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Showing posts from May, 2020

Smart Garden 2020: Recognizing Herbicide Damage on Berry Plants

Last week, I was concerned that the new primocane raspberries I just planted may have been damaged by 2,4-D and dicamba herbicides (i.e. Four Speed, Ortho Weed B Gon) that was sprayed on a lawn nearby to kill creeping Charlie. These herbicides are highly susceptible to drifting through the air and damaging (injuring) plants nearby. My grapes were showing injury symptoms, but they are the "canary in the coal mine" so to speak, for dicamba and 2,4-D injury because they are extremely susceptible.

So I went online to find photos of what herbicide injury looks like on raspberries, but did not find anything.

From there, I sent out an email to a network of fruit Extension specialists throughout the Great Lakes region for answers. Several of them provided helpful photos of herbicide injury on berries.

Below are a collection of photos of herbicide damage, primarily on raspberries, with a few on strawberries and blueberry as well. Fruit growers can refer to these photos if herbicide …

Elm sawfly just a curiosity

People across Minnesota have been sighting large, wasp-like insects recently. Fortunately, elm sawflies are harmless but if you have not seen them before, you would certainly be curious about them.
How to identify Elm sawflies are very distinctive in appearance.  They are stout and about 3/4 inch long.  They have a dark colored head and thorax (the middle section behind the head) with orange antennae.

Males have a reddish abdomen while females have a black and cream striped abdomen. However, both sexes have a whitish to yellowish spot on the abdomen near the thorax and they both have smoky colored wings.

You can see elm sawfly adults in May and June. They are associated with different hardwood trees, including willow, poplar, maple and elm, where they lay eggs. They may also be found visiting flowers.

The larvae are big.... Later in the year, the larvae themselves are also a curiosity.  They are the largest sawfly in North America, growing to 1 ½ to 2 inches long. Their body is…

What to do about eastern tent caterpillars

If you have a flowering fruit tree, like apple, chokecherry, crabapple, plum, and cherry, check it for silken tents in the forks of the branches. This is the work of eastern tent caterpillars.

These caterpillars are bluish black with a yellow and white stripe running down the top of their body. They are mostly smooth but do have hairs sticking out along the sides of their bodies. They are two inches long when fully grown.
Are they harmful? Healthy, well-established trees can tolerate eastern tent caterpillar feeding. Their feeding, as well as the presence of their webs, is usually a cosmetic problem, affecting just the trees’ appearance.

However, young trees, as well as unhealthy, stressed trees, are more susceptible to feeding damage and may need to be protected.
Can I manage these caterpillars without a chemical? A great method to deal with eastern tent caterpillars without pesticides is to wait until they have retreated into their tents at the end of the day or when it is rai…

Carpenter ant swarms

Carpenter ants are very common in Minnesota and are frequently found infesting homes and other structures. Like other ants, carpenter ants produce a mating swarm. This is when the reproductives, females and males, emerge from a nest, typically in large numbers. They are also accompanied by some workers. They mate and the females fly off as queens to search for suitable places to start nests.

Different ants swarm at different times of the
year; carpenter swarm in spring. Carpenter ant queens are typically black and large, about ½ inch long, although some carpenter ant species are smaller and can vary in color. Males are always smaller than queens. Regardless what species the carpenter ant is, they all have a one-segmented node between the thorax and abdomen.

Could they be termites?


Some people worry that these winged insects could be termites. Fortunately, termite colonies are very uncommon in Minnesota, only occurring in the southern 1/3 of the state.
Seeing winged term…

Smart Garden 2020: How to avoid stressing transplants

With the warm weather ahead, you're likely feeling excited to get out into your garden and plant all of the seedlings you started indoors. Before doing so, there are a couple of key things to do to set your seedlings up for success.
Condition your seedlings for success If you've been growing your seedlings in a warm window, they've had a pretty good life so far. Chances are, you maintain your home or apartment at a fairly stable temperature, and your plants have been relatively undisturbed. When you move them outside, they will suddenly be exposed to relatively intense temperature fluctuations, strong sunlight, gusting winds, insects, and potentially animals like mice or cats stepping or nibbling on them.  
When plants move from a well-protected indoor environment to your garden or field, they frequently experience "transplant shock". In order to prevent this, plants need to be "hardened off." 
Hardening off is a process of forcing your plants to invest…

Yard to Table 101: Planting warm season vegetables

Hurrah! Here we are in mid-May...and either the last spring frost date has passed where you live, or it's just about to. If you don't know what date that is, check out this interactive map by the Midwestern Regional Climate Center. Or this DNR map of frost dates based on average temperatures.

Once you get over that temperature hurdle, it is time to plant warm season fruits and vegetables in your garden.

Welcome to Part 3 of our "Yard to Table" series of articles that will help you get growing vegetables—even if you’ve never planted seeds before!  

(Look for Part 1 and Part 2 links in "Resources" at the end of this article.)
Is it time to plant warm season veggies?Timing is everything in the vegetable garden. Planting seeds at the right time ensures a bountiful harvest, and northern gardeners should be especially cautious about cold weather. 

Each crop has its own needs, including tolerance of cold temperatures. Take a few minutes and check out this Extension cha…

Smart Garden 2020: A new webpage about cleaning your gardening tools

Gardening tools need to be cleaned and disinfected.

People may forget this - especially this time of year when we are eager to get out into the garden. "My shovel looks clean, so it must be clean," you tell yourself. What you have forgotten is that you last used that shovel in your community garden plot. The soil remnants could be bringing microscopic bacteria or fungi into your home garden. 
Or you are pruning your apple trees. One has had its share of problems. Should you disinfect your pruner when moving from one tree to the next? Definitely yes.

But how to clean and disinfect tools safely and effectively? To help, Extension educators have produced a new webpage called Clean and disinfect gardening tools and containers. It provides background in how plant diseases are transmitted on tools, when to clean them and with what product, and how to do it successfully. We hope you'll take the time to read it and ready your equipment and slow the spread of plant diseases in y…

NEW VIDEO: Garden safely by testing for lead

It's exciting to see so many people starting new gardens this year. Growing food is a great way to get outside, learn something new (every year you learn new things in the garden!), and to feed your family and neighbors.

If you're gardening in a new spot, it's important to make sure you're not gardening in an area with elevated lead levels. Most Minnesota soils do not contain harmful amounts of lead, but it's still a good idea to get a test, especially in urban areas and near old buildings.

This test can be done with the same sample as your basic soil test. Lead is especially toxic to children, who are still developing, and who are more likely to be exposed when playing in the dirt.

Watch the video below to learn:
Where do we often see high lead levels in soil?How much lead is too much?How can you test for lead?What can you do if your soil contains lead?

Due to COVID-19, the UMN soils lab is not taking in-person samples, but you can mail your sample to the clinic.

A…

Clover mites are active now

If you are finding tiny creatures in sunny areas of your home, you may be seeing clover mites. Clover mites are tiny arachnids, relatives of spiders and ticks, and are about the size of a pinhead. They are reddish or brownish in color. If you look closely, you will notice that the first pair of their eight legs is particularly long and conspicuous.
Why are they here? During summer, clover mites feed on grass and clover. Fortunately, they are not pests on these plants and are rarely noticed. You might see them around homes in the fall but they are more commonly found the following April and May.

They can congregate on the outside of buildings in large numbers and have no problem getting inside because of their small size, especially around windows.

 They love being in the sun and are most common on the south sides of homes. Fortunately, clover mites do not harm people or our property.
How to remove them You can physically remove small numbers of clover mites, e.g. with a vac…

Purple Tansy: Pollinator power player & Cover crop

When I was an undergraduate, I studied abroad for six months in Stuttgart, Germany. While there at the University of Hohenheim, my friends and I would explore the Swabian countryside any chance we could get.  I was struck by a sea of purple created by what's commonly called "purple tansy" or phaceliain a once harvested cabbage field.

This flowering cover crop buzzed with buff tailed bumblebees (Bombus terrestris). These creatures were all trying to get the last bit of energy before winter arrived, and the plant happily obliged. Apt, since the German name for this plant was “bienenfreund”, or “bee’s friend” in English.

I knew it as lacy phacelia (Phacelia tanacetifolia). Despite the Germanic nickname “bienenfreund,” phacelia evolved in the dry southwest United States, not in the moist woodlands of Swabia.
What is Phacelia? Also known as purple tansy or scorpion-weed, phacelia is related to borage (Borago officinalis), this annual is known for its long bloom time of 6 to …

Ask Extension: Can I get rid of Creeping Charlie without using chemicals?

Q:What's the best way to kill Creeping Charlie in large yards without using harmful chemicals? My concern is the health of my children, and my well and septic system. We have this over a large portion of our lawn.A: First, a few facts about Creeping Charlie: 
Creeping Charlie (Glechoma hederacea) is a perennial lawn and garden weed that spreads via stolons ("runners") forming a mat, and will regrow from pieces of the plant left in the soil after digging or pulling it.Creeping Charlie is highly adaptable, and grows in full sun to full shade, in compacted soil and well-drained soil, and therefore difficult to eradicate once established. Ways to manage Creeping CharlieSmall areas of Creeping Charlie can be dug up, but large areas require sod cutting, solarization, broadleaf herbicide treatment or a combination of two or more of these. 
Longer-term management strategies:Choose grass seed that is high quality and a blend of species that will grow well in your site conditions. O…

What you need to know about invasive giant hornets

Note: While there is not an official common name for the subject of this article, this insect is commonly called Asian giant hornet. However, because names matter and influence people, this article will generally avoid using this name.

You may have heard recent news about “murder hornets” arriving in the U.S. In December 2019, a large hornet was found in Washington State and confirmed to be Vespa mandarinia. A little earlier this hornet was also discovered in two places in British Columbia, including a nest which fortunately was eradicated. The nest is now thought to be the source of the hornets found in Washington.

Why all this concern over one colony of hornets being found in North America? First, this is a very large insect. Vespa mandarinia is the world’s largest hornet, measuring between 1½ to 2 inches in length.

 They also impact honey bees. While these hornets eat many different insects, when they can find them, they prefer to eat honey bees and are capable of destroying …

Smart Garden 2020: What you can do in early May

At last! The weather is turning spring-like in much of the state and we can finally be out in our yards and gardens. It's always exciting to see new and old favorite plants coming up and the leaves opening on trees, shrubs and vines.

I was glad to see bright green buds opening on my new Autumn Revolution bittersweet (Celastrus scandens 'Bailum') a self-pollinating cultivar, and tons of flower buds on the edible Regent Sericeberry (Amelanchier alnifolia 'Regent') and on my Red Splendor crabapple (Malus 'Red Splendor').
To-do-list for May Aside from staring fondly at your spring garden, there are some tasks you can addressing during these early days of May.

Uncover perennials. Push aside the leaves to expose perennials to the sunlight. Keep leaves on the soil surface as a mulch. Mulch holds in soil moisture, moderates soil temperatures reducing stress on roots, and serves as habitat for beneficial insects. If you're a neat-nik or are afraid the plants won…

Ask Extension: We've got Answers for Your Lawn Care Questions!

It happens every year...things start greening up, and you notice everything that's not so great about your lawn--especially compared to the neighbors! Our "Ask Extension" service is getting a lot of lawn questions, too. So we've put together a list of some of them, plus links to UMN Extension's resources to help you tackle these problems.

Just want some general information? See the links at the end of this article. Let's get started!
Q:Because I wanted to limit my exposure to Covid-19, I purchased various stuff for my lawn all at once, but I need to figure out when and and in what order to apply. Can you help me? I have crabgrass preventer, fertilizer, weed & feed, something for grubs, something to control moss, some areas I will want to seed or sod, etc. A: You've got your work cut out for you, that's for sure! The first thing you need to look at is the Minnesota Lawn Care calendar, which tells you what to do and when--(crabgrass preventer, fertili…