How to Start with a Clean Crop: Biopesticide Dips Reduce Populations of Bemisia tabaci (Hemiptera: Aleyrodidae) on Greenhouse Poinsettia Propagative Cuttings

Abstract

(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.

Functional analysis of eight chitinase genes in rice stem borer and their potential application in pest control

“…Bb84 is one of the most widely used pathogenic fungal insecticides. It can be used to control SSB (Zibaee and Malagoli, 2014), thrips (Arthurs et al, 2013), whiteflies (Buitenhuis et al, 2016) and pine moths (Fan et al, 2013). Therefore, the joint use of fungal insecticides and chitinase inhibitors against the orthologues of CsCht10 could also potentially be applied to other lepidopteran insect pests (Sakuda et al, 1987;Hirose et al, 2010;Chen et al, 2014;Liu et al, 2017).…”

Variations in community assemblages and trophic networks of aphids and parasitoids in protected crops

“…However, these systems are not completely pest‐proof, as numerous harmful species still threaten greenhouse crops (Messelink et al 2012). Phytophagous insect pests can colonize greenhouses directly, via openings in greenhouses, or indirectly, via contaminated plant material (Buitenhuis et al 2016) or accidental transportation by workers between infested and uninfested crops. Once an insect pest colonizes a greenhouse, the crop system offers excellent conditions for its development, leading to rapid population growth (van Lenteren 2000).…”

Whitefly Abundance on Rooted Poinsettia Cuttings and Finished Poinsettias

“…Suppression of whiteflies has been considered unsuccessful using parasitic wasps, such as Eretmocerus eremicus, when initial whitefly densities were greater than 1.0 whiteflies (all life stages) per poinsettia cutting (Van Driesche et al, 1999). Propagative plant materials have been suggested as a major source of whitefly populations in poinsettia production (Buitenhuis et al, 2016); however, there is limited published data to support this assertion. Dipping cuttings, or ''immersion,'' in a pesticide mixture has been suggested as a method to start ''clean'' as a prerequisite for a successful biological control program (Brownbridge et al, 2014;Buitenhuis et al, 2016;Krauter et al, 2017).…”

“…Propagative plant materials have been suggested as a major source of whitefly populations in poinsettia production (Buitenhuis et al, 2016); however, there is limited published data to support this assertion. Dipping cuttings, or ''immersion,'' in a pesticide mixture has been suggested as a method to start ''clean'' as a prerequisite for a successful biological control program (Brownbridge et al, 2014;Buitenhuis et al, 2016;Krauter et al, 2017). More surveys of poinsettia cuttings from propagators will aid in determining whether the cost of preemptive insecticide treatments of poinsettia propagative materials is justified.…”