|Yard & Garden Line News
Volume 3 Number 4 April 1, 2001
Avoiding Woes in a Garden of Weedin'
Dean Herzfeld, Coordinator, Pesticide Applicator Training
Beth Jarvis, Yard & Garden Line
Spring lawn care season is fast approaching. If you're not going to have time to battle that field of yellow or get the drop on the crabgrass, how do you even begin to figure out who to hire? Referrals from friends? Or do you grab the five flyers that were hanging off your doorknob and start dialing?
Little bit of
everything--moss, grass and weeds.|
The best pest control is having a healthy lawn, one that out-competes weeds. Herbicides were designed to control weeds and, when used prudently, will do an effective job. Of course, you can always hand pull weeds and should first explore other plant health strategies to manage weeds in your lawn. If you'd like help with lawns, click on the mower at http://www.sustland.umn.edu/ or search the Extension website at http://www.extension.umn.edu.
In this article, we're going to discuss some things you should know before deciding to hire someone to tackle your weeds. Minnesota has many reputable commercial lawn care companies who offer convenience and high quality service. Some companies only apply pesticides. In Minnesota we are seeing companies who offer a wide range of turf and pest management services.
What IS a Pesticide?
According to state law, a pesticide is a substance or mixture of substances used to destroy or control any undesirable for of animal or plant life, including substances that prevents, repels, mitigates, or otherwise interferes with a pest. The pest can be mice, flies, bacteria or even weeds. According to federal and state law, if a product label or the manufacturer claims something is a pesticide, it is regulated as one by the Untied States Environmental Protection Agency .
Substances used in lawn care and gardening to manage pests, including 'organic' materials, are pesticides. Occasionally you'll hear people say "pesticides" meaning insecticides thinking herbicides are something else. Herbicides are pesticides as are insecticides, fungicides, and rodenticides. Something that's natural or "organic" may seem safer and usually is. But keep in mind, being toxic may be a plant's best defense against getting eaten! Just remember, some things that are 'natural' can also be quite toxic.
Who Can Apply Pesticides?
In Minnesota, anyone who applies any pesticide for hire (is paid for their service) must be licensed as a commercial applicator. If you hire a neighbor to spray your dandelions with something you bought from the hardware store, the neighbor must be licensed as a commercial applicator. Licenses are issued by the Minnesota Department of Agriculture. Each pesticide applicator must be personally licensed; there are no company licenses or supervisors' licenses that would cover a firm's employees.
Institute & State
University *(url below)
Licensing is a two step process in Minnesota. The first step is to be initially certified by passing closed-book, monitored exams. The exams are given by the Minnesota Department of Agriculture and are designed to meet state and federal laws regulating pesticide applicator licensing.
The second step is to provide the Minnesota Department of Agriculture a licensing fee of $90.00 and additional information including demonstration of financial responsibility through a financial statement or certificate of liability insurance.
Here are other things consumers should know:
To renew their license each year, Minnesota commercial turfgrass pesticide applicators are required to re-certify every two years by attending approved continuing education workshops.
- Commercial applicators must carry their license card at all times when making a pesticide application.
- Commercial applicators are not licensed until they receive their license card in the mail from the Minnesota Department of Agriculture. If they say "I've passed the tests and my card is in the mail" they are not yet a licensed applicator - do not let them apply pesticides to your yard.
- If a commercial applicator stops working for one lawn service and starts working for another, he or she is not licensed until they reapply to the Minnesota Department of Agriculture for a license under their new employer.
- All licenses expire each year on December 31. All commercial pesticide applicators must renew their licensed each year with the Minnesota Department of Agriculture.
Commercial applicators of lawn fertilizers don't need to be individually licensed, although their lawn care companies need a license from the Minnesota Department of Agriculture. (Local governments may also have licensing requirements.) "Weed and feed" fertilizers consist of fertilizer and herbicide, so anyone who applies them needs a pesticide applicators license.
Don't let anyone who is not a currently licensed pesticide applicator apply anything to your yard. Licensing helps ensure your safety and protects the environment.
ALWAYS CHECK THE LICENSE OF THE PERSON MAKING THE
PESTICIDE APPLICATION TO BE SURE IT IS CURRENT.
You can now check on anyone's Minnesota commercial pesticide applicator license
or a company's commercial fertilizer application license
at the Minnesota Department of Agriculture web site:
It's also a good idea to check references before you sign up for a service. Fly by night unlicensed pesticide applicator companies that operate out of a PO box and a telephone continue to cause problems. You may get a heck of a deal on lawn care services but they're impossible to catch if they damage your lawn. So, find out the physical address of their place of business.
When the Applicator Arrives:
First, the pesticide application should be both needed and timely - applied when it will do the most good. Look for other Yard and Garden Line articles on turf grass management for more information.
The applicator should be appropriately attired. No professional will show up in a tank top, tee shirt, shorts and some old sneakers. Gloves, long pants, long sleeved shirt, shoes and socks are adequate plus any personal protective equipment that may be required on the label. Some company uniforms are constructed to provide protection.
Ask the applicator what he/she is spraying and they should be professional about answering your questions:
What are you applying and why is it needed?
How long should people and pets stay off?
Are there any health concerns?
Are there any environmental concerns?
If you want additional information, ask for a copy of the label of the pesticides used on your property.
Look at the active ingredients. Yeah, the *really* tiny print. If they're treating dandelions, you'll probably see 2,4-dichlorophenoxyacetic acid (A.K.A. 2,4-D) alone or with
2-(2-methyl-4-chlorophenoxy) propionic acid (A.K.A. MCPP) and dicamba (Banvel).
The last step of the weed treatment may be to put up little warning flags. State notification rules pertain to turf-applied pesticides only. Spraying trees, shrubs or ornamental plants for disease or insect problems is exempt. Municipalities can choose if they want to require lawn care companies to post treated lawns. In Minnesota, advance notice to neighbors of pesticide applications is not required.
Heartbreak of Spray Residue
Problems generally become evident days after the application. If it is the neighbor's plants that show the damage you have a bigger problem.
Herbicide injury on lilac.|
Y &G files
A commonly asked question is about testing for herbicide residue. Unfortunately, lab tests for herbicide residue are expensive and sampling must be done fairly quickly after application. Tests must be run for each possible herbicide. There's no easy yes/no test for 'general' herbicide residue.
Some plants respond quickly to 2, 4-D and are considered indicator plants. These include: tomatoes, grapes, green ash and boxelder. Contorted, deformed leaves and stems may indicate herbicide use such as 2,4-D.
Two key factors that affect spray damage are wind and temperatures. Generally most home turf pesticides should be applied at wind speeds below 10 mph. Some common turfgrass herbicides should not be applied at temperatures exceeding 85 degrees as they may convert to a gas, or volatilize, and drift on to gardens or ornamental shrubs.
Pesticides and fertilizers should not be applied near a lake or wetland, within a shoreline buffer strip of 15 feet or more. No pesticides or fertilizers should be applied to hard surfaces of any kind, such as driveways, sidewalks, and streets.
Spray drift can occur when a sprayer emits a fine spray and the spray particles are less than 200 microns, the diameter of human hair. Commercial pesticide application equipment should be designed and calibrated to provide as coarse a spray as possible to reduce drift.
Minnesota has many reputable commercial lawn care services who offer convenience and high quality service. References are always helpful and knowing their physical location where the service operates out of is a plus. Be sure you check if the applicator who comes to your house has a current pesticide applicator license from the Minnesota Department of Agriculture.
Pesticides are tools of for dealing with pests and should only be used as part of a larger Plant Health or Integrated Pest Management program. Consider why you have the pest problem in first place. Then consider using other pest management practices. Anything that promotes a strong healthy turf means fewer weeds -- and less need to use a pesticide. Also, in some areas, such as shady spots, it is very hard to grow grass. For these areas other landscape plants that better fit the site should be explored.
The Yard and Garden Line has a lot of tips and information on good lawn care practices that promote a healthy turf. For information about the extension service's Pesticide Applicator Training program see this website: http://www.extension.umn.edu/pesticides/
Beware of Bathroom Mold
Janna Beckerman, Extension Plant Pathologist
Last month we received an interesting sample into the Yard and Garden Clinic. Inside a large box was a bra, a pair of panties, a shirt, a paper tissue with bits of blood on it, some carpet beetle carcasses and a chunk of drywall with a putative mold on it. The renter had complained about itching and wanted to know if we could find anything.
B &: C: spore-
D: conidia or
Genera of Imperfect
Fungi, 3rd Ed.
As John, the entomology technician, sifted through the clothing, I examined the piece of drywall, which definitely had mold on it. Household mold is a very common and very serious problem. However, one type of household mold in particular, Stachybotrys, has been implicated in the cause of death of numerous infants. Originally, I had planned on just confirming that the sample we received did have mold. I proceeded to tell John how this is only a serious problem if there are very young children, older or immunocompromised adults, or children with pre-existing respiratory problems. The homeowner mentioned to John that her children had such problems. So I began the difficult process of trying to identify the mold on the drywall.
When I teach Master Gardeners to diagnose plant disease, I always begin with the host. I approach any mystery disease that way because by identifying the host, I can eliminate over 99% of the causal agents. Unfortunately, there are no books to my knowledge that list the causal agents of bathroom mold. So I sat down with the microscope, my sample, and Barnett and Hunter’s Illustrated Genera to Imperfect Fungi.
Most fungal plant pathogens make spores, but not like this. There were spores everywhere. Not only that, but there were at least two and maybe three distinctly different types of spores. I quickly became disgusted, because the most ubiquitous spores appeared to be stuck to the conidiophore, a specialized structure that produces the spores. Because the spores were so well stuck to the conidiophore, this prevented me from identifying the way this fungus reproduces. How spores are produced is one of the key features needed to identify molds. Furthermore, the conidiophore had little pimples all over it. Did the spores come out of the pimply structures and aggregate to the top, or were those pimply structures diagnostic for other reasons?
After making several sample preps, and still not finding a conidiophore, I attempted to identify the fungus, guessing as to how it reproduced. Comparing my "guesses" to my actual samples resulted in the knowledge that I was still unable to identify this mold. Finally, I figured that I would just look up Stachybotrys and make certain that it wasn’t this mold. I was completely shocked at the description that presented itself to me: Stachybotrys was precisely what was growing in the drywall of this renter’s home. These spores were an identical match, and the pimply conidiophore considered a key diagnostic feature.
Why the concern about Stachybotrys? Stachybotrys has been implicated in causing pulmonary hemorrhage in children under the age of two. Unlike most other molds, Stachybotrys produces mycotoxins that weaken the vessels in the still developing lungs of small children. Severe bleeding and blood loss can result due to coughing up blood or nose bleeds. Another symptom of Stachybotrys is chronic cough and congestion with anemia. The two children of our caller were on oxygen.
This disease received tremendous attention in the mid-1990s when physicians in Cleveland reported 45 cases of pulmonary hemorrhage (PH) in young infants, with 16 of the infants having died from this infection. As serious as this sounds, flaws in the research methodology in the original reported cases of Stachybotrys associate- pulmonary hemorrhage has led both the CDC and the Minnesota Department of Health to consider any type of indoor mold as a problem to be taken seriously. As terrible as Stachybotrys appears, all indoor mold is potentially harmful and should be removed immediately regardless of whether it produces toxins or not. It is still inconclusive whether Stachybotrys is the causal agent of a type of fungal pulmonary hemorrhage.
What is not inconclusive is that any type of mold can cause serious health problems. Indoor molds have been implicated in causing asthma, chronic respiratory conditions, headaches, nasal and sinus congestion and skin and eye irritation. The risks are greater for young children, the elderly and the people with weak immune systems (such as persons undergoing chemotherapy, an organ transplant or has HIV). Most people realize they have a mold problem when they observe mold growth; However, mold can be present and causing problems but not be visible. For this reason, areas with noticeable moldy odors should be searched. Care should be taken to look under carpet and furniture pads, behind sinks or by anything exhibiting water damage. The best way to deal with mold problems is to prevent them. To do this, identify and fix any moisture problems (flooding, pipe leaks, ice dams, condensation etc.) to prevent mold from gaining a foothold. Dry any materials as soon as possible, removing and disposing of mold infected items. It is prudent to wear rubber gloves, goggles and a medium to high efficiency filter mask. Many molds are extremely allergenic. One severe inoculation is sufficient to induce allergy.
For common bathroom mold (like the type that occurs in showers, grout, etc), surfaces should be cleaned with a commercial detergent and a stiff brush. Because many spores are able to repel water, the detergent is an important wetting agent that allows the spores to be permeabilized and killed. After cleaning and removal of visible mold, a disinfectant is recommended to kill any mold missed by the cleaning process.
Finally, if you’ve previously found bathroom mold or household mold, remain on the alert. Continue examining areas with a history of water damage, or water exposure. Household mold, unlike some fungal diseases of plants, can be prevented.
For additional information on household mold, check out:
Damping-Off of Seedlings
Jennifer Love, Plant Pathology technician
As Minnesota gardeners prepare for the growing season ahead by starting seeds indoors, the most common problem they may encounter is damping-off. The symptoms of damping-off are seedlings that look healthy, then suddenly seem to collapse and die. On close inspection, the grower can see that the stems appear to have rotted at the soil line.
Seedlings shrivel at soil line.
Damping-off is caused by several species of fungi that are soil borne. There are two types of damping off: post-emergence damping-off when the seedlings are girdled and collapse. Pre-emergence damping-off affects the seeds and/or seedlings before they emerge above the soil line. The fungi involved may be Pythium, Rhizoctonia, Phytophthora, or Fusarium. Pythium and Phytophthora are the usual suspects in cooler soil while Rhizoctonia and Fusarium create problems in warmer soils.
Damping-off can often be prevented through following good cultural practices. Good hygiene is important to the success of seed starting. This means that sterile pots and soil must be used. It is possible to pasteurize soil in your own oven if all the members of your household can handle the smell. To do this, you put the soil 3-4" deep on a baking pan, preheat your oven to 200F and use a thermometer to monitor the soil temperature. Once the soil temperature reaches 160F you can turn off the oven and let the soil sit for 30 minutes. The other, easier, option is to purchase a soil mix for starting seed. If you are re-using pots you should sterilize them in a bleach solution (1 part bleach to 9 parts water for 30 minutes). Any tools used should also be sterilized to prevent spreading the fungus. Rinse the pots and tools well before use.
Using soil with good aeration and drainage is important. In addition, the growing area should have good ventilation. The seeds should not be sown too thickly or air circulation among the seedlings will be poor. Keeping the soil temperature warm enough can also help the seedlings to grow vigorously and discourage the fungi. There are several products available for creating bottom heat for your soil, including heating coils and heating pads. In addition, once the seedlings emerge you may try letting the soil surface dry between waterings. Through these cultural practices, you should be able to create an environment that is unfavorable to the fungi that cause damping-off, and gets your seedlings off to a healthy start.
Test your diagnostic savvy monthly with Disease Watch at: http://www.extension.umn.edu/projects/yardandgarden/PlantPathWeb/Plpa.htm
Time to Plan Weed Control Strategies for Lawn
Deborah Brown, Extension Horticulturist
Most people try to maintain an attractive lawn. Some really love the looks of a broad expanse of uniform green grass; others succumb to neighborhood peer pressure (who wants to be the only house on the block with a golden carpet of dandelions each spring?) While it's unrealistic to expect an absolutely perfect, weed-free lawn, there are some things you can do to keep those "leafy intruders" to a minimum.
The first weed you need to think about each spring is crabgrass -- not because it's the first to show up, but because timely application of pre-emergent herbicide makes a big difference in how visible the weed will be later in summer when heat slows our desirable Kentucky bluegrasses.
Crabgrass is named for its prostrate growth habit. With a bit of imagination you can think of it scuttling off like a crab on the ocean floor. If you spot a coarse, upright grassy weed growing vigorously first thing in spring, it's NOT crabgrass, but one of the perennial weeds, possibly quackgrass or tall fescue. (Small clumps of coarse perennial grasses may be dug out or spot treated with glyphosate .)
As an annual weed, crabgrass roots do not survive from one year to the next. Instead, new seedlings sprout each year from seeds left behind during past growing seasons. In the Twin Cities area, crabgrass typically begins to germinate around Memorial Day. You may see it a week or so earlier in exposed garden soil, along sidewalks and driveways, or on south-facing slopes -- areas that warm first each spring.
Crabgrass just isn't very distinctive looking as a youngster. True, its leaves are a little lighter colored than bluegrass, but it really doesn't stand out in the lawn until much later in summer. By then, it's a real eyesore, and there's no practical remedy. Worse yet, it's ready to drop about another crop of seeds into the soil, perpetuating itself and your weed problem.
The best time to go after crabgrass is before it even sprouts. Apply a pre-emergent herbicide to your lawn sometime in late April or early May, watering it lightly into the soil. As crabgrass and other seeds begin to germinate, the herbicide interferes with their ability to set down roots. Most seedlings never make it through the soil surface to see the light of day.
Lawn product companies usually offer their pre-emergent herbicides in combination with lawn fertilizer. However, if you can find the weed preventer packaged separately, you can be more flexible in its use, targeting only those areas that have been a problem in the past. Besides, not all lawns need to be fertilized in spring, particularly if you fertilized them once or twice last fall.
Effect on Seeding
There are many different pre-emergent herbicides formulated for home use, including "natural" products made from corn gluten meal. The vast majority of them affect crabgrass and desirable turfgrasses equally. That means you mustn't use them in any areas where you intend to plant grass this spring. They'll stop expensive grass seed from sprouting just as effectively as they stop weed seeds.
With most products, the effect will have worn off by early September, so you can reseed safely at that time. It's a better time to plant grass seed here, anyway. Corn gluten meal products are a slightly different story. To achieve the best results, they should be applied not only in spring, but also in mid-August each year. If you plan to seed in September, you need to skip the August application this year.
Only one pre-emergent chemical, Siduron (also called tupersan), can discriminate between the grass seeds you want to grow and the crabgrass seeds you want to prevent. Siduron is the active ingredient in several products including Scott's Starter Fertilizer Plus Halts. These products should be applied and watered into the soil after you've planted your grass seed.
Lawn Care Review
Regular attention to everyday lawn care is also important in preventing weeds. Anything you can do to make your grass grow thick and dense will help prevent weed seeds from sprouting by denying them the sunlight and warmth they need to germinate.
Dandelions and violets
compete with grass
in a thin lawn.
Setting your mower blade too low and "scalping" the lawn not only allows more sunlight to reach the soil, but it results in a shallow root system on your desired turfgrasses. Never remove more than 1/3 of the leaf length, any time you mow. And be sure to clippings fall back to the soil where they'll recycle some nutrients to your grass.
Most people understand the need for thorough watering, but it's equally important to allow the soil to dry partially between watering times. Constant surface moisture encourages seed germination, as do high levels of phosphorous in the soil. That's fine when you're planting grass seed. It's not so fine when all you're doing is encouraging weed seeds to sprout!
Regular aeration is vital on compacted or heavy clay soils, but schedule it for early autumn rather than spring. Aerating and power raking bring dormant seeds to the surface where they'll surely sprout in spring; most weed seeds will not sprout when churned up in autumn.
Don't Forget the Dandies
What about that golden carpet of dandelions? You can start working on them with a dandelion digger as soon as you see them or wait until temperatures are in the high 50's and low 60's to spray them with a broad-leaf weed-killer. Herbicide should kill the plants quite effectively, but any seeds they've made will still be viable. Whether you spray in spring or not, be sure to go after them in early autumn. Then there won't be many around to bloom and produce more seed the following spring.
Interesting New Vegetables for 2001
Deborah Brown, Extrension Horticulturist
Browsing through seed catalogs is a favorite activity for Minnesota gardeners. And for those of you who prefer to shop on line, you'll find many traditional mail order companies now also offer their product line over the Internet. This year, as always, there are dozens of different and intriguing cultivars to tempt us, but if you hope to try some of these interesting new cultivars, you'd better get those orders in right away.
When it comes to breeding vegetables, the emphasis is on nutrition AND flavor. The following new veggies deserve a place in the garden, alongside your old favorites:
"Blood" red carrots
One of the most interesting and unusual new vegetables is a carrot called ‘Nutri-Red.' Though shaped like traditional carrots – about nine inches long, tapering to a blunt tip – their color is far from ordinary. In fact, when you dig up these carrots, they're a washed out, reddish pink. You won't want to eat them raw, though; not only are they unattractive, they're a bit on the "woody" side. After cooking, however, their color darkens to a deep "blood" red, and both flavor and texture are appealing.
The real breakthrough associated with this extraordinary color is the concentration of the anti-oxidant lycopene, rather than carotene, in these carrots. They contain as much lycopene, pound for pound, as tomatoes, the chief source of lycopene in most peoples' diet. Nutritional studies suggest that eating at least one serving of a lycopene-rich food daily is believed to help prevent prostrate cancer and other cancers. They also show that people are better able to absorb lycopene when vegetables are cooked rather than eaten raw, a fact that dovetails nicely with the need to cook ‘Nutri-Red.'
‘Nutri-Red' carrots grow vigorously and will be ready to harvest roughly seventy-six days after you've planted the seed. In an average season you should plant in early May, then dig them some time in July. Despite their strange appearance and enhanced nutrient content, these carrots are not the product of genetic engineering, but were developed the conventional way, through cross-pollination.
Jalapeños without the heat
It probably comes as no surprise that many Minnesotans dislike flaming hot flavors in their food. On the other hand, Mexican-style food has never been more popular. How to bridge this apparent dilemma? Have I got a pepper for you!
The new jalapeño called ‘Fooled You' has the looks and flavor of standard jalapeño peppers with none of their mouth-blistering heat. This makes it the perfect pepper to use in mild salsas, picante sauces and other Mexican-influenced dishes. Sliced cross-wise, like coins, it's also a tasty topping on sandwiches and burgers, guaranteed not to bring tears to your eyes or send you screaming for pitchers of ice water.
‘Fooled You' matures early for a jalapeño, bearing ripe fruit about sixty-five days after it's transplanted into your garden, late May or early June. That means you'll be enjoying these peppers by mid-August or perhaps a bit sooner. ‘Fooled You' looks like ordinary jalapeños, though they're slightly larger than many varieties. And like other jalapeños, they'll eventually turn red if weather conditions allow you to let them ripen fully on the plant.
"Bean" there, done that
Have you ever planted green beans too early in spring, only to find that most of your seeds rotted in the cool, moist soil? Or perhaps you've planted green beans later, when the ground was warm enough, then left them essentially on their own, watering when you got a chance and hoping Mother Nature would look after them for you. Results, most years, would be pretty disappointing. Many of us have "bean" there, done that.
Two new green bean cultivars are available this year to deal with precisely those circumstances.
‘Tema' is a bush bean that tolerates cold wet soil and matures just fifty-two days after plants are up. Planting ‘Tema' will allow you to get an jump start in enjoying this favorite fresh vegetable. It's also an excellent choice to use as the first variety in a succession of green bean plantings that will provide fresh-from-the-garden beans all summer.
‘Tema's seeds are dark brown. Its dark green pods average a little over five inches in length and are so tender these delicious beans are only recommended for home gardeners or perhaps sales at farmers' markets. They aren't tough enough to withstand shipping.
‘Brio' bush bean has different strong points altogether. Its developers consider ‘Brio' a very "forgiving" variety, capable of high yields regardless of the growing conditions. Its big, robust plants exhibit a tolerance to heat and stress that allows for reliable bean production even when the care they receive is far from optimal.
Though ‘Brio' cannot survive cold wet soils like ‘Tema,' it is still a fairly fast maturing variety, producing ripe pods about fifty-three days after plants emerge from the soil. This is an excellent bean seed for beginning gardeners. It's also well-adapted to cabin gardens that are only tended on weekends or rented garden plots where regular watering may be difficult or impossible.
If your garden isn't huge, yet you'd like to try several different zucchinis, check out the Summer Medley squash collection. Each packet includes four cultivars: ‘Spacemiser,' a green zucchini that begins producing about forty-nine days after plants emerge, ‘Butterstick,' a lemon yellow, forty-eight day zucchini, ‘Goldbar,' an extra-early golden variety that's ready forty-three days after emergence, and ‘Topkapi,' a high-yielding Mediterranean squash with pale green, speckled skin.
All these zucchinis grow on compact or semi-compact plants, so space your seeds about three feet apart in a sunny, well-drained site – then stand back! You and your friends and neighbors will be enjoying zukes all summer long.
These new cultivars are available from many catalogs. Here are a few:
|‘Nutri-Red' carrots: ||E & R Seed Co., 1356 E. 200 S, Monroe, IN 46772|
J.W. Jung Seed Co., 335 S. High St. Randolph, WI 53956
Nichols Garden Nursery, 1190 North Pacific Hwy., Albany , OR 97321
Mellinger's, 2310 W. South Range Rd., North Lima, OH 44452
Territorial Seeds, P.O.Box 720, Cottage Grove, OR 97424
Vermont Bean Seed Co., Computer Operations Center, Vaucluse, SC
|'Tema' and ‘Brio' green beans:
Vermont Bean Seed Co., Computer Operations Center, Vaucluse, SC
|‘Fooled You' jalapeño pepper:
Tomato Growers, P.O.Box 720, Fort Myers, FL 33902|
Totally Tomatoes, P.O.Box 1626, Augusta, GA 30903
Nichols Garden Nursery, 1190 North Pacific Hwy., Albany , OR 97321
|Summer Medley zucchini:
Geo. W. Park Seed, Hwy. 254 N., Greenwood, SC 29647|
Mellinger's, 2310 W. South Range Rd., North Lima, OH 44452
Lady Beetles and Light Traps
Jeff Hahn, Assistant Extension Entomologist
Residents throughout most of Minnesota encountered large numbers of lady beetles congregating around homes last fall. Although it is common for lady beetles to cluster together when they overwinter, they normally don't do so around buildings. However, that is not true any more now that the multicolored Asian lady beetle, Harmonia axyridis, is in Minnesota.
Multicolored Asian ladybird beetlss.
This insect is a new species that only first arrived in Minnesota seven years ago. It has become abundant around buildings just within the last few years. They are usually considered to be a nuisance when large numbers enters homes during the fall. They may also be seen indoors during the winter and again in the spring when they emerge from wall voids and other hiding places.
Lady beetles are harmless insects and, despite the circumstantial evidence, do not reproduce indoors. But they can occur by the 100's or 1000's. Once they get into walls and other nooks and crannies, there are no practical methods to prevent them from coming out into the interior of homes. Spraying has essentially no effect on their presence indoors. Once they are seen, the best control is to physically remove them by hand or with a vacuum.
Another possible option is capturing the lady beetles with a light trap. Dr. Louis Tedders, a retired entomologist from the USDA has developed two light traps designed to capture live multicolored Asian lady beetles found indoors. The H&T 120 is designed to be placed in a corner or along a wall where it radiates a black light at a 120o angle towards the center of the room. The H&T 360 is designed to be placed in the center of a room where it radiates black light at 360 degrees. Both traps are the same size, although the H&T 360 is more effective in capturing lady beetles.
The traps are designed to capture but not to kill the lady beetles. The traps are coated with talcum powder so the beetles fall more readily into the lower portion of the trap. To maximize the traps' effectiveness, it is necessary for the room to be completely dark so competing light sources do not distract the lady beetles. Also room temperatures should be at least 68o and ideally be near 75o. If it is cooler, the lady beetles are less likely to fly. Although it has not been specifically tested in the upper midwest, it has been effective in trapping multicolored Asian lady beetles in the southeast U.S.
The H&T 120 sells for $98.50 and the H&T for $125.00 plus shipping and handling. You can find more information or order light traps by calling H&T Alternative Controls at 912-988-9412 or 1-877-967-6777 or writing them at P.O. Box 1546, Perry, Georgia 31069. You can also order the light traps online at http://www.critterridders.com/ladybeetles.htm
Get the low down on this month's insect pests at Insects http://www.extension.umn.edu/projects/yardandgarden/EntWeb/Ent.htm
Using Oils to Control Pests
John F. Kyhl, graduate research assistant and entomology technician
Introduction: Oils are a class of contact insecticides that can be used against many pest insects, mites, and their eggs. Due to their low toxicity and since they are considered ‘friendly’ to natural enemies, oils are a favorite of many gardeners to control insects on trees, shrubs, and herbaceous plants. Oils can also be useful in controlling parasites on cattle, and are sometimes used to control mosquito larvae.
How oils work: Oils kill insects in a couple of ways. First, oils can smother insects by blocking their spiracles (breathing tubes), smothering them. This is effective against small insects like scales, and works well against eggs. Second, oils can act as a poison by interfering with normal metabolism. Third, oils can work as a feeding disruptant, which can limit the transmission of viruses spread by insect feeding by discouraging feeding or impairing mouthpart function. In some cases, oils are often mixed with some other insecticides, as it allows better coverage and penetration.
Oil types: Many people have heard of dormant oils and summer oils. These terms are now largely relics of the past, when different oils were used during different seasons. Now, the same terms are used, but the difference is when they are applied. Some oils are applied during the dormant season (when the plants are not growing), while others are applied while the plant is actively growing. Oils are generally distilled from petroleum, but some have a vegetable origin (soybeans, canola, etc.)
How to use oils: Many different manufacturers produce oils. They are available for purchase in many places, including garden centers, home centers, hardware stores, and department stores. Most oils are mixed with water (at about a 2% rate, but check the label) and sprayed onto the surfaces of plants. Apply oils only when the temperature is between 40F - 100F, and if the plant is not under water stress. Do not spray oils if the plant tissue is wet, if it is very humid (>90%), or when the shoots are elongating.
When to apply: Oils can be safely applied at any time of the year on most plants. However, spring is one of the most effective times to apply. Applications in the early spring after insects begin to become active are the most effective. Applications in the late fall and early winter are not as effective because the target insect are minimally active and have low respiration rates. The higher the respiration rate, the more effective the oil.
Potential problems: There are some limitations to the use of oils. First, all oils can cause some phytotoxicity (plant injury). Signs of phytotoxicity are foliar discoloration (yellowing) followed by leaf discoloration, darkening, and death. In some extreme cases, growing tip or branch dieback can occur. Some plant groups are quite sensitive to oils, so don’t apply them to maples, walnuts, evergreens (junipers, cedars, or spruces). Phytotoxicity is more likely to occur if oils are mixed at a rate stronger than that suggested on the label, or if they are applied when environmental conditions are inappropriate. Second, oils should not be used on plants within a month of when sulfur is applied. Sulfur is applied to limit diseases such as scabs and rusts. When combined, sulfur and oil can interact, causing phytotoxicity.
My snow drops (Galanthus nivalis) started blooming over a week ago . They're amazing little flowers that come up through almost frozen ground, right next to snow. Truly the bulbs to plant for "first flowers in bloom" bragging rights! Well, maybe not. They're only a few inches tall, so they're not showy, much less visible over the adjacent snowbank.
Photo credits: Beth Jarvis
I used to confuse them with snowflake, Leucojum aestivum. They both have pendant white flowers and bloom in the spring but snowflake are about a foot tall and bloom with the dandelions. I have a planting on the south side of my house, along the foundation, that has come back reliably for over a dozen years, neither increasing nor decreasing. Both snowdrops and snowflakes are hardy to USDA zone 3.
Now, we're back to publishing twice a month. Next issue will be published 4/16-17. In that, we'll have the first of two articles on herbicides from Roger Becker, Extension weed scientist. Roger will tell us all about pre-emergence herbicides first, while there's still time to treat for crabgrass. Later, when the weeds are popping out all over, he'll follow up with information on post-emergence products.
Mary Meyer, our ornamental grasses expert, has agreed to write about ornamental grasses for this summer.
Lorrie Stromme, who wrote about hazard trees a while ago, will report on rain gardens, the latest trend in reducing runoff from lawns into storm sewers.
In the months ahead, we'll be learning about soluble salts. You've seen it on soil test reports, but what does it mean? Also planned is a piece on conservation biocontrol--what is it? Also this spring, we'll be hearing from Vince Fritz, Extension horticulturist, on research he and others are partcipating in on using cabbage to find a treatment for cancer.
In June, we'll have a report on the treated lumber study conducted by U soil scientists determining whether arsenic from treated lumber is sloughed off into garden soils and if it is taken up by plants.
I rely on your comments and questions for ideas for future articles.
Please, keep the story ideas coming! We really try to be responsive to your needs.
Please feel free to cut and paste any of the articles for use in your own newsletters. All we ask is that you give our authors credit.
Back issues Yard & Garden Line News are on the Yard & Garden Line home page at www.extension.umn.edu/yardandgarden/. Our home page has clickable links to most of the components of the Yard & Garden Line, such as Bell Museum of Natural History, INFO U and the Soil Testing Lab.
Deb Brown answers gardening questions on Minnesota Public Radio's (MPR) "Midmorning" program on the first Thursday of every month at 10 a.m. Katherine Lanpher hosts the program that is broadcast on KNOW 91.1 FM, and available state-wide on the MPR news radio stations.
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