In the good old days, a calendar was the main tool for deciding when it was time to treat for certain types of insects on crops. Unfortunately, this technique has proven to be a costly, time-wasting and ineffective procedure.
Many more factors than simply the time of year goes into finding the most optimal period at which certain bugs need to be treated.
The greenbug is a cereal aphid that can cause serious problems for wheat producers if untreated. Scouting for these aphids is well advised, especially in light of dry conditions this winter.
“In areas where it is really dry right now, greenbugs are starting to show up and cause some pretty severe problems,” said Tom Royer, professor of entomology with Oklahoma State University’s Division of Agricultural Sciences and Natural Resources.
The coordinator of the division’s Integrated Pest Management program, Royer warns that greenbugs have more of an effect on wheat when the wheat is under stress.
Producers may be hesitant to treat for greenbugs as their wheat is already weakened and dry, fearing that placing more inputs in the ground is a waste of time and money.
Royer recalls a similar type of spring in 1996, with dry conditions and wheat producers unsure of what to do. Some producers ended up treating, while others restrained. A survey done following the harvest showed that producers who treated for greenbugs, despite the dry conditions, turned over more than four times the yield of those who did not treat.
“The difference in yield more than paid for the insecticide applications,” he said.
However, just going out and spraying can be a waste of money. Greenbugs are attacked by a small parasitic wasp that builds up in the spring. As temperatures warm, they become very active and often take out a greenbug population.
“That is why I recommend using the ‘Glance-n-Go’ sampling system for greenbugs,” Royer said. “It accounts for wasp activity, and keeps a producer from wasting a spray when natural enemies have already taken care of the problem.”
The results from the scouting may provide good news to producers.
“Treatment may or may not be warranted, but scouting is definitely an import part of it,” said Eric Rebek, an assistant professor with the OSU department of entomology and plant pathology. “You’re just wasting time, money and product by putting out insecticides that don’t need to be put out.”
Rebek said there are various ways to scout a wheat field, but starting with the ‘Glance-n-Go’ sampling system is a good place to start.
“It sounds like it might be a hassle initially because you have to go out and walk the field,” he said. “But when it comes to the amount of time and money that goes into treating a field, you are actually saving yourself if you don’t have to treat.”
‘Glance-n-Go’ is proven to reduce sampling time by 25 percent or more and will produce an accurate treatment threshold for producers to apply. And, with any luck, greenbugs won’t be a problem.
“Don’t neglect the importance of the scouting program when making decisions,” Rebek said.
Additional information on the ‘Glance-n-Go’ system is available at http://www.ento.okstate.edu/gbweb/index.htm on the Internet.