Betsy A. Anderson, USDA/ARS, ATRU, Biological Science Technician, IR-4 Specialist; Michael E. Reding, USDA/ARS, ATRU, Research Entomologist; Michael G. Klein, USDA/ARS, ATRU, Research Entomologist; and Charles R. Krause, USDA/ARS, ATRU, Plant Pathologist.
Each test included untreated control plants and three pesticide treatment rates — 1X (the rate recommended by the manufacturer), 2X, and 4X. The tests had four, six, or 10 replications.
Field container test plants were transplanted into two-gallon containers using an amended pine bark medium and set up in an outdoor nursery in a randomized complete block design. Field test trees and shrubs were planted in rows separated by rows of grass in a completely randomized design. Greenhouse plants were planted in one-gallon containers and placed on benches in a greenhouse. Plants were rated for phytotoxicity four times during the growing season after the first treatment.
Efficacy data was requested for the insecticide trials — Thiamethoxam (Flagship) for control of white grubs, Japanese beetle larvae (Popillia japonica), and European chafer larvae (Rhizotrogus majalis), and trichlorfon (e.g., Dylox) for control of oriental beetle larvae (Anomala orientalis).
In an effort to get the needed data, the container tests were infested with eggs of European chafer and oriental beetle. Two field tests were conducted on rhododendrons in a nursery known to have problems with European chafer in field-grown nursery stock, and a third was conducted in a field of hemlocks that was naturally infested with third-instar larvae of European chafer.