Greenbugs are big insect threat to forage crops grown in Central Texas forage crops

By MANDY SPIKES | Central Texas Edition

December 25, 2003 -- Silage production is an important aspect of agriculture in the state of Texas. In order to help Central Texas producers learn more about crop production a Silage Shortcourse was held at the Comanche Community Center on Dec. 18 in Comanche. Dr. Chris Sansone, Extension entomologist, presented information on insect control on forage crops.

"You must look at integrated pest management (IPM) as a type of system. It's necessary to utilize all methods of pest suppression," Sansone explained. He stated that there are many seed treatments that work well on such insects as wireworms and fire ants.

The benefits of seed treatments he gave include - the product can be localized in the area it's needed, spray drift is eliminated, and there is an immediacy of the effect. Limitations are there must be good coverage of the seed, and it may be unnecessary in some areas. "It's better to be safe than sorry when dealing with insects on crops though," he advised.

One insect in particular that has caused problems with farmers is the greenbug. Greenbugs, light green bugs with a dark green strip, can cause leaf reddening on the plant by it's toxin.

"Females mature in 7-10 days and there is no need for mating. This is what makes them a problem," he said.

Farmers must pay attention to the natural enemies of the green bug in order to help with the population. These enemies include aphid parasites, lady beetles, and cattle grazing on the fields. "Parasites are critical. Lady beetles are very important. Do not underestimate the power of grazing," Sansone stated.

A good greenbug IPM is to start scouting the area once every week for the insect. "It's especially important to do this early in the season. Look at the wild hosts." He explained that it's good to recognize the growth stage. Look to see if the stage is early or late, if the plant is stressed or non-stressed or if there is a low or high plant population.

"The greenbug thresholds in sorghum is emergency to six inches. You can see visible damage with the aphids present. Greenbugs colonize showing leaf damage or before the death of one leaf. Then you will see the death of one leaf or two leaves. "

He recommended trying to keep the insects away from the plant during the first four to five weeks of growth. "Once the plant is up and going, it can tolerate a lot of greenbugs.

Treatment options Sansone gave include - planting greenbug resistant varieties. "Systematic soil insects can also help," he said.