Bay area vegetable regional report – May 27, 2015

We are still behind on rain, but crops are going in.

Weather

Some growers have reported frost damage to blooms on unprotected strawberries. Most vegetable transplants made it through the frosty mornings last week, but unprotected cantaloupes appeared most sensitive to it. Despite the recent rains setting back some field work, we need some more. We are still well below the average cumulative precipitation for all locations in the Bay area and Thumb.

Below are the rainfall and growing degree day (GDD) base 50 degrees Fahrenheit accumulations to date from Michigan State University Enviro-weather stations.

Rainfall and GDD summary

Location

GDD (50 F, March 1)

Rainfall (inches, April 1)

Linwood

324

3.81

Frankenmuth

383

3.08

Lapeer

413

4.54

Romeo

399

4.57

Crops

Tomatoes and vine crops are still being transplanted. Greenhouse tomato plants are getting big. It will be important to prune lower branches and roll up the sides for ventilation during peak temperatures. Proper pollination occurs below 90 F in the day and 55 F overnight, with relative humidity between 50 and 80 percent.

Bacterial spots and specks have been reported, and Michigan State University professor Mary Hausbeck would like growers who had a hard time with those diseases last year to send in samples for copper resistance evaluation this year. You can call me at 989-758-2502 to pick up some leaves, or send samples to MSU Diagnostic Services.

Long maturing Sh2s and Bt trait sweet corn varieties are going in for late season flavor and earworm protection.

Onions grown in a community garden in Lansing, Michigan, tested positive for downy mildew last week and were destroyed. This disease may be a problem this year.

Cucumbers for pickling are being planted and fresh market cucumbers are being trellised in greenhouses.

Carrots on the muck are ahead of dryland mineral carrots, which have just started to pop up.

Cole crops are being transplanted. Beware that their leaves will bleach for a while if transplanted into soil treated with Command herbicide. This appears to occur as late as 19 days after application. Cabbage loopers and flea beetles have started feeding. Scout for damage from these pests. The threshold for flea beetle damage is 10-30 percent defoliation of seedlings or transplants younger than the five-leaf stage. Once the plant has more than five leaves, it is usually big enough to handle flea beetles, and their population starts to go down anyway. The threshold for cabbageworms and loopers is 30 percent defoliation from transplant to cupping stage.

Cabbage maggots have also been a problem for growers north of our main vegetable production areas. The soil temperatures are low enough to support a strong population there. This fly loves organic matter and surface trash to jump-start their populations in the spring.

If using a cover crop, Michigan State University Extension recommends avoiding planting for three to four weeks after working it in, and consider working in the cover in the fall. If preventative measures have failed, radishes tend to be the first to fail. Consider successional planting to avoid complete loss, or to utilize the radish as a trap crop paired with a soil drench of Diazinon or Lorsban. Do not apply as a foliar spray, and do not apply more than once per season on the same crop. If under hoophouse protection, the sides need to be rolled up completely, and ends must be opened for use of these products.

Other notes

If you would like to support your farming community by hosting a MSU Enviro-weather station at your farm, please read about what you can do at Support Enviro-weather.

Please contact me at .(JavaScript must be enabled to view this email address) or 989-758-2502 to pick up any suspected disease samples, or send the diseased plant parts to MSU Diagnostic Services

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