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Showing posts from June, 2019

Organic management of black rot in cole crops: an overview

Author: Natalie Hoidal, University of Minnesota Extension - Horticulture

In certain regions of the state, black rot (Xanthamonas campestris pv campestris) is becoming a major disease of cole crops. Once black rot is present, it is exceedingly difficult to get rid of.


Black rot bacteria enter the plant through hydrathodes, or pores at the leaf margins. The bacteria can also enter the plant through wounds such as hail damage, mechanical injury, or in some cases insect feeding. Symptoms begin as yellowing at leaf edges, which turns into characteristic v-shaped lesions (see photo). As symptoms progress, plants can develop blackened vascular tissue in severe cases.

If you’re seeing black rot symptoms on your farm, there are a few strategies you can take to minimize the spread:

Remove infected plants as soon as symptoms appear (not just leaves, but the entire plant) if symptoms are isolated to a few plants.If one field is impacted but not another, make sure to practice excellent sanitat…

What's Killing My Kale Episode 22: Thinning Techniques for Apple Trees Through the Season

Author: Annie Klodd. Interviewee: Becky Wiepz. 

Today is June 24 - have you thinned your apple crop yet?In episode 22 of What's Killing My Kale, Annie took a deep dive into apple crop load management (thinning) techniques with fruit tree researcher Becky Wiepz. Becky recently received her Masters degree in Horticulture at Penn State, studying a crop load management technique called artificial spur extinction. This non-chemical technique may be a promising option for organic apple growers in the Midwest, as it reduces or eliminates the need for chemical thinners during the growing season. In addition to artificial spur extinction, we compared the advantages and disadvantages of various thinning techniques, and laid out what options apple growers have at this point in the season if they have not thinned yet.

You can listen to and download the episode here.

Consider Apple Nutrient Applications After Recent Warm Weather

Author: Annie Klodd. While May 2019 saw cool temperatures, low growing degree day (GGD) accumulation, and excessive rainfall, the warm temperatures in the last ten days have led to rapid growth on apple tree fruit and shoots. Many apple growing regions of Minnesota and Wisconsin accumulated up to 18 GGD last week, pushing growth along quite a bit. While we are happy that fruit development is "catching up," growers also must make management considerations based on this surge in growth.

Plant nutrient deficiencies are a risk with rapid growth after petal fall, because the rate of fruit and shoot growth may outpace the ability of the plant to uptake available nutrients from the soil. In some areas, this issue may be also be compounded with "wet feet" (saturated soil) which can interfere with nutrient uptake. While in some cases the trees are likely to outgrow temporary deficiencies, growers should check for signs of nutrient deficiencies on the leaves and decide wheth…

Pest alert: Black cutworm

The UMN Extension IPM program sets traps for black cutworm Agrostis ipsilon Hufnagel (Lepidoptera: Noctuidae) around the state each year, which are monitored by Extension educator Bruce Potter and a team of volunteers. In 2019, high numbers have been observed across the state but particularly in Southern MN. Coupled with late planting dates, cutworms may pose a challenge to growers this year. 
While cutworm is typically considered a corn pest, they can cause damage to vegetable crops as well. While most reports have cited cutworm feeding on plants in the cucurbit family (cucumbers, pumpkins, and melons), they also feed on beets, carrots, cucumber, leafy greens, peas, potato, pumpkin, snap beans, and sweet corn. Black cutworm moths fly north to Minnesota from early May through June, and lay their eggs in and around fields. As the larvae develop over approximately a one month period (with six to nine larval instars), they damage plants by feeding on the roots and stems, and young plants …

What's Killing My Kale Episode 21: Solarization for weed management with Courtney Tchida

In episode 21 of our fruit and vegetable podcast What's Killing My Kale? we talked to Courtney Tchida, farm manager at Cornercopia student organic farm. Courtney has been trying various weed management methods over the years, and has recently been experimenting with solarization using standard plastic as well as used billboards (as in billboards from roadside advertising!). Courtney shared her insight on how well these methods work, labor and equipment costs, convenience, and more. 

Click here to listen to the episode.You can listen to it now, or download it to listen later. 
You can find all previous episodes on FruitEdge.
What's Killing My Kale? is a podcast production of the University of Minnesota Extension, sponsored in part by the University of Minnesota Integrated Pest Management program. Co-hosted by Extension Educators Annie Klodd and Natalie Hoidal, the podcast focuses on innovative and timely pest management topics in fruits and vegetables, and sometimes ventures into…

Use DriftWatch to Communicate with Pesticide Applicators

DriftWatch is a state program that allows specialty crop growers to indicate the locations of their fields on a map so that pesticide applicators can take precautions to avoid crop injury due to spray drift. In Minnesota, Larry VanLieshout is the coordinator for the DriftWatch program. He has provided the following information about how to best utilize DriftWatch for your farm:
Let pesticide applicators know where your pesticide sensitive crops (and beehives) are located by using DriftWatch.
DriftWatch (and BeeCheck) are free, voluntary online registries that that allow specialty crop producers to communicate the location of their pesticide-sensitive sites to pesticide applicators. Applicators can then take precautions to avoid injury due to spray drift. Specialty crops include fruits, vegetables, and organic produce. (BeeCheck is a version of DriftWatch for beekeepers, who do not also have other specialty crops.)
This communication is done by indicating the location of the sensitive …

Practical Tips for Managing Grape Phylloxera in Minnesota

Authors: Bill Hutchison, Eric Burkness, Lu Yin, and Matt Clark. The foliar form of Grape Phylloxera (GP) is quite common throughout Minnesota and most eastern grape growing regions of the U.S. Although we have experienced a late spring so far this year, the first grape leaves for most hybrids have started to appear; this is a good time to begin monitoring for the “yellow crawler” stage of GP, as the crawlers hatch from their “mother” galls (including a female with several eggs, Fig. 1).
Grape Phylloxera Life Cycle In brief, the GP life cycle is quite complex, with galls formed on both root and foliar portions of the vine. However, given the genetic background of the cold-hardy grape hybrids in the Midwest region, the primary potential for damage is the presence of foliar galls formed by GP. Much of this information is taken from a recent publication by one of our graduate students in Horticultural Science, Lu Yin (Yin et al. 2019; see full citation below).
Following the hatch of overw…