Weekly Vegetable Report - 6/18/2020

Author: Natalie Hoidal, UMN Extension Educator, Local Foods and Vegetable Production

If you're seeing interesting things in your fields, insects and diseases, or just want to share photos, we'd love to hear from you! As always, don't hesitate to reach out with questions and pictures. We're still here for technical assistance over the phone, via text, or via email.

Vegetable questions go to me (Natalie): hoida016@umn.edu
Fruit questions go to Annie: kloddann@umn.edu
Food safety questions go to Annalisa: hultb006@umn.edu

Crop report

This week was hot and dry. This was great for holding off diseases, but many growers experienced drought stress, and insects continue to thrive in these conditions. Thankfully we have some water predicted in the forecast for the whole state. 

• Asparagus is reaching the fern stage for many growers. 



Asparagus is starting to put out ferns
NH




Nearly all garlic is now
producing scapes, NH

• Garlic: Most garlic across the state has now reached the stage where it's producing scapes. Make sure to remove them to ensure larger bulbs. 
• Potato beetles are out in full force; I scouted ~30 miles north of the Twin Cities late last week and found 2nd instar larvae already. This is the time to spray. I also noticed quite a few potato leafhoppers.  
• Cucurbits: Same update as last week - the main concern for cucurbits right now is cucumber beetle. In zucchini and summer squash we're starting to see flowers and even some fruit; don't expect the first fruit to be large, as they tend to be unfertilized. Consider removing them to allow your plants to put more energy into flowering and later fruit. Melons are starting to vine out. If you're using split fertilizer applications, initiation of vining is the time for your second application. 
• Tomatoes and peppers are coming along. Many of you are only a week or so away from your first high tunnel tomatoes. We're starting to see tomato diseases in the field, so make sure you're scouting regularly. Keep an eye out for aphids in pepers.
• Cole crops are at various development stages depending on succession planting. We're nearly past the window of flea beetle pressure and cabbage maggots, so caterpillars are the main issue. Thankfully we haven't heard as many reports of black rot and Alternaria this year. 

Problems in the field

Herbicide drift

Unfortunately, this remains a concern for another week or so. Crop canopies are starting to close in, and this weekend is the cut-off date for dicamba. So, the good news is: the threat of herbicide drift is nearly behind us for the year. Anticipate that your neighbors will be spraying this weekend and next week. Make sure they know you're growing vegetables and that they need to be extremely careful near your fields. Also consider calling your local co-ops to let them know you're there. There's a lot of turnover in co-ops, so even if they knew about you last year, it's a good idea to call and remind them to take extra care near your fields. Also, consider signing up for DriftWatch  If you suspect you've experienced drift on your farm, contact MDA immediately.

Bolting spinach, NH

More bolting

This week's hot weather has resulted in more bolting. Make sure that any new successions of brassicas, lettuce, and other cool season crops are planted with varieties well suited to heat.

Insect and disease forecast

Diseases

Disease problems have been generally much more manageable this year compared to the last three years or so, but keep scouting and reporting any issues.

Insects

Migratory Insects

Leafhopper damage in dry beans
NH

Many migratory insects come to Minnesota each summer, a few of which cause problems for crops. These insects such as leafhoppers and aphids tend to be carried north on currents of air from the south. Last week, tropical storm Cristobal reached parts of Minnesota, carrying air all the way from Guatemala, and thus likely carrying insects north along its path. We've seen tons of leafhoppers this year, and aphids too. While we can't definitively say that they came from this storm, we can say that these insects have arrived a bit earlier than usual. Aphids can carry viruses and other diseases, so keep an eye out for anything that looks a bit off such as mottled or crinkly leaves.

Bugs
The season of true bugs (Hemiptera) is upon us. We are starting to see squash bugs, and fourlined plant bugs have already done quite a bit of damage. No sightings of Brown Marmorated Stinkbug yet.

So many potato beetles
NH

The same insects we've been seeing for a couple of weeks are still causing problems. I am seeing more leaf hoppers than usual in potatoes and beans, definitely at threshold levels in some cases. (More info on leafhoppers). We are also seeing more cucumber beetles than usual (More info on cucumber beetles). Potato beetles are at multiple stages - we're still seeing overwintering adults, but we're not starting to see first and second instar larvae as well. Cabbage caterpillars are now the main insect pest in brassicas, as flea beetle populations are *starting* to wind down, and the threat of cabbage maggot has mostly passed. Potato beetles are laying eggs, and first and second instar larvae are already emerging. Your treatment options decrease substantially as larvae develop, so now is the time to treat if you need to. 

Educational opportunities

Great Lakes Vegetable Producers Network: join us during your lunch break on Wednesdays for a 30 minute discussion about vegetables. All previous episodes can be downloaded as podcasts. Next week's episode will be about powdery mildew.