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Showing posts from August, 2020

Managing fall Brassica diseases: Alternaria leaf spot and Black rot

 Author: Natalie Hoidal, Extension Educator, Local Foods and Vegetable Production At this point in the season, at least for diversified vegetable farms, the busiest part of the season is behind us. There’s still a lot of work to be done, but I encourage you all to take some time to make a plan for fall Brassica management, and in particular disease prevention. This season has been generally dry with fewer disease problems than normal, but we’re starting to see pressure from black rot (Xanthomonas campestris pv. campestris) and Alternaria leaf spot (Alternaria spp.) What can you do at this point in the season to prevent problems?   Late summer Brassicas are often a source of inoculum for fall Brassicas. Photo: NH What can you spray? I reviewed twelve recent trials assessing the impact of various fungicides on black rot and Alternaria leaf spot in Brassicas, and compiled the results of each product into a table for comparison (see below). The data is complicated. A few of the conventiona

Weekly vegetable update 8/26/2020

Author: Natalie Hoidal, UMN Extension Educator, Local Foods and Vegetable Production Crop report At this point in the season, a lot of crops are winding down. I'm going to stop giving updates about every crop, and instead only mention those that I have something interesting to say about. Cucurbits: Farmers have started to harvest some of the smaller winter squashes such as acorn and some hubbards. Watermelon harvest is ongoing. I spoke a bit too soon about melons and pumpkins / winter squash being relatively disease free this year. I saw a particularly bad case of Anthracnose in cantaloupe this week, as well as more virus symptoms in watermelons. At this point in the season it is still worth treating powdery mildew, as it's important to have good canopy cover in late August to protect ripening fruit from sunburn. Some growers may be seeing heat stress symptoms (wilt, slightly yellowing leaves).  Tomatoes and peppers: Tomatoes and pepper production are quite variable around

What to do with bad clusters during grape harvest

Authors: Matt Clark (Assistant Professor) and Annie Klodd (UMN Extension Educator - Fruit Production). Article originally posted on . Photo: Grape cluster infected with black rot-causing fungi Not all grape bunches are picked or retained at harvest, due to low quality attributes including diseases that can reduce wine quality.  Quality is more important than quantity when it comes to wine grapes for several reasons. First, disease-infected or spoiled grape berries lower the flavor and aroma qualities of the wine. High levels of volatile acidity in wines, attributed to fruit rots, taints the wine and the presence of those compounds are regulated by the government. Secondly, the grower’s reputation is influenced by their ability to deliver healthy, high quality fruit to the winery. Third, some wineries pay growers on a sliding scale based on quality attributes, and many will reject deliveries with defected fruit. For these reasons, it is in the growers’ best interest to o

Apple Orchards, Pumpkin Patches and Agri-Tourism - what COVID rules apply?

Annalisa Hultberg, Extension Educator - On-farm Food Safety Annie Klodd, Extension Educator- Fruit Production If your farm is considering agri-tourism activities this fall, here is a summary of rules that apply to your operation related to COVID-19 from the most recent executive orders from the state of Minnesota.   The  Guidance for Food and Agriculture was updated 8/26/20, so this information is new. All businesses must follow applicable guidance for their industry. All of the guidance for industries can be found here on the Stay Safe Guidance for Business and Industry page. This summary and examples of farm scenarios is meant to help direct you to the industry guidance that might apply to your farm and is not an exhaustive list of guidance requirements. You will need to read the guidance documents. Which guidance should my farm follow? Your farm might have to follow more than one industry guidance, based on your activities. Here is an overview of the two main scenarios. 1. If your

Weekly vegetable update 8/20/2020

Author: Natalie Hoidal, UMN Extension Educator, Local Foods and Vegetable Production After a truly devastating week for many farms (hail), this week was relatively calm with moderate temperatures and minimal rainfall. Most summer crops have reached peak production, and fall crops are coming along nicely. Crop report Cucurbits: Watermelons are ripe across most of the state. Acorn squash is close behind; many farmers in Southern Minnesota will be ready to harvest next week. Most cucurbits seem to be relatively disease-free this year (except for the mosaic viruses that showed up earlier this year), though powdery mildew continues to be a problem for growers not using resistant / tolerant varieties. I haven't received many reports of cucumber beetles being a problem at this point in the season. Continue to keep an eye on squash bugs.  Tomatoes and peppers: Tomatoes and peppers are reaching peak production. Chiles are heating up (after harvesting for a few hours I could actually fe

Food safety considerations when using apple "drops" due to recent weather events

 Annalisa Hultberg, Extension Educator, Food Safety The recent weather and derechos in Iowa, Minnesota and other areas of the North Central region have left many apple growers with questions about using their fruits that have fallen to the ground. While it might be tempting to want to use the apples so that they do not go to waste, these dropped apples should not be used for fresh eating, baking or in juice or cider production due to the potential for the presence of patulin. Patulin is a mycotoxin produced by molds like Penicillium , Aspergillus and Byssochlamys when apples or other fruits are injured. The toxin is heat-stable, meaning it is resistant to heating, even at pasteurization temperatures. You cannot see or smell or taste the toxin, so it is not possible to know if it is present without laboratory testing. Patulin has been shown to cause serious illness in animals and humans, especially to the nervous systems and might cause problems with blood flow, nausea, vomiting

When to Harvest Your MN55 Apples for First Kiss® Quality

Sampling First Kiss ®  apples at Pine Tree Apple Orchard on Aug. 17, 2020. Photo: Annie Klodd. I have enjoyed the opportunity to taste test First Kiss® apples from MN55 trees at Pine Tree Apple Orchard's Preston and White Bear Lake locations this week. The apples we tasted were just a few days away from harvest - sweet and crisp, but still too starchy to be picked. I also saw a photo of First Kiss® apples at a farmers' market last weekend that were harvested about a week too early and still had a green undercolor. So, this prompted a discussion with Dr. Jim Luby about when to harvest MN55. Key Points for Harvesting MN55 Harvest parameters:  80-95% scarlet red overcolor Undercolor starting to break from green to yellow 14-19 lbs pressure Starch iodine 5-6 on the Cornell scale Brix 12-13 Acid 9-7 g/L or lower.  Use these parameters to determine harvest timing; do not rely on color alone, or you will likely be harvesting overly tart fruit Additional important harvest information:

Corn Earworm Alert for Southern Minnesota Sweet Corn

Corn Earworm (CEW) moth flights have been relatively low this year up until this week. Although the flights remain low at most locations, during the past week CEW numbers increased at Blue Earth to over 160 per trap per night.  As noted in previous articles, CEW is not able to overwinter successfully in MN, but migrates north this time of year from southern states. We’ve had some major southerly storms pass through the state, including Aug 7-8th that likely assisted with the recent influx of moths.   Corn earworm larvae in sweet corn (E. Burkness, UMN) Although we have observed various levels of CEW resistance to pyrethroid insecticides (bifenthrin, lambda-cyhalothrin) in recent years, our results last year indicated good efficacy but we had low-moderate pest pressure. If you are not finding good/excellent control, consider one of the diamide options (e.g., Coragen) or methomyl.  Unfortunately, the organic-certified Entrust and Pyganic only perform well in low-pressure situations. The

What's the deal with late season flea beetles?

Author: Natalie Hoidal, UMN Extension Educator, Local Foods and Vegetable Production Typically we think of flea beetles as very tricky early season pests that start to wind down around mid-June. However, I've been receiving consistent reports of flea beetles throughout the summer, and even now in mid-August, growers are seeing substantial flea beetle damage on their most recent successions of cole crops. Flea beetles, NH What's going on?  Unfortunately, we don't have a great answer at this point. There are typically only one to two generations per year, and with the amount of heat we've had, we should have experienced enough degree days / accumulated heat units for them to complete those generations. If you'd like to help us solve the puzzle, and you're currently seeing flea beetle damage, please reach out to me at We're interested in collecting some flea beetles to ID them, since we've seen photos of what look like a couple of differen

Weekly Fruit Update - 8/14/2020

 In this week's update: COVID-19 guidelines for apple orchards and pumpkin patches - PLEASE READ What to do after blueberry harvest Prepping strawberry beds for winter COVID-19 guidelines for apple orchards and pumpkin patches - PLEASE READ In light of COVID-19, the state of Minnesota developed sets of guidelines that pertain to different types of businesses/entities such as recreational, entertainment, retail, restaurants, etc. While farms that operate solely to sell produce and/or offer U-pick are only subject to the  guidance for Food and Agriculture , farms also offering agrotourism activities such as corn mazes, jumping pillows, and petting zoos become subject to recreational or entertainment guidelines. These guidelines include a 250 customer maximum at any given time.  Our team is currently drafting an article to communicate details on this, based on a meeting yesterday with the Commissioner of Agriculture, Dept. of Labor and Industry, MN Dept. of Health, and MN Dept. of Agr

Fruit Insect Pest Update - August 14, 2020

Spotted Wing Drosophila (SWD)  Adult SWD captures remained high at most locations this past week; with captures at Forest Lake “exploding” to 1000 to 2000 SWD/trap (10-fold higher than last week). At Rosemount and Hastings, numbers increased to 200-300 SWD/trap. At all sites, summer raspberry is particularly vulnerable to attack at this time, and fall raspberry will soon be a concern as well. For these crops, high-tunnels fitted with fine nylon mesh continues to be the best management option. Where netting is not available, insecticidal protection will be necessary for most crops, since given the high numbers. For details on SWD trap numbers this past week, view the SWD page at the FruitEdge SWD page . SWD trap catch numbers are updated weekly (Tuesdays); comparisons are also available for 2018-2019.  SWD female (left), with close-up view of ovipositor (for egg-lay), and male (right) with characteristic dark spots on each wing (C. Guédot, Univ. of Wisconsin). As noted in previous artic

Weekly vegetable update 8/13/2020

  Author: Natalie Hoidal, UMN Extension Educator, Local Foods and Vegetable Production Many of you were hit by the storm this week. For most, it meant very heavy rainfall. For some, it meant devastating hail. Others were not hit at all, and instead had a busy and productive week of harvesting. For those of you who did see damage, please reach out to our team if there is any way we can support you.  We have some stormy weather predicted across most of the state this weekend (unfortunately with some more hail potentially predicted in certain regions), followed by a very reasonable week of high temperatures in the upper seventies, which should be great for harvesting. Crop report Cucurbits: Cantaloupe production is in full swing, and watermelon production is ramping up. Pumpkin and squash growers should continue to be proactive about powdery mildew and squash bugs.  Tomatoes and peppers: Tomatoes are at peak summer production, and peppers are getting there. I continue to see blossom e