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Extension > Yard and Garden News > Archives > September 2013 Archives

September 2013 Archives

September 16 Issue of Yard & Garden News

Plant Video Library 2014

Karl Foord - Extension Educator, Horticulture


Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture




Karl Foord


Photo 1: Royal Catchfly(Silene regia


Karl Foord

Photo 2: Wild Petunia (Ruella humilis




Karl Foord


Photo 3: Wild Bergamot(Monarda fistulosa


Karl Foord

Photo 4: Tall Boneset (Eupatorium altissimum

Karl Foord

Photo 5: Jewelweed (Impatiens capensis


Royal Catchfly (Silene regia)

Wild Petunia (Ruella humilis)

Wild Bergamot (Monarda fistulosa)

Tall Boneset Revised

Jewelweed Revised

Beauty is The Beast

Karl Foord - Extension Educator, Horticulture

DSC_0012 forest tent caterpillars jeff hahn shopped and sized

BEFORE PROCEEDING PLEASE CLICK ON AND ENLARGE THE ABOVE IMAGE.

When I first saw this image I thought I was looking at a beautiful tapestry.


However, given the fact that Jeff Hahn was showing me a collection of pictures of insects he had assembled for a slide show presentation at the Minnesota State Fair, I had to rethink that initial impression. On closer examination one can see the head and hairs of a caterpillar. Nonetheless, what beautiful colors and such an intriguing pattern. So much for the beauty.

The only problem is that when this caterpillar has reached the large numbers characteristic of its cyclic pattern of life, it can defoliate many trees. Thus the beast.

Jeff has a video describing more aspects of the caterpillar that will be aired as part of a virtual conference sponsored by the Minnesota Turf & Grounds Foundation. We will provide a link to this presentation in the next issue of the Y&G News.




Jeff Hahn


Photo 1: Forest Tent Caterpillar (Malacosoma disstria


Laura Maskell - butterfliesandmoths.org

Photo 2: Forest Tent Caterpillar (Malacosoma disstria

Laura Maskell - butterfliesandmoths.org

Photo 3: Forest Tent Caterpillar (Malacosoma disstria

Rust fungi infect fall blooming perennials

M. Grabowski, UMN Extension

Photo 1: Asters showing lower leaf death from rust infection

M.Grabowski, UMN Extension Educator


As the summer winds down, Minnesota gardeners look to fall blooming asters like goldenrod and New England aster to bring color to the garden. In addition to colorful blossoms, less desirable colorful rust fungi can commonly be found infecting the leaves of these perennials. Many gardeners first notice rust infection when the lower leaves of an aster plant turn brown and die. In severe cases, over 50% of the leaves can be killed, often from the bottom up. Upon closer examination, a gardener will notice bright orange or chocolate brown bumps on the lower surface of green leaves and along green stems. These rust pustules are filled with hundreds of fungal spores.




M. Grabowski, UMN Extension


Photo 2: Coleosporium asterum on aster



There are several different rust fungi that infect asters in Minnesota. Infection by Coleosporium asterum results in yellow leaf spots on the upper leaf surface and raised orange spore filled pustules on the lower leaf surface of New England aster and golden rod. Like many rust fungi, C. asterum needs two different host plants to complete it's life cycle. In addition to infecting asters, C. asterum also infects the needles of red, Scots and jack pines. Infected pine needles have small white column-like spore producing structures that release powdery orange spores in early summer. These spores are carried by wind and infect near by asters. Spores produced within aster leaf spots throughout the summer reinfect the aster plant and any nearby asters. In fall, however a different spore type is formed on the aster that is carried by wind to infect nearby pine trees.

M. Grabowski, UMN Extension

Photo 3: Puccinia sp. on aster

Aster plants with chocolate brown pustules on the lower leaf surface are infected by Puccinia asteris, Puccinia campanulae, or other species of Puccinia. The Puccinia rust fungi infect aster as well as several grasses and sedges. They do not infect pine trees.


If leaf death is not severe, rust can be tolerated on asters. Infection by rust fungi often results in little to no affect on plant growth or blossom production. To reduce the severity of the disease, gardeners should take steps to reduce moisture on the foliage. Dense beds should be thinned and overgrown plants divided. Water with drip irrigation or use sprinklers early on a sunny day so that leaves dry quickly. Mulch the soil with woods chips or other organic matter to keep soil moisture from evaporating and increasing humidity in the plant canopy. Plants with a history of infection can be scouted regularly throughout the summer. As rust infection develops on a few leaves, theses leaves can be pinched off and buried to reduce spread of the pathogen.

Flower Video Library for 2013 Sun Plants IV

Karl Foord - Extension Educator, Horticulture


Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture




Karl Foord


Photo 1: Golden Showers Coreopsis (Coreopsis verticillata 'Golden Showers')


Karl Foord

Photo 2: Prickly Pear Cactus (Opuntia humifusa)

Karl Foord

Photo 3: Brown-eyed Susan (Rudbeckia triloba)


Bush Honeysuckle (Diervilla)

Golden Showers Coreopsis (Coreopsis verticillata 'Golden Showers')

Prickly Pear Cactus (Opuntia humifusa)

Brown-eyed Susan (Rudbeckia triloba)

Purple Coneflower with Aster Yellows

Ground Clematis (Clematis recta)

Karl Foord - Extension Educator, Horticulture


Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture




Karl Foord


Photo 1: Vine Honeysuckle (Lonicera tellmanniana)


Karl Foord

Photo 2: Spiderwort (Tradescantia virginiana)

Karl Foord

Photo 3: Pale Coneflower (Echinacea pallida)




Karl Foord


Photo 4: Little Titch Catmint (Nepeta racemosa 'Little Titch')





Karl Foord


Photo 5: Creeping Phlox (Phlox subulata)


Vine Honeysuckle (Lonicera tellmanniana)

Spiderwort (Tradescantia virginiana)

Pale Coneflower (Echinacea pallida)


Little Titch Catmint (Nepeta racemosa 'Little Titch')

Clustered Bellflower (Campanula glomerata 'Joan Elliot')

Dianthus Firewitch (Dianthus gratianopolitanus 'Firewitch')

Creeping Phlox (Phlox subulata)

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