Identifying and Treating Aphids in Wheat

Identifying and Treating Aphids in Wheat

May 11, 2007

photo of an oat-bird cherry aphid
Oat-bird cherry aphid
Photo of a greenbug
Greenbug

I have received a few calls from southeastern and central Nebraska reporting aphids in wheat. In one case it was thought they were oat-bird cherry aphids. I have not received any samples, but greenbugs are another possible aphid in wheat at this time of year.

Often in Nebraska spring aphid populations are controlled by natural enemies such as lady beetles and parasitoid wasps. To determine if it is worth treating for aphids, it is necessary to determine the identity and number of aphids present. When scouting for aphids in wheat, estimate the number of aphids per stem at several locations in a field. Don't just count aphids in the "hot spots" because you need to get an estimate of the overall aphid population in the field.

Treatment threshold levels vary by aphid species and plant growth stage (Table 1)

Insecticides

A variety of effective insecticides are available for aphid control on wheat. Check the Department of Entomology Web site at http://entomology.unl.edu/instabls/waphids.htm for a list of rates and restrictions for suggested insecticides for aphid control in wheat.

Additional information on aphids in small grains, including photos of common species and a key for their identification, can be found in NebGuide G1284, Cereal Aphids.

Bob Wright
Extension Entomologist

Table 1. Number of aphids per stem to justify chemical control.
Type of Aphid
Seedling Stage
Boot to Heading Stage
Flowering Stage
Milky Ripe Stage
Milk to Medium Dough Stage
Greenbug
5 - 15
25
>25
>25
>25
Corn Leaf Aphid
20
30
>25
>25
>25
Birdcherry-Oat Aphid
20
30
>5
10
>10
English Grain Aphid
30
50
5
10
>10

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A field of corn.