Crops Bulletin
 August 9, 2016   
  Issue 8  
    
 

Prepared by

Paul Kassel

Extension Field Agronomist

 

Phone: 

(712) 262-2264

Email: [email protected] 

 

 

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.

Corn Rootworm:  Check corn on corn fields for rootworm control performance. Evidence of root damage and high numbers of corn rootworm adults indicate that rootworm may be resisting rootworm traits and/or insecticides. Dig and wash corn root systems and look for roots that are pruned back to an inch and half of the stalk.
 Aaron Gassman, ISU Research Entomologist is looking for fields this summer with a high level of feeding injury to Bt-CRW corn from corn rootworm. Feel free to contact us if you know of such fields.

Volunteer corn, corn rootworm (CRW).  Volunteer corn in soybean fields that has the Bt CRW trait that was controlled by the V5- V6 stage is not expected contribute to rootworm resistance issues. Volunteer corn present in soybean fields this time of year may attract CRW adults.
 
However, volunteer corn is often at a population that does not attract sufficient numbers of CRW adults to contribute to CRW resistance issues.

Palmer waterhemp. Palmer has not been identified in northern Iowa to date. The following are some guidelines on Palmer identification from Bob Hartzler. Palmer has been identified in some  areas of the state where various seed mixes for Conservation Reserve Program seedings have been used.
 
Sudden Death Syndrome. Sudden Death syndrome has appeared in northwest/northern Iowa. There are no management options to correct SDS now - but make plans to soil test for SCN and make observations of soybean varieties that resist SDS.
 
-Soybean cyst nematode (SCN) makes SDS worse.
-SCN resistant varieties will help reduce SDS.
- Crop rotation away from soybean will not eliminate  SDS, because SDS can survive for several years in the soil.
-Foliar symptoms - interveinal chlorosis - occur when the leaf area between the leaf veins turn brown.
- Alison Robertson has a good summary on SDS from 2010.
 
 

Prepared by Paul Kassel, Extension Field Agronomist

Phone: (712) 262-2264, Email: [email protected]