Home / News / Crops news / More soybean aphids popping up -- this time in Kansas

More soybean aphids popping up -- this time in Kansas

Agriculture.com Staff 07/21/2008 @ 1:22pm

Kansas is once again hosting an unwanted summer visitor. Kansas State University entomologist Brian McCornack discovered soybean aphids July 11 in some of his Riley County, Kansas, soybean research plots.

The aphids had started colonizing -- feeding on the soybean plants -- and to produce many young, according to a university report.

"That indicates they had probably been around for seven to 10 days prior to detection," says K-State Research and Extension entomologist Jeff Whitworth, who is encouraging producers to scout for the pests.

Soybean aphids were first detected in Kansas in 2002. But, most soybeans were well past the growth stages which are susceptible to soybean aphid feeding damage, Whitworth says.

"We've had soybean aphid migration into the state every year since then, but it was only in 2004 that environmental conditions allowed them to reach damaging population levels," he says.

Soybean aphids damage the plant by sucking juice from the phloem (veins). This can stunt plant growth, reduce pod set, and/or result in smaller seeds.

The aphids are tiny, lime-green to yellow insects with black-tipped cornicles (tailpipes). They are most commonly found on the underside of leaves of early vegetative plants but may be found on all parts of late vegetative to early reproductive plants.

Healthy aphid populations produce enough shiny, sticky honeydew to be very noticeable, and it may be covered with a black "sooty" mold. They can also transmit several viral diseases that further affect the plant.

When planning a strategy to manage soybean aphids, Whitworth says, a producer should take natural enemy populations and the weather into consideration.

Lady beetles, green lacewings, and other predators feed vigorously on these aphids. Along with aphid parasites, they help regulate these pests in most years.

High temperatures also help to slow soybean aphid reproduction, which helps the predators and parasites to keep populations in check, he says. Daytime temperatures need to exceed 97 degrees Fahrenheit for a few days, however, to have a negative impact on aphid populations.

According to a report from Makhteshim Agan of North America (MANA), entomologists recommend examining the upper trifoliate leaves on 11 plants about 30 paces apart. A plant is considered to be infested if it has 40 aphids or more, but you don't have to count beyond 40 on any one plant, which makes it easier to keep moving through the field. If 100% of the 11 plants are scored as infested, consider spraying. If there is uncertainly, scout additional sets of five plants up to 20 more plants. If 80% of the additional plants are infested, consider spraying.

"Timing an insecticide spray at 250 aphids per plant should reduce the amount and subsequent cost of a soybean aphid management program, while providing sufficient protection," says Don Guy, MANA field development and technical services manager.

Kansas is once again hosting an unwanted summer visitor. Kansas State University entomologist Brian McCornack discovered soybean aphids July 11 in some of his Riley County, Kansas, soybean research plots.

CancelPost Comment
MORE FROM AGRICULTURE.COM STAFF more +

Farm and ranch risk management resources By: 07/07/2010 @ 9:10am Government resources USDA Risk Management Agency Download free insurance program and…

Major types of crop insurance policies By: 07/07/2010 @ 9:10am Crop insurance for major field crops comes in two types: yield-based coverage that pays an…

Marketing 101 - Are options the right tool… By: 07/07/2010 @ 9:10am "If you are looking for a low risk way to protect yourself against prices moving either higher or…

MEDIA CENTERmore +
This container should display a .swf file. If not, you may need to upgrade your Flash player.
Looking Out for Soybean Cyst Nematodes