Integrated Crop Management News

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Consider Frost Seeding or Interseeding Pastures This Spring

March 6, 2019
interseeding into a pasture

Producers wanting to add to or improve the forage species in their existing pastures should typically consider using either the frost seeding method in February and early March, or interseeding later in the spring months. This has been an unusual end to the winter, so as soon as the snow melts, frost seeding can begin.

Managing Wet and Cold Soils

February 26, 2019
Soil temperature

The amount of snow we received and potential spring rain events can be challenging to an early start to the growing season. Approaching field operations for N applications, tillage, weed control, etc. need to be weighed against potential soil compaction and successful seed germination. Two of the greatest concerns during spring is excess soil moisture and cold soil temperature and their impacts on seed germination, especially in areas with poorly drained soils as in northern and central Iowa.

Toxin Levels in 2018 Corn

February 26, 2019

The two bu/acre Iowa corn yield reduction (from the previous 2018 report) shown in the February 9 crop report demonstrated the impact of late-season wet weather. Corn quality and potential food safety issues are also determined late in the growing season. According to data recently completed by the Iowa Department of Agriculture and Land Stewardship (IDALS), levels of the mycotoxins deoxynivalenol (also known as vomitoxin) and zearalenone are elevated in this year’s Iowa corn crop. Vomitoxin primarily affects digestion in swine, while zearalenone has negative effects on repro

Will the Insects Survive this Winter?

February 20, 2019

It is not easy for insects to survive Iowa winters. Some literally can’t - they freeze to death (corn earworm, black cutworm) or migrate to warmer climates (potato leafhopper). Insects are unlike mammals and birds because they must generate their own heat (called ectotherms). Insects die when they are exposed to temperatures below the melting point of their body fluids, termed the lower lethal temperature.

Evaluation of Foliar Fungicides on Soybeans in 2018

February 11, 2019

Soybean foliar fungicides were evaluated for foliar disease management and yield response across seven Iowa State University research and demonstration farms in 2018. These included the Northwest Research and Demonstration Farm (Sutherland), Northern Research and Demonstration Farm (Kanawha), Northeast Research and Demonstration Farm (Nashua),  Central Iowa Research Farms (Ames), Armstrong Memorial Research and Demonstration Farm (Lewis), McNay Memorial Research and Demonstration Farm (Chariton), and Southeast Research and Demonstration Farm (Crawfordsville).

Summary of Foliar Fungicide Applications on Corn in Iowa in 2018

February 8, 2019

In 2018, we tested various foliar fungicides on corn at six locations in Iowa: ISU Northwest Research and Demonstration Farm (NWRF), Sutherland; Northeast Research and Demonstration Farm (NERF), Nashua; Northern Research and Demonstration Farm (NRF), Kanawha; Southwest Research and Demonstration Farm (SWRF), Lewis; Southeast Research and Demonstration Farm (SERF), Crawfordsville; and the Ag engineering and Agronomy Farm near Boone.

Achieving Full-season Waterhemp Control in Soybean

February 1, 2019
Relationship between growing degree days and emergence of four weeds.

Although there are many ways weeds escape control in crop fields, one of the leading causes of waterhemp control failures is emergence of plants following postemergence herbicide (POST) treatments. Waterhemp requires more than twice as many growing degree days to reach 50% emergence as giant foxtail or velvetleaf (Figure 1), resulting in much of the population emerging after mid-June.  

2018 SCN-resistant Variety Trial Results Show Yield Effects and SCN Buildup

January 3, 2019
Table 1. Basic yield and SCN population information for eight variety evaluation experiments conducted throughout Iowa in 2018.

Each year, Iowa State University evaluates the agronomic performance and nematode control provided by hundreds of soybean varieties that are resistant to the soybean cyst nematode (SCN). The research is funded by the soybean checkoff through the Iowa Soybean Association, and the experiments are conducted in each of Iowa’s nine crop reporting districts. A report containing the results of the 2018 experiments will appear in an upcoming issue of the Iowa Farmer Today. The results show that even low SCN soil population densities in the spring can increase greatly during a growing season and cause yield loss. And the yield benefits of SCN control provided by good resistant varieties are apparent in the results.

Should You Use a Fungicidal Seed Treatment on Low-Quality Soybean Seed?

December 6, 2018
Diaporthe Seed Decay

With this year’s harvest of soybeans delayed beyond what is considered an ideal window of time, the opportunity for diseases to infect seed pods and in some instances, to the seed itself, was greatly increased. Across the state and the north central region, seed suppliers have reported that this year’s crops of seed soybean are frequently testing positive for the Diaporthe fungus (Phomopsis seed decay), which is resulting in lower than normal germination rates of seed. Seed decay is characterized by cracked, shriveled seed with white chalk-colored mold on the seed surface.

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