Yard & Garden Line News March 1, 2006

Yard & Garden Line News
Volume 8 Number 3 March 1, 2006

Features this issue:

Salad Dressing or Weed Control? An Organic Non-Selective Weed Control Product Evaluation
There's Snow Place Like Home For These Insects
Editorial Notes

Salad Dressing or Weed Control?
An Organic Non-Selective Weed Control Product Evaluation
Bob Mugaas, Regional Extension Educator-Horticulture

Introduction
In recent years there has been an increasing interest among homeowners in the use of organically-based, non-selective herbicide products as “alternatives” to the more conventional products of glyphosate (RoundUp and its many variations) or glufosinate-ammonium (e.g., Finale and others). To that end, a small observational study was conducted last summer at the University of Minnesota’s Outreach, Research and Education Park (UMORE Park) in Rosemount, Minnesota. The study was conducted such that any results would be visible for the public to view at the open house on August 18, 2005. This short report will summarize observations from that study.

Project Description
The products evaluated in the study were as follows. Information and active ingredients are those listed on the product label:

All Down Organic Grass and Weed Killer
Source: SummerSet Products, Inc. Bloomington, MN
Active Ingredients: Citric Acid - 5.0%, Garlic - .2%,
Other Ingredients: Acetic Acid, Yucca Extracts and water – 94.8%

Ground Force Organic Herbicide
Source: Abby Laboratories, Inc., Ramsey, MN
Active Ingredients: Citric acid - 10.0%, Garlic extract - 0.2%
Inactive Ingredients: Vinegar, yucca extract and water - 89.8%

Burn Out II - Weed and Grass Killer
Source: St. Gabriel Laboratories, Orange, Virginia
Active Ingredients: Clove Oil - 4.0%, Sodium Lauryl Sulfate - 3.0%
Other Ingredients: Vinegar, Lecithin, Citric Acid, Mineral Oil and water - 93%

Everything Must Go!^TM
Source: Farm Extracts, Inc., St. Paul, MN
Active Ingredients: Citric Acid - 10.0%, Garlic Oil - 5.0%, Lauryl sulfate - 1.0%
Inert Ingredients: Acetic Acid and water - 84%

Round-up Weed and Grass Killer - Ready-to-Use Plus
Source: Monsanto Chemical Co.
Active Ingredients: glyphosate 2.0%, pelargonic acid and other fatty acids 2.0%
Other Ingredients: (not specified) - 96%

Finale Ready-to-Use
Source: Fornam Companies, Inc., Phoenix, Arizona
Active Ingredients: Glufosinate ammonium - 1.0%
Other Ingredients: (not specified) - 99%

Control (No applications)

Scope of the project
It is important to note that this study was primarily observational in nature. It was set up to observe what effects, if any, these products impart and how long those effects last. Also, the design of the experiment was not replicated nor was specific data taken to make any direct comparisons or perform any type of statistical analysis. Digital pictures were taken regularly to document the observed application effects. These will form the basis for discussion of the observed results.

Location
The area chosen was a newly established lawn area located in full sun. The area was dormant seeded in late fall of 2004. The dominant turfgrass species in this area were Kentucky bluegrasses with smaller quantities of fine fescue and perennial ryegrass also present. Scattered dandelions averaging 3 or 4 small rosettes per plot were the primary broadleaf weed species present. There were essentially no warm season annual grasses or significant populations of other broadleaf weeds present in the plots at the initiation of the study. General turfgrass coverage of the area was 90 - 95% of the soil surface. Some small gaps of open soil did exist randomly throughout the study area. Soils in this area are generally of a medium soil texture.

Project Layout
The plot sizes were 2-foot by 2-foot squares with all three treatments of the same material located adjacent to each other in an east to west orientation. The plot layout is shown in Table 1 below. There was no irrigation provided at any time during the study other than natural rainfall. In no instance did it rain within 24 hours of any application. Mowing heights of those plots waiting future applications or those that recovered from any herbicide effects were maintained at about 3 inches during the study.

Table 1	Experimental Layout
Weeks Prior to OH*	Treatments						N
2 wks	EMG	All Down	Finale-- RTU	Control	BurnOut II	Round- Up RTU	Ground Force
4 wks	EMG	All Down	Finale-- RTU	Control	BurnOut II	Round- Up RTU	Ground Force
6 wks	EMG	All Down	Finale-- RTU	Control	BurnOut II	Round- Up RTU	Ground Force
*OH=Open House

Applications
All of the herbicide materials were either purchased from local retail outlets or donated for the study. Three application dates were carried out every two weeks beginning at six weeks (July 6) prior to the August 18 open house. The other two dates were at four weeks (July 20) and two weeks (Aug 4) prior to the open house. This would allow public viewing of the product's immediate effects as well as how long these effects lasted.

With the exception of the Everything Must Go!™ (EMG) product, all materials were applied with the manufacturer's ready-to-use container and according to label directions. The EMG product was mixed with water per label directions, (nine parts water to one part EMG concentrate), and applied with a hand-held spray bottle using the label rate of eight quarts of mixture per 1000 square feet. The ready-to-use materials indicated that plant material should be sprayed until uniformly wet.

For the purposes of this study, only general weather conditions were noted. Thus, weather conditions at the time of all applications were sunny-to-mostly sunny with temperatures in the range of 75º - 85º F. Rainfall did not occur 24 hours prior to, during or following applications. Soil moisture conditions at the time of the applications would have been considered to be on the dry side although exact soil moisture measurements were not taken.

Results and Observations

When viewing the pictures referenced in this section, there are just a couple of hints to ensure that pictures are observed correctly. First, be sure to reference the plot plan in Table 1 as the layout portrayed in the pictures is exactly as laid out in that plan. Second, the first set of treatments was applied six weeks prior to the open house. These will appear as the first row of 2 X 2 foot boxes toward the lower portion of the picture. The treatment applied four weeks prior to the open house will be the second set of 2 X 2 foot boxes and be located directly above the "six weeks prior to open house" application. Finally, the treatment applied two weeks prior to the open house will be the third set of 2 X 2 foot boxes and be located directly above the "four weeks prior to open house" application. These latter areas were kept mowed at about 3 inches until the time of application and appear a normal green color in the pictures.

One day after the July 6th treatment


Plant injury 1 day after July 6th application. Photo credit: Bob Mugaas

Three of the four organic materials (All Down, Ground Force and Burn Out II) showed very rapid browning and drying of plant foliage. Effects from these three materials were evident within 24 hours of application with complete browning and drying of the foliage within a couple of days. The EMG product exhibited some grass tip injury but did not completely brown or destroy any of the plant material foliage.

Plant injury 1 week after July 6th application. Photo credit: Bob Mugaas

Because the RoundUp product contained some pelargonic acid, a contact herbicide, some immediate injury was also observed with this product although not as dramatic as for All Down, Burn Out II or Ground Force. The Finale product took about three to four days for damage to become really evident.

One week after the July 6th treatment With the three organic materials that showed significant damage one day after application, the plants were already starting to show recovery from the injury one week after application. This was evidenced by an increase in visible green sheath tissue of the grass plants as they were beginning to outgrow the initial damage to the leaf blades. Dandelions and any other broadleaf weeds present were still showing damage at one week past application and had not yet begun to outgrow the initial damage.

Two weeks after July 6th treatment

Plant injury 2 weeks after July 6th application and 1 day after July 20th application.
Photo credit: Bob Mugaas

By two weeks after the first application, recovery from initial injury caused by All Down, Burn Out II and Ground Force had improved significantly as evidenced by an ever increasing amount of green tissue present. See first (lower) row of treatment plots in picture at left. However, they had not yet returned to the same healthy green level as expressed in the control plots. By this same time period, the Finale and RoundUp products, while taking somewhat longer to show initial effects, had completely killed all of the vegetation in the plots. Again, see the first or lower row of treatment plots in picture at left. Both Finale and RoundUp appear as a vivid, uniformly tan color with no regreening or regrowth present. The EMG treated plots had completely outgrown the initial application effects and the foliage had regrown to a normal green color and was no different than the control plants.

At this same time, the "four weeks prior to open house" application was put down. Again, one day post application, the same kinds of symptoms were observed as in the earlier application for all four of the organic materials. Likewise, some initial browning and drying effects were observed for the RoundUp treated plots and no real signs of injury observed (yet) on the Finale treated plots. See the second row of plots located directly on top of the "six weeks prior to open house" applications for damage expression of all seven treatments.

Three weeks after July 6th treatment; one week after July 20th treatment

Plant injury (and recovery) 3 weeks after July 6th application and 1 week after July 20th application. Photo credit: Bob Mugaas

By three weeks after the first application, greening and regrowth of the All Down, Burn Out II, Ground Force and EMG treated plots had recovered to that of the control level. That is, the treated plots were indistinguishable from those of the control. Visible evidence for that recovery can be seen in the first row of plots in picture at left. In stark contrast to that are the completely dead plots resulting from the RoundUp and Finale applications. At this point, there was no evidence of any green growth occurring in either of these plots.

Symptom expression was similar for RoundUp and Finale following one week after application. Note the second set of plots directly on top of the "six weeks prior to open house" applications. Likewise, symptoms for All Down, Burn Out II and Ground Force can be seen in that same row of plots. Again, by one week after application, there was green tissue already showing up in those treatments. The EMG application expressed very little injury and was essentially similar in color and growth to the control at this point in time.

Treatment Injury (and recovery) 7 weeks after first application Photo credit: Bob Mugaas

Final observations for all treatments taken seven weeks after the July 6th treatment; three weeks after the August 4 treatment
All treatments continued to follow the same damage expression and recovery (or lack of it) pattern as noted for the periods described above. As seen in picture at left, All Down, Burn Out II and Ground Force treated plots had all recovered to the levels of the control plots by three weeks after the last application on August 4. Again, the EMG application showed little damage expression in this same time period and was essentially similar in all color and growth characteristics to that of the control.

Finale and RoundUp treated plots showed no regrowth or recovery in any of the treated plots. These can be seen in photo as the more vertical set of plots showing the dead plant tissue in all of the treated plots. Treatment date labeling has been included with this picture for easier discrimination between application dates. These same areas were reseeded one week later from when these pictures were taken on August 24 with no evidence of any seedling damage or inhibition such that by late September these areas were again similar to the surrounding non-treated lawn areas.

So, what can be learned from these results, and needs for future study

1. The non-selective organic herbicide products of All Down, Burn Out II, Ground Force and Everything Must Go!^TM were not effective at permanently killing the established perennial grasses of Kentucky bluegrass, fine fescue, perennial ryegrass, or the broadleaf weed, common dandelion with only one application of the product. In some ways that should not be surprising as these products are considered contact herbicides and their active ingredients are not translocated to other sites of activity within the plant. Their primary site of injury is where they contact the plant tissue. Hence, thorough plant coverage is essential to be the most effective. Likewise, perennial plants with the capacity to regenerate new shoots and roots from plant parts not contacted by these materials would have a high probability of surviving a single application. Perhaps repeated applications would deplete plant carbohydrate reserves to such an extent that the plants would ultimately not be able to recover. However, that will have to be a question addressed in another study. It should also be noted that with each additional application of these products the cost of controlling the weeds goes up. Where costs are a major consideration in determining a product's use, this could put a damper on using these materials, especially if multiple applications were necessary.

2. Results of this study beg the question, "Where and under what conditions would these products be the most effective?" This particular study only examined one particular application situation. One must be very careful not to conclude from this study that these materials do not work at all. While it is clear from this study that a single application of these products on established perennial cool season lawn grasses and common dandelion was not effective at permanently destroying them, their use on small seedlings of annual broadleaf or grassy plants may be much more effective. A thorough coverage of small, annual seedlings just emerging from the soil might be one of those situations where they could be effective. In this particular situation, complete plant coverage with the material would leave little, if any, unaffected tissue to recover and outgrow those initial effects. However, that was not part of this study and it too will have to await another study to examine those specific plant growth stage situations.

3. As expected, the two conventional products performed as per product claims. That is, both resulted in relatively rapid browning and death of the existing plants without any recovery. Since excellent control was achieved with only one application of these materials, their cost effectiveness would be quite high. While providing rapid death of the plants in these plots, it is also important to note that there was no remaining residue that impacted reseeding of these areas. This would also be consistent with information contained on the product labels and past experience with using these materials.

4. As with all materials applied to affect plant growth in some manner, the degree of that effect depends on many different variables present at the time of application. Some of those variables include growth stage of the plant, plant growth activity, plant resistance to herbicide penetration and translocation, air temperatures, soil and plant moisture status, irrigation and/or rainfall prior to and following application, to name just a few. Hence, achieving desirable results with any herbicide takes some knowledge of the plant, prevailing weather conditions, and specific product characteristics. Properly applying the product is also extremely important. For example, being sure to get sufficient coverage of the plants to elicit the desired effect is very important. Perhaps this was the situation that contributed to the lack of results observed with the EMG product. According to label directions, we needed to apply a very small volume of material (about 1.1 oz.) on our 2 X 2 foot plot. That may have been insufficient volume to achieve the desired effect. As further evaluations are conducted on these materials we will hopefully refine our application technology to achieve effective weed control with them.

Final Comments
An interesting new area of product development is organically-based, non-selective herbicide materials available to homeowners. However, much remains to be learned about their specific uses and limitations. It is hoped that follow-up studies can be initiated and further contribute to this knowledge base.

There's Snow Place Like Home For These Insects
Jeffrey Hahn, Assist. Extension Entomologist

Snow fleas Photo credit:
Jeff Hahn

Snow scorpionfly Photo credit:
Tony Thomas

Crane fly, Chionea Photo credit:
Cedar Creek

Chironomid midge Photo credit:
Will Bouchard

Small winter stonefly
Photo credit:
Michelle Mahood

Caddisfly
Photo credit:
Thomas Ames

Although perhaps not as sure as death and taxes, most of us would still be willing to bet that we would not see insects outdoors during winter. Insects, being cold-blooded animals, are active according to the temperature of their environment. When it's cold out, insects usually survive by going into a dormant state. And that's the condition you find most outdoor insects in during March.

However, there are a surprising number of six-legged creatures, covering a wide variety of groups, that are active when it is cold, especially now. While it may seem strange that an insect would evolve to finish their development during winter, they certainly have the advantage of having few predators around. So whether you are out cross country skiing, snow shoeing, fishing, or maybe just walking through your front yard, be on the watch for these fascinating insects.

Perhaps the most familiar winter insect is the snow flea, Hypogastrura nivicola. Despite having ‘flea' in its name, it is not a relative of cat fleas or other fleas that bite us. Instead, it's actually a type of Collembola, a group commonly known as springtails. Springtails are wingless so they move by walking and jumping. Unlike true fleas which jump with their back legs, snow fleas and other springtails use an appendage called a furcula to spring. The furcula, located under the abdomen's posterior, is moved and locked into place underneath the body like a snap trap. When it is released, it propels the springtail up and forward. Snow fleas feed on microscopic fungi, algae, and decaying organic matter. They are only 1/10th inch long, so they look like pepper on the snow. However, they can become so abundant that they can turn snow black. Watch for snow fleas especially around the base of trees.

Another winter insect is the snow scorpionfly of which the most common species belong to the genus Boreus. This small, dark-colored, 1/8th inch long insect is not a true fly but belongs to the order Mecoptera (scorpionflies). Scorpionflies get their name because the males of common scorpionflies have a bulbous tail that curves over their body which resembles a scorpion. All scorpionflies have pronounced beaks and most are winged. However, like snow fleas, snow scorpionflies are wingless. They finish their development during winter. They are easy to see when they're on top of snow; they also found in moss where both adults and larvae feed.

Crane flies, found in the order Diptera, are a common long-legged group of insects that resemble mosquitoes. Unlike most crane flies, species of the genus Chionea (ki-OWN-ee-uh) are wingless, spider-like, and active during cold weather. Sometimes Chionea are referred to as snow flies. They are dark colored and measure about 1/8 - 3/16 inch long. While Chionea's summer dwelling cousins are relatively short-lived, surviving for about seven to ten days, Chionea can survive up to two months. This crane fly is quite mobile and is able to walk across snow easily. It is not clear what Chionea eats, although it is suspected that the larvae feed in rodent burrows on feces. It is not known what, if anything, the adults eat.

Not all winter insects are wingless. The aptly named winter stonefly is winged as an adult. Stoneflies (order Plecoptera) are small to medium sized insects with dark-colored, flattened bodies. They have four conspicuous appendages, two antennae about half the length of its body and two cerci (tails) on the tip of its abdomen that are about the same length. They have four wings which they keep folded behind them over their abdomen. This group of insects is represented by a number of different species belonging to the families Taeniopterygidae (winter stoneflies) and Capniidae (small winter stoneflies). As an immature nymph, this insect lives in water, particularly spring-fed trout streams and rivers where they feed on plant material. Generally, nymphs hatch in spring but then are inactive through much of the summer. They resume activity by fall, completing development sometime during winter or early spring. Adults emerge shortly after that. Adults generally don't feed.

Chironomid midges are true flies belonging to the order Diptera (just like crane flies). They are small, mosquito like-insects, although they do not bite people or animals. There are at least 11 species of chironomid midges that are active in Minnesota during winter. Although adults can emerge at most times of the year (except summer), they are most common during late fall, winter, and early spring. The most common type of midge belongs to the genus Diamesa (dye-uh-ME-suh). They spend most of their time as larvae, usually in ground water fed streams. While these streams are cool during summer, they remain relatively warm during winter. The larvae generally feed on tiny algae and microbes growing on rocks, wood, and other things in the water. Adults emerge during warm winter days and congregate in swarms in order to mate. Like crane flies, winter active chironomid midges typically live longer, up to three weeks, than their summer cousins which usually only live a few days. Adult chironomid midges do not feed.

Another common group of insects, the caddisflies (order Trichoptera), has several species that may be found during the winter. A common species is Dolophilodes distinctus. This caddisfly belongs to the family Philopotamidae or finger-net caddisflies. Caddisflies are generally small, moth-like insects with very long antennae, much longer than the length of their bodies. They possess scales on their wings which they hold tent-like over their bodies and are typically dull-colored. The larvae live in water, such as ponds or streams. Many construct a case made of small pieces of vegetation, twigs, sand, or tiny stones or will construct a silken net in which they can capture food. A few caddisfly larvae are free-living. Most caddisfly larvae eat plant material, although a few are predaceous. Like the other winter insects we have discussed where the immature stage is aquatic, Dolophilodes distinctus is typically found in spring fed trout streams where the water is generally warmer during winter. Interestingly, females have brachypterous wings, i.e., they are quite short while males possess normal length wings.

For additional readings see http://www.emporia.edu/ksn/v38n2-may1992/KSNVOL38-2.htm (snow flies in Kansas) http://www.entomology.umn.edu/midge/Winteractivemidges.htm (chironomid midges in Minnesota)

Get the low down on this month's insect pests at Insects
http://www.extension.umn.edu/projects/yardandgarden/EntWeb/Ent.htm

Editorial Notes

Orchid
Photo credit:
Beth Jarvis

For April 1, Bob Mugaas will provide the data from the two-year perennial evaluation program that he, Janna Beckerman and a host of Master Gardeners conducted. A bit later, we'll review the vegetable varieties trials conducted by the Master Gardeners. Nancy Rose has provided an article on "blue" trees that I'll run in a future issue. This article provides some alternatives to Colorado blue spruce,a popular landscape tree yet a poor landscape choice due to their disease susceptibility

The orchids at left were part of the February orchids display.

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/.

Deb Brown will be answering a few gardening questions with Cathy Wurzer on MPR, the first Friday of March, at roughly 8:40 am. The program is broadcast on KNOW 91.1 FM, and available state-wide on the MPR news radio stations. (Scroll down for map.)

For plant and insect questions, visit http://www.extension.umn.edu/askmg. Thousands of questions have been answered, so try the search option in the black bar at the top left of the board for the fastest answer.

If you would like to receive an e-mail reminder when the next issue of the Yard & Garden Line News is posted to the web, just send an e-mail to: listserv@lists.umn.edu (note: the second E in listserve is omitted), leave the subject line blank, then in the body of the message, type: sub yglnewslist or to unsubscribe, enter: unsub yglnewslist

Happy gardening!

Beth Jarvis
Yard & Garden Line Project Coordinator

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