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EAB is confirmed in Dakota County

Jeffrey Hahn, Extension Entomologist

(The following information is taken from a December 23, 2014 newsletter from the Minnesota Department of Agriculture)


Jeff Hahn, Univ. of MN Extension
Photo 1: Ash trees marked for removal due to EAB.

The Minnesota Department of Agriculture (MDA) confirmed an emerald ash borer (EAB) infestation in Dakota County. EAB was found in an ash tree in Lebanon Hills Regional Park in the city of Eagan, just north of the border with Apple Valley. The infested tree was detected through a routine visual survey of ash trees currently being conducted by the MDA. This survey is designed to find EAB in counties bordering the Ramsey and Hennepin County quarantine area.

Dakota County becomes the sixth county in Minnesota to confirm EAB. Additionally, EAB has also been found in Hennepin, Ramsey, Houston, Winona, and Olmsted (which was just confirmed this August) counties. These counties all have a state and federal quarantine established. The quarantine is in place…

Spotted lanternfly is now in U.S.

Jeffrey Hahn, Extension Entomologist

A new invasive insect species from Asia, the spotted lanternfly, Lycorma delicatula, was discovered last month in Pennsylvania. Despite its name, this insect is not a true fly but is actually a type of planthopper which is related to aphids, leafhoppers, cicadas and similar insects. 


Lawrence Barringer, Pennsylvania Dept of Agriculture
Photo 1: Spotted Lanternfly. Note spots on most of the wing and the lacey pattern on the wing tips.

A spotted lanternfly is a large insect, measuring about one and a half inches long. It is very distinctly colored and patterned. About 2/3 of the forewing is a light gray with small oval, black spots. The wing tips have a series of tiny rectangular black spots that give it a lacey appearance. The hind wings, when exposed, are brightly colored orange-red, black and white.

There are some native insects that could be confused with a spotted lanternfly, especially tiger moths and underwing moths which also can ha…

Mode of action of Neonicotinoids

Karl Foord, Extension Educator - Horticulture


Photo 1: Paired nerves

Photo 2: Neural synapse Insecticides

Insecticides can be characterized by the way in which they disrupt important biochemical functions. Many insecticides target the nervous system of insects by impairing the control of neural transmission. This can be done by disabling the system, and shutting it down. However, the majority of neural insecticides put the system in a continual state of ON giving the organism no opportunity to stop neural transmission. This results in uncontrolled and uninterrupted nerve firing. The insect that is exposed to such chemicals exhibits tremors, hyperactivity and convulsions. Sublethal doses of these chemicals can impair proper functioning behaviors such as flight orientation, and feeding while greater doses lead to a quicker death.

Normal neural transmission

A normal neural transmission proceeds down the nerve axon which splits into branches and eventually into smaller branches called dend…

Pine Wilt

USDA Forest Service
Photo 1: Scots pine killed by pine wilt
Dan Miller, MN Landscape Arboretum

Two mature Scots pines (Pinus sylvestris) at the Minnesota Landscape Arboretum started showing tan-colored needles at the end of the summer this year and by late September both trees were dead. When one of the trees was being removed, Assistant Gardener Mike Walters noticed a blue stain in the sapwood of the tree and from his previous experience with a tree care company in southeastern Iowa; he suspected the tree had been killed by nematodes. Cross-sections of the blue-stained wood were soaked in water and nematodes, microscopic roundworms, could be observed with a dissecting microscope. A sample was then sent to the University of Minnesota Plant Disease Clinic and they confirmed the presence of the pine wood nematode (Bursaphelenchus xylophilus). This nematode is the primary cause of pine wilt disease.


Dan Miller, MN Landscape Arboretum
Photo 2: Cross section of a Scots pine infected w…

November 3rd 2014 Issue of Yard and Garden News

The BEST Crabapples for Minnesota: Part III- Table & References

Mary H. Meyer, extension horticulturist and professor, University of Minnesota


Mary Meyer
Table 1: BEST Crabapples for Minnesota
References and Further Reading:

Beckerman, J., J. Chatfield, and E. Draper. 2009. A 33-year Evaluation of Resistance and Pathogenicity in the Apple Scab-crabapples Pathosystem. HortSci. 44(3):599-608.

Chatfield, J. A. E. A. Draper, and B. Cubberley. 2010. Why Plant Evaluations Matter. American Nurseryman 210(9):10-15.

Draper, E. K., J. A. Chatfield, and K. D. Cochran. 2005. Marvelous Malus--Ten Crabapples Worthy to Know, Show, and Grow. Brooklyn Botanic Garden. Accessed October 6, 2014.

Green, T. L. 1995. Results of the national crabapple evaluation program. Accessed online October 3, 2014.

Green, T.L. 1996. Crabapples--When you're choosing one of those apple cousins, make flowers your last consideration. Amer. Horticult. 75:18-23.

Guthery, D.E. and E.R. Hasselkus. 1992. Jewels of the landscape. Amer. Nurseryman 175(1):28-41.
Iles, J. 2009. Crabapples.…

The BEST Crabapples for Minnesota: Height, Fruit, Scab Resistance and Finally: Flowers - Part II

Mary H. Meyer, extension horticulturist and professor, University of Minnesota


Mary Meyer
Photo 1: Adirondack close-up
Mary Meyer Photo 2: Adirondack - whole tree
Mary Meyer Photo 3: Beverly close-up
Mary Meyerd Photo 4: Beverly - Whole tree
Mary Meyer Photo 5: Bob White close-up
Mary Meyer Photo 6: Bob White - whole tree
Mary Meyer Photo 7: Donald Wyman - whole tree
Mary Meyer Photo 8: Firebird close-up
Mary Meyer Photo 9: Firebird - whole tree
Mary Meyer Photo 10: Louisa close-up
Mary Meyer Photo 11: Louisa - whole tree
Mary Meyer Photo 12: Pink Spires close-up
Mary Meyer Photo 13: Pink Spires - whole tree Which one would I plant in my yard? Anyone from this list, but something in the name 'Professor Sprenger' does resonate with me! It is a lovely tree that greets visitors on the Snyder Terrace at the Arboretum. Others you can see easily at the Arboretum are: 'Donald Wyman' planted in mass in the first parking lot bay across from the Oswald Visitor Center; 'A…

The BEST Crabapples for Minnesota: Height, Fruit, Scab Resistance and Finally: Flowers - Part I

Mary Meyer
Photo 1: Prairie Maid close-up
Mary Meyer Photo 2: Prairie Maid - whole tree
Mary Meyer
Photo 3: PrairiFire close-up
Mary Meyer Photo 4: PrairiFire - Whole tree (left) Sargentii espalier (right)
Mary Meyer
Photo 5: Professor Sprenger close-up
Mary Meyer
Photo 6: Professor Sprenger - whole tree
Mary Meyer
Photo 7: Red Jewel close-up
Mary Meyer
Photo 8: Red Jewel - whole tree
Mary Meyer
Photo 9: Royal Raindrops close-up
Mary Meyer
Photo 10: Royal Raindrops - whole tree
Mary Meyer
Photo 11: Sargentii close-up
Mary Meyer
Photo 12: Sugar Tyme close-up
Mary Meyer
Photo 13: Sugar Tyme - whole tree Mary H. Meyer, extension horticulturist and professor, University of Minnesota

This summer I was asked so many times "What is wrong with my crabapple?" that I started LOOKING anew at crabapples. 2014 was a banner year for apple scab, discoloring the foliage and causing premature leaf and even fruit drop. Affected plants looked dormant, or as many homeowners feared, d…

Millipedes in vegetables

Jeffrey Hahn, Extension Entomologist


Jerry Wenzel
Photo 1: Despite the circumstantial evidence, the millipedes did not damage this carrot; they are taking advantage of previous damage.

A couple of home gardeners encountered millipedes in some of their vegetables during October. In one case they were in a few potatoes, in another instance they were infesting a carrot. There was concern whether the millipedes were attacking healthy vegetables. Fortunately, the millipedes were not causing damage in the garden. They have weak mouthparts and are only capable of feeding on decaying organic matter. It is possible for them to feed on plants that have already been damaged but they are not attacking healthy plants.

A 2012 research article in the Journal of Applied Entomology looked at the potential of millipedes and wireworms to attack carrots (also sweet potatoes). They found the presence of the millipedes was associated with wireworm damage to carrots. The millipedes themselves were no…

Don't worry about snowfleas

Jeffrey Hahn, Extension Entomologist


Diane Peterson
Photo 1: These strange black lines are composed of large numbers of snowfleas

A couple of homeowners discovered an odd situation in their lawns during mid to late October. From a distance, they could see long, black lines in the grass. Upon closer inspection, they discovered that the black lines were actually due to many tiny insects. Examining the insects under magnification revealed that they were snowfleas, a type of springtail.

Springtails get their name because of their ability to jump. They feed on decaying organic matter as well as fungi, pollen, and algae. They are very abundant insects but because of their small size and that they are usually found in leaf litter, soil, and other generally hidden places, people do not usually notice them. Until, that is, they occur in large numbers.


Jeff Hahn, Univ. of Minnesota Extension
Photo 2: Snowfleas are most commonly seen on top of snow.

Snowfleas are particularly interesting b…

WCCO "Smart Gardens" Radio Show - October 18 & 25, 2014

Thanks for listening!

We aren't always able to answer everyone's texted questions on the air, so we try to post a few along with answers here in the Yard & Garden News blog. Remember that you can always visit the U of M Extension Garden website for loads of gardening resources. And feel free to share your gardening stories here by clicking on "Leave a comment" above.
Hope you join us and our host Denny Long every Saturday, 8-9am, on WCCO Smart Gardens and happy gardening!

American Bittersweet 'Autumn Revolution': Thanks to to listeners last week who shared via text the bittersweet cultivar 'Autumn Revolution' (Celastrus scandens 'Bailumn') developed by Bailey Nurseries, Newport, MN. This bittersweet has 'perfect' flowers - male and female parts on each flower - unlike the species bittersweet which has separate male and female flowered plants.

Overwintering perennials in containers: Perennials are best overwintered planted in the soi…

Turf and Bees: What's the buzz on pesticides in lawns?

By Ian Lane, Graduate Research Assistant

If you have been paying attention to the news lately, you know that bees have been making headlines. News outlets have done an amazing job of helping scientists sound the alarm on unsettling declines in bee pollinators. While we have good evidence for declines in honey bees and some of their cousins, the bumble bees, the cause of this decline is hard to pinpoint. Current thinking in the scientific community puts the decline down to a number of interacting factors, including reduction in stable food sources, introduction of bee diseases, and the irresponsible use of insecticides. While it's difficult to tease apart how these factors interact, we do have some good knowledge about how lawns fit into this theoretical framework.


Sam Bauer
Photo 1: White clover and dandelion can provide great early season forage for pollinators in lawns


Herbicides
Lawns are home to a number of weeds that are the bane of homeowners. While our gut reaction may be …

Forest Pest Workshops Scheduled in SE Minnesota

Jeffrey Hahn, Extension Entomologist

Rochester will host two workshops in response to the recent discovery of emerald ash borer (EAB) in Olmsted County. The first will be a Forest Pest First Detector workshop to be held on Wednesday, November 5th from 9 AM - 3:30 PM. The cost is $40 (lunch included). In addition to EAB, other pests to be discussed include gypsy moth, Asian longhorned beetle, thousand canker disease, and Oriental bittersweet.



Jeff Hahn, Univ. of Minnesota Extension
Photo 1: Learn about emerald ash borer and other forest pests at a First Detector workshop.

The Minnesota Forest Pest First Detectors training program is designed to help identify the occurrence of Emerald Ash Borer and other forest pests in Minnesota. First Detectors are the front line of defense against likely infestations. Meeting, working with and educating the public about exotic forest pests are key activities of Forest Pest First Detectors.

Everyone is welcome to attend - even if you do not wish to…

Ground nesting BEES Colletes Part I: Building a nest

Karl Foord, Extension Educator - Horticulture

One of our early emerging vernal native bees is in the genus Colletes. These bees are commonly called plasterer bees, cellophane, or polyester bees. This is because the bee builds an underground nest and then paints/applies/lines her nest with a cellophane-like plastic material secreted from an abdominal gland. The bee applies this material with her two-lobe tipped tongue. This secretion helps protect the developing bees from fungal disease and acts as a waterproof barrier. It is so effective that ground-nesting species can occupy areas prone to flooding.

I photographed a Colletes bee digging a nest. The nest took several hours to dig which I videoed and then cut out much of the inactivity to create a 5 minute video.

One of today's landscaping rules-of-thumb is to cover bare soil with mulch to both prevent erosion and discourage weed encroachment. This makes sense, however should we reconsider this practice in light of our need to pro…

Late Fall Vegetable Gardening - Pest Management

Cindy Tong, UMN Extension Specialist


UMN Dept. of Entomology
Photo 1: Adult Colorado Potato Beetle

Take care of those pests, or they might just come back next year! Two of the recurring pests common to most gardens are weeds, weeds, weeds and Colorado potato beetles. Weeds are plants that have evolved successful strategies for competing against other plants, like developing spreading rhizomes (think Creeping Charlie) or lots and lots and lots and lots of small seeds (amaranth). If your garden has weeds that are blooming or forming seeds, it's worthwhile to take them out even now. Otherwise, those lots and lots and lots and lots of seeds will drop to the ground and stay in the soil, making up a big part of the seedbank, from which future generations of weeds will grow.

Colorado potato beetle adults may still be laying eggs, even if your potato plants are going to be dug up soon. Even if there soon won't be anything for those beetles or their young to eat, it's still worthwhi…

Don't Confuse Yellowjackets and Bees

Jeffrey Hahn, Extension Entomologist



Jeff Hahn, Univ of MN Extension
Photo 1: Yellowjackets are black and yellow with few hairs and construct nests made of a papery material.

As the summer winds down, people have been commonly finding insects nesting in and around their homes. There can be confusion whether people are seeing yellowjackets or honey bees. There is tendency for people to call all stinging insects "bees". This has been compounded with the recent attention in the media on honey bees so people are thinking about them even more. While yellowjackets and honey bees both can sting, they have very different biologies. At this time of the year, people are most often seeing yellowjackets.



Jeff Hahn, Univ of MN Extension
Photo 2: Honey bees are brown and black and hairy. Don't confuse them with yellowjackets.

A yellowjacket is about ½ inch long (this can vary some), black and yellow, and relatively slender with few hairs. A baldfaced hornet, actually a kind of y…

Butterflies in slow motion flight

Karl Foord, Extension Educator - Horticulture

I recently took a class on bee identification at the Southwest Research Station of the Museum of Natural History in the Chiricahua Mountains three hours west of Tucson, Arizona.
While traveling to one of the bee collection sites we passed a large puddle along the road. Two days previously a heavy downpour had soaked the countryside and this puddle downstream from an open cattle range provided the butterflies with water, sodium, and perhaps other needed nutrients.

I have always wondered about the flight of butterflies. Their flight often seems quite erratic. I understand this to be part of a strategy to avoid predators. Is their flight actually as erratic as it appears to us?

I returned to the puddle the following day and was happy to see that it was not completely dry. I was able to slow down their flight with a high speed camera capturing 3500 frames per second. If 30 frames per second is what we consider to be normal then this slows dow…

WCCO Radio "Smart Gardens" Q&A - September 13, 2014

Thanks for listening!

We aren't always able to answer everyone's texted questions on the air, so we try to post a few along with answers here in the Yard & Garden News blog. Remember that you can always visit the U of M Extension Garden website for loads of gardening resources.

Hope you join us and our host Denny Long every Saturday, 8-9am, on WCCO Smart Gardens and happy gardening!

Question: Paver stone patio on north side of house has mold / moss in between stones. How do I get rid of this?

Answer: You can use a sharp tool to scrape / dig out moss and fill in spaces with builders' sand. You can plant low-growing, creeping plants like creeping thyme or wooly time in the spaces.
Mold can be removed with a bleach / water solution and a wire brush. Be careful not to get bleach on the plants nearby, your clothing or patio furniture.

Question: I just planted a 2" Autumn Blaze maple. What are you recommendations for watering?

Answer: Here is an excerpt from the U of M Ext…

Just Wait Out Foreign Grain Beetles

Jeffrey Hahn, Extension Educator



Jeff Hahn, Univ. of MN Extension
Photo 1: Don't confuse tiny foreign grain beetles for flies or fleas

Very small, brownish beetles are being found in some buildings, especially homes that have been recently constructed. Proper identification is critical as these beetles may be confused for other insects, such as fruit flies, drain flies, or fleas. A foreign grain beetle is about 1/12th inch long and reddish brown with a flattened body.

Foreign grain beetles can also fly which is why they might be confused for small-sized flies. However, foreign grain beetles have a generally harder body compared to the softer bodied flies. Fleas also have a relatively hard body but are fattened instead from to side to side; fleas are also wingless and can't fly.

The favorite food of foreign grain beetles is fungi and so they are typically found in relatively damp areas. They are often associated with new construction because the moisture in wall voids when…

WCCO Radio "Smart Gardens" Q&A - September 6, 2014

Thanks for listening!

We aren't always able to answer everyone's texted questions on the air, so we try to post a few along with answers here in the Yard & Garden News blog. Remember that you can always visit the U of M Extension Garden website for loads of gardening resources.

Hope you join us and our host Denny Long every Saturday, 8-9am, on WCCO Smart Gardens and happy gardening!

Question: It looks like my Black-Eyed Susans have powdery mildew. Will they be OK next year and what can I do?

Answer: Powdery mildew is a common fungus in Minnesota landscapes that results in a white powdery covering over leaves. Usually damage is cosmetic and the plant recovers fine the next year. The best means of managing this pest is to (1) select resistant plants, (2) space plants properly to ensure air circulation, (3) water at the base of the plant (vs. overhead watering) to minimize splashing spores onto leaves, and (4) clear away infected plant material. Fungicides are available, but us…