Research was conducted to determine if soybean oil sprays may substitute for petroleum oil for control of insects on nursery crops. Dormant field-grown `Globe' arborvitae shrubs infested with Fletcher scale were sprayed on 9 Mar. 1997 with 0%, 2%, 3%, or 4% soybean oil. One hundred scales per plant were evaluated on 4 Apr. 1997. Spraying 2% to 4% soybean oil on dormant arborvitae caused ≥97% mortality of Fletcher scale compared to only 7% mortality on untreated plants. of white pine, viburnum, `Anthony Waterer' spirea, `Green Beauty' boxwood, western red cedar, `Blue Star' juniper, `Blue Pacific' juniper, `Japanese Garden' juniper, and arborvitae plants in trade gallon pots and `Densiformus' yew and dwarf `Alberta' spruce in trade quart pots were sprayed with 0% (water control), 1%, or 2% soybean oil (emulsified with Latron B-1956) or 2% SunSpray Ultra-Fine Spray oil on 26 Aug. 1997 for phytotoxicity evaluation. No phytotoxicity occurred on western cedar, spirea, boxwood, yew, arborvitae, or viburnum. Spraying Sunspray or soybean oil caused initial loss of blue color on blue junipers and white pine. Spraying 1 or 2% soybean oil or 2% SunSpray caused phytotoxicity to `Blue Star' juniper. The `Blue Pacific' juniper, `Japanese Garden' juniper, and Alberta spruce were slightly damaged by 2% but not by 1% soybean oil.
