Colorado potato beetles have emerged from overwintering and are feeding on potatoes in many areas of the state. (see photo) In most cases, growers applied at-plant neonicitinoid insecticides to control these overwintered beetles.

A few aster leafhoppers have been caught recently in celery and carrot fields in Michigan. At this point, the numbers are very low and they are not likely to cause problems. Aster leafhoppers spread the disease aster yellows. The risk to a particular crop depends on the inherent susceptibility of the crop, the percentage of leafhoppers that carry the disease, and the number of leafhoppers present. To assess risk and determine whether an insecticide treatment is warranted, all three factors must be known.

The inherent susceptibility of a crop to aster yellows is fixed and is reflected by the aster yellows index; the lower the number, the more susceptible the crop. The aster yellows index for celery is 35, for lettuce it is 25 and for susceptible varieties of carrots it is 50. The number of aster leafhoppers can be assessed easily by taking sweep net samples. The last factor – the proportion of leafhoppers carrying the aster yellows disease – can now be determined with molecular laboratory tests. Diagnostic Services will be testing aster leafhoppers for infection with aster yellows again this year. Grant funds will be used to support limited testing of leafhoppers in a couple carrot and celery locations over the season. Results, including percent infectivity and suggested treatment threshold will be provided to growers and will be published in the Vegetable CAT Alert.

In addition, Diagnostic Services will test leafhoppers submitted by individual growers or crop consultants. The test requires a minimum of 45 leafhoppers. The cost ranges from $25 to $35 depending on the number of leafhoppers submitted (the more leafhoppers, the more reliable are the results). Vegetable Entomology will provide growers with results (percent infectivity) and suggested thresholds (the number of leafhoppers per 100 sweeps) and which insecticide application is warranted.

If you are interested in submitting aster leafhoppers for aster yellows infectivity testing, please collect at least 45 leafhoppers and place them in a plastic bag. The leafhoppers do not have to be kept alive. The sample can be delivered to Diagnostic Services or it can be mailed. If mailing a sample, please place the bag in a small, hard container such as a plastic dish used for food or a small cardboard box, and mail to: Diagnostic Services, 101 CIPS, Michigan State University, E. Lansing, MI. 48824-1311. Please include the following information with your sample: Date collected, crop collected from, name and contact information of person submitting the sample.

Diamondback moths found in cabbage
Beth Bishop
Entomology

Diamondback moth larvae have been found in cabbage fields in southeast Michigan. The small (1/4 inch or less), pale green caterpillars consume foliage and produce a “windowpane” type of damage. When disturbed, they dangle from a silken thread. Larvae are sometimes imported into Michigan on southern transplants, and these can be resistant to several classes of insecticides. Bt (Bacillis thuriengiensis) insecticides are generally effective against diamondback moth and do not kill natural enemies. Several newer insecticides, for example SpinTor, are also very effective on diamondback moth larvae. Consult bulletin E310: 2006 Insect, Disease and Nematode Control for Commercial Vegetables, for a list of insecticides registered to control diamondback moth. This bulletin can be viewed at: http://veginfo.msu.edu.

Thinking of switching to organic farming?

The University of Wisconsin 's Center for Integrated Agricultural Systems has developed an Extension publication reporting on results of a two-year Sustainable Agriculture Research and Education project in which vegetable growers shared and compared various business information. The results provide insight about potential costs and returns for fresh vegetable operations. The way in which information was collected and shared also provides a basis for additional work in this area.

The entire publication can be downloaded free of charge. It is entitled: Grower to Grower: Creating a livelihood on a fresh market vegetable farm. Here is a description of the project and publication:

Growinig produce is not the biggest hurdle facing most fresh market vegetable growers; earning a reasonable living poses the greatest challenge. One way for farmers to analyze their operations in order to better meet their financial goals is to share information through farmer networks, conferences and coffee shop talk. Farmers may feel reluctant to share sensitive financial information, however.

To address this, the Center for Integrated Agricultural Systems worked with a group of 19 growers on a participatory, farmer-led case study from 2002-2004. The growers collected data on their sales, labor and other aspects of their businesses. They then created financial ratios that allowed them to compare small, medium and large operations in a way that respected their confidentiality. Their goal was not to provide a complete economic analysis of their operations, but to provide a basis for comparisons between farms and discussions of how to forge a quality livelihood from farming. The information contained in this case study can help guide growers as they set financial and quality of life goals for their farms and structure their operations to realize those goals. Download a pdf copy at: http://www.cias.wisc.edu/pdf/grwr2grwr.pdf

We invite you to make plans to attend the annual Michigan State University Weed Tour, beginning at the MSU Botany Field Lab on Wednesday, June 28. The MSU Botany Field Lab is located on College Road just north of Jolly Road, south of MSU’s campus. Registration begins at 9:00 AM with the field tour kicking off at 9:30 AM. The tour will provide ample opportunity to look at research plots and participate in some short field presentations (Be sure to bring a hat and sun screen!). Participants can compare their favorite corn and soybean herbicide programs to other commercial programs and evaluate how new transgenic crops (CRW-corn) interact with weed management strategies. The morning tour ends with lunch.

The afternoon tour will begin at 1:00 PM at the MSU Horticulture Farm (College Road, south of Jolly Road) and will include weed control research in horticultural crops.

Regional reports
1 -- Southwest
Ron Goldy

Weather
Continued cool and wet for the period with high temperatures ranging from 33°F to 69°F and lows of 32°F to 44°F. There was 0.25 inches of rain across the area and soil temperatures have actually decreased from the previous week. Heavy frost on Monday (May 22) and Tuesday (May 23) caused significant to no damage depending on location and crop. In some areas, the frost was worse on Monday, and in others it was worse on Tuesday. Peppers seem to have been hit the hardest. It is too early to determine if the entire plant is dead or just the leaves. Some direct-seeded cucumber fields have had to be reseeded due to poor germination attributed to too cool, too wet and too cloudy for too long.

Commodity reports
With the favorable forecast, transplanting has resumed for tomatoes, eggplant and peppers.

2 -- Grand Rapids Area
Amy Irish-Brown

Weather
Some light rain fell across the area over the last week. Air temperatures have been slightly below normal, and there were two mornings with frost on the ground early this week. We’ve fallen back a little on degree day accumulations and are only a day or two ahead of regular averages now.

Commodity reports
Celery planting continues.

Radish planting continues, and the first crops are being harvested.

Lettuces on muck soils are in various stages of growth.

First seedings of sweet corn are emerging, and there appears to be little damage from the frosts to most early sweet corn, but there is some damage. Additional planting continues.

Vine crop seeding and transplanting is being done where fields have dried out.

Asparagus harvest continues. Most growers had a good picking in on Saturday (May 20) and Sunday before the frosty mornings on Monday and Tuesday, so there isn’t much damage. Picking was slowed by the cooler than normal weather over the past week, but will move along quickly with the forecasted warmer weather to come.

3 -- Oceana County
Norm Myers

Weather
Much of the county experienced frost on Monday morning, May 22. Temperatures in the main vegetable growing area were reported as low as 27 degrees. There was also some scattered frost yesterday morning, but in general, temperatures were about five degrees higher yesterday morning. Soil moisture is still good as a result of last week’s rain.

Commodity reports
In asparagus, most growers did get a good picking off on Sunday before the frost. Growers did pick through the frost damage, but between that and the purple spot problems in many fields, most of our production over the last week has gone to processing. Cool weather has limited insect problems, although there is a little beetle and cutworm activity. The last week has put our harvest schedule behind average with most growers well behind their normal number of pickings for this point on the calendar.

4 -- Mason-Newaygo counties
Jim Breinling

Weather
Temperatures during the past week continued below normal. Compared to last year at the Fremont MAWN station during the past two weeks, we have gone from +18 GDD50, to even last week, to -18 at this time. The official low reported the morning of May 21 was 30.2 degrees with some reports as low as 24 degrees.

Rainfall amounts were in the 0.25- to 0.4-inch range. Growers have been back in the fields planting this week and crops are ready for the week of above normal temperatures that are in the forecast.

Early onion plantings are now at the 2 leaf stage.

Spinach continues to do well with cool weather conditions. Youngest plantings are at 4 to 5 leaf.

Planting of vine crops began this past week. A field of slicing cucumbers was seeded on May 17. B utternut squash for processing are being planted.

Snap bean planting will be in full swing this week.

Transplanting of peppers has commenced.

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

Weather
The rainy pattern since May 10 continued this past week with a break on Saturday (May 20) and two successive days of dry and windy weather on May 22 and 23. It has been a relief to get back into wet fields to cultivate and plant. There is a lot of planting to do yet on the mineral soils. Light frost touched some northern areas and low pockets for the past two mornings.

Commodity reports
Cabbage fields are variable in size and quality depending upon how much frost they have experienced. Some fields are showing purplish highlights from phosphorus deficiency due to cold and wet conditions.

Much of the first and second seedings of sweet corn are up, but looking very yellow. (Photo 1) Planting resumed on Tuesday in many areas after a 13 day break. I spoke with a grower today who is planting his earliest varieties to avoid a break in supply. Corn under clear plastic is well ahead in development this season.

Garlic is looking just great this season with hefty stalks and good color and growth. (Photo 2)

Tomatoes are being set out under row covers as are melons. Pumpkin seeding is beginning and rye cover crops are heading and being sprayed down.

6 -- Monroe County
Paul Marks

Weather
Less than one half of an inch of rain during the last seven days has not been as much of a factor as the continued cool temperatures. We have gone from being normal in degree days to now as much as 40 degree days, or four calendar days, behind normal at 346 degree days for the season. Soils have dried and growers are getting back to transplanting.

Commodity reports
Cabbage has been the crop in our area that has had significant problems show during the last week. Root maggots (Photo 1) have appeared in fields at low levels even if they were treated with insecticides. Damage ranges from little or none to up to 5% in several locations. Diamondback moth larva (Photo 2) has also appeared this last week in several fields. Small larvae are found feeding in the heart of the plant. Plant growth has been tremendous with the cool and wet weather.

Tomatoes for processing and/or for market are now being transplanted as soils allow. Cutworms (Photo 3) have been found this last week feeding in even larger plants in several fields. Earlier planted fields look very good except where water caused damage in low areas.

Cucurbits are also being planted and transplanted even though soils are cool and have only exceeded 60 degrees for less than 6 hours this entire last week.

Potatoes look good with very few potato beetles found even in volunteers in other vegetable fields where they have been untreated.

Following a series of frosty mornings, a significant warming trend is in progress across the Great Lakes region as the upper air trough that brought last weekend’s cool weather moves off to the east. Warm and dry conditions are expected Wednesday (May 24) with increasing clouds as an area of low pressure approaches the region from the west. This system will bring the next chance for rainfall in the form of showers and thundershowers beginning Wednesday evening and continuing through the day Friday. Best chances for rainfall through Friday will be across southern sections of the state Thursday and Thursday evening, where 0.25- to 0.50-inch totals are possible. Rainfall totals elsewhere will generally remain less than 0.25 inches.

Temperatures will increase significantly during the next few days with highs in the 70s and lows generally in the 50s over most of the state Wednesday through Friday. For the upcoming holiday weekend, mostly fair and warmer than normal weather is expected in response to the gradual formation a large upper air ridging pattern over the eastern half of the United States. Highs in many areas of the state will reach or exceed 80°F. Dew point temperatures will also be on the increase with muggy conditions possible during the day Sunday and Monday. Some scattered showers and thunderstorms will be a possibility once again by Memorial Day (May 29), but areal coverage is expected to be limited at best with most locations remaining dry. Mean temperatures for the next week will likely average 3 to 6 degrees above normal, so a flush of new crop and insect growth and development is likely.

Medium‑range forecast guidance for at least the next one to two weeks is suggesting that the upper air ridging pattern across the eastern United States will continue to be a dominant weather feature with some weakening possible during the 8-14 day time frame.

NOAA 6-10 day and 8-14 day outlooks (covering May 29 through June 2 and May 31 through June 6) both call for above normal below normal temperatures state- and region-wide. Precipitation totals during both time frames are forecast to fall back to below normal levels in the 6-10 day time frame, and for near normal levels during the 8-14 day period.

Officially, the outlooks for Michigan and the entire Great Lakes region call for near equal odds of below-, near-, and above-normal temperatures and precipitation during the month of June and the 3-month June-August period (the “climatology” scenario).

Nationally, warmer than normal temperatures are expected across much of the southern and western United States during these periods, and possibly for above normal precipitation totals across the extreme southeastern United States associated with what is expected to be a busier than normal tropical storm season in the western Atlantic Basin. Further ahead, the outlooks suggest warmer than normal temperatures for at least parts of the Great Lakes region for the late summer and fall.