• Crop development update
• Soybeans for hay or silage
• Insect pests: Western Bean Cutworm, Bean Leaf Beetle, Soybean Aphid and Alfalfa Webworm

Corn development is nearing partial or full dent in many fields. At R5 (Dent, 35-42 days after silking) all or nearly all kernels are dented or denting. The kernels are drying down now beginning at the top where a small hard white layer of starch is forming. This starch layer appears shortly after denting. The time to harvest corn for silage is when the milk line advances from ¼ to ¾ down the kernel. To learn more on harvesting corn for silage, go to this University of Wisconsin web site: http://www.uwex.edu/ces/crops/uwforage/Silage.htm

Cornell University http://www.cce.cornell.edu/yates/AgCorner11.1.00.htm
Ohio State University http://www.scas.cornell.edu/forage/comment/soy.html
University of Nebraska http://nerec.unl.edu/ipm/2000/Making

• I’ve been talking about the Western bean cutworm for several weeks now and I will mention it again. The pest has been reported in Ida and other counties, I would expect this pest is in other fields as well. Scout your cornfields now to determine if you have a problem with WBC. Refer to this University of NE web site for identification and management information on the WBC. http://www.ianr.unl.edu/pubs/insects/g1359.htm

• If you have late planted corn, 2^nd generation corn borers were laying eggs in these fields last week. Look for egg masses on the underside of the leaves, three leaves above and below the ear. Go to this IA State web page for a worksheet to use for control decisions http://www.ipm.iastate.edu/ipm/icm/1996/8-5-1996/ecbcostben.html

• The start of second generation Bean Leaf Beetle emergence in soybeans should be occurring now. If you scouted 1^st generation BLB and you were over the treatment threshold (1st generation threshold for 2nd generation treatment) you should be out in the field looking for beetles and damage now. If you did not scout 1^st generation beetles, use the thresholds in Table 1 to make management decisions. Most damage from 2^nd generation BLB will be from feeding on the pod, look for this when scouting.

 

Crop value ($/bushel)	Treatment cost per acre (insecticide + application)
	$7	$8	$9	$10	$11	$12	$13	$14	$15
	beetles per foot of row
$5.00	5.5	6.3	7.1	7.9	8.7	9.5	10.3	11.0	11.8
$6.00	4.6	5.2	5.9	6.5	7.2	7.8	8.5	9.2	9.9
	beetles per sweep
$5.00	3.5	4.0	4.5	5.0	6.5	7.2	7.7	8.3	8.7
$6.00	2.9	3.3	3.7	4.1	5.4	6.0	6.4	6.9	7.3

• The Soybean Aphid has progressed as far west as Webster County. Look for the aphid on the underside of new soybean trifoliate leaves.

• Potato leafhoppers and Alfalfa Webworm have been a problem in many alfalfa fields. Most fields are very dry and at or near bloom. Cutting the alfalfa may be the best control strategy for these fields. After cutting, keep a close eye on the field for continued injury from these pests.