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Showing posts from May, 2013

Carpenter ants in spring

Jeffrey Hahn, Asst. Extension Entomologist



Jeff Hahn
Photo 1: Carpenter ant worker. Note the one segmented petiole and the evenly round thorax in profile.

Although carpenter ants can be found in homes anytime during the year, they seem particularly noticeable in the spring as the weather becomes warm. Many people think of carpenter ants as big, black ants. And it is true the most common species here is black and approaches ½ inch in length.However, you can't always go by size and color; there is another carpenter ant species that is red and black and about 3/16th inch long.A more sure method is to look for a one-segmented petiole between the thorax and the abdomen (ants either have a one or two segmented petiole.  Also examine the shape of the thorax (the middle section of the body).In carpenter ants, the thorax is evenly round
in profile while other Minnesota ants have unevenly shaped thoraxes.
Finding carpenter ants inside in the spring can mean that a nest is present there; th…

Eastern tent caterpillars are now out!

Jeffrey Hahn, Asst. Extension Entomologist



Tom Voigt.
Photo 1: Young eastern tent caterpillars constructing their tent after just emerging.

Be on the watch for eastern tent caterpillars.There was a report of these insects at the end of last week in southeast Minnesota and it was reported in the Twin Cities at the beginning of this week.The caterpillars are bluish black with yellow and a white stripe running the length of the top of its body. They are also mostly smooth except for a series of hairs sticking out along the sides of their bodies. They are two inches long when fully grown.
However, the first sign you'll notice are the silken tents they create in the forks of branches. After the caterpillars first hatch, they'll construct this webbing which serves as a shelter they use at night and during rainy weather. The tent will be small at first but will increase in size and can eventually become quite conspicuous.During the day they crawl out of these tents and feed on tree le…

It's Tick Season Now!

Jeffrey Hahn, Asst. Extension Entomologist



Jeff Hahn
Photo 1: American dog tick that was picked after a hike in the woods.

We have endured a long cold spring but now the weather is finally getting warmer so it is enjoyable to be outside again.Finally, we are ready to enjoy our favorite outdoor activities.You definitely want to get outside but with the return of nice weather also come ticks.Take the proper precautions and protect yourself from these pests.
The two most common ticks in Minnesota are American dog ticks (also called wood ticks) and blacklegged ticks (formerly called deer ticks).While American dog ticks are not important vectors of disease in Minnesota, they are nuisances because they bite us (also dogs too!).Blacklegged ticks are
also nuisances but they can be potentially more serious as they transmit diseases, including Lyme disease, anaplasmosis, babesosis, and Powassan encephalitis to people in Minnesota.Of these, Lyme
disease is the most common.
You are most likely goi…

Rabbit Damage Revealed on Trees and Shrubs

M.Grabowski, UMN Extension
Photo 1: Rose bush with extensive rabbit damage

As gardeners inspect their landscapes this spring, many trees and shrubs have been found with extensive rabbit damage. Rabbits are one of the most commonly seen mammals in the urban environment. In Minnesota, our most common rabbit is the Eastern cottontail, Sylvilagus floridans.

Rabbits will spend much of their time eating grasses and other herbs but they will also chew on the bark of trees and shrubs and eat the buds of shrubs in the winter and spring. If left unprotected, rabbits will sometimes eat the bark from around the base of a tree or shrub. This is called "girdling" and can kill the plant.

Read Rabbits and Trees and Shrubs by wildlife expert Jennifer Menken of the Bell Museum to learn more about protecting landscape plants from rabbit damage.

Snow Molds Blight Minnesota Lawns - For Now

M. Grabowski, UMN Extension
Photo 1: Pink and gray snow mold on a Minnesota lawn


Michelle Grabowski, UMN Extension Educator

Persistent cold weather and late snow fall mixed with freezing rain have created ideal conditions for the growth of snow molds this year. Snow molds are caused by fungal pathogens that thrive in cold temperatures (just above freezing to about 60F) and high humidity.



M.Grabowski, UMN Extension
Photo 2: Small round patch of pink snow mold with a light center and dark border

Two types of snow mold are common in Minnesota. Pink snow mold, caused by the fungus Microdochium nivale, results in round dead patches in lawns that can be an inch or two across or as large as a dinner plate. These dead patches are often pale tan in color, matted down and may have a dark brown border. In sunlight pink snow mold patches turn pink to salmon colored as the fungus produces spores of these colors.



M.Grabowski, UMN Extension
Photo 3: Pink matted grass in a pink snow mold patch

Gray …

New Report on Bee Health from USDA and EPA

Jeffrey Hahn, Asst. Extension Entomologist

The following is from a news release that was issued on May 2, 2013

The United States Department of Agriculture (USDA) and the U.S. Environmental Protection Agency (EPA) released a comprehensive report last week on honey bee health. The report states that there are multiple factors playing a role in honey bee colony declines, including parasites and disease, genetics, poor nutrition and pesticide exposure.

In October 2012, a National Stakeholders Conference on Honey Bee Health, led by federal researchers and managers, along with Pennsylvania State University, was convened to synthesize the current state of knowledge regarding the primary factors that scientists believe have the greatest impact on managed bee health.

Key findings include:

Parasites and Disease Present Risks to Honey Bees:

• The parasitic Varroa mite is recognized as the major factor underlying colony loss in the U.S. and other countries. There is widespread resistance to th…

Psyllids Common in Homes this Spring

Jeffrey Hahn, Asst. Extension Entomologist

Strawberry Growers take Note!

Karl Foord - Extension Educator, Horticulture

Removing straw mulch on strawberries using lilac buds as an indicator

Sometimes nature is a better indicator of the best time to take action than our measuring equipment. Researchers Terry Nennich and Dave Wildung attempted to determine the best time to remove the straw mulch on strawberries using growing degree days (GDD) which are a measure of heat accumulation. GDD are often used to predict when a plant might flower, or how developed a pest might be to optimize the timing of control.


Karl Foord
Photo 1: Buds of Common Lilac (Syringa vulgaris)


In this case Terry and Dave found complications that made GDD a less reliable indicator for the timing of mulch removal. Given this they looked for other signs in nature that might be more useful. Their conclusion was that when the lilac buds open, it is time to take off the straw. This correlated well with the end of strawberry dormancy. Timing is critical as a delay in removal was shown to reduc…

Spring Flowering Bulbs

Karl Foord - Extension Educator, Horticulture

The recent snowfall and lower than normal temperatures should not harm the flowers derived from spring flowering bulbs. Low temperatures above 28 F and day temperatures in the 30s and 40s will not harm these cold tolerant frost tolerant plants.

However, if the temperatures drop into the low 20s or high teens, these plants can be injured.

Enjoy these hints of spring.

What a difference a year makes

Karl Foord - Extension Educator, Horticulture



Karl Foord
Photo 1: Autumn Blaze Maple 3 29 2012

Minnesota definitely offers us weather variability. And although we may remember last year's early spring it is often difficult to compare a memory with a memory in the making. To this I offer the following two photographs of buds from the same 'Autumn Blaze' maple tree (Acer freemanii 'Jeffersred'). The picture to the left was taken last year on March 29th. As you can see the samaras with whirligig characteristics permitting the seeds to move away from the parent tree have already started to form.

Contrast this with the picture to the right taken this year on April 30th. The bud is just beginning to break and this picture was taken a month later than the previous. And snow is predicted for tomorrow in many parts of the state. Mercy.



Karl Foord
Photo 2: Autumn Blaze Maple 4 30 2013

Veggies for Your Patio

By Mary Meyer, Extension horticulturist

Almost anyone can grow a few vegetables or herbs in the summer, even if you do not have space or time for a traditional garden. You do need sun, however and a container that can be placed where you can easily water and harvest the plants. The easiest plants to grow are greens, such as lettuce, spinach, swiss chard, pak choy or bok choy and herbs such as basil, chives, thyme and rosemary. Use a container that drains well, holds enough soil so you do not have to water more than once a day in the summer, and will be big enough for the plants you choose.

Here are some ideas: an 8 inch pot holds about 1 gallon and can grow 2-3 lettuce, spinach or Swiss chard plants or 1 herb; a 10 inch pot holds closer to 2 gallons and can grow 2 pepper plants or 1 small tomato plant, such as Tiny Tim, Pixie, Hybrid Patio, all smaller tomato plants that are good for containers. Cherry tomatoes such as Sweet 100 or Sweet Million are large plants and need large container…

Fascinating Fragrances - Three Perspectives

Karl Foord - Extension Educator, Horticulture

If someone hands you a flower, what is the first thing you do? Smell it, of course. How often have you exercised this ingrain behavior only to come up empty?

My colleague and a contributing writer to this blog, Robin Trott sells cut flowers for a living and reports, "I feel cheated when beautiful flowers lack fragrance. I insist on having fragrant flowers in the bouquets I sell. To provide fragrance, we use herbs such as basil, lavender, mint, dill, and cilantro as fillers, and grow stock (Matthiola spp.) fragrant snapdragons (Antirrhinum spp.), Sweet Williams (Dianthus barbatus) and fragrant oriental lilies (Lilium spp.)".




Photo 1: Testing flowers for fragrance


The Human Perspective

Fragrances have been a part of human culture for a long time. The mere presence of flowers has been shown to have positive effects on human emotions, and recent research has shown that fragrant flowers are a "positive emotion inducer".…

Wasp Queens in Homes during Early Spring

Jeffrey Hahn, Asst. Extension Entomologist

Some residents have recently been experiencing problems with wasps in their homes. The first reaction they generally have is that they have an active nest somewhere in their building. However, what people are actually seeing are just queens that have been hibernating since last fall.




Photo 1: Paper wasp queens (there is not a nest present when you see them in the spring.)

The old queen and all the workers die when freezing temperatures arrive in the fall; nothing is left alive in the nests. The only survivors are new queens that are produced at the end of summer. They leave their colonies and look for places to spend the winter. That could be under loose bark, under leaves, in or under logs, or in the cracks and crevices of buildings. Wasp queens usually overwinter individually. However, paper wasp queens tend to overwinter gregariously.

People can rest assured that if they see wasps in their buildings now, even if there are a lot of t…