Regional reports on Michigan vegetables – June 13, 2012

MSU Extension educators’ pest and vegetable updates for Michigan.

Southwest Michigan – Ron Goldy, Michigan State University Extension

Southwest Michigan
Southwest Michigan


Temperatures for the week were above normal with highs ranging from 71 to 91 degrees Fahrenheit and lows from 47 to 67 degrees Fahrenheit. There was no precipitation for the period. Conditions are extremely dry, not just at the surface but also 2 to 3 feet for many locations.

Crop reports

Sweet corn has responded well to the increased temperatures and is 16 to 20 inches tall for early plantings. Subsequent planting continues.

Pepper transplanting continues as does staking and tying. Early planted peppers are setting flowers and putting out secondary shoots.

Harvest of tunnel-grown cucumbers has begun. Harvest of summer squash and zucchini continues. Direct seeding continues. No squash vine borers have been caught.

Watermelon and cantaloupe transplants have gotten off to a good start and are beginning to runner off the plastic.

Tomato planting will continue through next week. Staking, pruning and tying continue. Fruit on early, tunnel-grown plants continues to size well. Fruit on non-protected, early plantings is 1 inch in diameter.

Early planted potatoes have 1- to 2-inch tubers. All stages of Colorado potato beetle can be found.

No serious problems have been reported on any vegetable crop. The biggest concern is the lack of moisture on non-irrigated sites.

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West Central Michigan – Norm Myers, Michigan State University Extension 

West Central Michigan
West Central Michigan


We’ve had no rain in the last week and unirrigated fields are getting pretty dry, especially with some of the very warm weather we had over the weekend. Irrigation is general where it is available.

Oceana and Mason counties

Asparagus production is beginning to slow and quality has suffered during the warm weather. Growers plan to begin shutting down production in full-season fields beginning early next week. There are enough weeds present that most asparagus growers will need to include a burndown material, like glyphosate, along with their residual herbicides. Growers need to be very careful with herbicides during very hot, humid conditions since you can get burn damage from materials that are safe in more normal temperatures.

Vine crops are growing rapidly. Our processing zucchini growers planted early this year because there will be no competition from cherries at the processors. Some of those crops are well ahead of normal and flowering will commence soon in the earliest fields

Aster leafhoppers collected in or near carrot fields remain highly infected with aster yellows. My most recent test showed infectivity over 19 percent, which generates a very low threshold. Fortunately, insecticides are doing a good job of keeping aster leafhopper numbers down in carrot fields.

Muck vegetable growing areas in Ottawa, Kent and Newaygo counties

Samples of aster leafhoppers collected last week in celery growing areas in Kent and Ottawa counties proved to be pretty highly infected with aster yellows, so we continue to recommend lower thresholds in celery. Irrigation is also general in muck growing areas, which were also missed by rains. I hope to collect more samples this week. Peas are forming pods near Fremont, Mich.

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Central Michigan – Fred Springborn, Michigan State University Extension

Central Michigan
Central Michigan


Dry weather was experienced over much of the central region this week. High air temperatures ranged from the upper 70s to mid-80s at Entrican, Mich. Low air temperatures were in the mid-40s to mid-60s. Low soil temperatures at 2 inches are in the mid-60s.


Dry bean and pickle planting is in progress. Dry bean planting is approximately 35 to 45 percent complete in the central region with significant progress occurring daily. Germination and emergence has been rapid in most cases.

Several early planted potatoes are covering the rows. In most of these fields, fungicide applications are being made. Potato leafhoppers are present in low numbers. Colorado potato beetles can readily be found on most volunteer potatoes in a wide range of growth stages. There are a few more reports from eastern states of late blight on tomatoes and potatoes. The newest reports I have are from Pennsylvania.

I continue to get very scattered reports of armyworm damage, mostly to field crops but this can be a concern to some vegetable crops, especially sweet corn. So far all of the armyworms I have seen have been true armyworms. Continue to scout fields and plantings. Most of these larvae are getting quite large and should pupate soon, but there may still be small larvae in some areas.

We continue to catch low numbers of western bean cutworm moths in pheromone traps.

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Southeast Michigan – Lina Rodriguez Salamanca, Michigan State University Extension

Southeast Michigan
Southeast Michigan


The dry weather continues in our area. Only 0.7 inches of rain was accumulated since last week. The lowest temperature was 40.1 degrees Fahrenheit (June 6) and highest temperature was 89.9 degrees Fahrenheit.


Zucchini and squash are bearing fruit and harvest continues. Cucumber beetles and thrips are abundant on those crops.

Cucumber beetle
Cucumber beetle in squash flower.

Watermelon and cantaloupe vines are up and growing. Some growers have planted pumpkins in the field. Tomato and pepper transplanting into fields is nearly complete.

Imported cabbage worm and diamond back larvae are still active in cabbage fields. Some cabbage aphids have been observed, as well as abundant thrips populations in cabbage and onion.

Abundant populations of leafhoppers were observed in a sweet corn field.


Cucurbit downy mildew counts remain low in the Monroe, Mich., spore trap. We had an average of 75 percent relative humidity and 16 hour of wet, overcast, but windy day yesterday (June 12). Those conditions can be conducive to dispersal and infection of both cucurbit and cabbage downy mildew. Check the Enviro-weather cucurbit downy mildew tool that will aid in decision making to protect your cucurbit or cole crop from these pathogens.

The potato and tomato late blight risk remains low (green). Visit to select the planting date for specific risk of you crop.



Status 6/12/12



Potato and other vegetables

Variegated cutworm

DD 1245

First generation larvae are hatching.

Time scout, and place trap out

Cucurbits, Sweet corn, Snap beans,

Seed corn maggot

DD 1734

First generation flight complete

Cole crops

Cabbage maggot

DD 1401

Peak egg laying of overwintering flies completed. Some flies are still laying eggs.


Squash vine borer

DD 893

Squash Vine Borer moths will be emerging soon.

Time to put pheromone traps out.

In southeast Michigan, we should be actively scouting for corn root worm. It has not been observed yet, but it is currently in the southwest area of the state and the risk for southeast Michigan is forecasted to increase as the week progresses (see

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