Development of a mechanical sexing system to improve the efficacy of an area-wide sterile insect release programme to control American serpentine leafminer (Diptera: Agromyzidae) in Canadian ornamental greenhouses.

BACKGROUND: American serpentine leafminer (ASL), Liriomyza trifolii (Burgess), is a significant pest of greenhouse ornamental crops, and females damage leaf tissue with their ovipositor during feeding and oviposition. The sterile insect technique has been advocated as a non-chemical alternative to currently available control methods. In area-wide sterile insect release programmes, males act as true vectors of sterility. Females should be eliminated from a cohort of pupae prior to irradiation to maximise production economics and sterility spread. The aim of this research was to develop a mechanical sexing system based on pupal size to reduce the proportion of ASL females. RESULTS: Cumulative frequency distributions were used to examine significant differences in male and female pupal length and dorsal and lateral width distributions. Optimum size cut-off points based on the largest differences in distribution curves were used to determine the dimensions of three different sieve designs. Sieve pores measuring 1.543 mm by 0.765 mm excluded 76% of female pupae and doubled the proportion of males in the throughput sample. CONCLUSION: Pupal sexual dimorphisms identified in this research can be used to design a sieve to aid in reducing the proportion of females prior to irradiation, thus improving the efficacy of an area-wide sterile insect release programme. © 2016 Society of Chemical Industry.

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

(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.

Amblyseius swirskii in greenhouse production systems: a floricultural perspective.

The predatory mite Amblyseius swirskii Athias-Henriot is a biological control agent that has the potential to play an important role in pest management in many greenhouse crops. Most research on this predatory mite has focused on its use and efficacy in greenhouse vegetables. However, an increasing number of growers of greenhouse ornamental crops also want to adopt biological control as their primary pest management strategy and find that biological control programs developed for vegetables are not optimized for use on floricultural plants. This paper reviews the use of A. swirskii in greenhouse crops, where possible highlighting the specific challenges and characteristics of ornamentals. The effects of different factors within the production system are described from the insect/mite and plant level up to the production level, including growing practices and environmental conditions. Finally, the use of A. swirskii within an integrated pest management system is discussed.

Demographic trends in mixed Bemisia tabaci (Hemiptera: Aleyrodidae) cryptic species populations in commercial poinsettia under biological control- and insecticide-based management.

Bemisia tabaci (Gennadius) is an economically important pest of agricultural and ornamental plants worldwide and is now widely recognized as a cryptic species complex. In North America, B. tabaci is a particularly important pest of greenhouse poinsettia. In poinsettia production, two cryptic species from the B. tabaci complex, Mediterranean and Middle East Minor 1, often infest crops simultaneously. Differences in pesticide susceptibility between these two cryptic species have the potential to influence growers' management decisions, including the use of biological control or insecticides, and the choice of insecticide active ingredient. However, the demographic behavior of mixed-species infestations in commercial greenhouses has yet to be investigated. We conducted a survey of B. tabaci populations in commercial greenhouses in Ontario, Canada, and provide evidence that under biological control-based management, Middle East Minor 1 can displace Mediterranean, whereas under insecticide-based management Mediterranean populations will persist. Furthermore, we comment on implications of this behavior on the management of B. tabaci, and comment on methods used to identify B. tabaci cryptic species.

Effectiveness of insecticide-treated and non-treated trap plants for the management of Frankliniella occidentalis (Thysanoptera: Thripidae) in greenhouse ornamentals.

The effectiveness of trap cropping as an integrated control strategy against western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), was explored in potted chrysanthemum, Dendranthema grandiflora (Tzvelev), greenhouse crops. The efficacy of flowering chrysanthemum trap plants, either treated with the insecticide spinosad or untreated, to regulate F. occidentalis populations was tested at different spatial scales (small cage, large cage and commercial greenhouse) and for different time periods (1 or 4 weeks). It was demonstrated that flowering chrysanthemums as trap plants lower the number of adult F. occidentalis in a vegetative chrysanthemum crop and, as a result, reduce crop damage. In the 4 week large-cage trial and the commercial trial, significant differences between the control and the trap plant treatments started to appear in the third week of the experiment. Larvae were only significantly reduced by the presence of trap plants in the 1 week small-cage trials. There were no significant differences between treatments with spinosad-treated and untreated trap plants in the number of F. occidentalis on the crop. This suggests that there was minimal movement of adult F. occidentalis back and forth between the trap plants and the crop to feed and oviposit. It is concluded that the trap plant strategy is a useful tool for integrated pest management against F. occidentalis in greenhouses.