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Posted 30 August 2013. PMN Crop News.

Scouting Key to Identifying Yield-Robbing Soybean Pests

Growers encouraged to closely monitor fields each year for pests that repopulate and overwinter

Source: DuPont Pioneer Press Release.

Des Moines, Iowa (August 6, 2013)--While high heat and drought conditions last year controlled some yield-robbing insect populations, including soybean aphids, this season may reveal a different story, caution DuPont Pioneer experts. Moderate temperatures and delayed planting, combined with aphids’ ability to overwinter, could increase the risk of this insect’s infestation.


Insect specialists recommend scouting for aphids this season and taking action to prevent the pest from impacting soybean yields. While scouting, you may also find new soybean pests in your fields.

“Identified as strong fliers with the ability to hitchhike, both brown marmorated stink bugs (BMSB) and kudzu bugs continue to migrate and increase populations,” says Paula Davis, DuPont Pioneer senior manager for insect and disease resistance traits. “Along with soybean aphids, these pests will challenge growers to closely monitor their fields and keep tabs on current threat levels.”

BMSB have already been detected in a number of states, up to 40 in total, including every state east of the Mississippi. Kudzu bugs have rapidly spread across 10 southeastern states since the first detection four years ago.

Soybean yields are reduced as a result of feeding damage from BMSB and kudzu bugs. Kudzu bug infestations in Georgia and South Carolina show an average soybean yield loss of 18 percent, with ranges up to 47 percent. Growers in Maryland have estimated yield losses greater than 50 percent at field edges as well as delayed maturity due to early feeding by BMSB.

Management options

Pioneer experts encourage close scouting and use of insecticides to manage risk from pest infestations.

Soybean aphids – The distinguishing soybean aphid characteristic is cornicles, or black “tail pipes” projecting from the rear of the abdomen. The pests are typically light green and less than one millimeter in length with an oval or pear shape. Symptoms of infestations include shortened plant height, curled leaves with yellow edges, excessive honeydew on leaves and the presence of ants. Excessive honeydew may also promote mold growth, reducing photosynthesis.

DuPont Asana® XL insecticide has proven to be a great option for soybean aphid control. For maximum effectiveness, apply when populations reach threshold levels. The economic threshold to justify insecticides is 250 aphids per plant. Insecticides should be applied before the R5 plant stage and populations reach 1,000 aphids per plant. Soybean aphids pose a threat to soybean yields if economic threshold levels are left untreated– reducing production by more than 10 bu/acre.