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Monday, December 30, 2013

Cold weather-loving cockroach discovered in U.S.

Jeffrey Hahn, Extension Entomologist


Lyle Buss, University of Florida

Photo 1: Japanese cockroach, male (left) and female (right)
Earlier this month, the Japanese cockroach, Periplaneta japonica, was confirmed for
the first time in the U.S. in New York City. This cockroach is originally from Japan and other parts of Asia.  Although it is not known how this cockroach arrived in the U.S., it is possible that it may have been transported in the soil of ornamental plants.  

This cockroach is fairly large, growing up to 1 3/8th inch long.  It is generally brownish black to black in color.  The male has wings which just extend past the end of its abdomen while the wings of the female cover only about half of its body.  The Japanese cockroach is closely related to the American cockroach, P. americana, a long time pest of the U.S.

The Japanese cockroach can live inside buildings like other pest cockroaches.  What is unusual about this species is that it is tolerant of cold weather; they have been observed outdoors in below freezing temperatures and on snow.  The pest cockroaches that live in the U.S. generally remain indoors in the northern U.S. and are normally not seen outdoors.

What does this mean for the U.S. and Minnesota?  It is not clear how well the Japanese cockroach can spread in here; it has similar habits to other structure-infesting cockroaches and it will probably be challenging for it to become too abundant as it competes for favorable harborages and food.  However, it would not be unexpected for New Yorkers to see this species occasionally outdoors this winter.  Like other cockroaches, the Japanese cockroach is a good hitchhiker so it is possible that it could one day be found in Minnesota.

Monday, December 2, 2013

December 1 Issue of Yard and Garden News

In this issue:

Do-it-yourself bed bug control: What does and doesn't work

Extension Publications: New and Revised

Minnesota's Native Holly

EPA Pesticide Labeling Changes to Protect Pollinators

Protect Your Young Trees from Rabbits

Good Question: Do you really need to rake those leaves?

Take a Survey and Win an iPad Mini

Do-it-yourself bed bug control: What does and doesn't work

Jeffrey Hahn, Extension Entomologist


Jeff Hahn, University of Minnesota

Photo 1: Bed bugs are a serious insect problem today.

After an absence that lasted for decades, bed bugs have become a significant pest problem in our lives again. Unfortunately, they are usually very challenging and costly to control. Still, the most effective solution to eliminate them is hiring a pest management company to treat them; they have the experience and understanding of bed bugs to effectively control them.

However, residents can become frustrated with controlling bed bugs (and its cost) and may resort to a variety of do-it-yourself solutions. Unfortunately, many of these methods are not only ineffective but can make the problem worse and be potentially harmful to people and pets.

The following is a list of what research has shown to be effective and ineffective in bed bugs control.


What does not work?
  • Insecticides purchased in hardware stores, retail variety stores, grocery stores,
    pharmacies, and other places that sell insecticides to the public.  The active ingredients in the products are not effective against bed bugs. This can lead people to use insecticides excessively and even apply insecticides that are not labeled for indoor use, such as landscape and garden insecticides which can be harmful to people and pets. Using ineffective insecticides can also cause bed bugs to disperse, making them more difficult to eliminate. 
  • Bug bombs or foggers (also called total release insecticides).  These products contain ineffective insecticides which does not reach bed bug hiding places when they are
    activated. Excessive use of bug bombs can potentially cause explosions and fires and cause severe damage to buildings. See also the December 2012 Yard and Garden News for more information.
  • Moth balls.  They have very little effect, if any, on bed bugs. They can be irritating to people's eyes and noses.
  • House cleaning products.  These chemicals are not effective in eliminating a bed bug infestation. They can cause bed bugs to disperse, making the problem harder to control.
  • Isopropyl alcohol.  A very labor intensive method that can kill some bed bugs but the alcohol has to come in direct contact with them. The majority of bed bugs will be unaffected. 
  • Ultra sonic repelling devices. The sound these devices emit does not kill or deter bed bugs. 

While working with a pest management service is the most effective means of eliminating bed bugs from a home, there are some effective steps that people can use to help in their battle against bed bugs. 
  • Heat treatment. Clothes laundered in hot water and/or dried in temperatures hotter than 122° F for 20 minutes will kill all stages of bed bugs. This is typically the medium-high setting. You can also heat treat curtains and other fabrics, rugs, shoes, backpacks, stuffed animals, toys, and similar objects by drying them for about 30 minutes (for a full load).
  • Cold treatment. All stages of bed bugs will be killed when infested objects are placed in a freezer at 0oF for four days.
  • Mattress encasements.  They protect mattresses that are bed bug free from becoming re-infested. Encasements on infested mattresses and box springs trap bed bugs inside them and allowing you to continue to use them.
  • Interceptors. Bed bug interceptors are placed under bed legs and captures bed bugs that try to climb up or down beds.  It is used primarily as a monitoring tool to help determine whether bed bugs are present (if that is an issue).
For more information, see Let's Beat the Bed Bugs web page.

Sunday, December 1, 2013

Minnesota's Native Holly





K. Zuzek, UMN Extension


Photo 1: Winterberry, November 11, 2013

Mention holly during the month of December and we all think of cut holly branches adorning homes during Christmas season. But our native holly, called winterberry or Ilex verticillata, is just as ornamental outdoors in our early winter landscapes because of its colorful and abundant fruit (Photo 1).

Winterberry is native throughout the eastern United State (Photo 2) and in Minnesota it is usually found growing in forested wetlands in the eastern half of the state along with larch, willows, and speckled alder. You may also see it growing along lakeshores and ponds or in acidic sandy soils with high water tables.




USDA Natural Resources Conservation Service Plants Database


Photo 2: Native range of Ilex verticillata

Although there are over 400 species of holly (Ilex spp.) worldwide, less than a dozen species are commonly used as landscape plants. Winterberry is one of these species. Approximately 35 cultivars have been selected within the species for fruit color (red, orange, and gold), fruit size and abundance, and compact plant size.

Winterberry cultivars range in size from 4-10 feet in the landscape. Small, inconspicuous flowers are produced from mid-June to early July. Winterberry's dark green foliage provides a beautiful backdrop to the brightly colored fruit that become showy in September. After leaves drop, the fruit will continue to light up a winter garden until birds find and eat it.

Winterberry is an easy plant to grow in light or heavy soils. Because it is native to swampy areas, it does well in wet conditions. It does prefer acidic soils with a pH between 4.5 and 6.5; chlorosis will develop in high pH soils. The other important fact to remember is that winterberry is dioecious, meaning male and female flowers are produced on separate plants. Besides planting a female cultivar that will produce the showy fruit, you must also plant a male plant whose pollen will be produced at the appropriate time to pollinate the flowers on your female cultivar that will later develop into the fruit. Two male cultivars are available at garden centers: the early blooming 'Jim Dandy' and the later blooming 'Southern Gentleman'. Plant labels and garden center staff can help you select the appropriate male cultivar for your fruiting female cultivar.

EPA Pesticide Labeling Changes to Protect Pollinators

Karl Foord - Extension Educator, Horticulture

The United States Environmental Protection Agency (EPA) has instructed the manufacturers to change the labels on those chemicals that have been designated as Pollinator Toxic Pesticides (PTP). One educational piece that has been released describes the changes (Exhibit 1). The label will contain a Bee Hazard Icon to alert users that this is a PTP (Exhibit 2).

The old label language for pesticides toxic to bees was as follows:


"For crops in bloom, do not apply this product to target crops or weeds in bloom."


The new language is as follows:


"Do not apply (product) while bees are foraging. Do not apply (product) to plants that are flowering. Only apply after all flower petals have fallen off."


The language is more extensive for commercial users and lists conditions under which one might apply chemicals even though bees are present. The main difference between old and new labels appears to be the last sentence stating that the product cannot be applied until all of the petals have fallen off the plant.


EPA

Exhibit 1:EPA Advisory Box


EPA

Exhibit 2: Bee Hazard Icon

At least one significant factor motivating the label changes by the EPA was the move by the European Commission to restrict the use of three neonicotinoids (clothianidin, imidacloprid and thiamethoxam) within the European Union. This would be for purposes of seed treatment, soil application and foliar treatment on bee attractive plants and cereals. The member states failed to generate a majority either for or against this proposal and so the decision went to the Commission.

As you might expect, there are those who felt that the move by the EPA fell significantly short of what was required to protect pollinators. The science behind this controversy is no doubt complicated. Traditional experimentation involves setting up experiments where all factors but the one under interest are controlled permitting a clear picture of the effects of this one factor. However, under field conditions it is difficult if not impossible to control all factors in this way and one is left to entangle interactions. For example, there is research demonstrating that the interaction between the neonicotinoid imidacloprid and Nosema (a gut fungus causing dysentery) hampered bees ability to sterilize colony and brood food (Alaus et. al. 2010). This effect was not seen in the control or the single imidacloprid or Nosema treatments.

Even though European Union members failed to achieve a majority vote, the commission still chose to restrict use. On the other hand the U.S. EPA chose to modify labeling language and revisit the issue in 2018 when the registration of these chemicals is subject to review.

Both entities had access to the same research findings. The difference in reaction may be a philosophical one. The European Commission took the position of, given the facts the safety of these chemicals needs to be demonstrated before their use will be reinstated. The U.S. EPA took the position perhaps of, given the facts the damage of these materials must be more definitively demonstrated before their use will be restricted.

Given that we live in the U.S. we have inherited the latter philosophy. However, as a gardener I will be keenly aware of the potential impact of neonicotinoids and only use them on non-flowering plants and only under extreme circumstances, if even that.

C. Alaus et. al. Interactions between Nosema microspores and a neonicotinoid weaken honeybees (Apis mellifera). Environmental Microbiology (2010) 12(3), 774-782.

Protect Your Young Trees from Rabbits

Karl Foord - Extension Educator, Horticulture

I noticed rabbit damage on my Frosty Canadian Hemlock (Tsuga canadensis 'Frosty') (photo 1). I was again reminded of the fact that I did not wrap or protect my young apple trees last winter (photos 2 & 3). Remedy (photo 4).


Karl Foord

Photo 1: BEFORE - Frosty Canadian Hemlock (Tsuga canadensis 'Frosty')


Karl Foord

Photo 2: Zestar! Apple (Malus domestica Zestar!)


Karl Foord

Photo 3: Chestnut Crabapple(Malus 'Chestnut')


Karl Foord

Photo 4: AFTER - Frosty Canadian Hemlock (Tsuga canadensis 'Frosty')

If you have young trees don't forget to protect them from rabbits. Two articles have been previously published on this topic.

Rabbits and trees and shrubs

and Trees - Protecting from Rodent Damage

Friday, November 15, 2013

Good Question: Do you really need to rake all those leaves?

Good question.png

View Video On WCCO

Here is some really good information for all of you homeowners looking to avoid the leaf raking process this weekend. The real answer to this question is NO, but it comes with one catch......he most important point with fall cleanup is that the tree leaves are not covering a significant portion of the turfgrass canopy. 10-20% coverage of your lawn might be okay, but I certainly would make sure the leaves aren't covering any more than that. Excessive leaf matter on your lawn going into winter is bad for several reasons. First, it will smother the grass and if not removed very soon in the spring it will inhibit growth. Second, it can promote the snow mold diseases. And finally, turf damage from critters (voles, mice) can be more extensive in the spring.

The homeowner basically has three options to make sure that leaves are not covering a significant portion of their lawn:

1) Rake them up or use a blower- compost the leaves or dispose of them

2) Use the bagging attachment for your mower: compost the leaf/grass mix or dispose of

3) Mulch the leaves with a mower (i.e. chop them into small pieces so they will fall into the canopy). This is my preferred option because the nutrients and organic matter will benefit the lawn and soil. Some leaf types have been shown to reduce weed seed germination when mulched into a lawn canopy (maples, others). The leaves of some particular tree species (legumes like honey locust, others) might actually add a significant amount of nitrogen to lawns because these species fix nitrogen from the atmosphere just like soybeans, so higher leaf nitrogen contents in these leaves is possible. Additional resources for these two concepts are here:

tree leaves and weeds.pdf

N content tree leaves.pdf


Tuesday, November 5, 2013

Take a Survey and Win an iPad Mini





K. Zuzek, UMN Extension





University of Minnesota Extension is looking for feedback from gardeners, horticultural professionals, and other members of the public to help direct future tree and shrub educational programming. Don't delay. Tell your friends. By taking a short 10-15 minute survey, you will be entered into a drawing to win an iPad mini. Find the survey here.

Thanks you for your help in planning future Extension educational programs! If you have questions regarding this survey, please contact: Kathy Zuzek, Extension Educator - Woody Ornamentals, University of Minnesota Extension at (952) 237-0229.


Sunday, November 3, 2013

November 1st Issue of Yard and Garden News

In this issue:

Fruit Flies Common Now

There is Still Time to Dormant Seed Your Lawn

Prevent Snow Molds on Lawns Now

Plant Video Library 2013 cont.


Tall Verbena

Big Bluestem

Characteristics of Big Bluestem

Identifying Big Bluestem

Little Bluestem


Fall Color Up Close


Fall Color up Close

Karl Foord - Extension Educator, Horticulture

The fall leaf color spectacular is alive and well this year, due to a warm fall and clear sunny skies.

I was curious about the variation in colors coming from one tree. The tree in question is Autumn Blaze Maple (Acer x freemanii) 'Jeffersred'. The variation in color is due to where the leaf was located on the tree and how exposed the leaf was to light. Bright light permits the leaf to produce significant amounts of sugars which are needed for anthocyanin (red pigment) production. Thus more light more red color. Another contributor to the color palate are carotenoid pigments providing orange and yellow. The various combinations give the leaves their variation in color.

Consider the following photos and see how many different colors exist in these fall leaves.



Karl Foord

Photo 1: Autumn Blaze Maple (Acer x freemanii 'Jeffersred')



Karl Foord

Photo 2: Autumn Blaze Maple (Acer x freemanii 'Jeffersred')



Karl Foord

Photo 3: Autumn Blaze Maple (Acer x freemanii 'Jeffersred')



Karl Foord

Photo 4: Autumn Blaze Maple (Acer x freemanii 'Jeffersred')



Karl Foord

Photo 5: Autumn Blaze Maple (Acer x freemanii 'Jeffersred')



Karl Foord

Photo 6:Autumn Blaze Maple (Acer x freemanii 'Jeffersred')

The next surprise was the beauty of the underside of the leaves not only in terms of color and color contrast, but also because of the architecture of the leaf veins. Consider these photos and the colors we don't see on the upper surface of the leaves.

Enjoy the color of this fall. Because the weather has such a strong effect on leaf color we cannot expect to see the same colors next year.


Karl Foord

Photo 7:Autumn Blaze Maple (Acer x freemanii 'Jeffersred')



Karl Foord

Photo 8:Autumn Blaze Maple (Acer x freemanii 'Jeffersred')



Karl Foord

Photo 9:Autumn Blaze Maple (Acer x freemanii 'Jeffersred')



Karl Foord

Photo 10:Autumn Blaze Maple (Acer x freemanii 'Jeffersred')



Karl Foord

Photo 11:Autumn Blaze Maple (Acer x freemanii 'Jeffersred')



Karl Foord

Photo 12:Autumn Blaze Maple (Acer x freemanii 'Jeffersred')

Prevent Snow Mold on Lawns Now

Editors note:

This is a link to an article that Michelle Grabowski wrote three years ago. This is an excellent article and is as relevant this November as it was that past November.

Prevent Snow Mold on Lawns Now

Friday, November 1, 2013

There's Still Time to Dormant Seed Your Lawn

For over a month now I've been receiving questions that go something like this, "I know I missed the best time for seeding my lawn which is mid-August to mid-September. Can I still seed even though it's October and temperatures have been mild?" My response is always the same, "Just wait, dormant seeding in November will be your best option." It is very true that if temperatures are warm during the month of October, you could get some seed to establish prior to winter, but temperatures are unpredictable and could change drastically within a day.

IMG_0441.JPG
Photo 1: Tired of your lawn looking like this every spring. Consider dormant seeding this fall to improve your spring lawn quality.Sam Bauer.

So, what do/did you risk by seeding in October? Well nothing really, except the cost of seed. Chances are that a good majority of this seed will germinate prior to winter, and complete loss of seedlings is possible over the cold winter months. Because of this, your time and money are better spent waiting for the appropriate dormant seeding time which is generally mid- to end-November.

Dormant seeding can be conducted with any turfgrass species. This practice involves seeding when temperatures are too low for the seed to germinate prior to winter. Germination prior to winter is bad and seedlings will generally die if they haven't matured. Sometimes it is a bit of a waiting game at this time of year. The trick is to find the time when soils are unfrozen so that seed can be worked in slightly, yet air temperatures must be cold enough so the seed won't germinate. Wait for high daytime temperatures of 35-40 degrees before seeding. You still should be waiting at least two weeks to seed based on the long range forecast for the Twin Cities. Regions of northern Minnesota will be able to seed much sooner, possibly even next week.

Is there an advantage to dormant seeding versus spring seeding? Yes and no. A dormant seeded lawn could mature as much as one month faster in the spring than a spring seeded lawn. This is because some of the germination process actually starts prior to winter in a dormant seed situation, although the shoots still haven't emerged from the seed. When temperatures are adequate in the spring, complete germination occurs. In this case the seed actually dictates when temperatures are warm enough to grow. Just like late-fall, temperatures and weather patterns can be unpredictable in the spring. For this reason, the best timing for spring seeding is difficult to predict, which can delay the timing to actually sow seed. Still, there some negative aspects of dormant seeding to consider. First, because of the spring temperature fluctuations, it is possible to have good seedling establishment initially, but a cold spell during this time will injure these seedlings. Also, there is a greater potential for seed loss over the winter due to erosion and water movement, predation, and decay. These positive and negative aspects should always be considered during this process.

Bob Mugaas wrote a fantastic article in the November 2009 issue of Yard and Garden News. Please visit this article by clicking the link for more detail on the dormant seeding process: Dormant Seeding Lawns

For turfgrass seeding options, have a look at the University of Minnesota Turfgrass Science Page

Wednesday, October 30, 2013

Fruit flies common now

Jeffrey Hahn, Extension Entomologist



Jeff Hahn, University of Minnesota

Photo 1: Look for red eyes when identifying fruit flies, although the color dulls after they die.

Fruit flies are common problems during the fall. They are associated with a variety of fermenting, moist, relatively undisturbed organic material, such as overripe fruits and vegetables.

Most fruit flies have red eyes which help to identify them. They also have a brownish body and a dark colored abdomen. There are other small-sized flies, such as fungus gnats, moth flies, and humpbacked flies, that can be confused with fruit flies. The control varies with the type of fly that is found so it is very important to correctly the insect you are seeing.

The best control of fruit flies is to find the source of the infestation and remove it. This often takes detective work to locate the problem as many times it is not obvious. It is tempting to just spray or kill the adults that are seen. However, as long as a food sources remains, it is very difficult, if not impossible, to get ahead of the problem and eliminate all of the flies.

For more information, see Fruit Flies.

Wednesday, October 2, 2013

October 1st Issue of Yard and Garden News

In this issue:



The video Cicada Killer Wasps has been removed at the request of the presenter. I apologize for any inconvenience.

Impatiens Downy Mildew - Part I: The Disease

Impatiens Downy Mildew - Part II: Management

Plant Video Library 2014 cont.


the video on American Bittersweet has been removed for editing. I apologize for any inconvenience.

Pale Purple Coneflower

Trumpet Vine

Mexican Sunflower

Bugbane or Black Snakeroot

Nodding Wild Onion

Great Blue Lobelia

Flowering Spurge

Pachysandra procumbens

Revised videos from the last issue of Yard and Garden News

Tall Boneset revised

Jewelweed revised


Editors note:
Photos of flowers were added to the above videos posted in the September 15 issue of Y&G News. Thumbnail photos of the other videos have also been added to this issue.


Impatiens Downy Mildew - Part II: Management

In a followup to Part I on Impatiens Downy Mildew, Extension Educator Michelle Grabowski discusses management of the disease.


Michelle Grabowski

Photo 1: Sporangia of the pathogen Plasmopara obducens that causes impatiens downy mildew

Impatiens Downy Mildew Part II: Management

Impatiens Downy Mildew - Part I: The Disease



In this highly informative video, Extension Educator Michelle Grabowski explains the symptoms of this disease and how to identify it.






Michelle Grabowski


Photo 1: Early stages of the disease Impatiens Downy Mildew (Plasmopara obducens)











Michelle Grabowski


Photo 2: Sporangia of Plasmopara obducens found on the underside of the leaf of an impatiens plant carrying the disease Impatiens Downy Mildew







Impatiens Downy Mildew

Plant Video Library 2014 cont.

Karl Foord - Extension Educator, Horticulture
Click on the link to see the video with host Dr. Mary Meyer, Professor of Horticulture


Karl Foord

Photo 2: Purple Coneflower (Echinacea purpurea) on left and Pale Purple Coneflower (Echinacea pallida on right



Karl Foord

Photo 3: Trumpet Vine (Campsis radicans



Karl Foord

Photo 4: Mexican Sunflower (Tithonia rotundifolia



Karl Foord

Photo 5: Bugbane (Actaea racemosa



Karl Foord

Photo 6: Nodding Wild Onion (Allium cernuum



Karl Foord

Photo 7: Great Blue Lobelia (Lobelia siphilitica



Karl Foord

Photo 8: Flowering Spurge (Euphorbia corollata



Karl Foord

Photo 9: Allegheny Spurge (Pachysandra procumbens



Pale Purple Coneflower

Trumpet Vine

Mexican Sunflower

Bugbane or Black Snakeroot

Nodding Wild Onion

Great Blue Lobelia

Flowering Spurge

Pachysandra procumbens


Monday, September 16, 2013

September 16 Issue of Yard & Garden News

In this issue:


Plant Video Library 2014

Royal Catchfly (Silene regia)

Wild Petunia (Ruellia humilis)

Wild Bergamot (Monarda fistulosa)

Tall Boneset (Eupatorium altissimum)

Jewelweed / Touch-me-not (Impatiens capensis)



Beauty is the Beast

Rust fungi infect fall blooming perennials


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 (Ruellia 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 (Ruellia 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




Thursday, September 12, 2013

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.

Tuesday, September 3, 2013

September 3 2013 Issue of Yard and Garden News

In this issue:


Flower Video Library for 2013 - Sun Plants IV

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)


Flower Video Library for 2013 - Sun Plants III

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)



Watch out for Yellowjackets!


Cicadas are common now


Extension Publications - New and Revised


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)


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