Agronomy Zone 11

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• Aaron Ahrenholz (12)
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• Kevin Ryan (12)
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• Brenton Schwab (9)
• Louis Sutton (12)

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An increase in relative humidity this summer, along with the more-than-adequate rainfall, has resulted in an environment conducive to Grey Leaf Spot and other fungal diseases.  This year is unlike the summer of 2009 which offered moisture and COOL temperatures . . . an environment ideal for White Mold in soybeans and not a high need to spray for GLS in corn.  

With pollen-shed now in full swing throughout much of Central and Northern Illinois, the crop dusting planes are in full throttle.  It is projected that a majority of the corn fungicide should be applied by the end of next week.  Check with your local crop scout or retailer for more information on exact timing of fungicide on your individual hybrids.  Timing may vary based on planting dates and heat units required for certain hybrids to reach the reproductive stage.

Remember: Never apply crop oil, non-ionic surfactants or other unapproved spray additives in combination with fungicides prior to tassel emergence to avoid Arrested Ears as found in 2007.  Certain products, such as CoRoN, are approved tank mixes and do not cause problems.

Corn nematodes are becoming more prolific in Midwestern soils, particularly due to the practice of continuous corn.  Corn nematodes are impacting corn yields by as much as 10-20% or more according to Greg Tylka, professor of plant pathology at Iowa State University.  Soil types, particularly sands, provide an environment that corn nematodes thrive.  However, various species of nematodes exist in all soil types.  In isolated areas of a silt loam soil in central Illinois, we have documented yield loss greater than 20% where spiral and lesion nematodes were present.  Sampling for corn nematodes should be done to identify infestations and thresholds in your fields.  Sampling should be done during the growing season.  Watch specifically for Needle nematodes, which are the most-damaging nematode species in corn.

Avicta, from Syngenta, is a nematicide sold in 2009 as a seed treatment in combination with Cruiser.  Like many nematicides, it is dangerous to handle.  See http://www.avictacomplete.com/corn/index.aspx for more information.  Conventional in-furrow application products, such as Counter 15G, are  labeled for nematodes, but are not specifically targeted for nematodes.  However, part of the increase in nematodes may correlate with the reduction in the use of organophosphates and carbamates.

Currently, available seed treatments are minimal, but Bayer Crop Sciences is expected to release a product in Spring 2010 called VOTiVO.  VOTiVO will protect corn roots from nematodes even though it is  NOT a nematicide.  Rather, VOTiVO is a biological that acts as a barrier which “repels” the nematodes from attacking the root.  Because this product is a biological, it is much safer than nematicides now on the market.  VOTiVO will be applied as a seed treatment, probably in conjunction with Poncho 500.   See www.votivo.us for more information on this product and nematodes in general.

The anticipated late harvest looks to be accompanied with high moisture corn.  In light of growers' hesitation to begin harvest due to the high cost of drying corn, it is recommended that growers start harvesting their corn plots first.

Growers can benefit in harvesting their plots early in the following ways:

• Ensures combine and harvest equipment is operating as expected
• Prepares drying facility for ensuing wet grain
• Helps identify any hybrids that may need special handling, (ie. weak stalks, aflotoxins, etc.)
• Train labor force on equipment
• Eliminates one more "tasks" before bad weather sets in
• Gives grower an early look at performance and assists in seed buying decisions

Take time now to prepare for this year's late harvest.  Taking out plots at high moisture can help this fall's harvest go smoothly. 

Growers are encouraged to maintain planned soybean varieties despite expected planting delays due to the wet spring now being experienced throughout Northern and Central Illinois.

It’s critical to understand that a soybean plant is a “short-day” plant (flowering occurs when the day length becomes shorter and the plant is at least 14 days mature). The soybean varieties adapted to northern latitudes i.e. Group I or II, that are moved south, will flower too early.

It is NOT desirable for a soybean plant to flower prior to the summer solstice (June 21st) because soybeans require repeated exposure to short days for maximum flowering. If flowering begins prior to the summer solstice, the number of cycles to produce flowers is limited. In other words, the long days which follow the short days prior to June 21st result in decreased flower production (Source: Fred Below-Crop Sciences 518 “Crop Growth & Development).  Knowing that pod set occurs at each flowering point, it is obvious that more flowers provides potential for more pod set (higher yield potential) and vice versa.

Adjustments a grower should consider would be to plant the crop in narrow rows, and at a 10 to 20 percent higher-than-normal rate. These practices are recommended because later planted soybeans remain shorter and have fewer pods and seeds per plant than the earlier planted soybeans of the same variety. Use of narrower rows and a slightly higher seeding rate increases the plant’s growth efficiency, resulting in more pods per acre and reduced weed competition (Source: “Soybean Replant Decisions” Iowa State University Extension Publication).