June 21, 2007
In this issue
§ Armyworms, other Lepidoptera rain out near lakes
§ Asiatic garden beetle in southern Michigan
§ Preharvest herbicide application in winter wheat
§
Identifying and
correcting manganese deficiency
§ Tips to avoid weed control antagonism when applying manganese fertilizer with glyphosate
§
§ Regional reports
§ Weather
Christina DiFonzo, Entomology
Between June 8 and June 10, storms dropped moths in large
numbers on the fringes of
It appears that this event was limited to areas near the
lakes, and that moths did not drop inland. In southern and central
Christina DiFonzo, Entomology
Purdue recently reported Asiatic garden beetle grub damage
in corn in northern
Asiatic garden beetle, as the name implies, was introduced
from Asia to
§
Garden beetles often are in mixed infestations
with other species, such as European chafers and Japanese beetles. In southern
§ Generally, minor turf pests, they are important in nursery and vegetable crops.
§ Adult beetles feed on flowers, weeds, vegetables and presumably field crops.
§ Adults hide during the day and feed at night, actively flying when temperatures are more than 70°F. They often come to lights at night;
§ Eggs are laid in July to October in clusters, preferably in weedy areas. Some weeds are preferred, particularly ragweed.
§ Larvae feed from August into the fall, overwinter in the last stage, and feed again in April. This is when crop damage occurs.
This is yet another species to add to our list of early-season grub pests. Several things have probably contributed to the increase in grub problems, including reduced/no tillage, mild winters, new grub species moving into the state and earlier planting dates. In the future, we will likely be dealing with a complex of species infesting fields in the fall, and damaging crops in April and May.
To identify Asiatic garden beetle, look at the butt end of
the grub at the raster pattern (pattern of hairs). Asiatic garden beetle has a
“smiley face” pattern of hairs. In southern
There is a video of a damaged field in the Purdue Pest & Crop newsletter. Visit http://extension.entm.purdue.edu/pestcrop/2007/issue12/index.html
Jim Kells and David Hillger
Crop & Soil Sciences
The primary benefit of pre-harvest herbicide application in small grains is in aiding harvest. This treatment will not increase yield. However, there are several negative aspects of a pre-harvest application including: the damage to the small grain caused by driving over the field with the application equipment and potential off-target injury. Therefore, this practice is generally not recommended.
2,4-D use
2,4-D is registered for pre-harvest application in wheat, barley, rye and oats. Many amine forms and low volatile ester forms can be used in wheat, barley and rye, and the labeled rates are 0.5-1 lb ai/acre (1-2 pints/acre of a 4 lb/gal formulation). Only certain amine forms are labeled for use in oats. Check the herbicide label for details. Application can be made after the small grain has reached the hard dough state. Earlier application carries a serious risk of crop injury.
When applying 2,4-D as a pre-harvest treatment, the two pints/acre rate will be most effective. Remember, that the weeds being treated will be very large and that one pint/acre of 2,4-D may not be adequate. The best choice between the amine and ester form of 2,4-D will depend upon the individual situation. The ester will be more effective on the weeds; however, the risk of off-target injury from volatilization must be considered. To minimize this problem, the ester form of 2,4-D should not be used if the temperature is expected to exceed 80°F within one day of treatment. The amine form of 2,4-D will be less effective, but does not have the risk of volatilization. Both herbicides can cause off-target injury from spray particle drift. Therefore, applicators must be very cautious about wind speed.
Both forms of 2,4-D have activity on broadleaf weeds, but not on grasses or yellow nutsedge. Expect that a minimum of ten days will be required for a pre-harvest application of 2,4-D to desiccate weeds sufficiently to aid in harvesting. Following harvest, the straw must not be fed to livestock.
Glyphosate
Several glyphosate products are labeled for pre-harvest application in wheat and feed barley. This treatment should not be applied to wheat grown for seed. Application can be made after the hard dough stage (30 percent or less grain moisture) and at least seven days prior to harvest. Refer to the specific product label for maximum rate, tank mixtures with other herbicides and spray volume. Ammonium sulfate should be added to all glyphosate products in order to minimize the negative effect of hard water on glyphosate activity. The addition of ammonium sulfate also can improve glyphosate’s efficacy on some species, especially velvetleaf, regardless of water quality. Dry ammonium sulfate should be labeled “spray grade” quality and applied at 17 lbs/100 gal. Liquid ammonium sulfate products are equally effective if applied at a rate equivalent to 17 lbs/100 gal.
Glyphosate applied at 0.75 lb ae/A will provide some control of perennial broadleaves, such as milkweed and Canada thistle. If temperatures are high at the time of application, quackgrass will not be actively growing and, therefore, will be much more difficult to control.
In general, the most effective system for controlling perennial weeds in small grains is to harvest the wheat, allow the weeds to re-grow, and apply an herbicide in the fall. If the patches of perennial weeds are too dense to harvest, they can be mowed following the wheat harvest.
Several factors must be considered when deciding whether or not to treat. These include the severity of the weed problem (both density and percentage of the field affected), the weed species and the risk of off-target injury.
Ron
Gehl
Crop
and Soil Sciences
Manganese deficiency is the most common micronutrient issue
found in
Due to the variability of our
The best way to be sure what is causing the deficiency is through soil and tissue analysis. But, if your field has a history of manganese deficiency, these areas will tend to show the deficiency (and will need to be corrected) on an annual basis, since most of the manganese in our soils is in an unavailable form. Even when a soil-applied manganese fertilizer is applied, a large portion of the manganese will be very quickly tied up, or fixed, in the soil in an unavailable form.
If you have a field, or part of a field, that is manganese-deficient, it is important to correct the problem as soon as possible to reduce the risk of yield loss. Foliar fertilization with an inorganic or chelated manganese source is the most effective means by which to correct a manganese deficient field crop. The foliar manganese should be applied at a rate of 0.5 to 1.0 lb Mn per acre with at least 20 gallons of water (30 gallons recommended). Chelated manganese sources have not been shown to be more effective and should be applied at rates equivalent to inorganic salts (manganese sulfate). Many products, particularly multi-nutrient products, are often labeled at very low rates, and care should be taken to assure that appropriate rates to correct the deficiency are applied. In some cases, a second application may be needed at a later date to correct the deficiency. Use caution if you plan on tank-mixing manganese fertilizer products with glyphosate products, as research has shown antagonism between many manganese fertilizer formulations and glyphosate. More information about this antagonism can be found in the accompanying article by Kurt Thelen.
Kurt Thelen
Crop and Soil Sciences
Manganese deficiency is the most common crop micronutrient
problem in
Field experiments showed a significant antagonism in common lambsquarters and velvetleaf, when glyphosate was tank-mixed with ethylaminoacetate- manganese, and slight antagonisms in tank-mixes with lignin sulfate- manganese and MnSO4-powder. Greenhouse studies have shown that an EDTA- manganese formulation enhanced glyphosate efficacy (by 25 percent in giant foxtail and 40 percent in velvetleaf). However, tank-mixes of each of the other manganese products caused significant antagonisms, reducing weed control by 10-30 percent when compared to glyphosate alone.
One possible method for avoiding the antagonism is to apply the manganese fertilizer at a different time than glyphosate. In a greenhouse study, the ethylaminoacetate- manganese fertilizer was applied six, four and two days before-, two days after-, and at the same time as glyphosate. There were no differences in herbicide efficacy in giant foxtail for any of the two-pass timings. In velvetleaf, manganese sprayed two days before the glyphosate application reduced weed control by 15 percent. But this was not as severe as the 30 percent reduction when glyphosate and ethylaminoacetate- manganese were tank-mixed.
A second method for avoiding the antagonism is to add an adjuvant to the spray tank that will prevent the antagonism, either by chelating the manganese tightly (with chelates such as EDTA or citric acid) or by preventing the manganese from binding to the glyphosate molecule (by adding ammonium sulfate). In greenhouse experiments, ammonium sulfate and EDTA improved herbicide efficacy in all glyphosate- manganese tank mixes except for EDTA- manganese, where efficacy remained the same. Citric acid antagonized the manganese -EDTA-glyphosate tank-mix, but improved the efficacy of all other manganese formulations. The degree that each adjuvant improved the different manganese -glyphosate tank-mixes varied, and will be the subject of future studies.
In summary, if conditions are optimal for glyphosate control of weeds, i.e. weed pressure is low and weed size is small, you may get adequate weed control with glyphosate tankmixes with commercially available manganese formulations. However, even under these optimal conditions it is still advisable to add ammonium sulfate (17 lbs per 100 gallons of water) to minimize the antagonism imposed by the manganese. If weed control conditions are marginal, i.e. moderate weed pressure or moderate weed size, a chelated form of manganese such as an EDTA- manganese formulation, plus ammonium sulfate is recommended with glyphosate tankmixes. Finally, if weed control conditions are poor, i.e. heavy weed pressure (especially lambsquarters and velvetleaf) or large weed size, manganese should not be tankmixed with glyphosate. Rather, in these tough weed control conditions, manganese should be applied in a separate application following the glyphosate application.
Lyndon Kelly
Extension Irrigation Educator
MSU Extension/ Purdue Extension
New wells and surface water withdrawals in
or from St. Joseph County MSU Extension at http://www.msue.msu.edu/stjoseph then navigate to the link for irrigation on the left side.
The latitude and longitude coordinates for the location are required for all new large scale withdrawal location. This information may be provided by handheld GPS units or the groundwater mapping website (http://gwmap.rsgis.msu.edu). Many MSU Extension offices or your local Conservation District office can assist with the use of finding the latitude and longitude coordinates. Providing the latitude/longitude location of withdrawals will allow mapping and analysis of effects of withdrawals on groundwater and stream base flow in the watershed basin.
Information at the St. Joseph County
MSU Extension website (http://www.msue.msu.edu/stjoseph)
can assist in estimating water use for irrigation and other agricultural water
uses. Lyndon Kelley, irrigation management educator for MSU Extension can
answer many of the questions related to
An estimate of expected water use by the month is needed. Most irrigators will estimate their water use from experience multiplied by the number of acres irrigated. As an example: 100 acres with 1.5 inches of irrigation applied in June would have an estimated water use of 150 acre inches for the month. Three inches of estimated irrigation needed in both July and August and 1 inch in September, would give an estimated annual water use of 550 acre inches for the year.
The registration process also calls for an estimate of consumptive water use. Consumptive water use is the amount of water that is lost from the area of withdrawal. Since most water pumped for crop irrigation ultimately goes into evapotransporation, the consumptive use is estimated to be high or about 90 percent. Water used for harvest cooling is mostly retuned back to the surface or groundwater so the consumptive use is estimated to be low or about 5 to 10 percent.
The registration process establishes a “baseline capacity” based on the available withdrawal capacity of a system. The baseline capacity of the system should be reported as pump capacity in gal/min along with a pump and system description, which is compatible with the well log. Baseline capacity applies to both wells and surface water withdrawals. Please note: You should report this baseline capacity value on the registration form on the line listed as “rated capacity.”
For further information, water resource specialist, Abigail Eaton of the Michigan Department of Agriculture Environmental Stewardship Division heads up the registration process for large water withdrawals. She can be contacted at 517-241-3933 or eatona@michigan.gov.
Ned Birkey
The weather has changed this week from hot and dry, to more seasonal temperatures with scattered and even localized heavy rain on Tuesday, May 19, ahead of the front that came through the area a couple of days ago. Temperatures have moderated to near normal temperatures now.
Alfalfa is generally re-growing fairly well, with potato leafhoppers present, though not at threshold levels. Some dairy farmers are taking their second cutting now.
Corn is growing evenly or unevenly, depending upon the soil, compaction, drainage and other conditions. Uneven fields are painfully apparent. Advanced fields are at the V10 growth stage. Corn borer trap numbers are very low. We have had leaf rolling in fields with sandy soils or compaction. I personally do not mind a somewhat drier than normal June, as I think the corn will root deeper, which will then benefit the plants later in the season.
Oats have headed out, are still nice and green, though stands appear thin.
Soybeans are showing a lot more yellow color than
normal for this early in the season, due to soybean cyst nematodes, seedling
root diseases, competition from weeds and herbicide injury from applications
made during the past week’s hot temperatures. Non-glyphosate fields are having
extra weed pressures, and in some cases the weeds are rapidly growing past the
point of control, unless a farmer still has a rope wick applicator from the
late 1970’s and 80’s. This job is harder now since most soybeans are drilled rather
than in nice, neat 30 inch rows to traverse. Variant Western corn rootworm
yellow, unbaited, sticky traps went up in Washtenaw and Lenawee counties’ soybean
plots this week, and a Western bean cutworm trap was installed in
Wheat is turning color very rapidly with diseases readily found on the flag leaf. Head scab is apparent on some varieties that were flowering during the hot, humid, hazy, muggy and even foggy weather over the Memorial Day weekend or the following week of similar conditions. I think that wheat yields will be highly variable and perhaps now may be lower than normal overall, though it is difficult for me to predict wheat yields. I also will speculate that wheat harvest will be slightly earlier than normal, around July 1. Thistles, giant ragweed and other weeds will make harvest more difficult in some fields.
Farmers are working hard to finish corn and soybean fieldwork before wheat harvest. Windy and hot weather conditions have made post emerge spraying harder to accomplish.
Bruce MacKellar
Rainfall was widely variable from thunderstorm events that
occurred on June 18 and 19. Precipitation totals ranged from around an inch
along the
Irrigated commercial
corn continues to look excellent. The most advanced fields are approaching
shoulder height, with V12 corn being the most common for the earlier planted
fields. ET rates are ranging between 0.15-0.18 of an inch of water per day on
the most advanced fields. Dry land corn has been suffering from drought stress
symptoms during the afternoon, especially earlier in the week when the
temperatures were in the lower 90’s. Corn is considered to be exhibiting severe moisture stress when leaf rolling
occurs for several hours during the afternoon. The accompanying chart shows an
estimation of the yield losses per day and over a four day period of severe
drought stress:
Final
yield decrease from severe drought stress
|
|
% per Day |
% per 4 days |
|
|
|
|
|
Early Vegetative |
-- |
5-10 |
|
10-Leaf |
1-2 |
-- |
|
15-Leaf |
2-4 |
-- |
|
Tassel – Silk |
5-15 |
-- |
|
Silk Emergence – Pollen Shed |
-- |
40-50 |
|
Blister |
3-6 |
30-40 |
|
Milk |
3-5 |
-- |
|
Dough |
3-4 |
20-30 |
|
Dent |
2-3 |
-- |
Source: Predicting the last irrigation for corn and soybeans
in Central Minnesota, the
Water Deficit Effects on Corn. Agr. J. 62:652-655
European corn borer moth activity is continuing to decline. Rootworm
larval feeding will continue until the beetles pupate and begin to emerge. We
are beginning to see the emergence of Japanese beetles adults in
Seed corn planting was completed last week. Early planted seed corn is approaching V-12, and ranges down to V-2. Most stands look good following side-dress nitrogen applications. Seed corn following commercial corn or seed corn seems to have the most consistent weed control challenges. We have seen some Johnson grass or shatter cane escapes becoming evident at this point, as well as crabgrass. Irrigation has been running on seed corn and potato fields as the crop is reaching the point of higher levels of evapotranspiration.
Early planted soybeans are beginning to flower. Bean leaf beetle feeding can still be found, but is dropping off. With the emergence of Japanese beetles, they will become the most significant defoliation threat. The high temperatures have pushed ahead the development of weeds, and many roundup ready soybean fields suffered at least some competition from fields where the weeds had gotten ahead of the herbicide application.
Most fields will have suffered minimal losses, but some
non-irrigated ones have reduced plant stands where dry conditions coupled with
weed competition has thinned out shallow rooted soybeans. Soybean aphids
continue to be found in very low numbers in fields. The treatment threshold is
250 aphids per plant, and in many fields, we struggle to find one to two aphids
per plant. Aphids will be on the increase, however, and hot spots from other
places in
Alfalfa harvest moved into high gear here this week, as the first really good extended forecast that has shown an extended dry period. Potato leafhoppers are prevalent. Watch your alfalfa re-growth carefully for this pest, because the early re-growth period is the most vulnerable to “hopper burn” injury. It does not take many leafhoppers to cause serious injury on 2-3 inch alfalfa.
Wheat has already turned and is in the final stages of development. Many fields were treated for fusarium head blight as a precaution because of the wet weather at flowering. The crop still looks to have good-excellent yield potential, especially where it was irrigated.
The
Fred Springborn
Much like last week, warm and dry sums up the weather for this past week, with an emphasis on dry. Irrigation systems are running across the county as rain fall totals have been in the range of 0.1 to 0.4 inch. High temperatures in the last week have ranged from the lower 80’s to the mid 90’s.
Wheat is beginning to turn in most fields. There is some evidence of head scab infection.
Oats progressing in most fields are heading well with few insect of disease problems at this time.
Corn growth
ranges from V5 to V10+ with the majority in the range of V5 to V8. Irrigated
corn is progressing exceptionally well. European corn borer trap catches are
down this week with an average of one moth per trap at our
Dry bean planting is nearing completion with 85 percent of the crop planted with many fields emerged.
First cutting hay harvest is nearly complete. Potato leafhopper is active with both adults and nymphs present.
Paul Gross
The region received scattered showers on Monday, June 18 and Wednesday evenings. The amount varied from one half to just over one inch. The rains were timely as crops were beginning to show moisture stress. For the most part, crops are looking good and off to a pretty good start. There is adequate soil moisture from the winter and spring rain that can carry the crops during these low rainfall times. It will be more important to get timely rains in July and August during more critical pollination and grain fill periods.
The corn crop is progressing normally with the tallest corn being waist high. Stands vary from very good to poor. It is very evident where fields were planted wet, compaction exists or fertilizer applications were not uniformly applied, stand suffered. This is a good time to assess problem fields and plan to make corrections next year.
Soybeans are doing very well with most stands uniform. We have found soybean aphids in several fields, but at low populations. Herbicide applications are being made at this time. The crop is off to a good start.
Wheat is just beginning to turn. Prior to this week’s rains, wheat on light soils were severely moisture stressed. I expect we lost yield in those fields. Wheat on heavier soils appears to be doing well with good yield potential. We have not seen any head scab at this point. There are various foliar diseases, and the amount varies by variety.
Harvest of second cutting alfalfa will begin next week. Leafhoppers are present in every field, but below threshold. Yields thus far are just average.
Dry bean planting is completed. Emergence has been very quick. Scout fields for leafhoppers as populations are high this year.
Sugarbeet fields have filled in the row, and the crop is doing well.
Mark Seamon
Warm temperatures with some light rain earlier in the week have advanced crop growth this week. The Northern and Eastern Thumb have fared better with rainfall than the rest of the thumb.
Alfalfa re-growth is limited due to the dry conditions.
Sugar beets continue to add growth and are filling the rows in many fields.
The wheat crop is responding to the dry warm weather with many fields drying quickly and losing color in the flag leaf and head. Rainfall is most welcome to help with grain fill.
Corn is growing quickly with some fields reaching 36 inches and more. Leaf rolling can be seen in many fields, but this is not advancing as much as expected with the lack of rainfall. Subsoil moisture seems to be adequate and is keeping the crop healthy at this point. Most fields seem to be picking up sidedressed nitrogen with good color and plant health.
In soybeans, most fields have good stands with some fields reaching the V5 growth stage. Soybean aphids are widespread, but variable in populations. Field to field variation as well as variation within fields is evident and increases the need for careful scouting. Some growers have added an insecticide with the first pass of glyphosate to control aphids.
Emergence of the dry bean crop is good in most places, but seedlings are slow growing. Potato leafhoppers are active with feeding on beans that were not treated with Cruiser.
Jeff
Andresen
Agricultural Meteorology
Geography
Weather News
Jeff Andresen, Geography
Showers and thunderstorms associated with a cool front
moving across
Looking ahead, the outlooks in general suggest a return of
warmer and drier than normal weather. In the near term, the frontal boundary
that moved through the state late Wednesday and Thursday is forecast to stall
out just to the south of Michigan across the Ohio Valley and eventually to
return northward through the state as a warm front, likely late this weekend. The
front will likely lead to widespread showers and thunderstorms in areas of the
central Cornbelt to the south and west of
A second frontal system will approach the state from the
northwest by late Monday, bringing the next best chance for significant
rainfall, initially across northwestern sections of the state overnight Monday
into Tuesday and across southern and eastern sections of the state by late
Tuesday into Wednesday. Temperatures during the next couple of days will remain
at near normal levels, gradually warming to much above normal readings by the
late weekend into early next week. Some of the warmest temperatures of the year
thus far are possible by next Monday and Tuesday across southern and central
sections of the state. Look for with highs ranging from the low 70's north to
near 80 south through Saturday, increasing into the 80's by Sunday. High
temperatures in the low to mid 90s are possible in the southern
Medium range forecast guidance is suggesting the formation
of an upper air ridge across the Great Plains and western