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Extension Entomology

Month: June 2016

Corn Update

–by Dr. Jeff Whitworth and Dr. Holly Schwarting

We sampled several corn fields in north central and south central Kansas this past week.  The youngest field was at V2 and the oldest was mostly at V8.  The lady beetles and green lacewings are still relatively plentiful.  I did not find any aphids, or many pests of any kind, really, for these predators to be feeding upon.  All of the lady beetles or lacewings were adults, no larvae.  Hopefully, all these adults of both species will successfully reproduce and therefore there will be numerous individuals present to help control any future pests.  There were however, numerous adult tarnished plant bugs in all fields sampled.  These will not cause any problems to the plants, but later are often confused with western corn rootworm adults when they are found on the corn silks.  Western corn rootworm larval feeding is still proceeding, probably for about another two weeks.  The only real plant damage noted was leaf-feeding by fall armyworm larvae but not even very much (>1%) of that.

May 2016 133

Corn Update

–by Dr. Jeff Whitworth and Dr. Holly Schwarting

Lady beetles are unusually common in corn fields right now.  Most corn plants in north central Kanas are from V2-V6.  Checking corn rootworm plots revealed western corn rootworm larvae of various sizes and thus they are starting to feed enough to cause a little root damage.

CRW larvae

CRW larvae_sizes

CRW larva on root

CRW root damage

Seems like, despite the recent cooler, wetter conditions, the rootworm development is about where it usually is at this time.  Most western corn rootworms have completed the larval stage by the 1st of July, thus root damage will be completed later this month as the larvae begin to pupate in south central and north central Kansas.

 

Alfalfa Update

–by Dr. Jeff Whitworth and Dr. Holly Schwarting

Potato leafhoppers continue to inhabit every alfalfa field sampled in north central Kansas.  Populations are still mostly composed of adults but a few nymphs are emerging.  These potato leafhoppers have few natural enemies and thus populations will just continue to increase.  There are still relatively plentiful numbers of lady beetles and green lacewings in most alfalfa fields, and while they probably won’t help with potato leafhoppers, they should continue to help control any developing aphid populations.