Extension > Yard and Garden News
Karl Foord - Extension Educator, Horticulture
I have a Meyer lemon (Citrus × meyeri) which goes outside in the summer and struggles through the long Minnesota winter. This is a wonderful plant with fragrant blossoms and nice fruit. I noticed a lot of very small white cottony blobs on the stems and leaves as well as some scale insects. I believe I have California red scale (Aonidiella aurantii). According to Whitney Cranshaw in his Garden Insects of North America this scale affects many ornamental plants and can be a serious pest of citrus. The adult females are round, reddish orange, and have concentric rings on the cover. Young stages produce some cottony filaments of wax around their body; later stages form the more solid cover.
This scale insect has a fascinating life cycle that features a sessile female and a winged male (Exhibit 1).
I clipped a citrus leaf and examined it under the dissecting scope. I found a sessile female (photo 1) and when I turned her over several crawlers exited (photos 2 & 3). I also found
white caps (photos 4 & 5), late first instars (photo 6) and an individual in first molt.
Photo 2: California red scale (Aonidiella aurantii) overturned female with exiting crawler
Photo 3: California red scale (Aonidiella aurantii) overturned female with exiting crawler
Such a lifestyle made me curious as to how such species mate (Exhibit 2).
To eliminate the scale, I put the pot in the shower and try to hose off the scale. This knocks them down but does not eliminate them. This is probably an excellent time to consider the use of imidacloprid as a systemic insecticide. The plant is showing some flowers now and no pollinators will have access to these flowers. In addition the material will only be in the pot in a plant holder box in the house and so no chance of contamination of our water systems.
For more information see the excellent publication from the University of California Division of Agriculture and Natural Resources.
Jeffrey Hahn, Extension Entomologist
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.
In this issue:
Mary H. Meyer, Extension Horticulturist
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
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.
Four Winds Growers in California is one supplier for indoor citrus plants:
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: