Thursday, May 27, 2010

Attack of the Yucca Bugs

This year you many have noticed abundant numbers of yucca bugs, Haticotoma spp. (Hemiptera: Miridae), if you have yucca in your landscape. The adults are about ¼ inches in length with a red head and pronotum and grayish-black wings. The yucca bugs are usually found in large groups on the upper leaf surface and will tend to move quickly when disturbed. The immature stage or nymphal stage (those without wings), will also be present on the leaves. The yucca bugs have piercing sucking mouthparts so their feeding causes small pale spots or blotches on leaf surfaces where the green chlorophyll has been removed.
Some control options for the immature stage include insecticidal soap or pyrethrins. Systemic insecticide products, such as those containing acephate, dinotefuran or imidacloprid, are also effective for control of these bugs.

Haticotoma (Hemiptera: Miridae) species on yucca. Photo by Bart Drees, Professor and Extension Entomologist, Texas A&M University.

Friday, May 21, 2010

Possible New Scale Found on Crape Myrtles in North Texas

This bark scale in the genus Eriococcus, is thought to be an exotic insect pest that has infested North Texas crape myrtles. These bark scales appear as white, waxy encrustations near pruning wounds or in branch crotches. Larger female scales “bleed” a pink liquid when crushed. Since this scale excretes honeydew, the limbs and leaves become sticky. In heavy infestations, black sooty mold will begin to grow on the truck and branches of the crape myrtle.
Currently, the crape myrtle bark scale has only been observed infesting crape myrtles in north Texas area (from South Dallas to Sherman). If you live outside this area and believe you have an infestation of this scale, please submit your sample or a picture of the infested crape myrtle to your local county Extension office or to Dr. Mike Merchant ( or myself ( at the Texas AgriLife Research and Extension Center, 17360 Coit Road, Dallas, TX 75252.

Some Control Options:

For heavily infested crape myrtles, it is recommended to wash the trunk and limbs with a soft brush and dishwashing soap solution to remove female scales and egg masses. Also, washing with the soapy water will remove some of the black mold.
Systemic insecticides such as those containing imidacloprid or dinotefuran as a drench applied to the root zone have shown good control when applied between the months of May and July. Also winter applications of dormant oil to the bark and crotches of the plants where scales shelter is an effective control option.