Invasive species are choking out native vegetation across the United States. From kudzu in the South to gypsy moths in the North, these foreign pests’ kryptonite is synthetic chemicals that have become a necessary evil for today’s landscape professional. As you’re preparing for applications, here are four tips to help you purchase and use the right chemicals.
- Read the label.
Reading the label may sound like an obvious suggestion, but it’s the most important, says Tad Grubbs, national sales director for C&S Turf Care Equipment. “Sometimes people get in a hurry and misapply chemical, which is not good for the plant and not good for the environment,” Grubbs says.
The label will tell you how much to apply, application method and target species. Dan Loughner, product technology specialist for Dow AgroSciences, says certain herbicides could kill certain desirable grasses. For example, 2-4D, a popular active ingredient, at too high of a rate could be injurious to some warm-season grasses, but is safe for cool-season grasses.
“You have to read the label and make sure the (desirable) grasses have an acceptable tolerance to the chemical,” Loughner says.
Then there are different formulations of the same active ingredient. For example, Roundup’s active ingredient glyphosate is found in several generic brands.
“One product may require 5 ounces per gallon of water to apply per 1,000 square feet – and another (glyphosate) brand requires a different amount. You can’t assume anything when it comes to chemical application,” Grubbs says. “You want to make sure you’re following the label precisely.”
- Listen to distributors.
Chemical distributors spend countless hours in the field, testing herbicides and tank mixes. From Helena Chemical Company to Wilbur-Ellis, there are dozens of chemical distributors throughout the United States and they’re experts with free advice, hoping to lure you in as a customer.
“(Distributors) will be able to point the end user in the direction they want to go. They’ll know what the problems are in the area, and most of them are good because it’s a competitive environment,” Loughner says.
Most distributors offer mixes that target specific trouble species in their region.
“It’s really up to the purchaser to determine in his geography what the major weed problems are and then work with a supplier to select a mix or herbicide to find a product that fits them,” Loughner says.
- Spray when plants are growing.
Most summer and spring applications are foliar. To achieve the best results, Loughner says, hit weeds when they’re actively growing, are lush and have good soil moisture.
“They’ll be more receptive to the herbicide under those conditions than when it’s mid-summer – when they’ve put on a waxy cuticle and it’s more difficult for the herbicide to penetrate,” Loughner says.
With low-pressure backpack sprayers, foliar applications should be made at rates of one gallon or less per minute. According to the Southeast Exotic Pest Plant Council, applicators should allow herbicide treatments to dry for at least three hours above 60 degrees Fahrenheit for good absorption and translocation.
In addition, Loughner says, an adjuvant will enhance the herbicide, but in high-volume situations, “you have so much water that the adjuvant doesn’t really matter – it will just be washed out and not add to the overall performance,” he says. “If it’s a concentrated application and you’re going for selective spot treating, an adjuvant will help.”
- Target individual trees for insects.
When insects are eating foliage and destroying your client’s beautiful hardwoods and pines, you may want to consider tree injections. This application has become especially popular for riparian areas and where there’s a stigma for pesticide applications.
“Tree injection is necessary when the situation is not practically controlled through spray or soil drenching,” says Peter Wild, founder and chief executive officer of Arborjet, a company that claims to have created the only injection system that provides a sealed vascular injection assuring rapid response and accurate dosaging.
Tree injection formulations will cover several invasive insects, including the Ambrosia Beetle, Emerald Ash Borer and mites. The chemicals also treat a number of diseases, including Dutch Elm Disease, Iron Chlorosis and Oak Wilt.
Wild says Arborjet’s tree injection systems have almost a 100-percent efficacy rate because the product moves up the xylem and down the phloem. He says applicators are injecting trees in the fall and seeing control the next spring. “In some cases it has residual of more than one year,” he says.