Southeast Michigan vegetable update – Sept. 9, 2020

Harvest continues for many crops. Quality is generally good but cool weather and rains are impacting warm-season crops.

Blossom end rot on peppers
Blossom end rot can still be found in fields. Areas can be infected by opportunistic molds and fungi. Photo by Marissa Schuh, MSU Extension.

Weather

A cool air mass moved into Michigan, and the last week has seen temperatures a few degrees cooler than is typical for early September. The cool weather will through early next week, with the coldest period being Thursday morning where lows will be in the mid-50s. Our area received anywhere from a half-inch to 2 inches of rain in the last week, with some periods of heavy rainfall.

Longer-range forecasts are calling for warmer than normal temperatures in late September and continuing for the rest of the fall season.

The table below shows rainfall totals for the Michigan State University Enviroweather stations in southeast Michigan, as well as degree-days calculated using the Baskerville-Emin Method. Degree-day average for Commerce and Hudson is over five years, while Deerfield is over four years. Rainfall is in inches. For a refresher on degree-days and how to get this information in your area, see “Accessing growing degree days with Enviro-weather” from MSU Extension.

Rainfall and degree day totals as of Sept. 9

Station

Degree days (base 42)

Degree days (base 50)

5-year degree day average (base 50)

Rainfall since April 1

Commerce

3633

2378

2319

15.24 (+0.91)

Deerfield

3766

2598

2603.3

12.4 (+0.73)

Hudson

3478

2354

2399.6

20.33 (+1.14)

General notes

While this is a busy harvest period, if you are seeing widespread fruit rots, I encourage you to contact me so we can work on a confirmed diagnosis. Every winter I get asked to identify a fruit rot someone saw months ago or to submit a soil sample to look for disease. Post-season conversations can only go so far and aren’t conclusive, the best way to get a firm diagnosis is to submit a sample of impacted plants/fruit now. A solid diagnosis will help you direct your time and money to the right management channels in 2021.

The recent rains mean phytophthora can flair up. With pumpkins, squash, peppers and other crops in the disease’s host range fully loaded with fruit, it can be easy (and heartbreaking) to spot and identify hot spots in fields. It is important to note where these hot spots are, as it allows you to limit how the disease may spread via cull piles and equipment. Culls from phytophthora-infested areas should not be dumped in cull piles in fields with not history of the disease, and equipment that is run through areas with phytophthora should be washed so that there are no major dirt clods on them. Bleach is not necessary and will cause wear on the equipment, instead focus on getting rid of dirt.

Never seen phytophthora on your farm before? That means it is the right time for you to learn about this disease. So much about managing this disease is making sure you never see it on your farm. Whether phytophthora is a familiar foe or not, I can’t recommend the Great Lakes Vegetable Producer’s Network conversation with Cornell plant pathologist Christine Smart enough.

Crop reports

Cole crop harvest continues. Imported cabbageworm/general worm pressure can be high this time of year, continue to scout and manage accordingly.

Cool weather is leading to blemishes in eggplant fruit.

In peppers, I’ve continued to see physiological issues like blossom end rot and sunscald. Cool weather has led to purple discoloration. Some bacterial spot is being seen in some plantings.

Pumpkins and winter squash are being harvested markets. Fruit look good, and powdery mildew arrived late this year, making management easier. See below for a discussion of end of season management and harvest decisions.

The recent rain is leading to some skin splits in tomatoes.

In sweet corn, we are seeing the typical fall uptick of corn earworm pressure. A flight of moths arrived in our area last week, with my trap in Monroe and Lenawee counties catching 76 and 115 moths, respectively. In the last week, my Monroe County trap caught 87 moths and my Lenawee County trap caught 128 moths. The cooler weather will slow down the silk growth and the corn earworm egg hatching, but regular control measures will be needed.

Reach out

Please contact me at schuhmar@msu.edu or 517-264-5309 with questions, concerns or to schedule a field visit. I have the ability to visit fields on a limited basis.

This is my last weekly crop report of the season, but that doesn’t mean I am not visiting fields and working with farms.

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.

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