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Extension > Yard and Garden News > April 2017

Thursday, April 27, 2017

Watch for eastern tent caterpillars

Jeffrey Hahn, Extension Entomologist

This is the time of the year that eastern tent caterpillars are active. The first sign people notice are silken tents in the forks of branches, particularly in fruit trees, including apple, chokecherry, crabapple, plum, and cherry. These tents are be small at first but will increase in size and can eventually become quite conspicuous. Eastern tent caterpillars feed on tree leaves during the day and will remain in their tents at night and during rainy weather.
Eastern tent caterpillars and tent.  Photo: David Paulson


Eastern tent caterpillars are bluish black with yellow and a white stripe running down the top of its body. They are mostly smooth but do have a series of hairs sticking out along the sides of their bodies. They are two inches long when fully grown.

Healthy, well-established trees can tolerate eastern tent caterpillar feeding. Their feeding, as well as the presence of their webs, is primarily 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.

A great method to deal with eastern tent caterpillars without using pesticides is to wait until they have retreated into their tents at the end of the day or on a rainy day and then pull out the webbing, along with the caterpillars. Then bury or bag them to properly dispose of them (you could burn them if it is permitted where you live).

If it is a consideration to treat these caterpillars make sure they are reasonably small, usually one inch or less. As they approach full grown size (two inches), the closer they are to finishing their feeding, making it less worthwhile to treat them.

There are a variety of residual insecticides that are effective against caterpillars. Consider using a product that has a low impact on the environment, such as Bacillus thuringiensis, spinosad, or insecticidal soap. Bacillus thuringiensis is a particularly good product if the tree is flowering since it will not harm visiting honey bees and other pollinators. If you use insecticidal soap, the product needs to directly contact the insects. There is no residual activity so you may need to repeat the treatment.



Monday, April 10, 2017

Video: The ragdoll method for starting seeds and testing viability

By Julie Weisenhorn, Extension Educator

Sometimes we discover seeds that we've saved and wonder if they are still viable (will germinate). The ragdoll method of creating a damp seed packet that will prompt germination is an inexpensive and easy way to test seed viability. It is also a good way to start warm season plants like tomatoes, peppers, etc. In this video, I'll demonstrate how to make a ragdoll for Pride of Wisconsin muskmelon. You'll need a sheet of damp paper towel, a sealable plastic quart bag, seeds or your choice and a marking pen. Watch the video.



Pepper seeds 8 days later: The first root has emerged from some of the seeds. Just gently remove and plant in potting soil. Place in a warm sunny window or under grow lights. Keep the soil moist (not wet). It should feel like a damp sponge when you touch it. These pepper plants should be large enough to plant in a large pot or a sunny garden location by end of May / early June.

New publication from the U of MN Bee Squad on befriending bumble bees

Reprinted from Extension In the News, a weekly email digest highlighting Extension coverage in news media, University of Minnesota publications and other channels. For more coverage, see In The News.

University of Minnesota Extension has published Befriending Bumble Bees: A practical guide to raising local bumble bees. The guide provides the step-by-step information needed to find, capture, house, and feed the next generation of bumble bees. Read more ...

Monday, April 3, 2017

What is Roundup for Lawns?

Recently, we’ve received several questions regarding a new product offering from The Scott’s Company called “Roundup for Lawns.”  There are several versions of this product, including both Northern and Southern grass options.  The Northern grass product, for use on Minnesota lawns, states that the product “kills weeds, not the lawn.”  Most of us are familiar with the original version of Roundup, which contains the active ingredient glyphosate, and we know that glyphosate is a non-selective vegetation killer- meaning that it kills most plants that it is sprayed on.  So, how does Roundup for Lawns not kill the entire lawn? 

The answer is simple; this product isn’t Roundup.  In this case, Scott’s is taking the liberty of using a widely known name of one of the most effective herbicides, and putting something else in the bottle.  So, what exactly is Roundup for Lawns?  The Northern version of Roundup for lawns contains the very well-known synthetic auxin herbicides MCPA and dicamba, as well as quinclorac and sulfentrazone.  You will find some of these same active ingredients in other products because they are so common.  For example, Ortho Weed B Gon Plus Crabgrass Control contains both quinclorac and dicamba, as well as 2,4-D; in this product, dicamba and 2,4-D are the broadleaf weed control products, and quinclorac provides the post-emergent control of crabgrass.  Bayer Advance Weed Killer for Lawns contains only the synthetic auxin herbicides and will not control crabgrass.  Additionally, Bonide Weed Beater Plus contains both quinclorac and dicamba, as well as 2,4-D.  Sulfentrazone is added to Roundup for Lawns because of its added benefit of controlling sedges, such as yellow nutsedge, in addition to broadleaf weeds.  And if you’re looking for a product that is very similar to the formulation of Roundup for Lawns, you can find that in the PBI Gordon product called Surge, although this does not contain quinclorac.


Some points to note.  1) if you plan to use Roundup for Lawns on your lawn, be sure you do not mistake this for a bottle of Roundup containing glyphosate, which will kill your lawn; 2) Roundup is an emotional topic for many, but just because this bottle says Roundup, it is not Roundup as we think of it; in fact, the herbicide active ingredients in Roundup for Lawns are regarded as more toxic than glyphosate (see: Toxicity of Pesticides); 3) if you’re looking for a good broad-spectrum post-emergent weed control product, Roundup for Lawns will work fine for you; 4) be sure to follow all label instructions when using this product, including proper personal protective equipment, application strategies, and re-entry intervals.  
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