(1) Global movement of propagative plant material is a major pathway for introduction of Bemisia tabaci (Hemiptera: Aleyrodidae) into poinsettia greenhouses. Starting a poinsettia crop with high pest numbers disrupts otherwise successful biological control programs and widespread resistance of B. tabaci against pesticides is limiting growers’ options to control this pest; (2) This study investigated the use of several biopesticides (mineral oil, insecticidal soap, Beauveria bassiana, Isaria fumosorosea, Steinernema feltiae) and combinations of these products as immersion treatments (cutting dips) to control B. tabaci on poinsettia cuttings. In addition, phytotoxicity risks of these treatments on poinsettia cuttings, and effects of treatment residues on mortality of commercial whitefly parasitoids (Eretmocerus eremicus and Encarsia formosa) were determined; (3) Mineral oil (0.1% v/v) and insecticidal soap (0.5%) + B. bassiana (1.25 g/L) were the most effective treatments; only 31% and 29%, respectively, of the treated B. tabaci survived on infested poinsettia cuttings and B. tabaci populations were lowest in these treatments after eight weeks. Phytotoxicity risks of these treatments were acceptable, and dip residues had little effect on survival of either parasitoid, and are considered highly compatible; (4) Use of poinsettia cutting dips will allow growers to knock-down B. tabaci populations to a point where they can be managed successfully thereafter with existing biocontrol strategies.

A generalist predatory mite, Anystis baccarum (L.), has been identified as a key predator of small, soft-bodied pest species in various agroecosystems around the world. The foxglove aphid Aulacorthum solani (Keltenbach) is a new problematic pest in Canadian greenhouses. Laboratory colonies of A. baccarum were established and its predatory efficacy against A. solani was assessed. In laboratory trials, A. baccarum ate approximately one adult aphid or seven first instar aphids in 24 h. In a greenhouse bench trial on sweet peppers with the free-flying aphid parasitoid, Aphidius ervi Haliday, the population dynamics of A. solani in the presence or absence of A. baccarum was evaluated. Although the parasitoid alone successfully eradicated A. solani, when A. baccarum were present on the plants, the aphid population was eradicated more rapidly. Fruit yield was also 15% higher from plants where A. baccarum was released than the control (without A. baccarum). Furthermore, plants were naturally infested by Frankliniella occidentalis (Pergande) during the trial, which caused visible feeding damage to the fruits. Anystis baccarum also predates on thrips and thrips’ feeding damage to the fruits was reduced on plants where A. baccarum was released. Anystis baccarum was able to establish in sweet peppers and was determined to be complementary to the current practice of using A. ervi for the biological control of A. solani.