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Extension > Yard and Garden News > February 2016

Monday, February 29, 2016

EAB verified in Wabasha County

Jeffrey Hahn, Extension Entomologist

(The following information is taken from a February 29, 2016 news release from the Minnesota Department of Agriculture)

The Minnesota Department of Agriculture (MDA) has identified emerald ash borer (EAB) in Wabasha County. MDA staff found EAB larvae in an ash tree in the southeastern corner of the county after being alerted to some suspicious trees by Minnesota Department of Natural Resources (DNR) staff. The trees displayed symptoms of EAB infestation, including bark splits and insect tunneling under the bark.
Emerald ash borer galleries, a symptom
of an infested tree. Photo: Jeff Hahn,
UMN Extension

This is not too surprising as EAB was found earlier this month in Winona County just south of the Wabasha County border. Because this is the first time EAB has been identified in Wabasha County, the county will be placed under emergency quarantine which will limit the movement of firewood and ash material out of the county. Currently 11 Minnesota counties and Park Point in the city of Duluth (St. Louis County) are under quarantine to prevent the spread of the emerald ash borer.

The biggest risk of spreading EAB comes from people unknowingly moving firewood or other ash products harboring larvae. There are three easy steps Minnesotans can take to keep EAB from spreading:

For more information about EAB, see Emerald ash borer in Minnesota. See also the MDA news release, MDA identifies emerald ash borer in Wabasha County.

Japanese Barberry Added to Minnesota's Noxious Weed List

Kathy Zuzek, UMN Extension Educator

Barberry fruit & seed are eaten & dispersed
 by birds.
Photo: K. Zuzek
Japanese barberry (Berberis thunbergii) is native to Japan and Korea and was introduced into the United in the late 1800s.  Although they provide beauty in gardens and landscapes, barberries have become naturalized and invasive in 30 states in the eastern U.S. including Minnesota.  The fruit are an attractive food to birds who disperse seed into native areas.  Barberries establish in the undergrowth of forested areas where they often form thickets and outcompete and displace native plants.  84 incidences of barberries in native ecosystems have been reported in Minnesota.  67 of the 84 reports are from the southeast quadrant of the state.

Early Spring: It's Time to Cut Back Grasses

Mary H. Meyer, Extension Horticulturist and Professor, University of Minnesota

Early spring or late winter is the best time to cut back ornamental or landscape grasses. Their winter appeal is usually low now, stems are likely partially down from numerous snowfalls. Hand cutting, an electric hedge trimmer, or a lawn mower set to the highest setting can be used to clean up the tops of grasses.

All warm season grasses, such as Miscanthus, switchgrass, big and little bluestem, along with prairie dropseed and Indian grass die completely back to dormant buds at the crown of the plant. You cannot cut these grasses off at “too low” a point. Their buds are at the root-shoot junction often buried in the soil. Tie large tops together to make them easier to cut. Cut warm season grasses back as low as your tools can reach. These grasses are slow to green up in the spring, so you have a few weeks to do the cut back.

Larger warm season grasses can be tied together before cutting back making them easier to handle. 

Cool season grasses however such as feather reedgrass (Calamagrostis), blue oat grass, blue fescue, tufted hairgrass (Deschampsia), most Carex, or sedges will start to grow as soon as temperatures warm in the spring. Plant to clean up these grasses as soon as possible, before they start to green up.  Feather reedgrass is so popular now (Is it overplanted?) and actually will grown much better if it is cut back early before any new growth begins to show. Tufted hairgrass is very similar to our lawn grasses and will begin to green up very early so cut back any brown foliage and the old seedheads now. Again, cut as low as you can, leaving 1-3 inches of stubble is fine.  Other cool season grasses that are semi-evergreen, such as blue oat grass, blue fescue and many of the sedges, you may only need to rake the foliage with your hands or with a hedge rake to remove brown foliage, leave any green foliage. With sedges, cut off any brown edges of tattered leaves, leaving green foliage.  

Ribbon grass is the showy white rhizomatous grass that can be invasive, and it one of the easier to control by mowing it off: in early spring as a clean up and again anytime during the year when it begins to look brown and drab. New shoots will be fresh and colorful, and this will help to keep it in bounds.

Mowing ribbon grass keeps it in bounds and is an easy spring clean up. The foreground has been mowed and the background right is about to be mowed. 

A good rule of thumb for grass cut back is: if its brown cut it down. Spring cut back opens up the crown of the plant to rain and sunlight, allowing it to green up faster. Grass tops decompose quickly in the compost pile, if necessary cut the taller stems into half or 1/3 to fit into your pile. 

Crane flies in homes

Jeffrey Hahn, Extension Entomologist

People have been finding “large mosquitoes” in their homes this month. Fortunately, they aren’t actually mosquitoes but a related insect know as a crane fly. Crane flies are common insects in Minnesota. You can recognize them from their slender brown or gray bodies and long, slender legs. Most crane flies range in size from 3/8 to 1 ½ inches long. Entomologists look for a ‘V’ shaped suture on the thorax to help identify crane flies.

Crane flies are common throughout the spring and summer. Outdoors, they are usually
Crane fly found indoors in author's home. 
Photo: Jeff Hahn, UMN Extension
associated with moist, damp environments with a lot of vegetation. Larvae commonly develop in streams or in moist soil, often feeding on organic matter (some aquatic larvae are predaceous). Despite looking like mosquitoes, crane flies do not bite. They usually live for only a few days and typically don’t even feed.

However, they do startle people when they appear indoors in the middle of winter. Where do they come from? In most cases, it is likely that the source of crane flies found indoors can be traced back to houseplants that were outside at some point during the summer. Female crane flies laid eggs in the soil and the larvae finished their development indoors and emerged as adults. There is not any special action that needs to be taken when these harmless insects are found indoors; physical removal is the only necessary control.

Friday, February 26, 2016

Start with Clean Tomato Seed and Transplants

M. Grabowski, UMN Extension Educator
MN Department of Agriculture

In 2015, the Minnesota Department of Agriculture found a bacterial pathogen of tomato responsible for the disease bacterial canker in community gardens and small vegetable farms. Although this tomato disease is common in other states, it had been rarely reported in Minnesota. That changed with thirteen confirmed cases in nine different counties in 2015.

Bacterial canker is caused by the bacteria Clavibacter michiganensis subsp. michiganensis (CMM). This bacterial pathogen is capable of infecting tomato, pepper and the weeds cutleaf nightshade and eastern black night shade. In tomato, when disease is mild, the pathogen causes browning of leaf edges and fruit spots. When disease is severe, the stem cracks and becomes discolored. Leaves wilt and the entire plant may collapse and die.

This disease is difficult to control once established in the garden so prevention is an important management tool. Bacterial canker can be brought into the garden on infected tomato seed or transplants. The bacteria can be attached to the outside of the seed coat or carried within the seed. Infected transplants and seeds rarely show obvious symptoms of infection.

There are several steps that a gardener can take to improve the chances of starting with healthy seeds or transplants.

Purchase seeds from a reputable supplier. Most seed companies will not guarantee disease free seed but a good seed company will take steps to reduce the chances of seed borne pathogens. 

If you are saving seed or swapping seed with neighbors, save seeds only from healthy plants. In Minnesota it is difficult to grow a completely disease free tomato in the garden. There are many fungal and bacterial pathogens that infect garden tomatoes. Choose healthy fruit from healthy plants whenever possible. If you suspect seed may be contaminated, there are two seed treatment options that can help to clean seed. Both treatments can reduce germination of seed that is old or of poor quality, but have minimal effect on fresh, good quality seed.

Bleach Treatment
Make a solution with one part bleach (5.25% hypochlorite) and four parts water. Add a few drops of dish soap. Add seed to the solution and allow it to sit for one minute, stirring occasionally. Seed should be able to float freely so that all surfaces come in contact with the solution. Pour the solution through a thin mesh sieve or a cheese cloth. Rinse the seed in cool running tap water for 5 minutes. At this point seed can be directly planted or dried completely on a screen, then stored. Direct planting after treatment is preferable.

Bleach seed treatment can be used on any kind of seed including tomato. It will remove pathogens from the surface of the seed coat but not from within the seed. This means for bacterial canker, bleach treatment only partially reduces the risk of infection from contaminated seed.

Hot Water Treatment
Sous vide set up as a water bath
Soak tomato seeds in water heated to 100 F for 10 minutes. Then move seed into water heated to 122 F and soak the seeds for 25 minutes. Pour the seed through thin meshed sieve or a cheese cloth. Rinse the seed in cool running tap water for 5 minutes. It is critical that the exact time and temperature requirements be met with precision. This is often accomplished with a laboratory quality hot water bath. A sous vide, is a cooking device designed specifically to maintain exact temperatures in water and could be used in the absence of a water bath. Finally seed can be directly planted or dried completely on a screen, then stored. Direct planting after treatment is preferable.

Seed in a plastic cup, ready to treat
Hot water seed treatment is effective in eliminating the majority of bacterial plant pathogens from both the surface of the seed coat and from within the tomato seed. The time and temperature requirements for hot water treatment varies by plant and some seeds like peas, beans and squash may be seriously injured by hot water treatment.  The description above covers only tomato seeds.

Tomato Transplants

Tomato transplants should be purchased from a reputable local grower. Inspect plants carefully and reject any transplants with discoloration of leaves or stems, or any signs of wilting. Avoid any transplants that have been pruned or cut back, as bacterial pathogens can easily spread on tools. 

Wednesday, February 24, 2016

Starting From Seed

M Grabowski, UMN Extension Educator

Starting vegetable transplants from seeds can be fun way to get a start on the growing season. To be successful start out with quality seed from a reputable source and provide seed with the appropriate, light, heat and water. Be sure to time planting so that seedlings have enough time to grow into a sturdy plant with 2 to 4 mature leaves but not so long that seedlings become pot bound and overgrown.

Broccoli, cabbage, cauliflower, and head lettuce can all be seeded in early March. Peppers and eggplants should be seeded in mid March. Wait on planting tomatoes until early April.

Find everything you need to know to get seeds off to a good start at Starting Seeds Indoors.

Monday, February 8, 2016

Rabbit Fence Reminder

M.  Grabowski,  Extension Educator

Rabbit feeding on unprotected rose stems

Rabbits use snow to easily cross protective fencing

Deep snow levels allow rabbits easy access to trees and shrubs. Don't forget to secure rabbit fencing and other protection to a height sufficient to keep rabbits out even after snowfall, Learn more about protecting trees and shrubs from rabbits.

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