If you do not wish to remove female boxelder trees from the landscape, then the exposed immature boxelder bugs can be chemically treated in the spring and early summer. Insecticides containing the active ingredients such as neem, pyrethrin, rotenone, cyfluthrin, deltamethrin, esfenvalerate and malathion can be used. Specialized equipment may be required to treat tall trees.

Photo of boxelder bug. Photo by Elizabeth “Wizzie” Brown, Program Specialist-IPM, Texas AgriLife Extension.