Fruit and Vegetable News

Annalisa Hultberg, Extension Educator, food safety Can you safely use apples and other crops that might fall to the ground before or during harvest? Is it safe to just wash off and then sell these crops? While it might be tempting to want to use the products so that they do not go to waste, produce that is dropped prior to or during harvest should not be distributed to the public for fresh eating, baking or in juice cider production due to the potential for the presence of patulin (in apples), and the risk of damage and internalized contamination in other produce. What happens when produce is dropped? When produce falls to the ground, damage such as cracks, bruises and other sometimes undetectable breaks in the surface of the produce skin or rind can occur. These cracks can cause the produce to be much more susceptible to infiltration during the washing step, such as with this cantaloupe pictured below. Dye was put into the water that the melon was submerged into.  You can see wher...

Have you struggled with soilborne diseases in your high tunnel? Our colleagues in Ohio are offering free soilborne disease testing to high tunnel vegetable growers in the Midwest. This is a collaborative project between USDA-ARS, Ohio State, Penn State and Virginia Tech funded by a grant from NIFA-CPPM. Some examples of common soilborne pathogens in tunnels in MN include: white mold (can affect lettuce, tomatoes, and a wide range of other vegetables), Pythium and Rhizoctonia root rot of various vegetables, and Fusarium and Verticillium wilt in tomatoes. Sometimes these diseases are hard to distinguish from one another, so if you've never tested diseased plants in your soil, assessing which pathogens are in your soil can help you make decisions about resistant varieties and preventative management. Verticillium wilt in tomato. Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org If you would like to submit a sample for analysis, reach out to Natalie Hoidal at hoi...

Author: Annie Klodd, Extension Educator - Fruit and Vegetable Production. kloddann@umn.edu Some areas of Minnesota are forecast to experience a frost or freeze tonight. This leaves grape growers debating whether to harvest today or leave the fruit on the vines. The goal of this article is to provide growers with information that they may use to help make their decision. University of Minnesota Extension is not responsible for an individual farm's decision - this information is for educational purposes only. A conservative estimate from Jorgensen et al. (1996) suggests that frost damage can be expected when temperatures dip below 31 degrees F.We do not have definitive data showing whether the berries of MN-bred grape varieties can withstand lower temperatures than other varieties. Therefore I am using this general, conservative threshold. There are two different types of frosts, advection and radiation. Just because a frost is predicted for a certain region of the state, that does n...

Author: Natalie Hoidal, UMN Extension educator, local foods and vegetable crops  This is the final vegetable update of the season! Thanks to all of you who followed along and shared questions and photos along the way. There is still no sign of a hard frost in the forecast for any part of the state, but many field crops are reaching their final days, and summer high tunnel crops are slowing down from diseases, insects, and other issues. This article includes updates about a couple of important diseases, curing tips, and reminders about soil testing + nitrogen credits.  Crop updates   Tomatoes and potatoes: Late blight was officially identified in Itasca County this week in a potato field. We've also been hearing reports of it from farms in and around St. Louis County. The bad news: late blight spreads very quickly under cool, wet conditions. Fall weather is great for late blight spread in Minnesota. It's also a water mold and not a true fungus, meaning many fungicides ...

Author: Natalie Hoidal, UMN Extension educator, local foods and vegetable crops  This is the second to last vegetable update of the season. This update includes an overview of some disease issues I've been seeing in the field, a discussion about what the hot fall nights mean for cool season crops, and reminders about fall tasks like thistle management and manure applications.  Crop updates Tomatoes and peppers: I've been seeing tomatoes here and there with fruit spots that look to be caused by a pathogen, but the leaves are still disease-free. Seeing these tomatoes reminded me of a case last year where a farmer was harvesting fruit that looked great at harvest, but was developing lesions in storage which were caused by Alternaria. The best things growers can do to prevent these problems are: 1. Harvest as often as possible so that fruit do not become overripe. Soft spots in overripe fruit are very prone to secondary infection. 2. Store fruit at the right temperature...

Sour rot on a grape cluster. Photo: Annie Klodd Author: Annie Klodd, UMN Extension Educator - Fruit Production. kloddann@umn.edu A few shriveled and rotten berries are a normal site during the harvest season. If you spot more than a few, find out what the cause is before deciding what to do about it. Each fruit rot disease has slightly different symptoms (described below). Based on the symptoms, we can usually make an educated guess about the disease or disorder. If we cannot identify it from visual symptoms, the next step would be to mail a sample to the Plant Disease Clinic for official diagnosis. We recommend against spraying the grapes unless you know the disease infecting the grapes and what is effective on it. Additionally, know the pre-harvest interval, cause, and the cost & benefit of spraying, before spraying anything. Remember that each application cuts into the revenue per acre, so each spray needs to be worth the money and environmental risk. Vineyards and Master Gard...

Photo: Hail netting being removed from high density apple tree rows in Preston, MN.   Annie Klodd, Extension Educator - Fruit Production, kloddann@umn.edu This is peak season for harvesting fruit crops in Minnesota. Thanks for taking a moment to read this fruit update, which will hopefully help with the harvest. Apples Orchards are harvesting Zestar!, SweeTango, Paula Red, and Chestnut Crabapples. The new Juicy Jewel pear was also recently picked at the Horticultural Research Center.   Review recommendations on deciding when to pick, here . Splitting: Some orchards experienced fruit splitting after the series of rainfalls two weeks ago. Un-irrigated orchards have more troubles with this than irrigated orchards. This is because apples that are water-stressed or slower-growing are less prepared for a large influx of water that occurs during heavy rainfall. The same principle applies with potato hollow heart - potatoes exposed to prolonged dry weather are more susceptible to...