East Michigan vegetable update – July 12, 2018
Zucchini and yellow squash are being picked. Pumpkins and winter squash are vining out. In both crops, thrips are becoming an issue with the hot dry weather. According to Elaine Roddy in Ontario, damage to older leaves may not be a concern, but stunting of new growth indicates the need to treat. Thrips can scar and deform fruits as well.
I have seen some symptoms that resemble bacterial wilt transferred by cucumber beetles. Isolated plants independent of soil moisture? Roots are healthy? No squash borer in the vine? If yes to all three, then it is probably bacterial wilt. Young plants can quickly melt down in the high heat and low moisture conditions we are experiencing.
Some crown rots have shown up in patchy patterns in plasticulture pumpkins. I suspect some of this is due to wind and hot plastic damaging stems and opening an infection point. Otherwise, the dry weather has kept most root and crown rots at bay in dryland pumpkins.
Cantaloupe plants are supporting fruits that are beginning to net, and some growers are moving their first loads. I have seen some low-level gummy stem blight symptoms in some fields, as well as thrips and two-spotted spider mites.
Pickling cucumber plantings are continuing. Downy mildew has not been confirmed in the Midwest yet. Last confirmed outbreak was in Maryland on July 6. Harvests have begun. The extended dry weather has had, and will continue to have an impact on new plantings. In my variety trial I witnessed what appeared to be three separate germination periods following a single planting, as limited soil moisture allowed germination to occur during small rain events between dry spells.
Read more from Michigan State Vegetable Extension.
