March 23, 2018

Not All Bugs Are Bad (or Biological Control)


Imagine walking outside and hearing a munching. A crunching vegetable sound fills your landscape. Chomp, chomp, chomp. The leaves are starting to disintegrate around you and the eventual demise of your favorite tree is clear as it looms over your house.  You look around and there are BUGS! EVERYWHERE!

Okay, that might not be at all accurate, but it is how it can feel when you have pests invading the trees and plants in your gardens.


Well, traditional insecticide sprays may seem like a good option. But... what about the butterflies that are pollinating your flowers? What will it do to your neighbors’ honeybee population? These sprays can inadvertently kill these beneficial insect friends. The sprays can be detrimental to the natural ecology of the landscape.


But wait. Here comes a hungry beetle, and he is not interested in your green garden. He has his eye on that troublesome tiny invader. He might not have a taste for all the insects in the landscape, but he and his friends can do some serious damage to the plant destroyers.

These are the good bugs. These are the ones you want. Predator insects control pest populations by feeding on the pests or by parasitizing them. In our industry, we call this biological control (biocontrol).

These tiny hanging nodules are lacewing egg sacs. Lacewings are a beneficial insect for plants.
These tiny hanging nodules are lacewing egg sacs. Lacewings are a beneficial insect for plants.

This method of suppressing plant pests using natural predator insects originated in the greenhouse production industry, but it has applications in the residential and commercial garden. Biocontrol programs often provide benefits to non-target landscape plants as well because the predators naturally seek out prey throughout the garden.


Don’t send your kids out with nets and jars just yet.

Due to the numerous pests of landscape trees and plants, weather considerations, and biocontrol insect lifecycles, effective biological control programs require a thorough understanding of entomology and plant biology. Consequently, biocontrol programs can be difficult to perform. Biological control predators include species of beetles, lacewings, midges, mites and many others. Most of these are extremely tiny. Microscopic almost, so not something you can go catch in your neighbors’ yard.

Tiny Lindorus lopanthe, Scale Destroyer Beetle, another beneficial insect, can be seen here. 
Tiny Lindorus lopanthe, Scale Destroyer Beetle, another beneficial insect, can be seen here.


NUF uses an inoculative method of biocontrol which involves releasing predator insects periodically in order to establish and maintain a balance between pest and predator. This method of treatment does not completely exterminate the pest insects but helps keep their population low enough that they don’t cause notable damage to landscape trees and plants. Rather than gambling on a single species of predator insect, we select a variety of biological control predators for each release. The mix of predator insects changes according to the pest we’re treating as well as the weather so that each treatment may include different predators, improving biodiversity in the gardens.

An effective biological control program works in harmony with nature by bolstering the ecosystems ability to maintain balance between predator and pest.  For the informed arborist or gardener there are advantages to using biological control programs. The most significant advantage is a reduction (or even elimination) of the use of pesticides in the landscape.

So next time you think about killing the bugs feeding on your trees, why not let the predators do all the hard work for you?