Posted 21 September 2009. PMN Crop News.
Late Start for Corn Crop Doesn’t Stop Spread of Western Bean Cutworm
Pioneer agronomists confirm eastern spread of destructive insect, appearance in new areas
Source: Pioneer Press Release. www.pioneer.com
Des Moines, Iowa (August 25, 2009) – Late planting and a milder summer in many areas have impacted the spread of western bean cutworm (WBC), but only in the sense of delaying the emergence of this destructive pest.
Recent trappings by university entomologists and field professionals from Pioneer Hi-Bred, a DuPont business, indicate the pest is moving eastward, with the heaviest infestations being reported in unprotected cornfields across northern Indiana, with some reports extending into Illinois and Ohio. Additional reports have confirmed the spread of WBC into central and northeastern areas of Michigan, areas new to WBC infestations.
“Traditionally, we’ve seen the heaviest pressure from Nebraska to central Iowa, but now we’re seeing WBC continue to move eastward along the I-80 corridor,” says Paula Davis, Pioneer senior marketing manager for insect and disease control traits. “Most of the time the spread of WBC is complete by mid-August. This year it appears to be a little late, just like everything else.”
WBC can reduce yields up to 40 percent in heavily infected fields. Young WBC larvae feed on tassels and silks, but eventually tunnel through the silk channel to reach developing kernels. Direct yield loss occurs as larvae consume all or parts of developing kernels. Because of the labor intensive nature of scouting, the critical timing needed for insecticide applications and the possibility that multiple treatments may be necessary, insecticides may not be an economical or effective solution to the WBC problem.
Spraying is occurring as signs of increased populations surface, but spraying must take place before the insect moves into the ear where it is protected by the husk. The threshold is 5 percent of the plants with egg masses or small larvae in the tassel. With moth flights reaching peak levels and approaching completion, increased feeding can be expected.
This makes it all the more important for growers to be prepared in advance. One of the most effective ways to be prepared is to get in-plant protection against WBC with Herculex® I and Herculex® XTRA insect protection traits, available in Pioneer brand hybrids. Fields planted with Herculex I and Herculex XTRA traits have shown to be effectively protected against WBC, which can be critical as WBC expands its reach.
“We really have seen certain insects starting to shift, and WBC is one of them,” says Davis. “This can be attributed to changing biotechnology developments, changing cropping practices and a changing environment. The key for growers is to know if there is a risk for WBC in their fields, and if so, they should monitor fields, contact their local agronomists and consider WBC-resistant hybrids.”
If growers have concerns or suspect WBC infestation, they can contact their local Pioneer sales professional or agronomist for management information. Growers also can visit university monitoring Web sites for current trapping locations.
In addition, insecticide products, such as DuPontTM Asana® XL, are available to assist in the fight against WBC and provide outstanding, longer-lasting control. With its unique cottonseed oil formulation, Asana XL resists washoff and provides superior UV stability, even under intense sunlight.