Crops Bulletin
May 23, 2013
       Issue 3           


Prepared by

Paul Kassel

Extension Field Agronomist



Serving Clay, Buena Vista, Dickinson, Emmet, Hancock, Kossuth, Palo Alto, Pocahontas, Sac and Winnebago Counties



The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, gender, religion, age, disability, political beliefs, sexual orientation, and marital or family status. (Not all prohibited bases apply to all programs.) Many materials can be made available in alternative formats for ADA clients. To file a complaint of discrimination, write USDA, Office of Civil Rights, Room 326-W, Whitten Building, 14th and Independence Avenue, SW, Washington, DC 20250-9410 or call 202-720-5964.



Cutworm: Black cutworm larvae are predicted to be large enough to damage corn on May 27-29 for north/north central/west central Iowa. No large problem is expected, but fields should be checked for this occasional pest of corn.


The transgenic traits Agrisure Viptera, Herculex 1, and Genuity SmartStax have activity on black cutworm and are expected to control moderate to low populations of black cutworm.


Seed applied insecticides - such as Gaucho, Poncho and Cruiser - will also offer some control of black cutworm. However, the low rates of these seed applied insecticides may not be effective against high populations of black cutworm. The combination of seed insecticides and cutworm effective transgenic traits should provide adequate control of cutworm.


Alfalfa Quality: Alfalfa quality can be tracked using PEAQ (predictive equation of alfalfa quality). The method uses alfalfa stand height and maturity stage to estimate the relative feed value (RFV). Current RFV values are in the 185 range. A value of 150 or greater is necessary for dairy quality alfalfa. The current PEAQ measurements are posted on the ISU Extension Dairy Team page.


Analog Years: The April rainfall and temperatures in 2013 have been analog or similar to 1947 and 1995. Both seasons then had a reversal in the weather that created above normal Stress Degree Days. The corn planting progress was also similar to 1984, 1993 and 1995. It is interesting to note that corn yields were 9 percent below trend line in 1995 and 3 % above trend in 1984. Analog years may help identify some trends but may not always be an accurate prediction of crop performance.


Rolling Emerged Soybeans: Land rollers have become a popular implement to use after soybean planting to aid with ease of harvest. Research by ISU has shown that land rollers can be used after soybean emergence. Land rolling after soybean emergence should occur before the V3 stage (about 6 inch tall soybean). Dry soil conditions and warm temperatures will minimize any potential crop injury.


Prepared by Paul Kassel, Extension Field Agronomist

Phone: (712) 262-2264, Email: