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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. | ||||||
| Weed | 1 | 2 | 4 | 6 | 8 | 10 |
| Giant Ragweed | 0.1 | 0.2 | 0.4 | 0.5 | 0.8 | 1.0 |
| Cocklebur | 0.4 | 0.8 | 1.6 | 2.4 | 3.2 | 4.0 |
| Pigweeds | 0.8 | 1.6 | 2.4 | 4.0 | 6.0 | 8.0 |
| Velvetleaf | 3.2 | 6.4 | 9.6 | 13.0 | 16.0 | 20.0 |
| Pennsylvania Smartweed | 3.2 | 6.4 | 9.6 | 13.0 | 16.0 | 20.0 |
| Morningglory | 3.2 | 6.4 | 9.6 | 13.0 | 16.0 | 20.0 |
| Giant Foxtail* | 2.0 | 4.0 | 6.8 | 10.0 | 13.0 | 18.0 |
| Volunteer Corn | 0.4 | 0.8 | 1.2 | 1.6 | 2.0 | 2.4 |
| *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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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.
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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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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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.
| Site and economic threshold | Insecticide | Rate per acre |
|---|---|---|
| Non-cropland areas 15 or more nymphs | *Asana XL | 2.9 to 5.8 oz per square yard |
| Imidan 70-W | 2 1/8 to 2 3/4 lbs | |
| *Penncap-M | 2 to 3 pts | |
| Sevin XLR Plus | 1 to 3 pts | |
| Sevin 80S | 2/3 to 1 7/8 lbs | |
| Sevin 4-Oil ULV | 3/4 to 2 pts | |
| Pastures 8 or more nymphs | malathion 57% | 1.5 to 2 pts per square yard |
| *Penncap M | 2 to 3 pts | |
| Sevin XLR Plus | 1 to 4 pts | |
| Sevin 80S | 2/3 to 1 7/8 lbs | |
| Sevin 4-Oil ULV | 3/4 to 2 pts | |
| Alfalfa and clovers 3 to 7 or more nymphs or adults per square yard | *Baythroid 2 | 2 to 2.8 oz |
| dimethoate | see label | |
| *Furadan 4F | 1/4 to 1/2 pt | |
| Imidan 70-W | 1 to 1 1/3 lbs | |
| Lorsban 4E | 1/2 to 1 pt | |
| *Penncap-M | 2 to 3 pts | |
| Sevin XLR Plus | 2 to 3 pts | |
| Sevin 80S | 2/3 to 1 7/8 lbs | |
| *Warrior T | 2.56 to 3.84 oz | |
| Corn 7 or more nymphs or adults per square yard and foliage or grain is being severely damaged | *Asana XL | 5.8 to 9.6 oz |
| dimethoate | see label | |
| Lorsban 4E | 1/2 to 1 pt | |
| *Penncap-M | 2 to 3 pts | |
| Sevin 4F or XLR Plus | 1 to 3 pts | |
| *Warrior 1E or T | 2.56 to 3.84 oz | |
| Grain sorghum (milo) 7 or more nymphs or adults per square yard | *Baythroid 2 | 1.3 to 2.8 oz |
| dimethoate | see label | |
| Lorsban 4E | 1/2 to 1 pt | |
| Sevin 4F | 1/2 to 1 1/2 pts | |
| Sevin XLR Plus | 1 to 3 pts | |
| Sevin 80WSP | 2/3 to 1 7/8 lbs | |
| *Warrior 1E or T | 2.56 to 3.84 oz | |
| Soybean (economic thresholds are listed below) | *Asana XL | 5.8 to 9.6 oz |
| dimethoate | see label | |
| Lorsban 4E | 1/2 to 1 pt | |
| *Penncap-M | 2 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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(Author: Don Day, Ag. Eng./Info. Tech. Spec., University Outreach and Extension)
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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 http://www.psu.missouri.edu/cropsys/ 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 Northeast and Central areas of Missouri producers and is supported by the University of Missouri Extension, the Missouri Agricultural Experiment Station, and the MU College of Agriculture, Food and Natural Resources. Managing Editor: Mary Sobba.
Send comments and suggestions to:
Mary Sobba, Agriculture Business Specialist
101 N. Jefferson St., Rm 304
Mexico, MO 65265
(573) 581-3231
sobbam@missouri.edu
