–by Dr. Jeff Whitworth and Dr. Holly Schwarting
We have not heard about, or observed any wheat aphids (bird cherry-oat, greenbug, English grain) or worms (armyworms, cutworms) in the last 7-10 days.
Category: Wheat
Wheat
–by Dr. Jeff Whitworth and Dr. Holly Schwarting
Some winter grain mite infestations have been noted in the last 7-10 days. These seem to become evident every fall, especially under dry conditions, but don’t warrant a pesticide application. Moisture and/or colder weather will alleviate these infestations, at least until warmer spring weather returns. For more information on winter grain mites, please visit: http://entomology.k-state.edu/extension/insect-information/crop-pests/wheat/winter-grain-mite.html
Wheat Update
— by Dr. Jeff Whitworth and Dr. Holly Schwarting
Very few wheat aphids have been noted recently in north central KS. There are a few present but there are also numerous lady beetles so hopefully, the lady beetles will take care of any migrating aphids relatively quickly.
Alfalfa and Wheat “Worms”
–by Dr Jeff Whitworth and Dr Holly Schwarting
Wheat and alfalfa fields throughout south central and north central Kansas should be monitored for signs of defoliation. Many pests can defoliate either crop this time of year, i.e. grasshoppers and flea beetles (usually around borders), and “worms”. These larvae are most commonly armyworms, fall armyworms, and/or army cutworms. Identification is important for these “worms” because armyworms and fall armyworms will feed until the temperatures cool into the mid-20’s or they pupate, whichever comes first.
Army cutworms, however, are and have been hatching from eggs deposited by moths as they return from over-summering, probably in Colorado.
These army cutworm larvae will feed a little this fall, overwinter, then start feeding again in early spring. So, if the “worms” causing the defoliation now are relatively large, ½ inch or more, they are probably armyworms and/or fall armyworms.
We have been hearing about and seeing a mixture of both armyworms and fall armyworms (see pics below). These small worms start by causing small “windowpanes” in wheat or alfalfa. No army cutworm infestations have been verified yet.
Flocks of birds in wheat or alfalfa fields in fall or early spring are often indicative of a “worm” infestation as the birds are feeding on the larvae. Fields with 25-30% of the plants showing “windowpane” feeding need to be monitored frequently as these larvae consume more as they get larger. Treatment should be applied before stands become threatened. For more information on treatment thresholds and management options please see the Wheat Insect Management Guide: http://www.bookstore.ksre.ksu.edu/pubs/mf745.pdf
Volunteer Wheat
–by Dr. Jeff Whitworth and Dr. Holly Schwarting
Frequent rain over the last few weeks has played havoc with volunteer wheat control. Each rain seems to bring another flush of volunteer.
This is an ideal situation for most wheat pests, i.e. Hessian flies, winter grain mites, wheat curl mite, and the wheat aphids (mainly greenbugs, bird cherry oat and English grain) as well as the pathogens they may vector. Thus, please remember to destroy all volunteer at least 2 weeks prior to planting to help manage these pests.
Volunteer Wheat
–by Dr. Jeff Whitworth and Dr. Holly Schwarting
Wheat harvest is completed, or at least real close, across the State. So, it is time to start thinking volunteer wheat control. As wheat producers know, volunteer wheat is very persistent. Every time it rains or the fields are irrigated, another flush or crop of volunteer wheat germinates. Thus, control needs to be just as persistent. Volunteer wheat can be a harborage for most wheat pests, especially bird cherry-oat aphids, Brown wheat mites, English grain aphids, greenbugs, Hessian flies, wheat curl mites, and many of the more common pathogens. Season-long control is always best, but rarely practical. So, volunteer wheat eradication at least 2 weeks prior to planting is the next best management practice.
Wheat Update
–Dr. Jeff Whitworth and Dr. Holly Schwarting
Aphid populations remain at minimal levels in all wheat fields monitored throughout northcentral Kansas. Lady beetle and green lacewing populations are still present in these wheat fields and therefore should prevent any aphid increases.
Wheat Update
By — Dr. Jeff Whitworth, Dr. Holly Schwarting
Wheat fields sampled in NC Kansas over the last week have diminishing populations of aphids. Many fields had to be sampled relatively vigorously to find any aphids. However, lady beetles are still quite plentiful which should bode well for not allowing the aphid populations to rebound.
Scattered white heads are starting to be easily distinguished in the green wheat. If the stem pulls out easily, with some apparent feeding in the stem, this is from the wheat stem maggot.
The number of infested stems in always negligible relative to yield loss but often causes concern because of the easily noticed white heads.
Wheat
–by Dr. Jeff Whitworth and Dr. Holly Schwarting
Still finding aphids in wheat throughout NC and SC KS. But in all fields sampled last week there were many lady beetles and mummies, indicating the beneficials are also very active. Spraying aphids will kill most of the aphids at the top of the plants– but won’t kill all the aphids down in the canopy just because the leaves in the canopy intercept the spray. But it will, typically anyway, kill all the beneficials as they move around searching for aphids to consume. Therefore, it is rarely a good idea to add an insecticide to a fungicide application to save application costs UNLESS the insecticide is warranted-not “just in case”
Wheat Update
–Dr. Jeff Whitworth and Dr. Holly Schwarting
Last week wheat aphid populations were active and had increased considerably from the previous couple of weeks in north central Kansas. Populations of bird cherry-oat aphids, English grain aphids, and greenbugs were all reproducing and still migrating in. This week however, in fields we sampled in north central Kansas, the aphid populations had decreased drastically and the beneficials, especially lady beetles, had increased greatly.
Last week these English grain aphids were inadvertently identified as greenbugs.
