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Vol. 18, No. 15, August 7, 2003 In
this Issue |
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August insect update |
Soybean aphid Aphid numbers have also increased dramatically in other states and over in Ontario. Ron Hammond from Ohio State says, "A few fields reportedly being sprayed in northern Ohio. Had a field where aphids (250 to 300) went from the top 2 leaves and spread throughout the plant onto leaves 3 to 5 with about 50 per leaflet (150 per leaf), easily less than 400 per plant or more. Most aphids were brand new and very small. Advised spraying. Another field being closely watched seemed to go from the 250 to 300 aphids on top 2 leaves throughout plant but not that many yet." Ron also reports seeing significant numbers of Japanese beetles, bean leaf beetles and Mexican bean beetles in fields as well. The spray window is probably short, limited to the next few weeks. After pods begin to fill, treatment seems not to pay. For scouting/ treatment advice, refer to the Field Crop CAT article about soybean aphid from July 10, 2003. My graduate student reports seeing significant numbers of honey bees in soybean at her research site in Cass County, so in areas with nearby apiaries or fruit/ vegetable production, that may be something else to consider. All of the products listed in E-1582 will kill bees. Perhaps spraying in the evening would reduce kill. Also, Bruce MacKeller in VanBuren County cautions that you must scout a field before just blasting it with insecticide, since he still finds fields with very few aphids. In my mind, there is no rhyme or reason for which fields seem to have buckets of aphids and which do not. Corn rootworm Incidental feeding damage is present on roots across much of central Michigan - this damage is interesting because it indicates a shift in rootworm behavior, but it is not economically significant. You must dig and wash roots to confirm that rootworms are causing significant damage. If you are in an area where storms recently hit, goosenecking may alert you to rootworm damage. On the other hand, areas with no recent wind may have significant root loss, but aboveground the plants appear fine. |
Perennial broadleaf weed control in the fall |
Wheat fields offer an excellent opportunity for perennial broadleaf weed control with fall-applied herbicides. The ideal timing for fall herbicide application is generally when the perennial weeds have reached the bud to flowering stage (early September), but before the plants are damaged by frost. Weeds vary in their sensitivity to frost; therefore, the application window is smaller for some species than for others. For example, perennials such as Canada thistle and dandelion survive light frosts and are most effectively controlled when the herbicides are applied through late October and early November. Perennials such as hemp dogbane and common milkweed will complete their life cycles by late summer and do not tolerate frost well, so herbicide applications cannot be delayed until late fall. For fall applications of Banvel refer to the label for rotation crop restrictions. Table 1 contains a list of recommended herbicides for controlling common perennial broadleaf weeds with fall herbicide applications. Table 2 provides the glyphosate product application rate in fl oz/A based upon glyphosate formulation and rate in lbs ae/A as found in Table 1. Always add ammonium sulfate (AMS) at 17 lbs/100 gal of spray solution to all treatments containing glyphosate. |
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Guidelines for spreading manure |
Wheat harvest has now come to an end across most of Michigan. With the end of wheat harvest comes an opportunity for many farmers to get back out onto the fields and spread manure. Planning ahead for your manure applications is more important now than ever. Farm operations of all sizes are coming under increased scrutiny as to how their farm is impacting the environment. The following are the guidelines for Manure Application to Land according to the Generally Accepted Agricultural Management Practices (GAAMPS) for Manure Management and Utilization. For more detailed information regarding these guidelines see the full text of the GAAMP for Manure Management and Utilization at: http://www.michigan.gov/mda/ or contact your local MSU Extension office. 1) All fields should be sampled at least every three years, and the soils tested to determine where manure nutrients can best be utilized. 2) Use fertilizer recommendations, consistent with those of Michigan State University, to determine the total nutrient needs for crops to be grown on each field that could have manure applied. 3) To determine the nutrient content of manure, analyze it for percent dry matter (solids), ammonium N (NH4‑N), and total N, P and K. 4) The agronomic (fertilizer) rate of N recommended for crops (consistent with Michigan State University N fertilizer recommendations), should not be exceeded by the amount of available N added, either by manure applied or by manure plus fertilizer N applied and/or other sources. The available N per ton or per 1000 gallons of manure should be determined by using a manure analysis and the appropriate mineralization factors (see Manure Management Sheet #2, MSUE Bulletin E-2344 by Jacobs et al., 1992b) for organic N released during the first growing season following application and the three succeeding growing seasons. 5) If the Bray P1 soil test level for P reaches 150 lb/acre (75ppm), manure applications should be reduced to a rate where manure P added does not exceed the P removed by the harvested crop. (If this manure rate is impractical due to manure spreading equipment or crop production management, a quantity of manure P equal to the amount of P removed by up to four crop years can be used for the first crop year, if no additional fertilizer or manure P is applied for the remaining crop years and this rate does not exceed the N fertilizer recommendations for the first crop grown.) If the Bray P1 soil test reaches 300 lb/acre (150ppm) or higher, manure applications should be discontinued until nutrient harvest by crops reduces P test levels to less than 300 lb/acre (150ppm). To protect surface water quality against discharges of P, adequate soil and water conservation practices should be used to control runoff and erosion from fields where manure is applied. 6) Manures should be uniformly applied to soils. The amount of manure applied per acre (gallons/acre or tons/acre) should be known, so manure nutrients can be effectively managed. 7) Manures should not be applied to soils within 150 feet of surface waters or to areas subject to flooding unless: (a) manures are injected or surface‑applied with immediate incorporation (i.e., within 48 hours after application) and/or (b) conservation practices are used to protect against runoff and erosion losses to surface waters. 8) Liquid manures should be applied in a manner that will not result in ponding or runoff to adjacent property, drainage ditches, or surface water. Direct discharge to adjacent property, drainage ditches, or surface water or applications that result in an increased flow in field tile lines is an unacceptable practice. Liquid manure applications should be managed in a manner to prevent manure runoff and soil erosion losses to surface waters and optimize nutrient utilization. 9) As land slopes increase from zero percent, the risk of runoff and erosion also increases, particularly for liquid manure. Adequate soil and water conservation practices should be used which will control runoff and erosion for a particular site, taking into consideration such factors as type of manure, bedding material used, surface residue or vegetative conditions, soil type, slope, etc. 10) Where application of manure is necessary in the fall rather than spring or summer, using as many of the following practices as possible will help to minimize potential loss of NO3‑N by leaching: (a) apply to medium or fine rather than to coarse textured soils; (b) delay applications until soil temperatures fall below 50o F; and/or (c) establish cover crops before or after manure application to help remove NO3‑N by plant uptake. 11) Application of manure to frozen or snow‑covered soils should be avoided, but where necessary, (a) solid manures should only be applied to areas where slopes are six (6) percent or less and (b) liquid manures should only be applied to soils where slopes are three (3) percent or less. In either situation, provisions must be made to control runoff and erosion with soil and water conservation practices such as vegetative buffer strips between surface waters and soils where manure is applied. 12) Records should be kept of manure analysis, soil test reports, and rates of manure application for individual fields. |
Can you say West Nile Virus? |
Last week I visited a local dairy farm to see if there were any photo opportunities for a poster on West Nile Virus (WNV). Unfortunately, it was easy to find mosquito breeding sites. They included an old gallon jug with the top broken off, a unused water trough, a 10 foot by 20 foot pile of tires used for bunk silo plastic and a half plastic barrel full of water. Each site has the ability of breeding thousands of Culex mosquitoes, which have been shown to be the primary carrier of WNV. According to Mike Kaufman with MSU Entomology, WNV affects mainly older people, 50 years old and older! The average age of Michigan farmers is about 55 years old. I feel that farmers and farm workers are at particular risk for WNV because they spend a lot of time outdoors and are often out early and late in the day when mosquitoes are active. They usually are not in the habit of applying mosquito repellant with DEET either. WNV can be fatal to people and horses. It only takes one bite from a mosquito carrying the virus to make you sick. My hope is that farmers will take the time to eliminate as many of the potential mosquito breeding sites around their farms as possible, treat those sites that will stay and use DEET repellents on a regular basis. MSU Extension has an excellent bulletin on WNV, E-2836. To get a copy contact your county Extension office or the MSU Extension bulletin office at 517-355-0240. For more information on West Nile Virus, see the
article by Mike Kaufman in the July
24, 2003 issue of the Field Crop CAT Alert. |
Regional reports |
Weather news |
In some parts of the world such as southern and eastern Asia, the bulk of the annual precipitation falls during a relatively short period of the year when available moisture is present near the earth's surface and upper air dynamics support convection. This precipitation is typically in the very repetitive form of afternoon and evening showers and thunderstorms on an almost daily basis. Given an almost stationary upper air trough with relatively cool air aloft over the Great Lakes region (which is associated with relatively unstable atmospheric conditions), Michiganders have had a chance to experience such monsoonal type climates recently. Scattered showers and thunderstorms have formed on a daily basis since late last week. Rainfall totals with this pattern have been extremely variable with some spots reporting more than 2 inches (and unfortunately in some areas, damaging hail as well) while in many other areas, totals were less than 0.25 inches. In the forecast the upper air trough is expected to edge eastward, but extremely slowly. This will set the stage for afternoon and evening showers and thunderstorms through Friday (August 8), especially in eastern sections of Lower Michigan. Rainfall totals and a real coverage will likely remain very scattered at best, with most spots remaining dry. Temperatures for the next several days will remain at or a couple of degrees below normal. After the trough finally weakens and moves into New England by Saturday, fair weather is expected to develop and continue into the middle of next week. Further ahead, the NOAA medium-range forecast guidance suggests an eventual end to the current upper air pattern across the eastern U.S. For both 6-10 and 8-14 day outlooks, covering August 12-16 and 14-20 respectively, temperatures are forecast to range from near normal in southern sections of the state to above normal in the north. Precipitation totals during the 6-10 day time frame are forecast to be near normal statewide while totals in the 8-14 day period are expected to range from below normal in western sections of the Upper Peninsula to above normal in the southern Lower Peninsula. New long lead outlooks |