July 24, 2007

 

High temperature may slow aphid growth in Kansas soybeans

 

 

Soybean aphids have been found in Kansas, but a Kansas State University (KSU) extension official says hot weather could slow growth in the insect's population and reduce the risk of crop damage.

 

"Aphids don't do well with temperatures above 95 degrees," said KSU entomologist Phil Sloderbeck told Dow Jones Newswires. Temperatures in the high 90s Fahrenheit can be detrimental to the aphid population and possibly decrease any chance of crop damage, he said. "We're kind of on the borderline," Sloderbeck said. However, "if temperatures are between the 80 and 90s, we can see an increased population."

 

According to private firm T-storm Weather, high temperatures across Kansas were hovering around 92-94 degrees over the weekend.

 

Kansas reported its first finding of soybean aphids July 12 in a university sentinel plot, aphids were discovered five days later in Riley County, KSU said in a press release Friday (July 20).

 

"They're somewhat earlier than in past years, although approximately in the same time frame as seen in 2005," said extension entomologist Jeff Whitworth. "But, populations that year never really became troublesome."

 

Aphids were a problem in 2004, when cooler temperatures favoured population growth and required some fields to be sprayed with insecticides. Unlike 2004, Sloderbeck said the temperatures for this summer are not as cool as they were then, which makes conditions less favourable for a similar an outbreak.

 

Kansas soybeans are still vulnerable to aphid damage, however, because the crop is still in the beginning and most critical stages of development, extension officials said.

 

The aphid populations discovered in Kansas so far are small and widely scattered, Whitworth said.

 

Aphids can transmit diseases, stress soybean plants and reduce yields through feeding, the release said.

 

As of Monday (July 23), there have not been any other reported findings of soybean aphids in the state, Sloderbeck said.

 

In 2006, Kansas produced 98.5 million bushels of soybeans, according to the US Department of Agriculture.