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It's that time of the year again! Time to gear up for the new crop production season and time to re-subscribe to the Northeast Nebraska IPM-Crop Production Newsletter.

The subscription rate for 2006 is once again only $20.00. For this reasonable sum you can expect objective information on pest management, fertility, irrigation scheduling, crop development, and other crop management information on a weekly basis during the growing season. This newsletter is designed specifically for Northeast Nebraska . The subscription fee basically covers our costs for supplies and stamps.

If you have access to the Internet, the newsletter can be read free of charge at http://nerec.unl.edu/ipm/ipm1.htm . If you do access the newsletter regularly on the Internet, we do ask that you call Pat Bathke at 402-584-3837 or email her at pbathke1@unl.edu so we can get a handle on how many people are using the information. Also, if you want an e-mail reminder of when the newsletter is on the web you can subscribe to a listserve that will automatically contact you when the letter is ready. To subscribe to the listserve, send an e-mail message to: LISTSERV@UNL.EDU and in the Message Field (Not subject) type SUBSCRIBE IPM. Do not include a signature, as LISTSERV will try to interpret each line as a command. If you have any problems, contact Pat.

For another option for subscribing to the IPM newsletter reminder or other agricultural listserves, go to http://nerec.unl.edu/aglistserv.htm . Just click the listservs you would like to receive and fill in the form. You'll receive any newsletters, ag notices, etc., that are sent.

Please fill out the accompanying form and get it to us as soon as possible so you can receive our weekly update on conditions influencing crop production in northeast Nebraska . (KJ)

Scout for Army Cutworms in Alfalfa

Army cutworms are the first pests usually reported in crops. While not a common a pest in northeast Nebraska , we have had occurrences in the past, where they have held back the initial green up of alfalfa in the spring. Ralph Kulm, Extension Educator in Holt Co., has received some calls about this insect already. Last year reports of activity occurred from southern and western Nebraska . Weather conditions could have favored the moths flying back from the Rocky Mountains where they spend the summer, then lay eggs in alfalfa and wheat in the fall. The winter was very mild which could have helped overwintering larvae survive. Lack of green up could very well mean an insect problem instead of weather- related winterkill or drought. What few wheat fields we have should also be scouted.

Army cutworms can be serious pests of wheat and alfalfa. The eggs are laid in the fall. The eggs hatch, the larvae feed for a short time and then overwinter in the soil. They begin feeding as soon as their host crop comes out of dormancy and starts to grow. Army cutworms are brownish-black without any distinguishing markings and will be found in the soil around the crowns of the plants during the daytime. They feed on the foliage above the surface of the ground at night. After completing development the adult moths fly to the Rocky Mountains before returning to complete the cycle.

In established alfalfa fields, stand loss is rarely observed, but the delay in green up may reduce yields of the first cutting if cutworms are numerous. Consider treatment in established fields when four or more cutworms per square foot are found. In fields less than a year old, food reserves in the roots are limited and feeding may be enough to kill individual plants and produce stand loss. Treatment should be considered if 2 or more cutworms are found per square foot in newly seeded alfalfa.

Wheat recommendations are similar, with stressed wheat at the lower level of 2 per square foot.

There are many insecticides labeled for control of army cutworm. There are many generics now entering the insecticide market, so it is becoming important to know the chemical name as well as the brand name of insecticides, since generics are usually cheaper and work just as well. In alfalfa, Ambush, Pounce, Arctic (all chemical name permethrin), Warrior, Silencer, Taiga (all lambda-cyhalothrin), Proaxis, Baythroid, Mustang and Lorsban (generic name chlorpyrifos) are compounds that should control army cutworms in alfalfa. Warrior, Proaxis, Lorsban and Mustang are registered for use on wheat. If surface moisture is adequate use the lowest labeled rates, they should work fine. For a completer list of registered products, go to http://entomology.unl.edu/fldcrops/pestipm.htm , select the crop, and select the insect to be controlled. (KJ)

Controlling Winter Annuals Helps Conserve Moisture

Winter annuals are species that germinate in the fall, overwinter and then continue growing in early spring. The rapid growth of winter annuals starts as soon as the soil temperatures reach around 50-55 o F. They also consume large amounts of moisture, which has negative effects on crop seed germination and early growth. The list of most commonly known winter annuals includes: field pennycress, shepherds purse, henbit, blue mustard and treacle mustard (bushy wallflower). You may want to watch for those species. They make the “green patches” that are commonly seen during late parts of the year (October-November) and early spring (March-April). In addition, dandelion and curly dock, which are not winter annuals, can be also seen in early spring and at the time of corn and soybean planting.

In no-till fields, winter annuals can be effectively controlled with various herbicides. In corn and soybean they can be controlled 0-45 days before crop planting depending on the herbicide or after crop planting but before crop emergence. The same is true for the fields that are planted with herbicide tolerant crops (e.g. Roundup-Ready or Liberty-Link crops). The use of pre-plant or pre-emergence herbicides with residual activity in Roundup Ready crops would also provide a longer comfort zone in which to apply glyphosate-based products. Winter annuals are usually controlled in the first two weeks of May, before they become too large for herbicide efficacy.

Examples of burndown herbicides that can be used in corn and grain sorghum include: Aim (0.3 oz/acre), 2-4-D Ester (1.0 pt/acre); 2,4-D Ester + Banvel (0.5 pt + 0.5 pt); Banvel (Atrazine (2 qt); Atrazine + Banvel (2 qt + 0.5 pt), Atrazine + 2,4-D (2.0 qt + 1.0 pt); Field Master (4 qts), Gramoxone Extra (1.5 pt); Gromoxone extra + Atrazine (1.5 pt + 2.0 qt); Roundup Ultra Max (18-26 oz), Touchdown (24-32 oz/acre) and one of many generic glyphosate type products (24-32 oz). The list of pre-emergence herbicides in corn includes: Atrazine, Axiom, Balance, Bladex, and Prowl.

Examples of burndown herbicides in soybean that can be used from 0-30 days before crop planting include: Aim (0.3 oz/acre), Canopy (5-7 oz/acre), Command 3E (1.5 pt/acre); Gramoxone Extra (1.5 pt/acre); Extreme (3 pts/acre), Gauntlet (co-pack, 5.33 + 0.6 oz), Pursuit (4 oz), Pursuit Plus (2.5 pt), Sencor/Lexone DF (16/13 oz), Roundup Ultra Max (18-26 oz), Touchdown (24-32 oz/acre) and one of many generic Glyphosates (24-32 oz). The list of pre-emergence herbicides in soybean includes: Axiom, Pursuit, Prowl, and Sencor/Lexone.

Also note that glyphosate based products (e.g. Roundup, or various generics) used alone may not provide good control of winter annuals if temperatures are cool. Weeds need to grow actively in order to move a systemic product such as glyphosate throughout the plant to get good plant kill. Therefore, during cool spring temperatures avoid using Roundup. Mixtures with atrazine, 2,4-D or other modes of action can improve weed control.

Another thing to watch for is the price you are paying for your glyphosate-based products. Our studies that were conducted over 3 years and 6 locations across Nebraska clearly showed that generic glyphosate provided equal level of weed control when compared the much more expensive Roundup-named products. Why spend more money than what is needed to get the job done?

Also, consult the label directions for additives and for the pre-plant and post-plant intervals. For example, corn should not be planted 5 days before or after application of 2,4-D. Also, 2,4-D can be used for burndown in soybean but at least 7 days prior to crop planting. More details on these herbicides and their use rates can be also found in the University of Nebraska Guide for Weed Management. It is a publication that is updated annually, and it can be purchased in every county extension office for the nominal fee of $3. (SK)

David P. Shelton
Extension Agricultural Engineer

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