Insects in alfalfa, corn, soybean and wheat |
Alfalfa weevils are still being reported in alfalfa, and potato leafhopper feeding was reported in the southern part of the state. The recent rains delayed cutting in some places, so the weevils and hoppers have had the chance for some extra feeding before first cutting. My recommendation is to cut as soon as the weather permits, rather than managing these pests with an insecticide. Cutting will kill most of the weevil larvae, any leafhopper eggs laid inside alfalfa stems and some leafhopper nymphs. Remember to scout new growth, and watch for PLH populations to increase as the weather warms (at least we hope it warms up some day). Few corn borers have been captured in traps so far this season. On the MSU campus, we still have not found moths in our traps. So far, things aren't looking good for first generation ECB. Cool, rainy nights will reduce mating and egg-laying success of moths. Also, the delay in corn growth means that egg-laying females will encounter corn at an unfavorable growth stage. Shorter corn contains DIMBOA, a natural plant chemical that is a feeding deterrent. Larvae emerging on small corn (less than 6 leaves) often fail to establish on the plant, wander off and die. When corn is unfavorable for ECB colonization, we sometimes find larval infestations in other crops. This happened last year (2002), when many first generation corn borer larvae were found in wheat, apples and vegetable crops. Soybean aphids were found on VO soybean on the MSU Campus on June 3. The numbers are still very low. Illinois also reported colonization of V1 soybeans this week. Finally, aphids are still being blamed for many problems in wheat. However, I still have not seen anything beyond the normal, low background population of aphids in any small grain field. In the latest incident, twisting of wheat stems and heads (see Photo 1) was blamed on aphid feeding and "viruses" transmitted by aphids, and growers were told they needed to treat for aphids. However, the injury was clearly from a growth regulator herbicide, either from spray drift or tank contamination. In this case, an insecticide application is not only unjustified from the yield standpoint, but driving over the wheat to make an application will likely result in a yield loss. Be skeptical of claims of aphid damage, and contact your local Extension agent so they can visit the field. |
Springtails up close and personal |
I've been talking about springtails for two months now. This week, I finally include a number of pictures, courtesy of several people who sent digital camera photos. |
Eveningprimrose (Oenothera spp.) identification |
I had several questions last season and a couple this season from agronomists and field crop agents regarding the identification of eveningprimrose (Oenothera spp.). While this weed is typically more problematic in nursery and ornamental plantings, eveningprimrose can be found in sandy agronomic fields in the state. There are a number of Oenothera species in Michigan. The two species that have been found in row crop fields are common or yellow eveningprimrose (Oenothera biennis) and cutleaf eveningprimrose (Oenothera laciniata). Common and cutleaf eveningprimrose can be winter annuals, biennials, or short-lived perennials that only reproduces by seed. They are characteristic of a thick, fleshy taproot from which a basal rosette of leaves is formed. Stems may be branched and erect, prostrate, to sprawling in nature. Stems are green to reddish in color and usually covered with hair. The leaves of common and cutleaf eveningprimrose are typically long, narrow and pointed. Leaves are alternate in arrangement, having petiolated lower leaves and sessile upper leaves. The leaf margins may be highly variable, from smooth, wavy, lobed, to toothed leaf margins. Cutleaf eveningprimrose has more deeply cut and lobed leaf margins. Both common and cutleaf eveningprimrose may have a pinkish to reddish coloration of the leaf midrib. Yellow flower petals are attached to a long, narrow tube of fused sepals. The seedpods split downward on four sides at maturity to release the seeds. Fall and spring tillage can effectively control common and cutleaf eveningprimrose. However, some plants can survive the spring tillage pass given the prostrate, sprawling, tap-rooted nature. Postemergence herbicide applications of glyphosate, dicamba, and 2,4-D seem to provide extremely variable results. |
EPA grants extension for Folicur |
The EPA has granted an extension of the Section 18 emergency use exemption for Folicur until June 30, 2003. The emergency exemption only allows Folicur to be used for scab control in wheat. Folicur has a 30-day pre-harvest interval (PHI). As of June 10, the scab prediction model at www.cips.msu.edu shows a low probability for scab at all weather station sites in Michigan. The southern Michigan counties are well into flowering, and the probability that scab will cause any significant problems is low. Heading and flowering are beginning in central Michigan and there is still a need to watch the probability model. |
Low cost high tech crop scouting with handheld GPS units |
Recent advances in handheld Global Positioning System (GPS) receivers have provided growers with a new low cost tool for crop scouting. A new satellite-based augmentation system has been developed by the government to improve the accuracy and integrity of information signals broadcast by GPS satellites. This technology is driving down the price and increasing the accuracy of handheld GPS receivers. The primary commercial market for these low cost handheld units is for travel and recreational navigation. However, the technology has many practical applications in crop scouting. Global Positioning Systems are not new to agriculture. In fact, they are custom equipment on most combines and large tractors. To achieve the level of precision needed for most agricultural applications, these units typically relied on land-based differential correction signals in addition to the GPS satellite signals. These land-based correction signals are available from several sources including U.S. Coast Guard beacons and pay-to-use subscription services. The correction signal, dual antennae requirements and correction factor software contributed to the relatively high price of these GPS units. The U.S. Federal Aviation Administration and Department of Transportation are currently working on a correction system called WAAS for "wide area augmentation system." WAAS uses a system of approximately 25 ground-based reference stations that monitor GPS satellite data. Two primary stations located on each coast receive data from the reference stations and calculate a GPS correction signal, which accounts for GPS satellite signal errors from ionospheric disturbances, timing and satellite orbit errors. The correction signal is then broadcast through one of two satellites with a fixed orbit over the equator. The correction signal is compatible with the basic GPS signal structure and is able to be picked up free of charge by any WAAS enabled receiver. The WAAS signal is currently operational on a test basis and is expected to be fully certified for aviation use by the end of the year. WAAS testing in the fall of 2002 confirmed performance accuracy of 3 to 6 feet horizontal and 6 to 9 feet vertical throughout the majority of the continental U.S. Handheld GPS units equipped to use the WAAS signal are currently commercially available in the $200 range and are available through the Internet and at most sporting goods and outfitting stores. How can these handheld GPS units be used in crop scouting? Many applications are possible, and given farmer ingenuity, many new uses will likely evolve over the next few years. The devices can be used to accurately identify the location of insect, disease, weed, nutrient and soil problems in the field observed while scouting. Once the problem areas are marked and electronically stored in the device's memory, the unit can be used to navigate back to them later for future monitoring or for corrective action. In addition to marking and navigating, many of these handheld units have the capability to measure distances and even calculate acreage. Since the units measure elevation in addition to lateral position, they can also be used to determine surface drainage patterns. Most units also have a limited memory, which can be used to store shape-files of fields. The possibilities are endless, but perhaps best of all, once the fieldwork is done, you can use the same unit to mark and navigate to your favorite fishing holes. A demonstration on the field crop scouting uses for handheld GPS units will be given at the July 25, Michigan State University Crop Management & Field Diagnostic School (CM&FDS). Contact your local MSU Extension office for more information on the MSU CM&FDS. |
Revised nutrient recommendations |
Effective July 1 the Soil and Plant Nutrient (SPN) Lab will begin using the new windows based on the Nutrient Recommendation Program. Recommendations for all field and vegetable crops have been revised according to the approach used in the Tri-State recommendations for corn, soybeans, wheat and alfalfa. This approach has three distinct phases; buildup, maintenance and draw down (see figure). When the soil test value for P or K is below a critical value the recommended amount of P2O5 or K2O includes an amount to build the soil test value up to the critical value plus an amount equal to crop removal (maintenance). At the critical value sufficient P or K is present to produce 95 to 100 percent of the maximum yield on the average across a range of growing conditions. When the soil test value is within the maintenance range, the recommendation is equal to crop removal. Above the upper maintenance limit the recommendation is less than crop removal to allow the soil test value to be drawn down. The crop codes have been revised to be more systematic. Field (agronomic) crops are assigned 100 level numbers. Vegetables are assigned 200 level numbers. Fruit crops are assigned 300 level numbers. Turf types are assigned 400 level numbers. Flowers, shrubs and trees are assigned 500 level numbers. Copies of the new information sheets with the crop codes on the backside have been sent to all county Extension office. Additional information will be forthcoming including nutrient recommendation information sheets and bulletins. |
| Regional reports |
1 - Southeast |
Weather Commodity reports Corn is finally growing rapidly with advanced fields at the V6 leaf stage, though most fields are about V3-4. European corn borer trap counts at the Dundee site were 13, 2, 156 on Tuesday and 0, 1, 0 at the Romulus site. A lot of sidedressing is going on now. Soybeans are still very small and growing slowly. Fields range from VE to about V2 leaf stage with bean leaf beetles still present, though is low to moderate numbers. Wheat is finishing flowering and I think most fields have good to very good yield potential. With the current weather pattern, flag leaves will be heavy with diseases. With June a third gone, at least we have not had the devastating hot weather of the past two June months. Miscellaneous |
2 - Southwest |
Weather Commodity reports Early soybeans are at the V1 stage and late-planted soybeans are emerging. Most of the wheat is flowering while the most advanced fields are beginning to fill kernels. The flag leaves in most fields remain free of disease. However, powdery mildew has infected the heads in some fields. Low numbers of cereal leaf beetle larvae were reported in Cass County. Harvest of alfalfa has been progressing slowly due to the frequent rains and poor drying conditions. Alfalfa fields that have not been cut have heavy weevil feeding and are beginning to show symptoms of early leafhopper feeding. |
3 - West Central |
Weather Commodity reports Early-planted oats are just about ready to put out the flag leaf and are beyond the growth stage where growth regulator herbicides such as 2,4-D can be applied safely. Rye is flowering. Wheat for the most part is in good condition at Feeke's growth stage 9 to 10.5. The wheat crop is highly variable this year in growth stage and in crop condition. Most of the wheat in Montcalm has not yet begun flowering. Corn growth stages vary from VE to V2. This crop is in slow motion this year. While it is getting greener some sunshine and warm temperatures, maybe even some global warming, would be very welcome. Sugar beets are growing well. Sugar beet stands continue to look good for the most part. Soybean planting is virtually complete with early-planted fields in the V1 growth stage. Like corn this crop is in slow motion. Dry bean planting is progressing slowly as we are waiting for warmer temperatures. Approximately 5 to 10 percent of the crop is planted in Montcalm. |
|
4 - Central |
Weather Commodity reports Soybeans are emerging slowly. Weeds are a problem is many fields. Herbicide applications will be made and fields dry out. The wheat crop is beginning to head. There is powdery mildew and septoria in many fields. This is a critical time to scout fields to manage diseases. With the rains there will be some risk of head scab. EPA just announced that Folicure label has changed to extend the use date to June 30. This was necessary because the crop is late this year. If you have any questions about disease identification or thresholds contact the Extension office. Alfalfa harvest is progressing as field conditions allow. The crop is budding so quality will start to decline. Fields need to be scouted for alfalfa weevil. If there is a problem these fields should be cut immediately. It has been nearly impossible to get any dry hay made. Sugar beets are progressing very well. There are reports of springtails and some leafminers. Fields should be scouted for these pests. |
5 - Thumb |
Weather Commodity reports Weed control in sugar beets is great in some fields where herbicide applications were timely. Springtails are fewer can still be found in many fields. Spinach leaf miners have been spotted in some fields. Corn is finally proceeding in development with somewhat warmer temperatures. Sidedress Nitrogen applications are occurring. Purpling symptoms are clearing up with new growth being green. Wheat in this area has headed in the past week. A few heads can be found that are flowering. Powdery Mildew and Septoria can be found in the lower canopy but most flag leaves are clear of disease. Cereal leaf beetle can be found in low numbers. Emergence, growth and development of soybeans are very slow. The most advanced fields are just pushing out a trifoliate leaf, but most are cotyledon seedlings or unifoliate plants. Planting of dry beans progress is slow. Most growers are still waiting for improved soil temperatures to be sure to get quick emergence. |
6 - Northern Lower Peninsula |
Weather Commodity reports Wheat is variable this year with some starting to head and others still only six inches high. Yields will be down significantly due to cold injury this spring and winter. Soybeans are coming along slowly. All are in now with most early beans emerging slowly. Some dry beans went in last week in great soil conditions. Wet soils will slow planting until later this week. Alfalfa is coming along nicely. Cutting should begin in earnest by early next week for dairy and early hay. About 10 percent is already cut and down. Conditions are very weedy with grasses and dandelions this year. Miscellaneous |
Weather news |
A change in the weather is predicted for the weekend, as skies clear and temperatures climb into the mid- to upper-70's. Low temperatures will be in the mid-50's to low-60's. Because of the probability of an upper-level ridge in the Great Lakes, above-normal temperatures are forecast for the 6-10 and 8-14 day periods. In the 6-10 day range, below normal precipitation is expected, while in the 8-14 day range, normal precipitation is anticipated. The precipitation forecast has been very unreliable this week. Heavy rains (up to 1 inch) are still possible for today (Thursday, June 12) in the southeastern parts of the state. Current forecasts are for partly cloudy weather for much of the state for the weekend, but there is a hint from some models that rain might occur in southern parts of the state. For next week, the weather should be clear Sunday through Tuesday, but there is more uncertainty in precipitation for Wednesday. Stay tuned to your local forecasts. |