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Vegetable Crop Advisory Team Alert newsletter

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Vol. 23, No. 2, April 30, 2008

In this issue

Early-season maggots

Spartan 4F receives Section 18 label for Michigan strawberries for 2008

Regional potato extension/research group meets

Evaluating new materials

Managing higher priced fertilizer inputs 2008

Workshop on cover crops for vegetable systems

Regional reports

Using Enviro-weather to look at freezing temperatures and temperature forecasts

Weather

Next issue May 7

Early-season maggots
Beth Bishop, Entomology

Degree-day accumulations (see table in this issue) are favorable for emergence of adults of the early-season maggots (seed corn maggot, onion maggot, cabbage maggot). These species overwinter as pupae in the soil and start to develop when soil temperatures near 40ºF.

Seed corn maggot flies lay eggs near germinating seeds of a variety of crops, including cucurbits, snap beans and sweet corn. They are attracted to decaying organic matter so muck soil and fields with manure or freshly plowed green manure are especially vulnerable to infestation.

Onion maggot flies, as their name implies, lay eggs at the base of onion plants. They are especially attracted to damaged onions. After hatching, the maggots feed on the roots, stem, and developing bulb. Cabbage maggot flies lay eggs on crops in the mustard family (cabbage, broccoli, cauliflower, radish, etc.). After hatching, cabbage maggots feed on the roots of these plants.

Damage by these maggots causes wilted plants (because of feeding on roots) and plant death resulting in reduced stand. Growers planting vulnerable crops when adult maggot flies are laying eggs should protect their crops with a soil insecticide or seed treatment. See MSUE bulletin E312, 2008 Insect, Disease and Nematode Control for Commercial Vegetables, (http://web4.msue.msu.edu/veginfo/E312/) for insecticides registered for control of these pests on various crops.

Spartan 4F receives Section 18 label for Michigan strawberries for 2008
Bernard Zandstra, Horticulture

On April 21, the US EPA issued a Section 18 label (specific exemption) for use of Spartan 4F on strawberries in Michigan for 2008. The label is similar to the Section 18 labels we have had for the past several years. A maximum of 1,000 acres of strawberries may be treated with Spartan in Michigan in 2008. The label is effective June 25 to December 15, 2008.

Spartan 4F may be applied to strawberries at renovation or after the plants have gone dormant late in the season. The primary target weeds are mayweed chamomile, puncturevine, redroot pigweed, common groundsel, field pansy, white campion and yellow woodsorrel. Spartan will control many other broadleaves and grasses as well.

Four to eight fluid ounces of Spartan 4F may be applied in any one application. A maximum of 12 fluid ounces may be applied per year. There is a 70-day preharvest interval (PHI), but this should not affect Michigan production, since Spartan is applied after harvest is finished for the year.

Spartan may be applied in tank mixes with Sinbar and postemergence herbicides such as 2,4-D, Stinger, Poast or SelectMax. The postemergence herbicides will kill emerged weeds and the residual herbicides will maintain weed control until fall frost.

Copies of the label will be available from chemical dealers and suppliers. As soon as we receive a copy, we will post it on the MSU vegetable website: www.veginfo.msu.edu.

This is the seventh year that Michigan has had a Spartan Section 18 label for strawberry. We hope to have a tolerance and label soon. To continue the Section 18 process, the Michigan Department of Agriculture must interview several growers who use it and obtain their reports on the effectiveness of the use. We encourage growers to cooperate with MDA personnel if and when you are called for a report. Growers for the interviews are chosen randomly from users around the state.

Regional potato extension/research group meets
Willy Kirk, Plant Pathology

The NCERA (North Central Research and Extension Activity) 205 group met in East Lansing during late March 2008. The group was composed of members from Michigan, Wisconsin, North Dakota, Minnesota, Colorado and Nebraska potato industries. Michigan attendees included representatives from Walther farms, Black Gold, Lennard Farms and ABC consultants as well as MPIC and MSU. The focus of the group is on pest management and agronomic practices in the North Central region of the United States. As a result of these meetings, which have been held since 2003, it is believed that pest management and agronomic practices have been improved and optimized in the north central potato production area through the interactions of the NCERA205 group.

The north central states produce about 35 percent of the potato crop for the United States. All participants in the potato industry benefit from the interactions of this group and indeed several participate in this group to set research and extension goals important in this area. The project has met several times and some strong linkages have been established. The groups have discussed and formed research programs addressing such issues as pesticide resistance. The group has also interacted with the National Potato Council to produce three bulletins, widely disseminated and used by the United States potato industry. The group has documented and quantified impacts of climate change on the industry; storage loss issues; prevention of contamination of ground water; sustaining soil quality profitability of potato production systems and loss of potato farmers.

At the meeting in East Lansing, this year’s issues such as management of corky ringspot disease caused by TRV, resistance of CPB to insecticides, and sustainability issues were discussed. Dr. Grandy (MSU) discussed soil quality issues and the timing of application of composts. Some research needs for future impacts were talked over and included; variety development practices for production and storage with improved interaction between the genetics (potato breeding) and the pest and agronomic practices NCERA groups; impact of climate change for the region in pest management and production; sustaining soil quality within erosive production practices; continued monitoring of pesticide resistance and determine methodologies and practices that prevent its development.

The next meeting will be held in Colorado in 2009 and anyone interested in attending should contact Willie Kirk at kirkw@msu.edu (517-353-4481).

Evaluating new materials
Darryl Warncke, Crop and Soil Sciences

Each year farmers are offered new materials or nutrient management programs that are advertised to improve crop vigor, growth, produce quality and yield, or increase the availability of nutrients. With higher fertilizer prices and limited supplies, it appears that more of these materials will be offered this year than in past years. Farmers need to ask questions about these materials. Is there research data available from an unbiased source and from an area with similar growing conditions? What is the cost of the material on a per acre basis, or more importantly what is the cost per pound of the nutrient being supplied? Compare this to the cost from traditional fertilizer materials.

Contact your local MSU Extension educators to see if they have any information about the material. They can check with university specialists in Michigan and other states in the region. If you do decide to use some of these products, be sure to leave untreated check strips in the field to determine if there is in fact a benefit. Be aware that an improved appearance of the crop does not always put more money in your pocket. Be sure to check produce yield and quality at harvest.

Managing higher priced fertilizer inputs 2008
Darryl Warncke, Crop and Soil Sciences

Increasing worldwide demand for nitrogen, phosphorus and potassium has brought about record high prices for fertilizer materials for the 2008 growing season. The supply of potassium may also be limited. Faced with this situation, farmers may have to make decisions on how to get the best return from the fertilizer they are able to purchase. The following are some suggestions.

1. Soil test. A soil test indicates the available nutrient status of the soil, the need for lime and how much nitrogen, phosphorus and potassium are needed for the crop to be grown. Test results from samples collected within the last two to three years can be used as a guide. For fields where no soil test information is available, collect soil samples as soon as possible and have them tested.

2. Apply lime where needed. Maintaining the soil pH between 6.0 and 6.8 improves nutrient availability and crop growth. In many situations, the return on invest is best with lime, both short and long term. When the soil pH is below 6.0, applied fertilizer nutrients or indigenous soil nutrients are not used as efficiently by crops.

3. Take credit for nutrients contained in manures, composts or other materials applied to crop fields. Nutrients contained in these materials are readily available and can offset the need for purchasing any additional fertilizer. Have manures and compost analyzed for the nutrient content.

4. Apply phosphorus only where needed. As the result of past buildup, 65 to 70 percent of Michigan vegetable farm fields contain adequate or above levels of phosphorus. Now is the time to use some of that phosphorus banked in the soil.

5. Focus on potassium. Only 20 to 25 percent of Michigan farm fields contain adequate levels of potassium. Increase the amount of potassium included in starter. When banding fertilizer at a 2 inch by 2 inch placement, look to include up to 50 pounds of K2O per acre. By including some potassium in the band fertilizer the total amount applied per acre may be reduced because of the increased effectiveness.

6. Band-apply nutrients. Band-applied nutrients are used more effectively than broadcast nutrients. In high P testing soils, early growth from banded fertilizer comes more from nitrogen and potassium than phosphorus. Overall, reducing phosphorus in favor of nitrogen and potassium may prove beneficial.

7. Apply P and K first to fields most in need. The crop yield response to incremental additions of potassium or other nutrients can be characterized as the “curve of diminishing returns.” This means that the increase in yield from the first increment of potassium added (say 30 lb K2O per acre) is greater than the second. And return from the second increment is greater than from the third, and so forth. Eventually the cost of an additional increment of potassium is greater than the value of the yield increase. This being the case, it is better to apply or allocate potash first to fields with lower soil potassium values, where there will be a good yield response, than to those fields that have close to adequate levels.

8. Reduce amount of K applied uniformly across all fields. In fields that need K, applying slightly less, e.g. 25 pounds per acre, than is needed will have only a minimal, if any, effect on net income. Work from soil test results.

9. Apply preplant nitrogen close to planting time. This will minimize the length of time nitrogen is at risk of loss by leaching or denitrification before crop demand increases.

10. Use a presidedress soil nitrogen test for crops that sidedressed to determine need for more nitrogen. Some soils can provide significant amounts of available nitrogen, especially where cover crops or animal manures or a previous legume crop is incorporated prior to planting.

Cover crops for vegetable systems
Vicki Morrone, C.S. Mott Group for Sustainable Food Systems

Use of cover crops in all agricultural systems is growing, especially with the rising cost of fertilizers. More farmers are seeking alternatives to grow healthy plants and build soil quality while recycling nitrogen to reduce loss of this valuable resource. Cover crops contribute in multiple ways to the farming system, over the short and long term. One of the major challenges of using a cover crop is to find a window of time when a cash crop is not growing. A wide variety of cover crops are available that provide a sustainable foundation for organic production of field crops or vegetables and fit into various windows.

The Michigan State University Vegetable Area of Expertise Team invites you to participate in a day-long workshop on Cover Cropping in Vegetable Systems-An essential tool for sustainable and organic farmers. The day will offer farmers and educators an opportunity to learn about cover crop systems that work for this region with practical advice and the latest research. Anyone interested in optimizing production of healthy crops will find the workshop useful. This field workshop will be held on June 12 from 9:00 AM to 5:00 PM at the Kellogg Biological Station in Gull Lake, Michigan located about 30 minutes west of Battle Creek, Michigan. The workshop will feature Dr. Anne VerHallen, who is a soil management specialist for horticulture technology, with Ontario Ministry of Ag and Food and Rural Affairs. She works with farmers to investigate opportunities afforded by cover crops in vegetable systems and their ability to contribute to soil quality.

The other keynote speaker will be Dr. George Abawi, professor in Plant Pathology and International Agriculture from Cornell University located at New York Agriculture Experiment Station in Geneva, New York. He will present information on how cover crops impact crop health, including how to use cover crops to control soil borne pathogens such as nematodes and root rots and how to implement this type of system on your farm.

Cost of this workshop is $25.00 for the day including educational session, lunch, a copy of Managing Cover Crops Profitably published by SARE in 2007 and a tour of the research fields at Kellogg Biological Station that demonstrate cover crop systems including pumpkins intercropped with rye and hairy vetch grown as a source of nitrogen for corn.

For registration and the agenda, please go to http://www.michiganorganic.msu.edu/ or call the MSUE Oceana County office at 231-873-2129 or email Kathy Walicki: walicki@msu.edu. Checks should be made out to Michigan State University Extension and mailed to Cover Crop Workshop, 210 Johnson St. E, Hart, MI 49420. Registration must be received by June 6 and after this date walk-in registration is $40.00 and can be paid the day of the event.

Regional reports
1 -- Southwest
Ron Goldy

Weather
Temperatures over the past two weeks at SWMREC ranged from below to above normal with lows of 26 oF to 56oF and highs from 46 oF to 82 oF. There was 0.56 inches of rain. Surface soil moisture was getting low on sandy sites and recent rains have added needed moisture for good plastic mulch laying and bed shaping. Soil temperatures averaged in the low 50s. Cloudy weather has slowed greenhouse transplant growth.

Crop report
Asparagus harvest began last week but has slowed in recent days due to low temperatures. Low temperatures across the region ranged from 22 oF to 26 oF on April 30. This will delay harvest until early next week.
Some early sweet corn has been planted.
Limited amounts of early tomatoes, cucumbers and squash have been planted on plastic and under tunnels.

Miscellaneous
Producers have been preparing sites for the past two or three weeks and planting for the past seven to ten days. Cool temperatures and dry soil have made fumigation activities difficult until just recently.

2 -- Grand Rapids Area
Bill Steenwyk

Most farmers are satisfied with progress in the field this spring, with little out-of-the ordinary taking place. Field preparations and final equipment repair and maintenance chores are typical.

Crop report
Vegetables such as cabbage, peas, early sweet corn and potatoes have been or are being planted. The fairly dry soil conditions will certainly mean less soil compaction than occurs in rainier seasons. A little rain in the near future would be desired to activate herbicides and prevent the diversion of time to running irrigation systems.

On muck fields, some onion producers are finished or nearly finished planting, others are well along the way.

Celery producers are busy raising transplant seedlings in the greenhouses and placing them in the fields.

Leek, lettuce, beets and radish are being planted.

3 -- Oceana County
Norm Myers

Weather
Morning temperatures have been very cold, well below freezing at the Asparagus Research Farm north of Hart. Yesterday’s low as recorded by the Enviro-weather station there was 25.8ºF and this morning’s low was 23ºF. April rainfall has been well ahead of normal, and we should have very adequate soil moisture or even excess moisture in nearly all fields.

Crop report
Last week’s 70ºF-plus temperatures put every asparagus grower behind, but these frosts should put us back on track for a Mother’s Day (May 11) start to the harvest season, assuming normal temperatures from here on. Before the frost, there were some spears up, especially in fields without rye cover crops, but very few where good rye cover was present. Needless to say any spears up before the freezes are gone now. Planting of asparagus crowns is still underway. Labor supplies appear to be adequate so far, but it is still too early to tell how we will do by the time harvest begins.

Rains have been ideal for germinating carrots and barley/oat cover crops. Some irrigation for protection from high winds was done last week, but it is too early to know the damage from those winds. Recent rains should also have been perfect for incorporating pre-emergent herbicides, where they had been applied. Most of the large growers are not finished planting carrots, especially if they had some wetter soils.

4 -- Mason-Newaygo counties
Jim Breinling

Weather
The weather pattern for the month of April has been general in the area as reported at the Enviro-weather stations located at Fremont (Newaygo County) and Ludington (Mason County).

Rainfall totals for the month of April were 3.3 inches at Fremont and 3.46 inches at Ludington. Rain events were generally the same during April 8-13 and April 24-26. The 10-day period between rain events was consistently above normal for temperatures with highs in the 70’s and allowed for timely field work and planting.

Below normal temperatures predominated in the area after April 26 through April 30 with frosts and freezing temperatures for three nights.

Crop report
Carrot planting got underway during the week of April 7 in Newaygo County and has progressed on schedule the past two weeks in both Newaygo and Mason counties. The first planting has germinated with some emergence and plants in the cotyledon stage. Water was being applied on this field during the afternoon of April 29 in an attempt to warm the soil and protect the carrots from anticipated record low temperatures the next morning.

Planting of onions in Newaygo County also began the week of April 7. Planting has progressed well with target completion by the end of this week (May 3). First planting show some emergence with plants in the seed cotyledon “loop” stage of growth. Barley cover crops in these plantings have also gotten off to a fast start.

Planting of parsnips, turnips and potatoes are all underway.

Spinach planting is scheduled to begin next week.

After 37 years a vegetable crop has returned to Newaygo County. Some acreage of processing peas has been planted. The plantings are off to a good start and at the third node growth stage.

Biofumigant cover crops were no-till planted into wheat cover crop on April 23. The wheat cover crop will be killed in the next 7 to 10 days. The biofumigant cover crops will be incorporated in mid-June prior to the field being planted to snap beans in early July.

5 -- Macomb, St. Clair and Lapeer counties
Hannah Stevens

Weather and crop conditions
April was a dry and warm month in this area with a scant 1.3 inches of precipitation in the Romeo area. On the morning of Tuesday, April 29, temperatures dropped to just below freezing for several hours, and this morning we have experienced nine hours of temperatures below 32oF and down to 27.3oF, much colder on the muck soils. These were the lowest temperatures in the last two weeks. In fact, soil temperatures on mineral soil have reached 77oF and with limited rain and windy conditions the soils were on the dry side for seeding and planting. Growers are not taking many chances, and no one has been in a rush to seed warm season crops other than some of the southeast sweet corn varieties. After the predicted rainfall ends this week, I expect planting will get underway.

Over the last two weeks, a new agricultural weather station has been added to the state-wide Enviro-weather system. The station is in Romeo and is located at Westview Orchards and Cider Mill. The addition of this weather station in Macomb County will fill another gap in the network that we rely upon heavily for agricultural weather across the state. This new weather station and the data it generates will be particularly helpful for not only fruit growers in the region, but for the vegetable and landscape industries as well. Many thanks to the Jacobson, Schumacher and Roy families of Westview for their contributions to get this station up and running. Information on this station can be assessed at www.enviroweather.msu.edu. (Thanks to Bob Tritten for this report.)

Crop reports
Over-wintered parsnips are in perfect condition and are being dug and shipped.

The region’s famous hothouse rhubarb is being shipped and may be found in some local chains.

On organic soils onion transplanting and seeding got underway on in mid-April. Barley cover crops are becoming established.

Early cabbage has been established for the past few weeks.

Carrot seeding is underway.

Early lettuce has been seeded and transplanted. Growers in Macomb going for a very early crop have established leaf lettuce on plastic
for the past two weeks. Salad greens are a beautiful sight in several unheated hoophouses and have been moving to specialty and local markets all winter.

Sweet corn and Indian corn have germinated, but have not emerged yet.
Miscellaneous crops such as beets, parsley, peas and other cool season crops are seeded.

Using Enviro-weather to look at freezing temperatures and temperature forecasts
Tracey Aichele, Enviro-weather

After a few weeks of warm weather and relatively quick degree-day accumulation, a low-temperature event may have affected crops throughout Michigan. Enviro-weather (enviroweather.msu.edu) offers a few tools for evaluating potential damage on a regional basis.

During a potential freeze event, you can look at the latest temperature observations. These are available as “rollovers” on the map on the Enviro-weather homepage in most newer browsers or by clicking on a station dot. The latest observations for stations associated with a Michigan Agricultural Experiment Station Field Station are also available on the MAES station pages. (e.g. SWMREC, KBS)

For a look back in time, the Overnight Temperatures Report lists the hourly average temperatures at stations in a region. This can help you look at the duration and distribution of the event, as well as pointing out the actual temperatures. To look at past events (from a day ago or from years ago), select the option to “Change date range.”


Click image for larger image.

In this report, all temperatures below freezing are highlighted. Note that this report also highlights warm nights (nights with temperatures above 70ºF), which may be of interest in summer.

For a look forward, the Overnight Low Temperature Forecasts lists the model results from the GFSX forecast for the nearest forecast locations; these are usually airports. The Late Afternoon Dew Point Report may seem slightly esoteric, and is only valid under certain conditions. When the forecast is for a clear night with low winds and stable atmospheric conditions, the temperature may fall as low as the dew point, but not farther, as the moisture in the air condenses and releases heat into the environment. In most events, there is movement of air masses, so these numbers are not relevant, but under special cases, they may drive the low temperature forecasts.

We hope these tools are of use to growers, consultants, and MSUE Educators. As always, your suggestions, comments and questions are welcome at eweather@msu.edu.


Overnight Temperatures Report (Click image for larger image. )

Weather news
Jeff Andresen
Agricultural Meteorology
Geography

The large area of high pressure that brought sub-freezing minimum temperatures to much of the Great Lakes region the past couple of mornings will edge eastward and out of the region by Thursday, May 1. An area of low pressure over the central Great Plains Wednesday morning is expected to strengthen and move towards Michigan, bringing an extended period of unsettled weather to the region for the end of the workweek and much of the upcoming weekend. A warm front extending eastward from an area of low pressure will approach the state by early Thursday morning, bringing the chance for showers to western and southern sections of the state. The low pressure will move slowly northeastward through Michigan by late Saturday or Sunday, bringing an extended chance for showers and thunderstorms through Sunday. Best chances for rainfall statewide will be late Thursday, Friday, and early Saturday. Some severe thunderstorms are possible across southern and central sections of the state Friday into early Saturday, especially if there are more breaks in the cloud cover Friday than expected (i.e. more sunshine). Precipitation totals through Sunday will range from 0.5-inch in far northern sections of the state to more than 1-inch (some totals in excess of 2 inches are possible) across central and southern sections of the Lower Peninsula. Fair and drier weather is expected again by next late Sunday and Monday.

Temperatures will warm from highs Thursday ranging from the mid-50's north to upper 60's south to a range from 56ºF north to the low 70's south Friday. Low temperatures should increase from lows in the upper 30's north to mid-40's Wednesday morning to the mid-40's north to low 50's south by Friday. Slightly cooler temperatures are likely this weekend, with highs in the mid-50's to low 60's and lows in the upper 30's to low or mid-40's. Following fair and dry weather early next week, another area of low pressure is expected to move into the region by the middle of next week with the next chance for significant precipitation.

Further ahead, medium‑range, forecast guidance suggests a series of upper air troughs moving from the western United States eastward into the Midwest, with an active storm track across the Great Lakes region. Both 6-10 day and 8-14 day outlooks covering April 5-9 and 7-13 call for above normal precipitation totals and for temperatures to range from near normal levels across southeastern sections of the state to below normal levels in the northwest. Due to some disagreement among the models used in the development of the outlooks, forecaster confidence is considered lower than normal.

The MSU IPM Program maintains this site as an access point to pest management information at MSU. The IPM Program is administered within the Department of Entomology, fueled by research from the Michigan Agricultural Experiment Station, delivered to citizens through MSU Extension, and proud to be a part of Project GREEEN.
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