As digging got underway and loads of peanuts were arriving at buying points for inspection, David Adams’ and John Beasley’s cell phones started ringing. County agents and buying point managers were calling on the University of Georgia’s top Extension peanut entomologist and Extension peanut agronomist to come look at what was causing load after load to grade Segregation (Seg) 2.
Burrower bug had come out in a big way, and growers were losing money because of this tiny, black bug.
Tiny Bug, Big Problems
“It seemed like we had an explosion in the population for a time,” says Adams, “It was like armyworm will do, but it was mainly in non-irrigated and strip-tilled peanuts.”
Was it the heat and drought just ahead of harvest that triggered the severity of the outbreak? Adams says that insects can respond to conditions just like the crop or weeds can.
“Everything grew faster this year and insects can do that too. This year we may have had a full three generations, when in previous years at most we would have had two,” he says.
Like its relative, the stinkbug, burrower bugs have needle-like mouthparts that pierce through the pods and into the kernel, making a “sting” on the seed. Damage is not evident until it is shelled out and the skin is removed, then damage can be easily seen.
“Sometimes the damage may show on the testa or seedcoat, but not at all on the pods,” Adams says. “They may feed on a lot of different items, but maturing peanuts are a delicacy to them.”
Non-Irrigated, Minimum Tillage
Previous research has shown that burrower bug tends to be more of a problem in reduced-tillage fields under drought stress.
“Thus far,” Beasley says, “the greatest concentration of burrower bug damaged loads are from Brooks, Cook, Berrien, Colquitt and Tift Counties. We’ve also had reports of Seg. 2 loads attributed to burrower bug from Dodge and Emanuel Counties.”
At this point, almost all of the reports of burrower bug damage at levels severe enough to cause a load to go Seg. 2 have been from fields that were non-irrigated and had reduced or minimum tillage,” Beasley says. “There have been a very few reports of irrigated fields that had levels high enough to go Seg. 2.
“I haven’t heard a report on any fields that were deep turned that went Seg. 2 from burrower bug. That is not to say when all loads are graded that there won’t be a few isolated cases of deep-turned fields with the damage,” he says.
Adams says, “There is evidence that if you disturb the land, even for a cover crop, then you interrupt the population.
“We don’t deep turn as much as we used to, but in a drought year like this, we may see some minor problems even in cultivated fields,” he says.
However, Beasley says to keep in mind that there were some isolated areas of Seg. 2 damage in the 2009 crop, but very little of the damage was from burrower bug. “We concluded that most of the Seg. 2 damage in 2009 was from inadequate calcium uptake.”
Adams says they did start to see less problems as harvest went along, but continued to get a few calls.
“We got a lot more rain in August, so maybe that reduced the problem. Also, with all that rain, you get other things growing like weeds, and maybe they started feeding on other things.”
Until all the loads are graded, it is impossible to know the severity of the problem or percentage of the crop affected. Beasley and Adams will use their county agent surveys to assess the situation.
“We have a survey out to the county agents right now, and we will use that information to better understand what we are dealing with,” Adams says. “We have county agent meetings in December and then grower meetings soon after, so we have a lot of work to do between now and then.”
Recommendations? Stay Tuned
Beasley and Adams agree that it is too soon to discuss what growers should do for 2011.
“We do know that Lorsban has an impact, but that is not the overall answer. In a year like this, even if you get some control, you may still have a problem, similar to situations with lesser cornstalk borer at times,” Adams says.
“We need to discuss our options before we can come forward with a recommendation,” Beasley says. “I don’t know that we need to tell every grower producing peanuts in a conservation tillage system, they have to now start deep turning.
“We also don’t know that we need to tell every producer growing peanuts under rain-fed only conditions that they have to deep turn every acre,” he says. “It is a complex issue.”
Adams says, “Maybe we’ll get the rainfall we need in 2011 and we won’t see the burrower bugs.”
In the meantime, as harvest tapers to a close, maybe Adams and Beasley can give their cell phones a rest. PG