Corn

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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.

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.

Resistant Palmer Amaranth Management Field Day at Shickley

June 8, 2016

Nebraska Extension will be hosting a Resistant Palmer Amaranth Management Field Day Tuesday, July 12, near Shickley to demonstrate control options in corn. Keynote speaker will be Jason Norsworthy, professor and endowed chair of Weed Science at the Unversity of Arkansas. Norsworth has documented eight herbicide-resistant weeds in Arkansas, including glyphosate-resistant Palmer amaranth.

Corn nematode damage — Figure 1a. Severe sting nematode injury to corn. When sampling severely affected areas, collect samples from the edges of damaged areas in the field. That's where you'll find the most nematodes. (Photos by Tamra Jackson-Ziems)

Corn Nematodes: Scout Sandy Soils Now, Other Soils Any Time

June 7, 2016

This year nematode damage in some Nebraska fields may be masked by the ample rainfall we’ve received, but rest assured, these plant parasitic nematodes are still there in almost every field. Their impact ranges from no obvious sign to severe crop injury and tremendous yield loss.

Inconsistent corn stand indicating possible seedling disease — Figure 1. Scout corn stands for intermittent gaps indicating missing or lost plants as well as diseased or dead plants.

Seedling Diseases Continue to Develop in Nebraska Corn

June 2, 2016

Following several weeks of rainy conditions, seedling diseases are becoming more apparent in corn. See what symptoms to look for when scouting fields.

Nitrogen cycle — Figure 1. The nitrogen (N) cycle illustrates how complex this nutrient is. There are several ways this essential nutrient for corn production can be lost. (Source: Nebraska Extension guide, Nutrient Management for Agronomic Crops, EC155)

Q&As: How much N is Left? Do I Need More Starter When Replanting?

May 27, 2016

Well, it seems not much has changed since the last article I wrote on nitrogen (N) management a few weeks back: more rain, more to come, and more uncertainty with regard to N. So, what do we do now and why I am not worried about the other nutrients? Why is it always about N?

Corn seedling disease — Figure 1. Stunting, discoloration, damping off, and root rot are all common symptoms of seedling diseases, like the plant on the left compared to the healthy plant (right).

Seedling Diseases Developing in Corn

May 20, 2016

With cool wet conditions favorable for corn seedling disease development, growers are urged to scout for inconsistent stands and disease pressure. This week seedling diseases were documented in 10% of surveyed fields in Dodge County in eastern Nebraska, mostly in corn-after-corn fields in river valleys. Be sure to monitor seedling emergence and stand establishment across the state during the coming weeks so that if problems occur they can be detected as early as possible.

Yellowish corn seedlings — Yellowish corn seedling

Why are Emerged Corn Seedlings Yellow?

May 19, 2016

The yellow hue to corn seedlings reported in multiple fields this week may be indicative of several conditions, but is likely due to the cool wet weather plants have experienced since emergence. The symptoms do not necessarily point to a nitrogen or potassium deficiency which may also cause a yellow hue. In addition, corn seedlings subjected to water-saturated soils, soil compaction, and certain herbicide applications may appear yellow.

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