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Extension > Yard and Garden News > Archives > February 2014 Archives

February 2014 Archives

Drugstore beetles: A common stored food pest

Jeffrey Hahn, Extension Entomologist

Jeff Hahn, Univ. of MN

Photo 1: Drugstore beetle

There are a variety of beetles that attack stored food products in our homes. One of the most common is the drugstore beetle. This beetle is 1/10th - 1/8th inch long, dark brown, stout, and oval. Its head is hidden when you look at it from above. With magnification, a series of striations or lines running down its wing covers can be seen. They are able to fly and are attracted to lights.

Drugstore beetles feed on almost anything edible and even a few items that aren't (to people). This includes, but is not limited to, flour and other grain-based products, including bread and breakfast cereals, dried fruits, nuts, and spices, such as dried red pepper, as well as dry pet food. They will also feed on drugs (hence their name), dead insects, hair, leather, paper and books, and horns and antlers. They have even been documented chewing through tin foil, lead sheathing, and wood.

When drugstore beetles are found in a home, the first step in controlling them should be to find out what they are infesting. Because they are able to feed on many items, be sure to make a thorough inspection. Start in the kitchen and check all food items for their presence. However, don't forget about any susceptible items that may be stored in other areas on your home, e.g. pet food. Throw out any infested food material that you find. Keep in mind that there can be more than one infestation source so don't stop looking after you find the first one. For more information on drugstore beetles, see Insect pest of stored foods.

Favorite plants for Valentine's Day

What is Valentine's Day without expounding on some favorite, romantic plants? Roses are the traditional flower to give on this day of lovers, but as many of my gardening cohorts know, orchids are one of my favorite types of plant life.

According to Orchids of Minnesota by Welby Smith, estimates note upwards to 23,000 P1210761.JPGspecies of orchids in the world (7-10% of flowering plants). In Minnesota, we have 42 wild orchids that migrated here - a surprise as we think of orchids as fragile plants and tropical. But think of our state flower - the showy lady's slipper (Cypripedium reginae) - it is an orchid and grows in ditches along our roads! These are some tough organisms - and I find them a real pleasure to grow. Today it's easy and inexpensive to buy orchids - especially moth orchids (Phaleanopsis or "phals" ). I admit to buying one of my most reliable phals at IKEA! (it was my first and pictured here in full bloom).

I have found the limitations for growing orchids as houseplants similar to other houseplants: light, water, and patience - especially true in the case of orchids. Growers also need to appreciate the whole plant - not just the blossoms - as healthy leaves and firm, strong roots mean flowers are in the future. Most orchids perform best in a bright window in the winter months and filtered sun in the summer. Moth orchids are more tolerant of lower light situations indoors (another good reason for trying one). Keep leaves clear of dust too using a soft damp cloth.

Let your orchid dry out between watering and use rainwater, melted snow, or RO water (reverse osmosis and refillable at many grocery stores). Don't use tap water as it is usually softened and treated. Add a dilute amount of orchid fertilizer each time you water and flush plants once a month with clear water to eliminate salts that have collected. Note that plants growing in sphagnum moss will hold salts in the moss, soorchid6.JPG fertilize less often. Once a plant has finished flowering, leave the flower stem on the plant till it turns brown as sometimes they re-bud. After blooming, the leaves may appear wilted and dull, but continue good care and they will return to their thick, green condition. Celebrate new leaves and the crazy silvery roots as they indicate a a healthy plant and more flowers to come.

Take a look at our publication Phalaenopsis and Paphiopedilum species: Easy orchids to grow as houseplants. A great field trip for any orchid enthusiast - beginner or expert - is to the Como Park Conservatory, the conservatory at the U of MN Landscape Arboretum or, if you need a greenhouse shopping experience (as I recently did on a -20 degree day), visit Orchids Limited in Plymouth MN.

Recently, a new Extension Master Gardener intern told how orchids grew everywhere in her homeland. All I could do was sigh.... Enjoy these pics and happy Valentine's Day!

February 3, 2014 Issue

Yes, You Can Grow Oranges in Minnesota!

Mary H. Meyer, Extension Horticulturist

Mary Meyer

Photo 1: Calamondin orange trees need maximum light, such as the south facing window, shown here. Photo taken January 4, 2014

"Oh my! How do they expect me to grow an orange tree in Pennsylvania?" my Grandmother Rena Anderson exclaimed as she unwrapped her Plant-of-the-Month gift on a summer day in the 1960's as we sat in her screened porch amid her many plants. She laughed and potted the tiny plant. Today I enjoy this same orange tree in an even colder Minnesota climate and yes, it produces oranges!

The calamondin orange ( Citrofortunella mitis) is a tough houseplant IF you have enough sunlight and can keep it watered in well drained soil. My plant spends May-October in an unheated porch with large south facing windows and the rest of the year in a corner of my living room with south and west facing windows (Photo 1).


In other words: the brightest light we can supply in Minnesota. Over the nearly 50 years since my grandmother received it, I have moved it through 5 states, 12 homes and many repottings. In October 1986, the orange tree was the last thing I put on the moving van in Philadelphia and the first thing I took off when the van doors opened in Plymouth, Minnesota a few days later.

I am attached to the orange plant as it was my grandmother's, and she was one of my plant mentors. But this orange can fill my porch or living room with a sweet orange blossom fragrance and it sets fruit well enough, that most years, I can make marmalade.


Here is a brief history of some recent orange harvests:

Calamondin Oranges ------------- Harvest Date

112-------------------------------- January 9, 2011
52-------------------------------- November 25, 2012
25-------------------------------- September 21, 2013
27--------------------------------January 5, 2014




Mary Meyer


Photo 2: 112 oranges were harvested from the tree in January of 2011.



Here is what I have learned from, yes, only 1 orange plant, over the years:

Bright light for several hours every day is necessary for citrus to do well in Minnesota. Moving the plants outdoors in the summer really helps. Gradual exposure to direct sunlight in the summer is important, as leaves that develop indoors are not able to grow outdoors unless they are acclimated; they easily get sunburned.

Adequate water is also essential. Citrus leaves are thin and easily wilt. Regular watering is essential for good growth. Just as important is good drainage, water should never stand at the bottom of the container. For many years, I used a plastic container, so I did not have to water as often, however today the plant is in a clay pot and it prefers the better air exchange for the roots.

Citus requires a lot of nitrogen and iron to grow well, and iron is often unavailable in high pH soils, which tends to happen over time with the alkaline water we use on indoor plants. Yellow foliage is a common sign of iron deficiency in citrus and means you need to add a fertilizer that has available or water soluble iron. Throughout the summer, I use a readily available, water soluble fertilizer, such as 20-20-20 once or twice a month. In the winter, I rarely use fertilizer. And about once a year, I use an iron supplement to keep the foliage a healthy green color.

After a few years of treating mealy bugs, I gave up on insecticidal soaps, which will control most insects and used a stronger systemic control that eliminated the mealy bugs. However, I did not eat the citrus for two years. Careful, regular inspection is necessary to prevent insects from becoming a problem, especially if plants are exposed to other plants or outside conditions.

Meyer lemons are also fun to grow and will produce a few lemons in Minnesota. I bought two plants a few years ago and they have produced about 5 lemons in total. These lemons take a long time to ripen (months) and are a pale orange instead of yellow when ripe. These semi-sweet lemons are a cross between a lemon and an orange, so they are much milder than regular lemons.

The tree was brought to the United States from Beijing, China in 1908 by Frank Meyer, a plant explorer of the U.S. Department of Agriculture, (no relation to me :(). The plants can be gangly and leggy plants; you should prune them after harvesting the fruit, to keep the plants in a manageable size and shape. Growing conditions are similar to calamondin oranges, however be sure to purchase plants from a reputable garden center so you do get the true Meyer, or Improved Meyer lemon.

A fun fact about citrus plants is they can have evergreen foliage, flowers, immature and mature fruit all at the same time. For Minnesota, it is fun to have fragrant flowers, and developing attractive fruits over the months when we often see too little green.

I have two daughters, and I may have to propagate my orange from a softwood cutting in the spring so they each have a plant to enjoy in their homes.

But for now, I plan on harvesting Grandma Rena Anderson's calamondin oranges for many years to come.

Resources:

Growing Citrus Indoors in Minnesota


Calamondin

Four Winds Growers in California is one supplier for indoor citrus plants:

Take a Survey and Win an iPad Mini


K. Zuzek, UMN Extension

Photo 1: Rose frost

University of Minnesota Extension is still looking for feedback from gardeners, horticultural professionals, and other members of the public to help direct future tree and shrub educational programming. Don't delay. Tell your friends. By taking a short 10-15 minute survey, you will be entered into a drawing to win an iPad mini. Find the survey here. Thanks you for your help in planning future Extension educational programs! If you have questions regarding this survey, please contact: Kathy Zuzek, Extension Educator - Woody Ornamentals, University of Minnesota Extension at (952) 237-0229.

Dear Yard and Garden News Readers,

For those of you that are interested in learning more about lawn care and turfgrass science but have been unable to attend the School of Turfgrass Management in the past, we've developed a new offering for you, The 2014 Great Lakes School of Turfgrass Science. Much like the traditional turf school, this class was designed as a basic foundation of turfgrass science education for those that don't have a formal degree in turfgrass science or those looking for a refresher. Along with the traditional instructors from the University of Minnesota (Sam Bauer and Dr. Brian Horgan) and the University of Wisconsin-Madison (Dr. Doug Soldat, Dr. Paul Koch, and Dr. Chris Williamson), we've also added instructors from five other universities:

Dr. Dave Chalmers- South Dakota State
Dr. Kevin Frank- Michigan State
Dr. Dave Gardner- Ohio State
Dr. Aaron Patton- Purdue
Dr. Frank Rossi- Cornell University

This ten person team of instructors brings a whole new level of turfgrass science knowledge to this short course. Other features of the new format include:

- Fully online course; view session live on Wednesday nights from 6-8pm or watch the recordings

- Half the cost of the traditional School of Turfgrass Management

- Topics relevant to 21st Century Turfgrass Management

- The opportunity to take part from the comfort of your home or workplace

If you have any questions regarding this new school, please contact me at:

Sam Bauer
sjbauer@umn.edu
763-767-3518

Registration now open for Forest Pest First Detector Workshops

Jeff Hahn, Extension Entomologist

Jeff Hahn, University of Minnesota

Photo 1: Attendees at a Forest Pest First Detector workshop

Are you tree care professional or a forester? Are you a Master Gardener, Master Naturalist, Tree Care Advisor or other Master Volunteer interested in trees? If so and you would like to learn about early detection forest pests like emerald ash borer, gypsy moth, Asian longerhorned beetle, thousand cankers disease, Oriental bittersweet and other pests of special concern, please consider attending a Forest Pest First Detector workshops.

Workshop information can be found here; register early, registration is limited. Please note our first of six workshops will be on Wednesday, February 19 at the MN Arboretum. Our last workshop will be at the Woodland Owner Conference in Rochester on Arbor Day. Also, if you'd like to register to take the Tree Inspector Exam you MUST preregister (a choice on the Forest Pest First Detector workshop form) to take it after the workshop.

SAF and ISA credits and Tree Inspector recertification will be offered. After the workshop we will also offer the Tree Inspector exam for those that preregistered for the exam.

Stay warm,
The Forest Pest First Detector team



Cold snap is no snow day for emerald ash borer management

Rob Venette, Lindsey Christianson and Mark Abrahamson

Summary

  • Emerald ash borer (EAB) causes problems when it becomes very abundant in an area. Populations grow slowly until they reach a "tipping point" after which they can grow very rapidly - killing many trees in a short time (1-3 years).
  • We have found that some EAB larvae begin to freeze and die at around -20 F and that survival is very unlikely when temperatures reach below  -30 F.
  • In areas where the coldest winter temperature is generally warmer than -20°F, cold mortality is unlikely to have much or any impact on the population increase of EAB.
  • Rob Venette - USDA Forest Service

    Photo 1: Hypothetical example of EAB population increase to illustrate the possible effects of yearly 60% mortality and 90% mortality

    In areas where the coldest winter temperature is generally between -20°F and -30°F, cold mortality may delay the increase of EAB to levels that kill trees, but EAB should still be expected to reach tree-killing levels.
  • In areas where the coldest winter temperature is generally colder than -30F, cold mortality may have a major impact on population increase of EAB - perhaps to the point of constraining populations below tree-killing levels. We cannot confirm this right now, but we are working to answer this question.
  • We speculate that temperatures within known EAB-infested areas in Minnesota have been cold enough in recent weeks to cause a moderate to high level of larval mortality. This winter mortality should slow EAB population growth in these areas but it is probably not enough to justify changing management plans. EAB populations will likely recover and should still be expected to grow to tree-killing levels. 

Recent media reports have described the potential impact of extreme cold weather on emerald ash borer.  Data collected by us from the winters of 2009-2012 indicate that a substantial fraction of emerald ash borer larvae may die as temperatures fall below -20°F. At that temperature, mortality should be about 50%. Mortality rates increase quickly to about 90% as temperatures approach -30°F. Recent cold temperatures were unlikely to eliminate emerald ash borer populations.  In most cases, the cold has simply set the populations back.  Without additional, severe periods of cold, emerald ash borer populations would be expected to rebound to current densities in a generation or less (<1 to 2 years); however, this brief population setback provides additional time for communities to develop or implement plans for ash borer management.

EAB is a problem because of their potential for rapid population growth and resulting tree mortality. When EAB invades an area there is a characteristic lag period where populations are too small to kill trees and typically too small to detect. However, EAB populations eventually grow to a "tipping point" where population growth accelerates and tree mortality occurs rapidly. Winter mortality of larvae would help to slow population growth and consequently the rate of tree mortality. However, unless winter mortality is consistently very high, EAB populations should still be expected to reach tree-killing levels, albeit more slowly than in areas where no winter mortality occurs.

For these reasons, the authors are not advising any short-term changes to the implementation of municipal or state plans to manage emerald ash borer.  Forecasts of emerald ash borer mortality need to be confirmed with independent observations. 


Impact of cold weather on insects

Jeffrey Hahn, Extension Entomologist

Jeff Hahn, Univ. of MN Ext.

Photo 1: Boxelder bugs aggregate into clusters and use supercooling to protect themselves from extreme cold

With the intense cold weather we have recently experienced, a natural question to ask is what effect this will have on insects.  While the optimistic amongst us are hoping that it will wipe them out, especially the types we like the least like boxelder bugs and mosquitoes, the truth is it will probably have a minimal effect on most insects, especially our native species.

Like their human counterparts, native insects have lived in Minnesota a long time and know how to survive during the winter, even in extreme weather conditions.  That is not to say that some insects won't die as a result of temperatures around -20o F or colder, but most will live to see spring.  So how do they do that?  Insects have several strategies for surviving cold.  These options were nicely outlined in the fact sheet Tough Buggers: Insect strategies to survive winter in Minnesota by Cira et.al,

First, insects survive by avoiding the cold.  This could be like boxelder bugs that find shelter in large numbers under the bark of a dead tree or in our homes.  Some insects, like monarchs, leave Minnesota, migrating to warmer weather for the winter.

Second, they can avoid freezing.  Insects can go through a process call supercooling, i.e. adding a chemical similar to antifreeze into their blood (hemolymph).  This lowers the temperature water will freeze and helps keep their body fluids liquid.  This is a common method for many insects in Minnesota to protect themselves from extreme cold temperatures.  Forest tent caterpillar, a native insect, supercools to protect itself during winter.

Jeff Hahn, Univ. of MN Ext.

Photo 2: Woollybear caterpillars can seek shelter and alter their blood to tolerate freezing

Third, some insects can tolerate freezing.  These insects can release proteins into their blood to help control where, when, and how much ice forms.  By controlling how their bodies freeze, insects can minimize damage to their tissues.  Woollybear caterpillar is an example of a freeze tolerant insect.

It is not unusual for an insect to use more than one strategy for surviving winter weather.  Multicolored Asian lady beetles seek sheltered sites as well as using supercooling.  Of course, some insects do not even survive our Minnesota winters.  Insects, such as aster leafhopper and striped cucumber beetle, migrate into the state from the south during the growing season but are not able to survive our winters.

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