Pecan weevils begin to emerge from the soil around the first of August so emergence is underway.

Pecan weevil management is directed at preventing female weevils from laying eggs in nuts and successful oviposition cannot happen until late gel/early dough formation occurs at the tip of the nut.

First application of and insecticide should be made when this kernel formation stage has been reached, regardless of any trap catches or lack of. A second application will be needed 10 days later. Any adult emergence traps need to be monitored until the latest maturing cultivar has reached shuck split.

Female weevils are not known to oviposit after shuck split.

COCKLEBUR

The cocklebur is an introduced annual plant in the sunflower family. It is a course, rough weed that is found all across Texas.

This plant spreads rapidly around tanks and down draws when moisture is adequate for germination. The leaves are toothed or lobed and are located alternately along the stem. Separate male and female flowers grow on the same plant, although both are inconspicuous.

The male flowers occur in dense clusters on the ends of the stems; female flowers occur in the leaf axils. Cocklebur fruits are conspicuous and covered with many spines. The fruit has two compartments, each containing a seed. The plant's forage value for wildlife and livestock is poor, and cocklebur in the seedling stage is poisonous to livestock.

The cocklebur is found throughout most of the United States. Its habitat is found in dry regions, it is most common around water holes, playas, arroyos and disturbed areas.

Cockleburs poison all classes of livestock. The toxic substance in the seeds is a glycoside which causes hypoglycemia and massive liver damage. Although livestock generally do not eat the seeds, problems can occur when cattle are fed whole cottonseed or hay contaminated with cocklebur.

The toxic agent remains present in the seedling through the cotyledon stage. The toxin concentration drops rapidly when the first true leaves appear. A toxic dose of seedlings is about 0.75 to 1.5 percent of the animal’s weight. Seedlings are toxic even when dead and dry.

Symptoms generally occur 12 to 48 hours after cocklebur seedlings are eaten. They include general weakness; depression; unsteady gait; rapid, labored breathing with a weak, rapid pulse; subnormal body temperature with nausea and regurgitation. Once the animal is down, it convulses, makes running motions with its legs or shows a marked curvature of the neck. Death usually occurs a few hours to 3 days after the first signs appear.

For more information, call the Erath County Extension Office at 254-965-1460.

Lonnie Jenschke is an Erath County extension agent.