May 2017 Bonsai Tips

Pest Control

In the springtime, when things are growing rapidly, various pests can become more active too. Pests can range the gamut of plant animal life, from weeds to squirrels. Fortunately, here in Hawaii, we don't have squirrels digging in our bonsai, but insect pests can become a problem.

Many people think of chemical solutions to pests as their first resort. I have known bonsaists who spray glyphosate (Roundup) on weeds in their bonsai. Certainly, pulling weeds by hand can be difficult and time-consuming, but using weed killer chemicals can result in accidental death if a sudden gust of wind blows overspray onto some of your prized trees. Also, excess glyphosate can get into your garden soil and into your food supply. The same goes for chemical insecticides.

For insect infestations such as aphids, scale, and mealy bugs, I use chemical weapons only as a last resort. The first line of defense is simply spraying with water from a hose. White fly and aphids are especially treatable this way. Aphids knocked off a plant with water spray are unable to find their way back. You can also prune severely infected growing tips or leaves. Scale on bark can be scraped off. If you inspect your plants for pests when you water, you can usually stay ahead of infestations using mechanical means (pruning, scraping, water spray). If you do get a severe infestation and must resort to insecticide, use it sparingly and only on your infected plants.

Email Richard dot J dot Wagner at gmail dot com