East Michigan vegetable regional report – July 20, 2016
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EmailHarvest is picking up for most summer crops, with limited pest pressure overall.
Weather
It is likely that the warmest week of the growing season is upon us. There are chances of rain Friday and Sunday, July 22 and 24. Wilting plants in the field and greenhouse should be checked to make sure emitters are securely in place and that tape is not plugged.
The table below includes rainfall (inches since April 1) and degree-day (base 50 degrees Fahrenheit since March 1) accumulations to date from Michigan State University Enviro-weather stations in the region.
Rainfall and degree-day totals as of July 20, 2016 | ||||
|---|---|---|---|---|
|
Location |
Degree days |
5-year average |
Rainfall |
5-year average |
|
1,314 |
1,344.5 |
9.21 |
11.00 |
|
|
1,363 |
1,360.5 |
5.57 |
10.40 |
|
|
1,402 |
1,405.2 |
6.13 |
10.78 |
|
|
1,357 |
1,392.9 |
6.13 |
11.76 |
|
|
1,358 |
1,398.2 |
9.07 |
12.96 |
|
|
1,235 |
1,303.0 |
7.39 |
12.41 |
|
|
1,358 |
1,398.5 |
6.78 |
10.96 |
|
|
1,425 |
1,394.5 |
7.84 |
12.02 |
|
|
1,248 |
1,299.0 |
10.83 |
10.79 |
|
Crops
First plantings of cabbage and broccoli are nearing their last pickings. Fall-harvested plants are at various stages. Cauliflower is getting close to the softball size and tying will occur soon on some farms. Brussels sprouts are thigh-high.
Winter squash and pumpkins are in full flower, and powdery mildew is starting to show up. Quintec and Torino are two products that work well to prevent and treat light infestations tank-mixed or rotated with Bravo.
Summer squash and cucumber harvest continues. Lots of oversized crops are being left in the field. Aphids are showing up in greenhouse cucumbers, but I have not heard or seen any in field crops. Beleaf and Fulfill are two good, general use products for field or greenhouse that work specifically on insects with a proboscis, or straw-like mouth. They are safe to spray during bloom when bees are around, and they both have a zero-day pre-harvest interval. Use the higher rate for outbreak populations. They work by paralyzing the aphid’s straw mouth and starving them. It will take a few days for them to die, and may require an additional spray if more aphids arrive.
Pickling cucumber harvest started last week but is currently on hold because of dry weather. Downy mildew has been confirmed in St. Clair, Bay and Tuscola counties and has been spreading more slowly than the last two years with this dry weather. Growers in those counties should be on a four- or five-day schedule on new plantings when conditions are overcast and mornings are dewy. Growers outside those counties should be on a seven-day schedule. Rotate between Gavel 75WG (five-day pre-harvest interval), Presidio 4FL (two-day PHI), Tanos 50WG (three-day pre-harvest interval) or Zampro 4.4SC (zero-day pre-harvest interval), and tank-mix with broad-spectrum protectants like Dithane (five-day pre-harvest interval), Bravo (zero-day pre-harvest interval) or Zing! (zero-day pre-harvest interval). Save *Previcur Flex 6SC (two-day pre-harvest interval), *Ranman 3.6SC (zero-day pre-harvest interval), *Orondis Opti (zero-day pre-harvest interval) for high pressure and favorable mildew conditions. There is a special 24(c) label for Orondis Opti.
Serious cantaloupe and watermelon harvest has just started on some farms. Size and quality are good. Some cracking occurred on a Bay County farm that received intense rain a few days before harvest, which then attracted sap beetles around the cracks. These beetles are scavengers that show up after the damage is done. They also love sweet corn after bird injury. Melon growers need to be vigilant with downy mildew as well. See the recommendations for pickles above.
Fresh market tomatoes and peppers are being picked from the field. The prolonged dry heat has caused tomatoes and bell peppers to start ripening before getting very large. Bananas and Hungarians do not seem to be as affected. Early varieties of processing tomatoes are just beginning to fill the row middles and some fruit are turning red. Blossom end rot is showing up in all types of tomato plantings due to the dry weather. Even irrigated plantings are showing blossom end rot, which may indicate the need for more frequent irrigation.
Early potatoes, red and white, are being harvested. Most are 2 inches in diameter, but many are 4 inches. Late blight has not been seen in any other fields since the confirmation of the disease in Branch County the first week of July. There was a great opportunity for it to spread with rains, warm nights and dewy mornings last week, but this dry week is likely reducing the chance of infection.
Small sweet onions are being harvested and sold as groups. Colossal sizes are starting to show up at markets as well. Thrips populations explode in this hot and dry weather, and I can see damage from the road on some farms. There may be an association between thrips and bacterial leaf blight, which can be a larger problem where thrips are not managed. This is a larger concern for seeded storage onions, which have a much longer season than sweet onions. These growers should be on to their first of two applications of Radiant if thrips are over the threshold of three thrips per leaf. Start with the lower rate, and follow up with the higher rate the following week.
Sweet corn picking has started at most farms this week. The size and quality of ears is good, though some stands suffered through dry soils and ripening has been uneven, or plants are extremely short and ears are too close to the ground for convenient picking. I have four corn earworm traps set up and have only caught two moths, but corn harvested last week had about 5 percent earworm damage. So, they are out there in localized areas despite low catches. Placing water-sensitive paper among the silks will help determine if your sprays are getting to where they need to be for controlling earworm. Sprayers may need to be adjusted between plantings because of the extreme height variation that I’ve seen. Field corn will be silking very soon and will draw earworms from sweet corn patches.
Washing produce
Ag-use sanitizers, such as Sanidate or Tsunami, have recommended rates on their labels. However, common household bleach is 5.25 percent sodium hypochlorite, and can be used in a wash/pack line as a sanitizer as well. See the table below from MSU Extension educator Phil Tocco’s article, “Chlorine as a Sanitizer,” for appropriate rates bleach.
If the produce is really dirty, they should be pre-washed or brushed before the chlorine bath. That will allow the chlorine to remain active longer. If your chlorine bath gets too dirty, you will need to make a new batch. pH should be 6.5–7.5, and water temperature should be similar to the center of the produce that is being washed to reduce bacteria or chlorine from being sucked across the temperature gradient and could reduce shelf-life or affect flavors. Chlorine test strips help gauge if the chlorine solution is too dilute and should be checked periodically.
Recommended Chlorine Concentrations for Sanitizing Fresh Produce | ||
|---|---|---|
|
Type of Produce |
Recommended PPM of Chlorine |
Bleach per gallon of water1 |
|
Berries (blackberries, blueberries, raspberries, strawberries, etc.) |
No Washing |
N/A |
|
Apples, pears, squash, cucumbers |
65 ppm |
1 tsp per gallon |
|
Leafy greens, peaches, peppers, tomatoes, asparagus, broccoli, carrots |
130 ppm |
2 tsp per gallon |
|
Melons, root crops |
400 ppm2 |
2 tbsp. per gallon |
1 Based on using common household bleach without fragrances or thickeners and base concentration of 5.25% Sodium Hypochlorite
2 Sanitizing wash should be followed by a potable water rinse
Table excerpted with permission from “Farm to School Program: Tips, Tools & Guidelines for Food Distribution and Food Safety.” Oklahoma Department of Agriculture, Food and Forestry
Special events
Agritainment growers who invite more of the public to their farms and markets than your average grower may be interested in a pollinator planting workshop. Visiting customers may wonder what you are doing about bees. A small planting near the parking area or a large one on your property could be a selling point. The same plants that help pollinators also help natural enemies combat pests in the crop. Come to the Aug. 2 workshop, Supporting Beneficial Insects with Flowering Plants, at the Clarksville Research Station to learn more.
MSU’s Dan Brainard is hosting an in-row cultivation workshop in Milan, Michigan, on Sept. 8 at Zilke Farms. Contact Dan at brainar9@msu.edu or Vicki Morrone at sorrone@msu.edu for details.
Reserve your hotel early for the Great Lakes EXPO in Grand Rapids, Michigan, Dec. 6-8! Registration is not open yet, but hotels often fill up before then. Anyone can access educational session summaries from the Great Lakes EXPO at the website. View the session summaries.
Please contact me at phill406@msu.edu or 616-901-7513 to grab any suspected disease samples from your farm, or send the diseased plant parts to MSU Diagnostic Services.
