Saginaw Bay area vegetable regional report – July 2, 2014

Harvests begin on summer squash and zucchini and continue on lettuce, string beans, greenhouse tomatoes and cucumbers.

Posted on July 3, 2014 by Ben Phillips, Michigan State University Extension

There was heavy rainfall scattered throughout the region last week. Expect to see phytophthera take off in fields that have it. Foliar fungicide applications can help protect fruiting parts for harvest. Send any suspected diseases to the MSU Diagnostics lab. There is no charge for sending suspected downy mildew samples to the Hausbeck lab. Mary Hausbeck recommends starting to apply preventative downy mildew sprays.

The rainfall and growing degree day (GDD) base 50 degrees Fahrenheit accumulations as of July 1, 2014, from Michigan State University Enviro-weather stations at the following Bay and Thumb area vegetable growing regions are as follows:

• Romeo: 10.29 inches, 946 GDD (+0.01 inches, and +139.6 GDD from last week).
• Lapeer: 11.42 inches, 937.5 GDD (+0.04 inches, and +130.6 GDD from last week).
• Frankenmuth: 11.73 inches, 943.7 GDD (+0.13 inches, and +127.7 GDD from last week).
• Munger: 13.84 inches, 954.6 GDD (+0.04 inches, and +128.8 GDD from last week).
• Linwood: 12.5 inches, 856.4 GDD (+0.53 inches, and +127.1 GDD from last week).

In my Michigan State University Extension visits to the major Macomb, Lapeer, and Bay county vegetable areas, my best estimates of crop progress are below.

Sweet corn is at full tassel in areas. Corn earworm has been spotted in Southeast Michigan.

Cabbage is getting large, and starting to form heads. Many caterpillars are getting larger now, and treatment with a Bt will be less effective. Radiant is more effective on larger caterpillars, or an organic spinosad like Entrust. Lettuce and kale are continuing successional harvests in field and greenhouse.

Carrots are 3-6 inches tall in areas. Aster leafhopper infectivity is increasing.

Onions are 8-15 inches tall in areas, and thrips have not yet reached threshold where I have scouted in Bay and Lapeer counties. Consistent 85 degree F and dry weather will bring them on fast.

Potatoes are getting past the hilling stage and should be scouted for early and late blights, and treated for Colorado potato beetles if larvae are spotted.

Red beets are being harvested. Snap and shell peas are being harvested. String, bush, and wax beans are flowering and setting fruit.

Melons are vining and flowering heavily. Some plantings have 1-2 set fruit. Honey bees will visit these into the evening, so avoid neonicitinoid sprays.

Summer squash and zucchini are being harvested daily, and flowering. They will produce for another two weeks or so. Winter squash and pumpkins are vining, with male flowers in the bud stage. More and more breeders are making these into bush types, so don’t be surprised if they are not spreading across rows.

Slicing cucumbers are being harvested in greenhouses. Pickling cucumbers are continuing to be planted, with some at the 4-leaf stage. Downy mildew traps have not captured significant numbers of cucurbit downy mildew spores yet.

Tomatoes are being harvested in greenhouse systems, and gray mold and bacterial diseases are becoming apparent where the plants are getting big and crowded. Magnesium deficiencies are common to see in greenhouses as plants put on fruit. The king set of field fruit are reddening.

Peppers and eggplants are growing lateral branches, flowering and setting fruit in Saginaw County, but are at various stages of growth in other regions. Plants that were flowering at transplanting, came from high density cell trays, or were held back due to weather are having trouble getting roots out of the rootball and putting on branches and leaves.

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