East Michigan vegetable update – August 8, 2018

Vegetable disease reports have increased across the region.


Growers across the region received between one tenth and two inches of rain this week. This is good for fruiting vegetable crops, though Michigan State University Extension notes some tomato splitting may be observed. Sometimes rain events can also affect insecticide performance. Learn more about optimizing insecticide applications in this article from Purdue: Why your insecticide may not be working as well as you would like.

Click the links below to view MSU Enviroweather’s data on maximum and minimum air temperatures, as well as degree day and rainfall accumulations from January 1 through the last 14 days:


All heading brassicas harvest continues. Over the last two weeks, onion thrips populations have gone down. Sites with the heaviest diamondback moth pressure are at around 2.5 caterpillars per plant. Swede midge trap catches remain at mostly less than 5 per trap.

Vine crops are at risk of more diseases now with the rains. Crows, raccoons and rodents are chewing fruit. You can identify crows and raccoons from smaller rodents by the location of the holes. Small rodents like voles usually chew on the underside of the fruit, while crows and raccoons make holes on the tops of the fruits. Some sites are experiencing heavy squash bug pressure. Pumpkins at some sites are already ripening. These will need to be cured and stored until September. Acorn, butternut and spaghetti squash are being picked at some sites. Smaller varieties of butternut, called honeynuts, are becoming more popular. I wish customers felt the same about small cauliflower.

Pickling cucumber harvests are rolling. Downy mildew reports are coming in from the Thumb, and southeastern Michigan. It is a good time to use Ranman or Orondis Opti on new and older crops. Orondis can only be 30 percent of the total spray program.

In onions, stemphylium leaf blight symptoms are now showing up. Mary Hausbeck’s lab is trialing fungicides for this disease and found that the Luna line of products is working exceptionally well. Quadris and Cabrio were not looking better than the untreated control. Bravo has been working better than Manzate.

Tomato disease pressure is now increasing, but late blight has still not shown up. I have seen a lot of Physiological Leaf Curl, which is a response to moisture and high light conditions. Red Deuce is a variety of beefsteak tomato whose leaves curl up tighter than other varieties, but yield is not impacted by this leaf curl.

Pepper harvest has begun. Bacterial blights are showing up in certain varieties and one grower is following up with a seed company to see if other folks are seeing a similar pattern from the same seed lot. If you are a commercial pepper grower who regularly uses copper and are detecting leaf spot, please let us know (email me at phill406@msu.edu). The vegetable pathology lab is testing isolates for copper sensitivity.

Sweet corn is now under attack by birds and raccoons in many areas. Over the last week, my trap in Lapeer caught 10 corn earworm moths, zero fall armyworm moths, and 3 western bean cutworm moths. Field corn silks are turning brown, and corn earworm moths will begin laying eggs in sweet corn in higher numbers.


Aug. 13, 9:30 a.m. – 1:30 p.m. Variable Rate Seeding Focus Group. MSU Agronomy Farm. 4450 Beaumont Rd, Lansing, MI 48910. Seeking focus group participants about seeding rate decisions. Participants will be paid $80. Manni Singh, msingh@msu.edu, 517.353.0226.

Aug. 21, 8:00 a.m. – 4:15 p.m. Biological Control in Protected Agriculture: Strategy & Planning Short Course. Great Lakes Greenhouse, 6573 East N Avenue, Kalamazoo, MI 49048. This course places emphasis on controlling insect pests in spring floriculture crops, but is highly applicable to other crops grown under protection. Event registration is $125 (Lunch included). https://events.anr.msu.edu/BioControlPlanningAug2018/.

Curious about using drones in agriculture? Attend the Tri-State UAV Field Day, Aug. 27 in Ohio. Contact Ricardo Costa at costasil@anr.msu.edu or 573-639-8971 for more information and registration.

Sept. 19, 8:30 a.m. – 1:30 p.m. Organic Management Field Day. MSU Kellogg Biological Station. 9701 N 40th St, Hickory Corners, MI 49060. Lunch included. https://events.anr.msu.edu/organicfieldday/.

Sept. 26, 9:30 a.m. – 4 p.m. The Midwest Mechanical Weed Control Field Day. PrairiErth Farm. 2073 2000 Ave, Atlanta, IL 61723. See in-row cultivation tools demonstrated on vegetable crops, with a trade show, and grower experiences with mechanical cultivation. Event registration is $20 (lunch included). Check it out on Facebook: facebook.com/mechanicalweedcontrol.

It is never too early to make accommodations to attend Great Lakes Fruit and Vegetable EXPO, Dec. 4-6, 2018, in Grand Rapids, Michigan. Hotel blocks are open and tend to go fast. The combination of grower-focused, research-backed presentations and an exhibit hall featuring a diverse set of vendors make it a can’t-miss event.

Need your water tested for the Food Safety Modernization Act (FSMA)? Check out the Michigan Ag Water Lab Map: http://bit.ly/MIagwaterlabmap.

Please contact me at phill406@msu.edu or 616-901-7513 with questions, concerns, or to schedule a farm visit. You can also send plant materials to MSU Diagnostic Services.

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