East Michigan vegetable update – Sept. 9, 2020

A cooling weather pattern has customers anxious for canning vegetables and fall flavors. This is the last regular field season report for 2020.

Pumpkin farm
Pumpkins are looking fantastic this year. On this farm, low-growing sunflowers are also being employed as a billboard along the road (behind the pumpkins in this photo), directing customers to take a look. They are not blooming yet but are just about to. Photo by an anonymous grower.


We are currently parked under a stationary cold air mass that extends from Canada all the way to Texas, and degree day accumulation has slowed down dramatically. This should be lifting by early next week with more sunny days and late-summer temperatures returning.

Most of the region received something between 1.93 and 4.41 inches over the last two weeks. There is a continuing chance of rain until tomorrow morning, and then the next best chance in the near term is Saturday, Sept. 12, through Sunday. Friday will be a good harvest day.

On the whole, our season has a surplus of degree days, which is probably why the warm season crop harvest has been so good this year. Peppers and pumpkins colored early this year from the heat.

The long-term forecast suggests a mild fall followed by a La Nina winter with above average snowfall.

This is the last regularly scheduled crop report of the 2020 season. Stay tuned for more opportunities to interact this winter in new and interesting ways.

You can find more detailed weather information for your area by visiting the Michigan State University Enviroweather station closest to you.

Here is a table that summarizes European corn borer activity, based on growing degree day models. I used Lapeer as an example.


European corn borer emergence – base 50 F

Current degree days (Lapeer)


Overwintering generation start to emerge and lay eggs

450 (occurred June 11)

Peak flight and egg laying of overwintering generation

700 (occurred June 28)

Peak flight and egg laying of first generation

1,700 (occurred July 31)

Peak flight and egg laying of second generation

2,450 (forecasted for Sept. 16)

Phytophthora Phthought

This disease is kind of like diabetes of the farm. If diagnosed, you will be living with it and will need to change certain practices and behaviors to reduce its effects on the long-term productivity of your business. It can be overwhelming to read about this plant destoyer. So, here is just one thought at a time for anyone going through this.

Did your fruit rot this year? Did they rot last year? Think things will be better next year with no further information or changes to your process? Working without the best information leads to crazy-making decisions that have no effect on the actual problem.

Consider sending a sample to the MSU Plant & Pest Diagnostics lab for Phytophthora testing. This could be a fruit with a soft spot or the root crown and roots of a wilting plant. However, plant parts that are fully melted down do not usually work well for shipping or for finding the pathogen with a lab test. So, you will need to look for something showing early symptoms of wilt and rot, but not full-on liquidated or dried brown tissue.

Crop progress and pests

Sunflowers were a new addition to many farms this year. I received a number of inquiries about weed control options in the spring, and now they are blooming. There must be a YouTube video fueling this hivemind. In any case, they make a great billboard for your on-farm market and an attractive addition to displays at centralized farm markets.

Sweet corn corn earworm moth catch has increased in southeast Michigan, but traps in east central Michigan are still at a trickle of one or two moths per night. The last holdouts for sweet corn sales are still harvesting their final crops through the middle of the month.

Zucchini and yellow squash are being picked clean of their large fruits this week and being marketed as “bread squash.” Unfortunately, zucchini bread doesn’t actually use that much zucchini. Breads call for approximately 1 to 1.5 cups of grated fruit per loaf. That is about 5 ounces. Any more and there is too much moisture. They are mostly water after all.

If you are looking to dump a lot of zucchini into a recipe, soup is the way to go. Soup recipes vary in their measurements, from 4 cups on up. That is 1 pound or more, and you can cook it down to improve flavor and reduce storage space required in the fridge or freezer.

Many growers are having a bumper crop of pumpkins and winter squashes this year. There were some new growers entering the market this season, and powdery mildew pressure was surprisingly low. So, at this point, more people have been successfully bringing fruit to bear, which may depress prices at auction. On the flipside, the market also seems hungry for pumpkins NOW. So, you will likely be able to sell some early stuff before a glut. Some growers are picking for covered storage this week to limit sunscald and potential for fruit rots as the fall gets wetter.

Watermelon and cantaloupe harvests continue but they are past their prime. At this time of year, ripening will start to slow down and cantaloupes that ripen now will have less of a netting than they normally would.

Leafy green harvest continues with lettuce and the kales/collards/chards. They like this weather. Cabbage white/cabbageworm pressure is high this time of year. So, expect to treat for those, or use row covers.

Brussels sprouts topping is starting in order to bulk up the sprouts and make them more uniform along the stalk for fall markets. “Jingle-bell” stalks are a popular way to sell them that requires minimal cutting. But you may need a sickle bar mower, brush cutters, chainsaws, limb saws or large loppers to make those cuts!

Strawberry renovation is still occurring. Growers are multivating between rows to clean up emerged weeds and applying Stinger (clopyralid) for emerged thistles and Select (clethodim) for actively growing grasses in the rows.

Storage onion field curing and harvest is underway.

Carrot harvest is ongoing.

Peppers and eggplants are also a bumper crop this year for some growers, particularly for colored pepper varieties. The higher degree days pushed them along faster than normal. The quality and variety of colored peppers is a sight to behold at some markets. Paired with the colors and shapes of early hard squashes, some markets are looking Wonka-like.

We can sometimes see corn earworm and European corn borer come into pepper, eggplant and tomato crops this time of year, but I have not heard it reported. Brown marmorated stink bug is another insect that has been steadily increasing as a fall pest of some veggies, including peppers, tomatoes, sweet corn and beans.

As temperatures start cooling, peppers will start getting squattier in shape, and eggplants will develop a scabby-like skin texture.

Brown marmorated stink bug damage in jalapeno peppe
Brown marmorated stink bug damage in jalapeno pepper. The circular brown spots on the leaves and the white, “skin-deep” splotching on fruit are from their straw-like mouth poking into the tissue. This is an emerging pest of concern in late summer in many vegetable crops, including sweet corn, beans, tomatoes and peppers. I have not seen much damage from them, aside from a few plants here and there. Photo by Ben Phillips, MSU Extension.

Tomatoes are hitting the market with force for canning. With the recent rains, the fruit will be dirty if they were not trellised. So, washing lines will be running this week. One word of warning about dunk tanks. Tomatoes will readily take in dunk tank water, which results in splits after boxing. There will be more splits if the water is much cooler than the fruit core, if they are held underwater by fruit above it, and if they are left in the tank for longer time. My best advice would be to harvest in the morning before fruit get warm and work in smaller batches to reduce their time and depth in a dunk tank. Also, be very careful with your sanitizer rates. You should not be able to smell it. If fruit absorb over-sanitized water, it can cause off flavors.

Need canning supplies for your market?

Here are some bulk wholesalers of jars and lids to try. Perhaps you could split a load with another farm marketer. Some of them sell other canning supplies too, such as jar lifters, funnels, canning spice mixes, etc.

Tune in to the Vegetable and Root Crop Virtual Field Day

The Vegetable and Root Crop Virtual Field Day on Sept. 16 from 6-8 p.m. will highlight research by MSU specialists and MSU Extension educators in supporting vegetable and root crop production in Michigan. The field day aims to inform growers about timely management issues involving disease, parasites and insects, and fertilizer timing throughout the growing season.

Draft agenda

6:00 p.m. - Welcome, Ben Werling
6:10 p.m. - Asparagus Beetle Research Update, Jennifer Zavalnitskaya and Zsofia Szendrei
6:30 p.m. - Nitrogen rate and timing for Michigan Veggies, Michael Metiva and Zach Hayden
6:50 p.m. - Plant-parasitic Nematode Carrot and Parsnip Research, Ellie Darling and Marisol Quintanilla-Tornel
7:10 p.m. - Disease Control of Vegetables,  Mary Hausbeck
7:30 p.m. - Root Crop Research Update, Ben Werling
7:50 p.m. - Question & Answer, Wrap-up, Ben Werling

Certified Crop Adviser and Restricted Use Pesticide credits

This event will count for two restricted use pesticide (RUP) credits. Certified crop advisor (CCA) credits will also be available, pending approval from the state.

Register for the Vegetable and Root Crop Virtual Field Day

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 Plant & Pest Diagnostics.

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