Odour masking of tomato volatiles by coriander volatiles in host plant selection of Bemisia tabaci biotype B

Abstract

The silverleaf whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), is one of the most important pest insects in tomato crop systems worldwide. It has been previously demonstrated that intercropping tomato [Solanum lycopersicum L. Mill. (Solanaceae)] with coriander [Coriandrum sativum L. (Apiaceae)] reduces the incidence and severity of damage caused by B. tabaci. However, it is not yet known how coriander affects the insect′s behaviour. We evaluated the attractiveness of tomato constitutive volatiles to B. tabaci and what effect coriander constitutive volatiles have on the insect′s behaviour. To this end, we conducted three bioassays in a multiple‐choice four‐arm olfactometer (‘×’ type), measuring B. tabaci behaviour when offered tomato and coriander constitutive volatiles presented alone as well as together. We also evaluated the colonisation and establishment of B. tabaci in experimental plots with only single tomato plants and tomatoes intercropped with coriander in a greenhouse. Bemisia tabaci males and females recognised tomato constitutive volatiles as a positive stimulus (kairomonal effect), indicating that semiochemicals from this plant can play an important role in the insect’s host plant selection. Coriander constitutive volatiles reduced the attractiveness of tomato volatiles but no repellency to these volatiles was observed. Greater numbers of adults and nymphs of B. tabaci per plant were observed in tomato monoculture plots than in tomato intercropped with coriander. We suggest that coriander constitutive volatiles have an odour masking effect on tomato volatiles, thus interfering in the host plant selection of B. tabaci.

Secondary plants used in biological control: A review

“…However, intercropped plants can directly reduce the occurrence of herbivores even when the plants are not repellent, for example, due to masking of volatiles (Togni et al 2010). The associational resistance hypothesis proposes that non-host plants release ''odour masking'' substances into the air making the crop ''unapparent'' to the herbivore (Tahvanainen and Root 1972;Poveda et al 2008).…”

Control of tomato whiteflies using the confusion effect of plant odours

“…It should be noted that making use of the mild effects demonstrated here would first require that they are not subject to habituation and, if they are, determining what could be done to overcome this. Numerous studies indicate that non-host plant volatiles can have negative performance consequences for pest insects either through repellence or masking of host odours (Thiery and Visser 1986;Regnault-Roger 1997;Foster and Harris 1997;Ngoh et al 1998;Isman 2006;Szendrei and Rodriguez-Saona 2010;Togni et al 2010). Imagine a biological model for whitefly control consisting of one non-host plant that omits repellent volatiles, one non-host that emits odour-masking volatiles and a tomato host that is infested with whiteflies.…”

Utilizing Genetic Resources and Precision Agriculture to Enhance Resistance to Biotic and Abiotic Stress in Watermelon

“…The best method to identify if a line has resistance or is susceptible to whiteflies is by performing an olfactometer bioassay (Togni et al, 2010). By performing this type of bioassay it can be determined whether whitefly has a nonpreference for volatiles produced by the host plant (Togni et al, 2010;Coffey et al, 2015).…”

“…By performing this type of bioassay it can be determined whether whitefly has a nonpreference for volatiles produced by the host plant (Togni et al, 2010;Coffey et al, 2015). Combining resistant watermelon lines with reflective mulch proved to be the best method to control whiteflies (Simmons et al, 2010).…”