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Volume 8, Number 6 - June 2002

This Month in Ag Connection

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Weeds to Watch in Beans

Dandelion weed

How competitive are weeds in soybean is a common question asked of agronomists. The chart below will help producers determine the effect weeds have on soybean yield. The numbers at the top refer to the number of weeds or clumps per 100 sq. ft.

Percent Soybean Yield Loss
 Weeds per 100 sq. ft.
Giant Ragweed0.
Pennsylvania Smartweed3.26.49.613.016.020.0
Giant Foxtail*
Volunteer Corn0.
*5-8 Foxtail stems per clump

Research has determined that weeds in soybean should be controlled before they exceed 6" in height and the soybean reaches the V5 (4 trifoliates) stage. Be aware that a weed can grow 2" in one or two days in good growing conditions.

Do not postpone treatment because of concern for second flushes in 15" or narrower rows because you may let weeds in the first flush get beyond effective control and lower yields.

(Author: Tim Schnakenberg, Agronomy Specialist)

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EPA Phase-Out of CCA Treated Lumber

Chromated copper arsenate, or CCA, is a chemical compound that has been used for wood preservative since the 1940's. CCA is injected into wood under high pressure to protect wood from dry rot, fungi, molds, termites, and other pests.

Sawing lumber

During the past several months, CCA-treated wood has been the subject of an EPA evaluation under provisions of the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). This Act directs EPA to periodically reevaluate older pesticides to ensure that they meet current safety standards. EPA has announced a voluntary decision by industry to move consumer use of treated lumber products away from a variety of pressure-treated wood that contains arsenic by December 31, 2003, in favor of new alternative wood preservatives. This affects virtually all residential uses of CCA treated wood including wood used in play-structures, decks, picnic tables, landscaping timbers, residential fencing, patios and walkways/boardwalks. By January 2004, EPA will not allow CCA products for any of these residential uses.

EPA has not concluded that CCA-treated wood poses unreasonable risks to the public for existing CCA-treated wood being used around or near their homes or from wood that remains available in stores. EPA does not believe there is any reason to remove or replace CCA-treated structures, including decks or playground equipment. EPA is not recommending that existing structures or surrounding soils be removed or replaced.

Arsenic is a known human carcinogen, thus, any reduction in the levels of potential human exposure to arsenic is desirable. Safety steps that can be taken to reduce any potential health effects from CCA include:

EPA is continuing to proceed with a risk assessment that includes input from public comments and an external scientific review panel on methodologies to perform a risk assessment for residential settings and potential exposure to children from CCA.

(Author: Jim Jarman, Agronomy Specialist, University Outreach and Extension)

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Taxation Tidbit: Switching CCC Loans From Income to Loans Just Got Easier


In January 2002 the IRS issued Rev. Proc. 2002-9 making it much easier for taxpayers to change the reporting of CCC loans from income to loans. Code Section 77 allows a taxpayer to elect reporting CCC loan proceeds as income in the year the loan proceeds are received, instead of treating the loan as a loan. Once the election is made, it is applicable to all CCC loans in that tax year and all subsequent taxable years. Permission must be obtained from the IRS to switch back to treating CCC loans as loans (i.e. deferring the reporting of income).

For tax years ending on or after December 31, 2001, the IRS has ruled taxpayers reporting CCC loans as income under Section 77 can switch automatically to treating CCC loans as loans. For CCC loans still outstanding and taken out prior to the tax year of the change, those loans are to be treated as if the election to report loans as income was still in effect.

Source: Rev. Proc. 2002-9, 2002-3 IRB 327, 1/8/2002, IRC Sec. 446

(Author: Parman R. Green, University Outreach and Extension Farm Business Management Specialist)

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Watching for Grasshoppers

Grasshoppers are present in Missouri fields every year; however, some years they reach economic thresholds and require control. Scout on a regular basis to determine if control is economically justified. Begin scouting by looking for small grasshoppers in grassy field margins, ditch banks and roadsides. These areas are called "hatching beds." No-till fields and forage fields provide undisturbed soil from late summer through June for egg laying and hatching.


Weather conditions influence the potential for problems during the growing season. Warm moist soil conditions at the time of hatching - late May to early June - help the newly hatched grasshoppers emerge from their subsoil egg cases. After emergence, dry, warmer conditions speeds growth and helps them avoid dying from fungal and other diseases. Like most pest insects, grasshoppers can over-come low egg laying with ideal weather allowing most eggs to hatch and survive.

In Missouri, there are three species of grasshoppers which typically cause the greatest damage. The Red-legged and Migratory are almost identical in appearance and smaller size. Red-legged grasshoppers are more general feeders. They are more likely to feed on soybean leaves and pods. Migratory grasshoppers live up to their name, flying long distances to feed mostly on grassy vegetation. The third and larger species is called the Differential or Big Yellow grasshopper. It is easy to identify by its size, color and the black chevron shaped markings on its jumping legs. They can travel long distances to feed on field crops.

Tillage can help in controlling grasshoppers by destroying eggs and exposing them to weather and predators. However, no-till may be more beneficial as it will conserve much needed moisture and topsoil.

The size and age of grasshoppers make a big difference in control. Small, newly hatched grasshoppers are easier to control. Often they are confined to field margins, waterways, ditch banks, and roadsides. These areas are easier to spray than entire fields and require less total pesticide. If they are found soon after hatching, monitor them for a couple of weeks because wet weather may control them without the need for pesticides. Typically, they will not move far until they are larger, older, get wings, or run out of food. As grasshoppers grow from half- grown to adults, higher rates of recommended insecticides will be required for control.

If ground application equipment is used, apply a minimum of 15 gallons of spray per acre for better coverage in thick crop canopies.

Below are example economic thresholds, insecticides and rates for control of grasshoppers in non-cropland, pasture and field crops.

Economic thresholds, insecticides and rates for control of grasshoppers in non-cropland, pasture and field crops.
Site and economic thresholdInsecticide Rate per acre
Non-cropland areas

15 or more nymphs

*Asana XL2.9 to 5.8 oz
per square yard
Imidan 70-W 2 1/8 to 2 3/4 lbs
*Penncap-M2 to 3 pts
Sevin XLR Plus 1 to 3 pts
Sevin 80S2/3 to 1 7/8 lbs
Sevin 4-Oil ULV3/4 to 2 pts

8 or more nymphs

malathion 57%1.5 to 2 pts
per square yard
*Penncap M2 to 3 pts
Sevin XLR Plus1 to 4 pts
Sevin 80S2/3 to 1 7/8 lbs
Sevin 4-Oil ULV3/4 to 2 pts
Alfalfa and clovers

3 to 7 or more nymphs or adults per square yard

*Baythroid 22 to 2.8 oz
dimethoatesee label
*Furadan 4F1/4 to 1/2 pt
Imidan 70-W1 to 1 1/3 lbs
Lorsban 4E 1/2 to 1 pt
*Penncap-M 2 to 3 pts
Sevin XLR Plus2 to 3 pts
Sevin 80S2/3 to 1 7/8 lbs
*Warrior T2.56 to 3.84 oz

7 or more nymphs or adults per square yard and foliage or grain is being severely damaged

*Asana XL5.8 to 9.6 oz
dimethoate see label
Lorsban 4E 1/2 to 1 pt
*Penncap-M2 to 3 pts
Sevin 4F or XLR Plus1 to 3 pts
*Warrior 1E or T2.56 to 3.84 oz
Grain sorghum (milo)

7 or more nymphs or adults per square yard

*Baythroid 21.3 to 2.8 oz
dimethoate see label
Lorsban 4E 1/2 to 1 pt
Sevin 4F1/2 to 1 1/2 pts
Sevin XLR Plus1 to 3 pts
Sevin 80WSP2/3 to 1 7/8 lbs
*Warrior 1E or T 2.56 to 3.84 oz

(economic thresholds are listed below)

*Asana XL5.8 to 9.6 oz
dimethoatesee label
Lorsban 4E1/2 to 1 pt
*Penncap-M2 to 3 pts
Sevin XLR Plus 1 to 3 pts
*Warrior 1E or T 3.20 to 3.84 oz

Economic thresholds for soybean: 30% or more defoliation prebloom; 20% or more defoliation bloom to pod; or 5 to 10% of pods damaged.

*Restricted Use Pesticide. Follow all label directions, restrictions and precautions.

(Information from this article is from Wayne Bailey, UMC professor of Entomology, 573-882-2838, and Jim Jarman, Agronomy Specialist, 573-642-0755.)

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Useful Crop Management Tool

  • Crop replant information can be found in UMC Guide G4091, Corn and Soybean Replant Decisions.
  • Click here to view the U.S. Soybean Diagnostic Guide.
  • The Integrated Pest Management web site contains information on scouting guides, problem solving aids, pest identification and management resources, and diagnostic services at the University of Missouri.

(Author: Don Day, Ag. Eng./Info. Tech. Spec., University Outreach and Extension)

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Small Grain, Grain Sorghum and Alternative Grain Crops Website Now Available


A website is now available that focuses on small grain, grain sorghum, and other alternative grain crops production. The website provides up-to-date information regarding crop and pest management issues. It is jam packed with information including the following:

The website contains links to University of Missouri Extension publications and newsletters, as well as links to other useful resources. For the most current information please explore the News and Notes section located on each page.

The website is located at and is supported by the Department of Agronomy and the Plant Sciences Unit in the College of Agriculture, Food and Natural Resources at the University of Missouri, Columbia and by University of Missouri Outreach and Extension.

(Author: Shawn P. Conley, Cropping Systems Specialist, UMC)

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Publishing Information

Ag Connection is published monthly for Central Missouri Region producers and is supported by University of Missouri Extension, the Commercial Agriculture program, the Missouri Agricultural Experiment Station and the MU College of Agriculture, Food and Natural Resources. Managing Editor: Kent Shannon.