Regional reports on Michigan vegetables – August 22, 2012
MSU Extension educators’ pest and vegetable updates for Michigan.
This week’s regional reports:
- Southwest Michigan – Ron Goldy
- Central Michigan – Fred Springborn
- Southeast Michigan – Lina Rodriguez Salamanca
Temperatures for the period were mostly below normal with highs from 70 to 82 F and lows from 46 to 65 F. The area received 0.5 to 1 inches of rain. Heavy morning dew has been normal for the period.
Harvest continues on all crops at a slower pace given the more normal temperatures. Growers continue to remove earlier planted fields and are starting to remove plastic.
Powdery mildew in squash and pumpkin plantings has been encouraged by recent, heavy dews. Virus symptoms are also increasing in these two crops.
Some fruit scarring has occurred in cucumbers due to copper applications during the cool, wet weather a couple weeks ago. Copper applications should be made when conditions are good for quick drying, otherwise there is the risk of burning young fruit which will be culled at harvest.
Conditions continue to be favorable for downy mildew, so cucurbit growers need to be diligent in applying proper products for adequate control.
Recent rains have led to some fruit cracking in tomatoes.
Cool nights will tend to limit fruit elongation in peppers.
High air temperatures ranged from 73 to 82 F this week. Lows were in the mid-40s to mid-50s. Rainfall has been light this week; 0.25 inches in most cases with heavy morning dews.
Potato harvest continues in chip potatoes. Few fields are remaining with actively growing vines. Growers should continue to make fungicide applications to actively growing fields and vines.
Most farm market tomato plantings that were not protected by fungicide applications are succumbing to early blight and Botrytis.
Powdery mildew is increasing in prevalence on susceptible cucurbits such as pumpkin and squash.
Powdery mildew is increasing in prevalence on cucurbits such as these
pumpkins in Ionia County.
Southeast Michigan – Lina Rodriguez Salamanca, Michigan State University Extension
In the past week, the southeastern part of the state had 6/10 of an inch of rain in five rain events. For the present year, we have had a total of 14.4 inches of rain. Cooler temperatures have averaged in the mid-60s with a minimum of 43 F to a maximum of 82 F. Humidity has ranged from 30 to 94 percent, with nine to 16 hours of wetness.
Crops and pests
Vegetable crop harvests continue. However, fruit development and ripening have slowed due to the cooler weather.
Cucurbit downy mildew was found in a cucumber field in Monroe County. Currently, the forecasted risks for cucurbit downy mildew are moderate for our area. Scout your fields and keep up with the recommended spray program for your crop. Nine Michigan counties have confirmed reports of cucurbit downy mildew. More information on cucurbit downy mildew can be found in the MSU Extension News article Influx of cucurbit downy mildew sporangia detected in eastern Michigan.
Pumpkin fruit is ripening. Powdery mildew and scab are present in several fields.
There are no reports of late blight in Michigan; however, it was reported in Wisconsin in early August. No spotted wing Drosophila have been caught in any of the tomato fields with traps in our area (Lenawee, Monroe and Washtenaw counties).
The Monroe County sweet corn trap caught 30 corn earworm moths on August 20. Monitoring will continue. No European corn borer moths were caught.