Abstract

ABSTRACTS

MACLURE, M.S. 1983. Chinese ladybugs hold promise for controlling Japanese scales in the U.S. Am. Nurseryman 158(3): 30-33.

Insects introduced into different areas of the world from where they evolved often become very serious pests. Gypsy moth, Japanese beetle, and Mediterranean fruit fly are familiar examples. In a new habitat with a hospitable climate, a suitable host plant and no natural enemies from the homeland, a population of introduced insects can increase in number very rapidly. Examples of successful biological control are few compared to those of chemical control. The most effective predator and the one with the best chance for establishment in the northeastern United States is a ladybug, Harmonia axyridis. I observed large numbers of those ladybugs feeding voraciously in scale-infested pine stands throughout eastern China. Scale mortality from this ladybug of 70 percent is common, but mortality as high as 90 percent has been observed. I have obtained a colony of H. axyridis. I am now conducting experiments in Connecticut to determine if this ladybug can control red pine scale populations and successfully over winter.

WILSON, P.J. 1983. The shigometer technique in practice. Arboric. J. 7: 81-85.

The shigometer technique was developed to detect decay in living trees and telegraph poles. The technique is almost non-destructive and if proved to be quick, easy, and reliable to use in practice it would have applications in arboriculture, forest management, research, and the maintenance of some wood in service. In any practical application of the technique, the internal condition of a tree or pole would be predicted from one or more radial patterns of resistance readings. This test was designed with this in mind. The test material consisted of discs of New Zealand red beech (Nothofagus fusca) selected randomly from part of Maruia State Forest, Westland, New Zealand. The shigometer technique proved to be neither quick, nor easy, nor reliable to use in practice. It did not work in red beech and the evidence that it works in other species is inconclusive. The high variability encountered in red beech remains unexplained because the technique lacks any firm theoretical foundation.