It’s Time to Help Your Trees Resist Pests

On your property, insects and microorganisms abound. If this is new news to you, don't go running for the sprays and granulated "Bug Kill Stuff." This is a natural and beneficial state, since insects and microorganisms are key components in nutrient recycling, decomposition, plant succession, natural pest control and wildlife habitat.

"A landscape without insects and microorganisms would be a very unhealthy environment," notes Tchukki Andersen, BCMA*, CTSP**, staff arborist for the Tree Care Industry Association. "The trick is to balance the threshold of healthy with having too much of a good thing, when the naturally occurring insects and diseases become a problem. This is where an integrated pest management (IPM) program may benefit your landscape plants." Even if your goal is to have the best looking yard on the block, your yard will look better if it is naturally healthy.

Periodic outbreaks of destructive tree insect pests, as well as diseases, occur as part of natural fluctuations in ecosystems. When homeowners take unguided actions against these pests, they often make these outbreaks more severe. A homeowner, with guidance regarding the use and importance of IPM, can often lessen pests' impact locally. IPM provides the steps needed to promote a healthy landscape and to prevent destructive pest outbreaks, and to ensure diversity and vigor on your property.

Begin by keeping your healthy trees healthy. Monitor for pests and use preventative and cultural controls (such as proper irrigation and mulch). Many qualified plant health care companies can assist you in this first step.

Increase diversity

Many property owners have just a single tree or a few trees. Others have small backyard woods, which have become an important component of the urban environment. Small woodlands with a mix of tree species are often less susceptible to pest outbreaks than woods with a single species.

A diversity of tree ages also reduces the risk of pest outbreaks. As with species diversity, age diversity increases the complexity and stability of the ecosystem. A natural balance of organisms is more likely to develop as age diversity increases. For example, potential pests of young trees could be regulated by parasites and predators already well established on older trees.

"A healthy landscape is less susceptible to pest outbreaks and is more resilient if an outbreak does occur," stresses Andersen. "When trees are overcrowded in your landscape, competition for light, water and nutrients results in increased stress. Trees under stress are more likely to be attacked by pests."

The first clues of a tree health problem may be symptoms such as yellowing needles or leaves, thinning foliage or dieback on upper limbs. These problems may be caused by insect pests or disease pathogens; or they may arise from "abiotic" factors such as soil problems, construction damage, drought, pollution or herbicide injury.

What to do

A professional arborist can examine your trees to find the source of the problem. A professional arborist can also recommend treatments, including planting new trees, correcting soil deficiencies, increasing water and nutrients, monitoring for pests or providing pest management. Contact the Tree Care Industry Association (TCIA), a public and professional resource on trees and arboriculture since 1938. It has more than 2,000 member companies who recognize stringent safety and performance standards and who are required to carry liability insurance. TCIA has the nation's only Accreditation program that helps consumers find tree care companies that have been inspected and accredited based on: adherence to industry standards for quality and safety; maintenance of trained, professional staff; and dedication to ethics and quality in business practices. An easy way to find a tree care service provider in your area is to use the "Locate Your Local TCIA Member Companies" program. You can use this service by calling 1-800-733-2622 or by doing a ZIP Code search on www.treecaretips.org.

TCIA arborists, safety and business professionals are available as sources for tree related articles and issues. Call 1-800-733-2622 or email andersen@tcia.org.

BMCA* - Board Certified Master Arborist

CTSP* - Certified Treecare Safety Professional