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Extension Entomology

Tag: pupating

Alfalfa Update – Alfalfa caterpillars and Potato leafhoppers

–by Dr. Jeff Whitworth and Dr. Holly Schwarting

Alfalfa caterpillars are currently active throughout north central Kansas.  These caterpillars are feeding on foliage, and based upon the size of the larvae in fields, will soon be pupating.  In many fields, swathing is currently, or has just been done and this should help lessen alfalfa caterpillar populations.  However, if the timing is such that these larvae are pupating in the soil and thus swathing does not remove/destroy the pupae, the emerging butterflies may lay eggs on recently cut fields and the developing larvae may feed on regrowth.  This may retard regrowth for a couple of weeks until larvae pupate.

Potato leafhoppers are also very numerous throughout north central Kansas in uncut alfalfa fields.  Thus, their characteristic feeding damage, called ‘hopper burn’, is common.  Swathing should reduce potato leafhopper populations significantly and, hopefully, they will not rebound.  Continued monitoring is prudent as alfalfa caterpillar feeding and potato leafhopper damage may lessen the plant’s ability to store reserves in their roots for overwintering.

 

For management decisions for all alfalfa pests, please refer to the 2017 Alfalfa Insect Management Guide: https://www.bookstore.ksre.ksu.edu/pubs/MF809.pdf

 

Alfalfa Update

–by Dr. Jeff Whitworth and Dr. Holly Schwarting

Alfalfa weevil feeding activity has slowed significantly in north central Kansas, at least south of I-70.  North of I-70, larvae are still developing and thus feeding, but even in the northern counties this feeding and resultant damage should be significantly reduced by the end of the next week.  There are still some small larvae but the majority of populations are pupating or have pupated.  Adult weevils are still hanging out in alfalfa fields and probably will until that 1st cutting, or temperatures get into the mid-80’s or warmer.

Soybean Pest Update

–by Dr. Jeff Whitworth and Dr. Holly Schwarting

Double cropped soybeans are still very much in the reproductive stages throughout north central Kansas.  Thus, they are still vulnerable to a variety of pests – and pest populations seem to be increasing.  Green cloverworms (see pic) have been feeding on leaves for the past couple of weeks but are starting to cease feeding to begin pupating.  They rarely cause actual yield loss but usually cause concern because of the amount of defoliation they often cause.  While green cloverworms don’t feed on the pods or seeds, adult bean leaf beetles and corn earworm larvae (a.k.a. soybean podworms) do (see pics).  Both species, bean leaf beetles and corn earworms, seem to be increasing throughout south central and north central parts of the state.  The corn earworm larvae will usually feed on the seed within the pod and will only feed for about 10-14 days.  However, bean leaf beetles will continue to feed until harvest, or they disperse to overwintering sites.

green cloverworms

 

Adult BLB

BLB pod feeding

 

CEW pod feeding

 

There are still a few soybean aphid populations in north central Kansas, however there are more winged adults present which probably means they are mostly finished feeding and preparing to migrate to overwintering sites (they probably do not overwinter successfully in Kansas – we hope).

We have received several calls this week relative to these “interesting little green worms” in soybeans.  These are silver spotted skipper larvae and will feed on leaves but should not defoliate enough, on a field-wide basis, to impact yield.

silver spotted skipper

 

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