Demographic Trends in Mixed <I>Bemisia tabaci</I> (Hemiptera: Aleyrodidae) Cryptic Species Populations in Commercial Poinsettia Under Biological Control- and Insecticide-Based Management

Abstract

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.

DNA barcodes for bio-surveillance: regulated and economically important arthropod plant pests

“…Cryptic species have important implications for taxonomic, evolutionary, and biodiversity studies, but their presence in pest taxa also has economic and regulatory implications (Piffaretti et al 2013;Rebijith et al 2014). Several studies have considered the impact of cryptic species on pest management (Frewin et al 2014;Ovalle et al 2014), biological control strategies (Derocles et al 2015), the detection of invasive species (Blacket et al 2015;Li et al 2015), and quarantine inspections (Kang et al 2015). The most obvious implications of DNA barcoding relate to its capacity to discriminate the members of cryptic species complexes (Robe et al 2013).…”

“…Since DNA barcoding reliably identifies both immatures and adults (Shin et al 2013), and can differentiate introduced and native pests (Chown et al 2008), it has been used to help manage species complexes in agricultural systems (Li et al 2011;Frewin et al 2014). Such applications are important because insecticide resistance can vary between closely related species, and even between genotypes of the same species (van Toor et al 2008).…”

“…For example, two cryptic whiteflies in the B. tabaci complex, Mediterranean and Middle East-Asia Minor 1 (MEAM1), differ in their susceptibility to insecticides. A study on the response of mixed populations of these species showed that the Mediterranean species prevails under insecticide-based management, but it is displaced by MEAM1 under biological control (Frewin et al 2014).…”

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

“…The most prevalent species in North America (formerly considered biotypes) are characterized by a high invasive ability (Middle East-Asia Minor 1 (MEAM1) or B biotype) and an innate ability to rapidly develop a high-level of insecticide resistance that persists in the absence of exposure (Mediterranean or Q biotype) [3,4]. Resistance to conventional pesticides including newer chemistries is observed [5].…”

“…Studies from the UK, where B. tabaci is subject to eradication, demonstrated that it has been intercepted annually in the UK on imported plant material since 1987, in particular on poinsettias [8]. In Ontario (Canada), where B. tabaci is not known to overwinter outdoors, surveys of commercial greenhouse operations routinely find this whitefly in young poinsettia plants [4]. Starting a crop with high pest infestations makes it very difficult for growers to successfully use biological controls, which are best used in a preventative rather than a curative manner.…”