Insect Management

First Generation European Corn Borer Scouting & Treatment

June 14, 2016
Growers are noting shot-hole feeding from European corn borer in non-Bt corn. Nebraska Extension offers several resources to monitor moth activity and determine when treatment is necessary.

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Map showing accumulated DD indicating scouting window for common stalk borer

Predicting Stalk Borer Development in Corn

June 13, 2016
Based on accumulated degree days, scouting should be underway across the state for common stalk borer in corn.

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Corn plant damaged by wheat stem maggot
Corn plant damaged by wheat stem maggot

Wheat Stem Maggot Damaging Corn after Rye

June 9, 2016
UNL has been tracking an unusual insect pest the past couple of years in northeast Nebraska that may be a potential concern to farmers growing corn after rye or other grass cover crops. A number of producers and crop scouts have reported stunted corn plants at V1 to V2 with brown flagging in their fields due to the wheat stem maggot (WSM), a species of Chloropid fly. These are small flies that are typically about 1/8 inch long with black and yellow markings. The wheat stem maggot overwinters in the stem of its host plants as a larva and emerges in May to begin feeding.

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Mature stalk borer larva in corn stalk
Mature stalk borer larva in corn stalk

Stalk Borer Scouting & Management in Corn

June 8, 2016

Common stalk borer eggs have hatched throughout Nebraska and scouting should begin when 1300-1400 degree days have accumulated (Figure 1). This is when larvae start moving into corn and other crops. Stalk borer growth is based on accumulated degree days since January 1, using a base of 41°F.

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Yellow sugarcane aphid. (Photo by Patrick Porter, Texas Cooperative Extension, Bugwood.org)
Yellow sugarcane aphid. (Photo by Patrick Porter, Texas Cooperative Extension, Bugwood.org)

Insecticide Approved in Nebraska to Treat Sugarcane Aphids

June 3, 2016
The US EPA has approved sulfoxaflor (the active ingredient in Transform WG) for use against sugarcane aphids in Nebraska sorghum. This is a Section 18 emergency use exemption for 2016.

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Potato leafhopper
Potato leafhopper

Potato Leafhoppers Feeding in Alfalfa Earlier than Normal

May 25, 2016
Potato leafhoppers have been reported in alfalfa in southeastern and northeastern Nebraska. This is somewhat earlier than usual and growers should be alert to potential damage and protecting their alfalfa where numbers indicate treatment thresholds would be met.

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Insect Pheromone Trap Reports 2016

Moth traps have been established at 12 sites in northeast, east central, southeast and south central Nebraska to monitor flights of armyworm, black cutworm, and variegated cutworm moths. Find weekly updates in CropWatch:

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Biological control insects and alfalfa aphids
Biological control insects and alfalfa aphids

Aphids Active in Nebraska Spring Alfalfa

May 6, 2016
Examination of an alfalfa field in northeast Nebraska this week revealed some alfalfa weevil larvae (under threshold at just over one larvae/sweep) and a surprisingly high population of pea aphids. This was somewhat unexpected due to the recent winds and rain which often dislodge aphids from plant stems, resulting in reduced pea aphid numbers. See story for biocontrol information and aphid scouting and treatment recommendations.

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