Strategies to get the best results from tree and shrub applications

Accuracy counts with pesticides, as an inaccurate application could lead to poor control. (Photo: Arborjet)

To ensure the effective management of trees and shrubs, operators must make the most of their applications — including selecting the right products for the job and proper timing.

Enhance plant defenses

Understanding the threshold of pest damage is important when selecting products to apply to trees and ornamentals, says Chris Sherrington, technical director at Lawn Doctor. The franchise offers residential lawn care and pest control.

To achieve the best results with trees and shrubs, the Lawn Doctor team inspects, identifies and then only treats if necessary. Lawn Doctor ensures the plants receive balanced nutrition throughout the growing season, along with insect and disease control during high pest pressure times. In general, the company offers six service programs for the cool-season market and eight services for the warm-season market.

“Balanced nutrients enhance the natural plant defense against disease, insect and environmental stresses,” Sherrington says.

Plant misidentification and selecting the incorrect product for treatment is a common mistake with tree/shrub management, he says. Applicators also should avoid impacting beneficial insects like pollinators and non-targeted insects during the application window. 

Make proper diagnoses

To maximize the effect of applications, Cal Leggett, Orlando-based manager of technical services at BrightView Landscapes, says pros should select products that are effective on the target pest or deficiency and apply them at the correct label rate and time. BrightView provides commercial design/build, maintenance, snow/ice control, water management and tree care services. The company, which ranked No. 1 on the 2021 LM150 list, reports an annual revenue of $2.6 billion.

“Understanding the life cycle of pests and when treatments are most effective for different stages of pest development help improve efficacy of tree/shrub programs,” Leggett says. 

BrightView follows integrated pest management (IPM) practices for tree/shrub applications, with a combination of preventive and curative applications, Leggett says. Project managers schedule fertilizer applications based on the needs of the plants while also following recommendations from university and regulatory agencies.

“When planning a schedule of applications, I recommend that predictable issues, such as recurring annual insect or disease pests, be treated preventively prior to outbreaks,” Leggett says. “Keeping detailed notes of when outbreaks occur is very important to help determine proper timing of preventive applications in following years. Effective treatment timing can also improve preventive programs and reduce the need for curative applications.”

He says pros should apply contact pesticides to the parts of the plant where the pests are. This often means an application must reach the underside of leaves or deep into the plant canopy. Systemic and translaminar products, when appropriate, can lead to easier applications because they move through the plant to reach the target pest.

“An inaccurate application can lead to poor control when applied at a rate lower than the label recommends,” Leggett says. “Improper applications at rates higher than label recommendations are both illegal and uneconomical due to excessive product use.”

Responsible applications

Scouting on a regular basis allows technicians to identify issues before pests or diseases reach damaging levels and reduce the amount of control products needed. 

“This is not only an environmentally responsible approach to tree/shrub care, it is also a more economical approach,” Leggett says.

The biggest mistake he sees with tree/shrub applications is when a technician improperly diagnoses an issue or selects an incorrect product for treatment. “Both of these can lead to ineffective treatments and increased costs,” Leggett says.

He encourages professionals to find resources that will help them make their applications more effective, like university research, communication with product vendors and becoming active in industry associations.

“Creating a network of other industry professionals can help when searching for advice, help with identification of an issue or recommendations for product selection,” Leggett says.