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368 Ag Hall OSU Plant & Soil Sciences Department Stillwater, OK 74078 |
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| March/April 2000 | |
NEWS |
CONTENTS OF NEWSLETTER
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We welcome contributions and suggestions. Comments about and
contributions to the NEWS are welcome and can be submitted to any of the directors. |
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The combination of warm winter and warm spring seems to have speeded up weed development about 3 or 4 weeks. Alfalfa development toward first cutting is highly variable. The warm temperatures have hastened development, but there are some sites in the state that were suffering from drought until early April. Some individual fields were delayed by aphids and/or alfalfa weevil infestations. Without rain delays, first cutting will go from about mid April to late May this year. If we get our normal big rains in early May the range in dates will be larger. With this variability in mind, alfalfa producers need to pay special attention to their weed control this year. The following are some general tips. Warm-Season Weeds in Established Alfalfa If you currently have a good alfalfa stand (more than 30 stems/sq. ft.), then you may not have summer weed problems this year. Alfalfa will essentially shade-out and out-compete the emerged annual weeds and none will result in the hay. However, if your stand is getting thin, or you are not keeping it fertilized properly, then expect summer weeds to start showing up in the third harvest. Summer weed control options are: 1. Do no weed control. This may be most profitable option for most producers. Second cutting will not have any summer weeds in the hay because the weeds are still small. Then, if it is dry in late June and July, there will not be that much growth of the annual weeds. If weeds do grow, they can be utilized for beef cattle hay. A mixture of alfalfa-grass is excellent hay for beef cattle. Also, producers should consider grazing weedy alfalfa. Weeds in alfalfa minimize bloat problems, and good gains can be obtained by grazing (see Alfalfa Harvest Management Circular E-943). 2. Use Herbicide options: If a producer has no beef
cattle, and wants to sell dairy quality hay, then it could be profitable
to control summer weeds. I discussed herbicide options that could be
applied after 1st harvest last month. Normally, most producers
would have their 1st cutting done by now, but weather has not
cooperated. PURSUIT DG is also labeled for alfalfa. It is a 70% dispersable granule formulation of imazethapry that comes in water-soluble packets. The 1.44 oz/acre rate of PURSUIT DG would be the same rate of imazethapyr as the 4 oz/acre rate of PURSUIT. The price of 1.44 oz of PURSUIT DG was only about $13.50, according to one of the suppliers, so that is a big decrease from $20/acre for PURSUIT recently. Be aware of rotational crop guidelines after using PURSUIT. It is 4 months for wheat and 18 months for sorghum (see label for other crops). SINBAR gives fair to good control of pigweeds when applied after first harvest. However, grass control has only been fair. SINBAR should be applied at 0.7 to 0.9 pounds of product/A as soon as the hay is off of the field. A 1-inch rain is required to move the herbicide into the soil so it can be taken up by weed roots. GRAMOXONE EXTRA is a contact nonresidual herbicide that can be used to control emerged weeds between harvest. Most alfalfa will be browned-off with application, so it has to be applied within 5 days of cutting to minimize damage. Small emerged pigweeds are killed, but poor control of emerged grasses and the emergence of new weeds after spraying can be a problem. Best use for Gramoxone Extra has been for dodder control after second cutting. BUTYRAC 200 (2,4-DB) is a nonresidual herbicide that can give good control of small pigweeds. Control of other summer broadleaf weeds is only fair, so read the label for listing of susceptible broadleaf weeds. POAST PLUS and SELECT 2EC are nonresidual herbicides that can give good control of most emerged summer grasses, but neither herbicide has any activity on broadleaf weeds. It is essential that 1 quart of crop oil concentrate/acre is added to the spray mix and that grasses are small and actively growing. It is important to read the label to determine the exact rate listed for the various grasses. For many of the susceptible annual grasses, I have found that the 1½ pint/acre rate is a good use rate for POAST PLUS, and a good use rate for SELECT 2EC is 6 fl. oz./acre. When using herbicides such as BURYRAC 200 for pigweeds and/or POAST PLUS or SELECT 2EC for grass control, it is important that weeds be actively growing at time at application. Also, since none of these herbicides have soil residual activity, it will be necessary to check cut fields about 10 days after each cutting during the summer to determine if new weeds have emerged. All of these herbicides should be applied just before the alfalfa canopy completely shades the soil. See herbicide labels for additives, mixtures and additional information. ZORIAL (a preemergence herbicide) applied before summer grasses emerge can give summer-long control of grasses like crabgrass and foxtail. However, summer grasses have already emerged in many alfalfa fields. So, if you want to apply ZORIAL now (either after 2nd cutting, or after 1st cutting) to control summer grasses, it will be necessary to control escaped grasses with POAST PLUS or SELECT just before canopy closure on next cutting. By that time, the ZORIAL will be controlling germinating grasses and the small grasses up now can still be controlled by POAST PLUS and SELECT. -- Jim Stritzke |
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SUBJECT: Oklahoma Cooperative Extension Service Legislative Request Last year, thanks to the dedicated efforts of many individuals and organizations across the state who believe in the mission of the Oklahoma Cooperative Extension Service (OCES) and support its programs, the state legislature provided OCES with a significant boost for increased staffing at the county level. This action addressed what was termed Level I, the first phase of our three-part strategy for enhancing the quality of OCES programs. This year, we are seeking state support for the two additional parts of the plan, which are summarized on the attached sheet. Level II (this year’s highest priority) is to increase compensation levels to improve recruitment and retention of OCES staff. To meet this need, we are proposing that $1,323,000, over and above OCES’ appropriation via the Oklahoma State Regents for Higher Education formula, be added to our funding base - phased in over a three-year period, with $651,000 allocated for FY 2001. Level III is to upgrade our communications technology infrastructure. To accomplish this goal, we are asking the legislature for $1,200,000 additional funding for FY 2001 and a $600,000 addition to our funding base in FY 2002 to provide for annual maintenance and periodic upgrading. I am very hopeful that the legislature will act positively in response to these requests. In order for this effort to be successful, it is essential that there is well-coordinated, widespread support among statewide organizations, county commissioners, county clientele, Division advisory groups, and OCES employees speaking with a unified voice in contacts with members of the state legislature. We are hopeful that you are supportive of this strategy. On behalf all the employees of OCES throughout the state, we will greatly appreciate your contacting your legislators on our behalf. The one-page summary (enclosed) is for your use in that regard. We suggest that a copy of the summary sheet be attached to each letter that is sent. You may wish to make additional copies, or we will be pleased to send these to you upon request. Please share this information with others as you deem appropriate. Together we can build on the great successes of OCES and assure that we can help Oklahoma and Oklahoma’s citizens to be successful in the future. Your consideration and support are deeply appreciated! Sam E. Curl
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