East Michigan vegetable update – May 29, 2019

Some fields are drowning worms, but nobody is fishing but crayfish.

Burrowing crayfish hole
This a burrowing crayfish hole in a Brussels sprout field, revealing a lighter colored subsoil that was excavated from below. What this tells me is that the field had standing water over the weekend, with pregnant female burrowing crayfish out eating some of numerous drowned worms that were also on the soil surface where water pooled the longest. When the field started draining, the female crayfish were triggered to dig the burrows where she pastes her eggs to the outside of her body and sits under the surface of the water table, like in an indoor pool. Once hatched, they crawl out together. Michigan has five species of burrowing crayfish*. They are not crop pests of economic concern and do not require control. Photo by Ben Phillips, MSU Extension.


I visited fields yesterday, May 28, that were sandy without tile, mucky with tile, and clayey with tile. The sandy and clayey fields were still saturated from the rain on Saturday and Monday, which brought between 0.75 and 3 inches measured by Michigan State University Enviroweather stations in the region. The word in the countryside was up to 6 inches in some places, but the tiled muck ground was being worked with tracked tractors and some growers with fewer acres, lighter equipment and hand labor have been transplanting steadily.

After Saturday, the next good chance of rain is the middle of next week. It will also remain cool.

You can find more detailed weather information for your area by visiting the Enviroweather station closest to you:


Plant damage from preemergent herbicides are showing up due to the wet, cool soils and low light conditions. They will grow out of it. However, weeds are coming through in some crops and if you decide to apply a postemergent spray, use a lower rate to avoid further damage.

Insect pests

Seed and root maggots in cole crops and onions are nearing their peak egglaying stages this week. It could be a good time to target a spray on crops that are in the ground. A pyrethroid like zeta-cypermethrin (Mustang Maxx) works well. An organic option is spinosad (Entrust). Row covers work excellent for those with time, labor and small areas. If you are delayed in transplanting cole crops, all the better. You may miss their first big egglaying window.

Here is a table the summarizes the maggots of concern and the degree days that signify when they will be laying eggs in the areas around seedlings. I used Lapeer as an example. The seed corn maggot and cabbage maggot models are from Michigan State University’s Enviroweather, and the onion maggot model is from NEWA.


Seed corn maggot emergence - base 39 F

Onion maggot emergence – base 40 F

Cabbage maggot emergence - base 43 F

Current degree days (Lapeer)




Overwintering flies start to emerge and lay eggs

201 (occurred April 18)

390 (occurred May 15)

298 (occurred May 11)

Peak flight and egg laying of overwintering flies

342 (occurred May 4)

735 (a spray could be targeted this week)

565 (a spray could be targeted this week)

Peak flight and egg laying of 1st generation flies




Peak flight and egg laying of 2nd generation flies




European corn borer is a caterpillar pest of corn. Genetically engineered corn varieties have worked well on this pest for many years by using a range of Bacillus thuringiensis (Bt) proteins, which kill the caterpillars when they eat the plant. Think of these proteins as the active ingredient. Recently, resistance to one of those active ingredients has been found in Eastern Canada. The protein is Cry1F, and field corn hybrids that contain that protein alone are now ineffective against European corn borer in that region. Fall armyworm and western bean cutworm are already resistant to that protein.

Trait stacks are a genetic technique similar to tank-mixing pesticides. They feature proteins with slightly different ways of working, similar to pesticide modes of action. If you are wondering whether your Seminis Performance Series or Syngenta Attribute Series sweet corn has this protein in it alone or with a trait stack, here is your answer.

Seminis Performance Series sweet corn has Cry1A.105, Cry2Ab2 (for caterpillars) and Cry3Bb1 (for rootworm beetle larvae). Cry1A.105 is a three-pronged protein that basically uses the same mode of action as Cry1Ab, Cry1Ac and Cry1Fa. According to a 2013 study published in PLOS ONE, the cross-resistance to Cry1A.105 protein may occur if a population of corn borer is already resistant to any of those individual proteins. However, the stacked trait, Cry2Ab2, is still effective. When referring to the Handy Bt Trait Table for field corn, these varieties are analogous to Genuity VT Triple Pro and VT Triple PRO RIB Complete field corns. Genuity was owned by Monsanto, who also owned Seminis, and that is why they use similar trait packages. They are now all owned by Bayer.

Syngenta Attribute I Series corn has Cry1Ab. It is effective on corn borer. When referring to the Handy Bt Trait Table for field corn, these varieties are analogous to Syngenta Agrisure GT/CB/LL 3010 and Agrisure Artesian 3010A field corns.

Syngenta Attribute II Series corn has Cry1Ab and Vip3A. The Vip3A protein has never been effective on European corn borer but works on other caterpillar species. When referring to the Handy Bt Trait Table for field corn, these varieties are analogous to Syngenta Agrisure Viptera 3110 and Viptera Artesian 3110A field corns.

Upcoming meetings

The upcoming Young Growers Exchange Bus Tour is designed to allow the next generation of vegetable growers to network with each other while visiting west Michigan farms and is open to all growers in the Midwest. The tour will take place over two half-days on July 17-18. Day one will focus on soil health, showcasing Morgan’s Compost and a major potato grower who is part of a soil health initiative. Day 2 will include another major potato grower plus muck vegetable production. There has been a lot of grower interest, so early registrations in the grower category are filling up fast. We are also offering a single-day option to allow for additional participants to caravan and leave on their own. Please consider registering.

Last year, I grew peppers at the research farm for a trial to determine how well we can ripen and dry some large-fruited Mexican peppers here. There are some capacities to sell them as a winter or early spring farmer’s market product or added value sauce-making. Now, a collaborating sauce maker has taken all nine of the poblano varieties we grew and dried and made enchilada sauces with them to compare against a sauce made from imported Mexican poblanos. Do Michigan poblanos take on a regional flavor that differentiates them like wine grapes? To find out, she is hosting a public Michigan Enchilada Sauce Taste Trial at the Saginaw Farmer’s Market Demonstration Kitchen on June 15 from 11 a.m. to 1 p.m. Come by!

We are planning one more Produce Safety Alliance (PSA) Grower Training event in South Haven on June 4. If you were hoping to sign up for an On-Farm Readiness Review (OFRR) this season, we ask that growers attend a PSA Grower Training before scheduling an OFRR.  This will be the last opportunity to participate in a grower training, and therefore an OFRR, until this coming October. Register at Produce Safety Alliance (PSA) Grower Training.

It is never too early to make accommodations to attend the Great Lakes Fruit, Vegetable and Greenhouse Growers EXPO, Dec. 10-12 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.

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.

* To learn about Michigan’s five species of crayfish, visit “Crayfish of Michigan” from Michigan Department of Natural Resources.

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