The turf industry has experienced a revolution in the types of products that lawn care companies have at their disposal for controlling diseases and insects. Similarly, tree and ornamental care practices and products have undergone changes in methods and products of choice.
The foliar application of pesticides is still used by many maintenance contractors, but research at the university level is focused on alternatives to this method, including soil and trunk injection. Research is also building on the success that many contractors are having with non-traditional products, such as horticultural oils and insecticidal soaps.
With the strong emphasis on plant health care and integrated pest management in tree care, contractors agree that the more options they have, the better they can care for customers’ trees.
CLOSER LOOK. Like products in the turf industry, pesticides for trees are receiving a great deal of scrutiny from the gov-ernment, end users and university researchers. Tried and true chemistries, such as organophosphates and carbamates for insects and daconil for diseases, are still relied on to fill the need for consistent and proven insect control. Now more than ever, though, users and universities are exploring some of the alternatives that are becoming available.
| Getting The Right Rig |
So, you’ve decided to get into the tree care business. Join the club, because it’s a growing area of business that has been taking off over the past few years. In fact, manufacturers of spray rigs for lawn and tree care report that the most significant rise in purchases of tree care spray equipment has occurred over the last two years. "It’s especially true for equipment to spray larger trees in the 100-foot range," said Ron Revis, sales manager, Westheffer Co. Inc., Lawrence, Kan. "Sales of this equipment make up about 20 percent of our sales, which may not sound like much, but that’s five times more than we sold two or three years ago." Besides the technical expertise required to set up a program and recognize tree problems in the field, contractors will also need an appropriately apportioned truck. Manufacturers of spraying systems for trucks are quick to note that tree care requires a totally different setup for storing pesticides, and the pumping system must provide significantly more psi pressure and gallons per minute volume than a system designed for lawn care. The main reason for this is both efficiency and liability. "To spray a 100-foot tree, a contractor needs to generate 60 gallons per minute at 800 psi to create a solid stream," explained Tom Sayward, owner, Tuflex Manufacturing, Pompano Beach, Fla. "This allows enough product to drip through the canopy and provide good coverage without creating a lot of mist that causes drifting." Drift is one negative to an inadequate pump, but so is reduced productivity. "Most guys in the business want to be able to pull the trigger, make the application and move onto the next site," stressed Sayward. "The right equipment allows them to do that." The other consideration is the number of tanks that will be required, which varies depending on the type of program to be implemented. Tanks for the water, fungicide, insecticide and fertilizer would be optional, as would an additional tank for horticultural oil, an add-on that Sayward said is gaining in popularity. If you’re concentrating your efforts on clients with smaller trees in urban settings, then a less powerful, lower volume unit may be appropriate. The manufacturers said that a thorough review of your goals with a tree care program, your client base, the kind of applications you’ll be making and the equipment you already own would be factored into any recommendation they make. - Paul Schrimpf |
Cathy Zahirsky, pesticide programs coordinator, The Davey Tree Expert Co., Kent, Ohio, explained that the company has placed an even greater focus on its screening program to test the viability and use of new chemistries. "We have three primary concerns with this testing - protection of the environment, applicator safety and efficacy," Zahirsky stressed.
Before any efficacy tests are run, Davey first learns all it can about the chemistry in question. "We call the Environmental Protection Agency for information, we contact medical sources and a variety of pesticide databases to get the information we need," said Zahirsky. If the chemistry falls within predetermined risk parameters, the product goes to the company’s research facility in Ohio for efficacy testing.
If this round of testing proves successful, then the product is moved on to field testing for a season. Chemistries that pass all of the testing are added to the company’s treatment booklet, and the products are then available to the company’s branches for use.
Along with new chemistries, such as Conserve, Davey is putting some of the more established products, such as pyrethroids, chlorpyrifos and diazinon, through the same regimen of testing, Zahirsky said.
On the university side, alternative products are getting a closer look due in large part to the EPA’s plan to closely scrutinize pesticide use patterns as part of the Food Quality Protection Act of 1996, noted Mike Raupp, professor and chair of the department of entomology at the University of Maryland, College Park.
"In the future, we could end up losing some of the products that the industry relies on so heavily," Raupp cautioned. "We need to be prepared to have alternatives."
Raupp said the department’s research includes studying nematodes for insect control, as well as comparing species of trees and shrubs for natural resistance.
Classes of products that aren’t new but that are seeing ever increasing usage for the control of scale and aphid pests are spray-applied horticultural oils and soaps. Although proven effective, Frederic Miller, extension entomologist, University of Illinois Cooperative Extension-Countryside Office, has been experimenting with a tank mix of horticultural oil and a reduced rate of Dursban for insect control.
Miller said the results have shown that the oil plus reduced rate Dursban combination is as effective as applying Dursban at the full rate. Although it isn’t legal in most states to apply such a mixture, experimentally the combination has shown promise.
What's New in Trunk Injection? |
Another alternative to traditional spray and soil injection is the use of delivery systems that place the active ingredient directly into the trunk. As this method grows more accepted in the lawn and landscape industry to cure a variety of tree maladies, manufacturers are adding products to their lines. Nate Dodds, director of marketing, J.J. Mauget Co., Arcadia, Calif., said that the company is working on getting new combinations of materials registered for the market, including fungicide-pesticide formulations. "We’re focusing our development efforts on getting more of the low toxicity chemistry into the trees," Dodds said. Dodds said that the majority of lawn and landscape contractors who use microinjection cite insect problems as the main reason for using the products, followed by micro-element deficiencies and fungus problems. "In general, it’s more difficult for contractors to accurately diagnose disease problems, which makes them less confident in making a treatment recommendation such as microinjection," said Dodds. Chip Doolittle, president, Arbor Systems, Omaha, Neb., said that the company’s recently registered abemectin-based insecticide has preformed well against spider mites, and Arbor Systems is conducting research that may lead to registration for the control of lepidopterus caterpillars, including the gypsy moth caterpillar. Roger Webb, president, Tree Tech, Williston, Fla., said the company recently received registration for its microinjected abemectin-based product, as well as a new bactericide for the treatment of leaf scorch and other tree bacteria problems. Webb also noted that his company and Novartis have reached an agreement that will allow Tree Tech to sell a microinjected version of Novartis’ Vanquish herbicide. The product would be available for use in right of way tree clearance or for killing non-native trees in environmentally sensitive areas. - Paul Schrimpf |
INJECTING LIFE. "There have been some big changes in the way we apply pesticides to trees," noted John Gibson, tree and ornamental program manager, Swingle Tree Co., Denver, Colo. "We’re trying to get away from the traditional foliar application and change over to soil-injected products."
There are two primary drivers of this trend. "Customers perceive soil injection to be a safer method of applying pesticides, and it is so much less weather dependent," explained Gibson. "And, because of the duration of control and the ability to treat in inclement weather, being able to do soil injection has allowed us to extend our season by as much as 40 to 55 days."
"We’ve been switching to soil injection slowly so we don’t have to spray," concurred Bob Biel, partner, K & B Tree and Lawn Care, Beaver Dam, Wis. "With spraying pesticides, you’re at the mercy of the weather. We do soil injection treatments as soon as the frost is out of the soil. It puts some flexibility in the program."
"We’ve been in the business of tree care for 25 years, and our history had always been to spray trees," agreed Roger Albrecht, director of franchise development, Nitro-Green, Atlanta, Ga. "Now, we’ve evolved to the point where we won’t spray larger trees, and we only spray where necessary. The scariest thing is the liability issues that come with spraying."
Soil injection of chemistries like imidacloprid (Merit) is convenient and highly effective, according to contractors, but does require some customer education, Gibson noted. "It can be difficult to get customers to convert from a spray program," Gibson said. "You have to explain that a soil injection treatment early in the year will cover them in the upcoming season and why the injection product will cost more to apply. They have to comprehend the value of the application and not simply look at the dollars."
Gibson said that Swingle’s goal is to convert the majority of customers to injection application, and at this point they’ve gotten about half of their customers on the injection program. "It was about 10 percent three years ago," he recalled.
Reducing spray-applied pesticides has also been a goal of university research exploring the possibility of soil injecting some of these same chemistries.
"I think that the traditional means of applying pesticides via spray is not going to be acceptable in the near future," predicted David Tatum, extension entomologist, Mississippi State University. "We’re looking at different ways to deliver the products without the problems that sprays can create."
Unfortunately, not every chemistry is effective as a soil-injected product. The plant must be able to take up the product through the roots and then deliver it to the parts of the plant that the target pest infests. One chemistry that Tatum has found success with is orthene, an insecticide.
Tatum conducted a two-year study using a soil-injected formulation of orthene, and observed the effects of the product on aphids on crape myrtle and river birch. In both cases, the injections were effective in suppressing aphid populations, he said.
MICRO WAY. Microinjection, injecting active ingredients directly into the trunk of a tree, has also gained in popularity as a cure for specific tree problems.
"We’ll do a trunk injection treatment for difficult problems such as bronze birch borer or dutch elm disease," explained Gibson. "When we’re considering a trunk injection product, we really weigh the product’s ability to work in that format, and we’ll test it in-house to see how well it works and whether we get the results we expect."
"We’ve done some microinjecting of nutrients in cases where the tree was older and sicker, and they’ve been effective for us," noted Ed Walter, president, Washington Tree Service, Seattle, Wash.
The author is Managing Editor of Lawn & Landscape magazine.
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