Upon visiting a project of mine, which was done last year, I discovered insect problems on a Quince and a White Pine. I had a notion what could be bothering the Quince, but was not sure about the White Pine’s ailment. In addition, I know that good diagnosis takes into account numerous factors, and it’s critical to get the “whole picture” so that treatment is quick and effective.
The home was quite a distance from our normal working area, so I photographed the symptoms and showed them to Michael Hirsch, plant health care specialist. These are his findings:
- Tent caterpillar lay eggs in summer which hatch early the next spring; in mid to late summer they appear as brown moths.
- Fall web worm build similar nests to tent caterpillars in early summer and pupate at the soil. As many as four generations may occur June through September.
- Control can be systemic injection in early spring or a variety of spray chemicals can be used when caterpillars are present. A more organic approach would be to hand pick egg masses or use sprays such as horticultural oil or soap-based sprays.
- Under the white sugary mass is an insect that feeds off the tree. Under severe infestations it tends to look as if the tree is covered in snow.
- I have found that many trees with heavy infestations of adelgid are stressed in some manner; possibilities include: girdled roots, trees still tied from time of planting or possibly over watering.
- Control methods can be a variety of chemical sprays or systemic injections. A more organic approach would be horticultural applications or manual hosing or washing of the trunk; remember to alleviate original source of stress.
Mike was correct with his thought that the White Pine could be stressed. I found the soil to be too wet and discovered the automatic sprinkler system was cycling on too frequently.
Both insect problems will now be treated and the irrigation program will be adjusted.