brown stink bug nymph

STINK BUGS are increasingly a problem for many southern soybean growers. Photo is of a brown stink bug nymph.

Beat down soybean insect pests before they cause damage to your crop

Scouting is critical, especially in a late-planted year like 2013.

When you see soybean loopers blowing out the top of the canopy, you’ve waited too long to take action,” says Gus Lorenz, Extension IPM specialist at Lonoke, Ark. “They start at the bottom of the plant and work their way up, so you can’t windshield scout loopers.” 

Scouting is critical, especially in a late-planted year like 2013.

“For example, we had really spotty bollworm infestations, Lorenz says. “You could walk across the turnrow from one field that was blooming into another field, and one field would have treatment level while the other field would hardly have any worms. That’s why scouting by the grower and/or consultant is critical. 

“There’s no rhyme or reason why bollworms infest one field and not one beside it. I saw some drilled beans that had higher numbers than row beans with open canopy.

“We need to scout every field and don’t assume that just because the middles have lapped that we’re safe. I encourage growers to use newer products like Belt, Prevathon or Besiege for bollworm control.”  

Stink bugs, which have been a perennial problem for South Carolina soybean growers for some time, were very pronounced in 2013.

“We experienced a lot of pressure from stink bugs because of lush plant growth from all of the rain,” says Jeremy Greene, Clemson University entomologist at Blackville. “Stink bugs represent a group of our most damaging insect pests — they infest a large percentage of our fields regularly, particularly late in the season.” 

The corn earworm can also cause problems in the state’s soybeans.

“We can’t stand many of these pod feeders — not the way we can tolerate some defoliation from caterpillar pests, including soybean loopers and velvetbean caterpillars, which can be troublesome in southern South Carolina,” Greene says. “Additionally, the kudzu bug is expected to remain an important soybean pest in 2014.” 

To maximize profit, he urges growers to use a crop consultant to check acres and to recommend timely IPM strategies.

“For the price of an insecticide application, you can have a consultant look at every field,” he says. “It is an old cliché, but the best thing a producer can apply to his field is the shadow of a consultant.”

Much of Mississippi’s insect pressure depends on planting dates.

“If we continue to grow a lot of grain, we’ll have many mixed planting dates and more later-maturing varieties,” says Angus Catchot, Mississipppi State University Extension entomologist at Starkville. “Later-planted beans are exposed to intense insect pressure. 

“We’ve seen an increase of stink bugs. Depending on the winter’s severity, we’ll probably deal with more of them in 2014. All later-planted beans also need to be monitored extremely closely for bollworms and migratory pests such as soybean loopers and velvetbean caterpillars.”

The kudzu bug, a new pest for the state, has been spotted in 26 counties. This invasive pest reproduces rapidly.

“We made a few applications this year, but we expect much higher numbers next year in our state,” Catchot says. “In 2014, this pest’s status will be greatly elevated in Mississippi, based on the findings and its reproductive capacity. Scout and spray.”  

The kudzu bug is expected to be Alabama’s next big insect problem statewide. “We’ve found it in every county,” says Tim Reed, Extension entomologist at Belle Mina.

“We sprayed for the pest in about a dozen of our 67 counties in 2013. Hotspots include some counties along the Georgia line and counties near Interstate 85 between the Georgia line and Montgomery/Autauga Counties.”

The highest density Reed observed in Alabama was in August 2013 — 70 kudzu bugs per sweep across two rows of full-season soybeans at the Prattville Research Station. With the population being established in other counties in 2013, the numbers could explode in 2014.

“Caterpillar populations in soybeans were extremely low throughout Alabama in 2013,” Reed says.

“However, when you have sub-threshold levels of several traditional pests and you add kudzu bugs to the list, it is difficult for growers to leave out an insecticide for their soybeans following wheat in August through early September.”

Stink bugs are still considered Georgia’s No. 1 soybean insect pest. They are followed by foliage feeding caterpillars, such as soybean loopers and velvetbean caterpillars and kudzu bugs.

“We scout and treat as needed for these  pests,” says Phillip Roberts, Extension entomologist at Tifton. “We can also have seedling pest problems with lesser cornstalk borer, especially in really dry conditions.

“Some growers apply a preventive treatment at planting for lesser cornstalk borer if we’re really dry and if lesser cornstalk borers are active in nearby crops such as peanuts. We’ll also make a preventive treatment if we’re planting behind burned wheat straw.

“Once we establish a stand, we scout and treat kudzu bugs, foliage feeding caterpillars and stink bugs. In addition to using a scout, educate yourself so you can scout your fields from emergence until maturity.” 

Tennessee soybean growers deal mainly with stink bugs and late season caterpillars, including corn earworms and soybean loopers. Growers also need to be more aware of the kudzu bug in 2014.

“The kudzu bug is spreading rapidly in Tennessee and Mississippi,” says Scott Stewart, Extension entomologist at Jackson.

“It’s not in every field every year and will not always require treatment. However, we treated some fields in eastern Tennessee in 2013 and expect to treat some fields in 2014 in central and western Tennessee.

“They’re not difficult to control with products containing bifenthrin, such as Brigade. Other pyrethroids like Karate and Mustang Max also work.

“Kudzu bugs have a history of appearing in small numbers and suddenly exploding into a large population. They seem to move into soybeans near blooming, R1 and R2.

“It remains to be seen, but in western Tennessee, our biggest problems may occur in our later maturing beans. We will have some lessons to learn as this new pest expands its range northward.”

See more articles from the Southern Corn and Soybean Production Guide!

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