What is in this article?:
• Though these tiny sucking bugs can do significant damage to soybeans, sometimes it’s the threat of damage, combined with the large numbers of these pests found in a field that can cost growers the most money.
• North Carolina State University Entomologist Dominic Reisig says, in general this year, many acres in North Carolina were treated for kudzu bugs that didn’t need to be treated.
NORTH CAROLINA State University Entomologist Dominic Reisig explains kudzu bug treatment at a recent field day.
Wide area of adaptation
“A recent USDA climatological model indicates kudzu bugs are best adapted to the entire South and lower Midwest. “We thought it needed kudzu as a host plant to undergo a first generation. After this season, we now know, it can produce two generations without kudzu,” Reisig says.
Exactly how far north, kudzu bugs can over-winter is not clear. Reisig says these bugs easily over-wintered throughout North Carolina. These bugs are fairly easy to find behind bark on pine trees and in commercial structures. Or, digging around in kudzu in the winter months, it’s easier to find, he adds.
Kudzu bugs range from green to a brown so dark it's almost black and are about the size of a mature soybean. They look a bit like ticks and a bit like dark ladybugs, and if observed under a microscope, have a definite ‘wobble’ when they walk.
University of Georgia Entomologist Wayne Gardner was one of the first to study kudzu bugs after they were first found in that state in 2009.
"If a kudzu bug was on you and sitting still, you might say, 'Gosh is that a tick?' If they were moving you might say, 'What kind of lady beetle is that?'" Gardner says.”
Kudzu bugs are distantly related to commonly occurring green and brown stink bugs, and like their distant relatives, these Asian imports do emit a protective odor. The kudzu bug odor is most prevalent along roadsides during or immediately after highway crews mow these roadways.
Gardner says kudzu bugs emit a fruitier smell than stinkbug — a stench that has been mistaken for other things. In one strange case, he says a woman called 911 to report a gas leak.
"There was no gas leak, but there were kudzu bugs all over her screens and doors and windows and porch," Gardner says.
For the remainder of this year, veteran North Carolina State University Entomologist Jack Bacheler says indications are good as of early August that kudzu bugs haden’t targeted late-planted, double-crop beans, planted behind wheat.
In a test in Scotland County, N.C., and checked in early August, kudzu bug nymph levels were close to the 15 nymphs per 15 sweep threshold in untreated plots and on several maturity groups in the April and May plantings.
Levels in beans planted later and behind wheat, were far lower at both the Scotland County and the Sandhills, N.C. locations, he says.
The first kudzu bugs in commercial soybeans in Tennessee were reported in the last week of July, by UT Extension IPM Specialist Scott Stewart. The find in extreme southeast Tennessee in Polk County should not cause growers in Tennessee or Kentucky too much concern this year.
However, Stewart says, kudzu bugs are definitely moving northward and growers in eastern Tennessee and Kentucky should pay attention to what is going on in states to the south and east, because 2013 could be a whole different story with kudzu bugs.
There are many unknowns about this unwanted pest from China, but entomologists agree it is still on the move and capable of doing a lot of damage on a multitude of crops in a fairly short period of time.