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Monday, October 31, 2011

Contents: November 1, 2011

Disease Resistance of Cold Hardy Grapes

Disease Resistance of Cold Hardy Grapes

Michelle Grabowski, UMN Extension Educator

Clemson University - USDA Cooperative Extension Slide Series,

Photo 1: Anthracnose on grape berries

New research published in Plant Health Progress provides Minnesota grape growers with more information about disease resistance of cold hardy grapes. Canadian researchers tested several cold hardy cultivars of wine grape for resistance to Anthracnose. Anthracnose, a disease caused by the fungus Elsinoe ampelina, can infect leaves, tendrils, shoots, and immature berries of grape vines. Leaves have dark brown to black spots. As leaf spots grow, the center of the spot turns gray to white and eventually falls out. Leaves may appear peppered with small shot holes. Anthracnose lesions on stems and petioles are sunken oval spots that almost look like hail damage, but the edges Anthracnose spots will always be black. Berries infected with anthracnose have brown to black spots with a pale white center. These spots are often described as 'bird's eye' spots.

Anthracnose thrives in warm, wet weather. In Minnesota, some vineyards see Anthracnose every year, and others rarely have a problem says University of Minnesota Grape Breeder Dr. Jim Luby. The Canadian researchers found Frontenac and Frontenac Gris to be resistant to anthracnose, Frontenac Blanc and La Crescent to be susceptible, and Marquette to be highly susceptible. Growers interested in trying new wine grape cultivars should learn about disease resistance to several grape diseases in addition to anthracnose. Downy mildew, black rot, powdery mildew and Botrytis can all be problematic in Minnesota vineyards. More information about disease resistance and culture of cold hardy grapes can be found at the University of Minnesota Cold Hardy Grape webpage.

The Beneficial Challenge

Karl Foord, UMN Extension Educator

Do you actually see things that you do not recognize? I was hunting for agates near Custer, South Dakota and went through a great agate field and picked a number of nice specimens. I then visited a rock shop and was introduced to the prairie agate which I had not seen in any of the rock books. I went back to the agate field and found quite a few prairie agates. I had been in that field earnestly searching for agates before and did not even see these types until pointed out at the rock shop. This begs the question, can you be looking right at something and not see it or rather not recognize it for what it is? It is not that your eyes did not see it but rather your brain was not ready to discern.

This brings me to the subject of beneficial insects in the garden. Have I not seen them because I did not know what I was looking for? As I look forward to next year's gardening, I want to put the idea of discovering more beneficials at the forefront of my mind. To aid the process I would like to be able to see what it is that I am looking for. As advanced responsible gardeners I think we have an obligation to recognize the dynamics at work in our gardens. To this end I offer the following challenge: how many beneficials will you be able to see and identify from your garden in 2012?

What follows is a gallery of 8 beneficial insects with pictures of their mature and immature stages. Also included is a table showing the types of insects on which they prey.

Please click here for the pdf of the gallery: Beneficials.pdf

Calendar: November 1, 2011

Dave Hansen, UMN

Last chance! The Arboretum Apple House will remain open until at least November 6. They have the best supply of Honeycrisp in years and have been picking some high quality late season apples this week. Whether you prefer a tart and juicy Haralson, a sweet Fireside or SnowSweet with a balanced flavor, you will find the apples you enjoy the most right now. For updates on the Applehouse inventory, call 952-443-1409. For more information about the Apple program at the U of M, please visit the U of M Apples website.

Dave Hansen, UMN


Potted chrysanthemums in rich, autumn hues are traditional for Thanksgiving. Choose plants with some buds just opening, rather than in full bloom. They'll last three or four weeks when kept in a bright locations. Discard the plants once their flowers fade. It's not worth trying to plant them outdoors. Even though they might survive our winters, most florists mums won't bloom before hard frost, so they aren't useful in Minnesota gardens.

Apply winter mulch over bulbs and the flowering perennials buy mid-month if the soil hasn't frozen yet. (Ideally you'd wait until it freezes.) You can even spread straw, leaves, or partially finished compost on top of snow. Winter mulch's most important function is to insulate plant roots from fluctuating soil temperatures and keep them safely dormant during early spring warm-ups.

Move houseplants to brighter locations within your home, to compensate for reduced-light levels as days grow shorter and cloudier weather increases. South-or west facing windows are not too bright-- even for "low light" plants, this time of year. Pull the shades or draw the drapes at night, thought to protect houseplants from cold air near window panes. Continue to rotate the plants 1/4 turn every couple weeks so they don't bend toward the light.

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