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Extension Entomology

Tag: Double cropped sorghum

Sorghum Update

–by Dr. Jeff Whitworth and Dr. Holly Schwarting

 

Chinch bugs are very active in double cropped sorghum in north central Kansas.  They are also numerous in corn but the field corn is mature enough that chinch bug feeding should be of little consequence.  However, young sorghum plants, especially under less than ideal growing conditions may be seriously stressed.

For more information on chinch bug biology, management decisions, and insecticides registered to control chinch bugs please see the Sorghum Insect Management Guide: https://www.bookstore.ksre.ksu.edu/pubs/mf742.pdf

and Chinch Bugs: https://www.bookstore.ksre.ksu.edu/pubs/MF3107.pdf

 

 

Sorghum Pests Update

–by Dr. Jeff Whitworth and Dr. Holly Schwarting

Double cropped sorghum may still have some ragworm feeding during the whorl stage (see photo).  In addition, there will probably be at least one more generation of headworms and thus later planted sorghum needs to be monitored for headworms between flowering and soft dough when it is vulnerable.  Also, continue monitoring for aphids as there still seems to be a pretty good mixture of greenbugs, corn leaf, yellow sugarcane, and sugarcane aphids.  Some of the fields treated for headworms have reduced numbers of beneficials so they may not be there in sufficient numbers to help control these aphids.  However, some of the fields sampled this week that were sprayed for headworms at least 2 weeks ago had pretty good populations of beneficials already building back up.

sorghum headwormsfall armyworm_sorghum

 

 

Sorghum Update

–by Jeff Whitworth and Holly Schwarting

Double cropped sorghum in north central KS seems to have a significant infestation of “ragworms”.  The larvae are a combination of fall armyworms and corn earworms and are of various sizes.

corn earworm_ragworm

windowpane ragwormfall armyworm_ragworm

 

Leaf feeding in the whorl by either species is highly visible but should not have a significant effect on the plants or yield.

windowpane ragworm

ragworm feeding

Also, most fields in north central KS are infested with aphids.  Corn leaf aphids can produce a great deal of honeydew but mostly in the whorls.  This honeydew may retard head extension but usually does not affect many plants over a large area.

corn leaf aphids

greenbugs

Yellow sugarcane aphids

Also found greenbugs and yellow sugarcane aphids.  None of the invasive sugarcane aphids were detected in north central Kansas.  However, many beneficials are, and will continue to be, present in sorghum fields as evidenced by the numerous green lacewing eggs and lady beetle eggs.

lacewing eggs

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