I am getting an increasing number of calls about armyworms in northern Ohio and the southern counties of Michigan, in corn but especially in wheat. Back in 2004, our last big armyworm outbreak in wheat, many people commented on how fast damage seemed to occur – one day the field looked fine, a couple days later the wheat had thinned considerably. (view photos) This highlights the importance of scouting. There is no substitute for walking into a field to see what is going on. For many insects that feed as larvae or nymphs, the younger the insect, the easier it is to kill. This means a higher percent control, or the use of a lower rate of insecticide, which saves money. Also, larger larvae eat more and are often responsible for the majority of damage. This is why a field can go from looking fine to looking funky overnight – the larvae are getting bigger and eating more, faster. Thus catching an infestation early prevents loss from larvae and improves control. Use thresholds to make a spray decision, as there are biological controls that kill armyworms naturally (disease, parasitic wasps, predators). Spot spraying may be possible along field edges or in areas that had heavy weed growth, a problem this spring.

In wheat, in many cases the caterpillars are still small and feeding on leaf margins, but feeding on the flag leaf is starting. Treatments are targeted not only to prevent defoliation of the critical flag leaf, but also to prevent larvae from clipping heads later in June and marching en masse to neighboring fields. The threshold in wheat that is heading is only two armyworms per square foot. If you see feeding injury but cannot find larvae easily, shake the plants vigorously so that larvae fall to the ground, and look carefully at the base of the plant, pushing the residue aside. Armyworms often hide out at the base of plants during the day, moving up on the foliage in the evening to feed. They may also be more active on cloudy days.

When making a spray decision in wheat, note pre-harvest intervals. The insecticides below are listed in order of PHI. All are effective at controlling small to medium-sized armyworms.

• Lannate = 7 days, LV 0.75-1.5 pt or SP 0.25-0.5 lb. Lannate is also used on sugar beets, and may be more readily available in the Thumb.
• Mustang Max = 14 days, 1.76-4.0 oz
• Penncap / Declare / Methyl parathion = 15 days, 2-3 pt.
• Tracer = 21 days, 1.5-3.0 oz. Tracer is a newer biological-based product containing the active ingredient Spinosad.
• Warrior / ProAxis = 30 days, 2.56-3.84 oz. Very effective in killing armyworms, but have a longer PHI.
• Baythroid 2 = 30 days, 1.8-2.4 oz. Also very effective, with a long PHI.

Please note that Lorsban 4E cannot be used on wheat in Michigan. I confirmed this with the Michigan Department of Agriculture. The Lorsban label is confusing in this regard – wheat is on the label, but 4E use is restricted to just 18 western states. Most of the Great Lakes states (IA, IL, IN, MI, OH, and WI) are not on this list.

The labels of most products give a range of application rate. If larvae are small, you probably can use a midrange rate of insecticide rather than the full rate. I have heard, for example, that a 3 oz rate of Mustang is working well in southern Michigan. If possible, spray a bit later in the day, as larvae will crawl across the treated surface later that evening as they climb plants to feed.

For organic production, several Bt products are available, but they are effective only on small larvae. Pyganic, which contains pyrethrin, can also be used in some organic certification schemes. The PHI for both Bt and Pyganic is 0 days. Entrust (1-2 oz), a spinosad-based insecticide approved for organic use, has a 21-day PHI.

On corn, larvae often hide in the whorl or at the base of plants. Large cylindrical frass (excrement) pellets in the whorl are a sign that larvae are present. Armyworms feed on the leaf margins; in severe cases, all leaf material is eaten leaving only the midrib. The threshold is 25% of plants with at least two larvae per whorl, or 75% of plants with a single larva per whorl. Sprays directed down into the whorl should kill the larvae hiding out there quite easily, unless the larvae are large. Pre-harvest interval is obviously not an issue with corn. Products include Ambush, Asana, Baythroid, Capture, Intrepid, Lorsban, Mustang, Pounce, Proaxis and Warrior, as well as Bt insecticides and Entrust for organic production (targeting small larvae).

Bean leaf beetle is still creating holes in soybean leaves. Generally not at threshold, although Bruce Mackellar in southwest Michigan reports a few fields heavily fed on.

Black cutworms are reported as well in corn and soybeans, up to an inch long. Fields with poor weed control – and there’s a lot of those – or a cover crop are at risk.

Fireflies are flashing, so corn rootworms are hatching.

Potato leafhopper are increasing in alfalfa. They can be easily controlled if caught before number go over threshold.

Soybean aphid was found this week in Ingham County. Colonization remains low in Michigan. Most other Midwest states have also reported finding aphids. Suction trap catches will be on line soon at: http://www.ncpmc.org/traps/state.cfm?state=MI. A fourth aphid suction trap went up in western Michigan in Mason County, hosted by Extension agent Norm Myers and Oomen Brothers Farm. A fifth trap will go up next week at the Monroe County MSU Extension office.

Scouting in Michigan sentinel plots has started, but is off to a slow start due to the weather. Soybeans are still fairly small. No rust has been detected.

Further south, soybean rust is still being found on kudzu in Florida, and was found on kudzu in Georgia yesterday. There have been no finds on soybean yet in either location. Soybeans are at early bloom (R1-R2) in Florida.

This year, spore traps will be installed in two Michigan soybean rust sentinel plots. The spore traps, provided by Syngenta Corporation, collect wind-blown spores. Additional spore traps are located throughout the sentinel plot network. Positive spore trap information does not imply that soybean rust infection has taken place. Only plant samples are used to determine a positive occurrence of rust. The data from the Michigan spore traps will not be released to the public unless there is a positive confirmation of soybean rust in the North central region. The spore traps are being used in the Michigan sentinel plots primarily to evaluate their potential as a research tool. All the spore trap samples will be processed at the University of Arkansas.

One of the challenges in using wind traps is that currently, identification of the rust spores obtained is done solely on the basis of visual identification. The spores are collected on a glass slide coated with petroleum jelly. It is difficult to separate the spores from the petroleum jelly to permit the use of analytical methods to confirm that they are positively Asian soybean rust. Researchers at The Ohio State University are working on a screening process that uses a fluorescent antibody that reacts with only Asian soybean spores, to fluoresce under ultra violet (UV) light.

Antibodies are coupled with molecules which fluoresce under ultra violet (UV) light, to improve detection of specific antigens. After the cells (rust spores) are mounted on a slide, fluorescent labeled antibody is placed on the slide and given time to bind to the cells. Antibody that doesn’t bind is washed off. The slide is viewed under a microscope using UV light. Fluorescence indicates the presence of the antigen-in this case, Asian soybean rust spores. Additional testing of the procedure is underway to make sure that the antibody only binds to (and fluoresces with) soybean rust, and not with other spores.

Results for the PSNT (Presidedress Soil Nitrate Test) show significant nitrogen credit can be taken to reduce the amount of nitrogen to apply in about one-third of the samples tested by the MSU Soil & Plant Nutrient Lab. There is a moderate credit for another one-third and for the other one-third the credit is rather low. Table 1 shows the distribution of soil N credits from the PSNT.

2006 Ag Expo returns to MSU July 18-20
Farmers, educators and families are invited to Michigan’s largest agricultural equipment exposition July 18-20 when the 27th annual Ag Expo takes place at Michigan State University (MSU).

The exposition will feature a skid-steer ride and drive, zero-turn mower demonstrations, utility vehicle ride and drives, livestock handling demonstrations, an antique and garden tractor pull (July 19 only), a toy tractor show and an FFA tractor driving contest.

More than 250 commercial exhibitors, including equipment, seed, fertilizer, building and service suppliers will be on site. Visitors can expect to see tractors, implements, trailers and other equipment, and can talk to representatives from manufacturers, dealers and agencies.

“This year’s Ag Expo will offer visitors the opportunity to see new equipment and demonstrations, and we’ve brought back the popular toy tractor show along with a tractor pull event,” says Kirk Heinze, Ag Expo director.

Ag Expo will also feature a number of educational exhibits from MSU colleges and departments. The College of Agriculture and Natural Resources will host a tent with displays and information from the Michigan Agricultural Experiment Station, the MSU Land Policy Program, the Animal Science Department, Project GREEEN (the plant industry initiative at MSU), 4-H Youth Development, and the IPM Program.

Ag Expo features commercial farm equipment from throughout the Midwest and several Canadian provinces on the 35-acre main exhibition site and the 40-acre field demonstration area.

The event runs from 9:00 AM to 4:00 PM, July 18, 8:00 AM to 7:00 PM July 19, and from 8:00 AM to 3:00 PM July 20. Admission to the grounds and parking at Farm Land and Mt. Hope Road are free.

For more information about Ag Expo, call 800-366-7055 or visit www.agexpo.msu.edu. Ag Expo is sponsored by the MSU College of Agriculture and Natural Resources.

Farmers, educators and families are invited to Michigan’s largest agricultural equipment exposition July 18-20 when the 27th annual Ag Expo takes place at Michigan State University (MSU).

The exposition will feature a skid-steer ride and drive, zero-turn mower demonstrations, utility vehicle ride and drives, livestock handling demonstrations, an antique and garden tractor pull (July 19 only), a toy tractor show and an FFA tractor driving contest.

More than 250 commercial exhibitors, including equipment, seed, fertilizer, building and service suppliers will be on site. Visitors can expect to see tractors, implements, trailers and other equipment, and can talk to representatives from manufacturers, dealers and agencies.

“This year’s Ag Expo will offer visitors the opportunity to see new equipment and demonstrations, and we’ve brought back the popular toy tractor show along with a tractor pull event,” says Kirk Heinze, Ag Expo director.

Ag Expo will also feature a number of educational exhibits from MSU colleges and departments. The College of Agriculture and Natural Resources will host a tent with displays and information from the Michigan Agricultural Experiment Station, the MSU Land Policy Program, the Animal Science Department, Project GREEEN (the plant industry initiative at MSU), 4-H Youth Development, and the IPM Program.

Ag Expo features commercial farm equipment from throughout the Midwest and several Canadian provinces on the 35-acre main exhibition site and the 40-acre field demonstration area.

The event runs from 9:00 AM to 4:00 PM, July 18, 8:00 AM to 7:00 PM July 19, and from 8:00 AM to 3:00 PM July 20. Admission to the grounds and parking at Farm Land and Mt. Hope Road are free.

Regional reports
1 -- Southeast
Ned Birkey

Weather
It has been great for parades, camping and wheat as we had cooler and drier than normal air temperatures. This past week has seen generally sunny days with temperatures in the low 70s. Despite all the rain in May, some soils are very dry, and I saw field and sweet corn wilting yesterday on sandy soils. About 0.5 inches of rain this past week was a big boost to all crops except for cut hay.

Commodity reports
Alfalfa first cutting is quickly winding down and has been of generally good quality. Alfalfa weevil problems should be finished and potato leafhopper problems increasing.

Corn is still not growing well in some fields with highly variable soils. Most fields are at the V6 growth stage, and yellow corn is still obvious in some fields. Soil sampling down to 12 inches yesterday, I found very dry soil in the top several inches and very wet soil about 8 to 12 inches. I think some sub-soils are still wet and not allowing good root growth. Replanting is winding down. Some fields have both tall plants and short replanted corn – a real succotash!

Soybeans seem to take a long time to really get growing, especially that planted no-till into 200-bushel corn stalks from last year. Advanced fields, planted just prior to Easter, are at the V4 growth stage. Planting and replanting are continuing. Replanting is hard to justify in thin but uniform stands, as fewer soybeans plants will compensate with more pods per plant. Post herbicide spraying is gearing up, and thistles and hemp dogbane are “ruling the roost” with nice healthy plants. Some bean leaf beetle feeding is evident but is not near threshold levels. A soybean rust and aphid sentinel plot was identified for Monroe County this week and will be monitored weekly for the rest of the season. Our conventional soybean variety plot host farmer reminded me of the high cost of conventional herbicides, $53 per acre in his case.

Wheat generally looks very good, though leaf rust is heavy on the flag leaf in susceptible varieties. Septoria is also present. I have not seen any head scab. The cool and dry air has been very helpful for kernel fill.

2 -- Southwest
Bruce MacKellar

Weather
The roller coaster ride that is the temperatures during this growing season was definitely on the low side over the last week. Temperatures were 5 to 10 degrees below the normal highs. This cooler spell has definitely slowed down the growth of the crop plants, but with warmer conditions on the horizon over the upcoming weekend, look for growth of plants to really recover quickly.

Commodity reports
Early planted commercial corn is at the V8 to V10, and is ready for side-dress N applications. European corn borer moth activity that was on the upswing two weeks ago probably has put some of the earlier planted fields at risk. For the most part, the commercial corn in our area looks pretty good with some areas that are uneven for corn that had not emerged during the wet period in the middle of May.

Seed corn is looking pretty good. There are a few fields that have used growth delaying techniques on their male rows to help extend the period of pollen shed. European Corn Borers have been above seed corn company thresholds, and some fields have been treated this week. Nitrogen applications are going on this week.

Early planted soybeans are growing well. Lots of the earlier planted fields have been treated with post emergence herbicides. Bean leaf beetle feeding continues to be significant but below threshold in some no-till fields near Mendon. Leaf diseases have been non-existent at this point in the soybean rust sentinel plots in St. Joseph and Kalamazoo counties. I have walked through several fields that did have septoria leaf spot (brown spot) on the lower leaves.

There are lots of acres of tofu soybeans planted in southwest Michigan. These varieties are usually not noted for being resistant to soybean cyst nematode. I would encourage producers to sample for soybean cyst nematode and evaluate the varieties that they are raising for yields, and compare these back to the soybean cyst nematode levels in the fields at the end of the season.

Alfalfa re-growth is growing quite quickly. Watch for potato leafhoppers, especially in smaller alfalfa. Alfalfa weevil larvae that can be found are quite large and adult weevils can be found in some areas, signaling the end of the significant damage we should expect from this pest this year.

The wheat crop is nearly turning in the southernmost fields. Irrigated fields continue to look exceptionally good. I have not seen bleached heads in fields that I have looked at, so I am hopeful that fusarium head scab will be light this year. We did have a couple of fields that were heavily infected by Septoria leaf and glume blotch. There were significant variety differences in the incidence of this disease.

3 -- West Central
Fred Springborn

Weather
Dry and comfortable sums ups this past week’s weather. Highs have been in the 70s with lows in the 40s and lower 50s. At this time we still have quite adequate soil moisture for most field crops.

Commodity reports
Corn growth has been slow this week, growth stages range from just planted to V6.

Dry bean planting is progressing rapidly. Soybean planting is winding down, advanced fields are at V3.

Grain fill is under way in most wheat fields. Neither head scab symptoms nor have armyworms been observed at this time. Oat growth is progressing. Many fields have headed. Low levels of cereal leaf beetle have been observed.

Alfalfa harvest of first cutting is well underway. Many producers have taken advantage of this week of dry weather to get dry hay put up. Some alfalfa weevil feeding has been observed on regrowth. Potato leafhopper is present in many fields.

4 -- Central
Paul Gross

Weather
This is the first week in several that we did not receive any rain. Fields are drying out and farmers are getting back into the fields. We should wrap up planting of corn and soybeans this week. There are many fields being replanted or patched up. This may create harvest problems this fall. The temperatures have been cool and comfortable for humans, but less than ideal for crop growth. This is the year that tile really pays. One grower indicated that all his fields that did not have tile were in need of replanting. We will benefit from the warmer weather that is predicted.

Commodity reports
The corn crop is all over the board. Some is very good while some is very poor. Farmers will finish planting this week. Many fields have been replanted all or in part. Stands are variable and replant decisions have been tough based on field conditions and the calendar. Some are patching in the poor spots while others will take what is out there. There were reports of armyworm in a couple of corn fields in Gratiot County. Scout for this pest.

Soybean planting will be completed this week. Many fields have been replanted all or in part. Many fields are weedy and herbicide applications will be going on this week or as fields dry out and planting is complete.

The wheat crop is done flowering. We have found septoria and powdery mildew, but no head scab at this time. There are reports of armyworm in the southern counties. Scout fields for this pest. Look first at the field edges next to grass fence rows.

Alfalfa harvest is nearly complete. Most of the crop that is to be harvested will be baled. The nice weather over the past week has allowed hay to get dry enough to bale. There are still a few alfalfa weevils in some fields, but it appears the worst is behind us. Scout the new growth for leafhoppers as we have found them in every field but at low numbers. That could change very quickly with the warm weather.

Dry bean planting is progressing and the crop should be planted in the next few days.

5 -- Thumb
Mark Seamon

Weather
Normal temperatures and good soil moisture have combined to help crops put on a lot of vegetative growth this past week.

Commodity reports
The alfalfa crop looks good in most cases. Second cutting should be good where first cutting was made early.

In sugar beets, top growth is adding to the crop canopy quickly. Herbicide applications are still active, and some are trying to kill those larger weeds that have been hanging on for several weeks

In wheat, a few reports and some insecticide applications have been made for armyworm infestations. Be sure to watch for preharvest intervals (PHI) when choosing an insecticide since some have as long as 30 days PHI.

Corn health is very good in most fields. Some areas have significant replanted, low areas in fields due to excessive rainfall and extended soil saturation. Plant growth has slowed with recent cooler night temperatures. Sidedress nitrogen applications are being wrapped up.

In soybeans, growth and development of later planted fields is catching up to early planted fields since weather conditions have improved in the past couple of weeks. Most fields have just a couple of trifoliate leaves emerged. Weed control in glyphosate resistant fields has begun with weed size being the deciding timing factor.

Dry bean planting continues at a steady pace. Seed bed conditions are mostly good with warm moist soils while some areas are becoming dry.

The northwesterly flow aloft that has led to cooler than normal temperatures across the Great Lakes region during the past week will gradually give way to a large ridging feature currently across the Great Plains. This pattern change will result in a significant warming trend across Michigan during the next one to two days.

In the short term, high pressure will lead to one more day of fair and dry conditions Thursday (June 15). A warm front will move northeastward through the state beginning Thursday evening into Friday, bringing much warmer and more humid air back into the region on southwesterly winds. Some showers and thunderstorms will be possible mainly in northern sections of the state with this frontal passage, while fair, dry and warmer conditions are expected across the south. A weak frontal boundary will approach the state late Saturday into Sunday and likely linger in the region, resulting in the chance for showers and thunderstorms on an almost daily basis through the first half of next week. Rainfall totals by next Monday are expected to range from 0.25 to 0.5 inches over most of the state.

Temperatures will increase from highs Thursday ranging from the mid-70s north to the low 80s south to the 80s to low 90s by Saturday. Low-level moisture and dew point temperatures will also be on the increase with lows warming to the upper 50s to upper 60s by this weekend. Given the outlook for much warmer temperatures and the drier than normal conditions experienced since late May in many areas of the state, water stress symptoms may appear in some areas.

Jet stream flow across North America is gradually expected to take on a western troughing, broad eastern ridging pattern during the medium range forecast time frame. This would place Michigan in the vicinity of a strong southwesterly jet stream with warm, humid, subtropical air to our south. Given general southerly or southwesterly winds, above normal temperatures are a good bet.

The 6-10 day and 8-14 day outlooks (covering June 20-24 and 22-28) both call for above normal temperatures over large portions of the central and eastern United States including all of Michigan. Precipitation forecasts for the 6-10 day time frames are for rainfall to range from near normal levels across central and southern sections of the Lower Peninsula to above normal levels elsewhere across the state. In the 8-14 day time frame, some westward retrogression of the upper air ridge is expected with precipitation totals forecast to fall back to below normal levels statewide.