Control of tomato whiteflies using the confusion effect of plant odours

Abstract

Glasshouse tomato production is reduced by the whitefly Trialeurodes vaporariorum, a major worldwide pest of glasshouse crops. Whitefly control is achieved using pesticides or parasitoids, which have drawbacks. There is thus a need for other control methods. For instance, the use of volatile compounds from plant odours could profoundly change the behaviour of plant-eating insects. This practice should be safe because plant odours are usually harmless to humans. Therefore, we have studied the effect of plant volatiles on whiteflies feeding on tomato plants. The rationale was to use the confusion effect by supplying whiteflies with a super-abundance of volatiles. We removed plant headspace volatiles from multiple whitefly host plants. Then, we presented these volatiles to whiteflies feeding on tomato plants. At the same time, whitefly stylet penetration is monitored using electrical penetration graphs (EPG). Plant colonisation, egg laying and honeydew production are analysed in separate experiments. Data are compared to controls in which extracted volatiles from tomato and air alone are presented to the whiteflies. The only significant effect produced by exposure to multiple-host volatiles is a pronounced reduction in the incidence of phloem-related waveforms during the 15-h EPG recording. This represents a delay in, rather than a cessation of, phloem-related activities as there is no related reduction in long-term performance. The confusion effect thus does not appear to exert strong effects on whitefly behaviour here.

Naturally occurring bioactive compounds from four repellent essential oils against Bemisia tabaci whiteflies

“…also showed that coriander ( Coriandrum sativum ) volatiles masked tomato volatiles in host plant selection. Tosh and Brogan also put forward the idea of supplying whiteflies with a superabundance of volatiles to confuse this generalist insect. In conclusion, this study identified volatile candidates that may be emitted by companion plants or by diffusers, e.g.…”

Novel resistance mechanisms of a wild tomato against the glasshouse whitefly

“…To investigate the feeding behaviour of whitefly on S. lycopersicum Mill., 'Elegance' and L. pimpinellifolium, the electrical penetration graph (EPG) technique was used, as developed by Tjallingii (1978) and used previously to investigate whitefly feeding behaviour on tomato (Tosh and Brogan 2015;Lei et al 1997Lei et al , 1999Lei et al , 2001. The different waveforms produced by the completion of a partial electrical circuit between the plant and the whitefly's stylet when the whitefly probes the plant correspond to different feeding behaviours of the whitefly.…”

“…An eight-channel DC EPG system supplied by EPG Systems (EPG-Systems, Dillenburg 12, 6703 CJ Wageningen, the Netherlands, http://www.epgsystems.eu/ contact.htm; Tjallingii (1978)) was used. Tosh and Brogan (2015) developed a modified EPG apparatus (Fig. 2b, c) to monitor whitefly feeding under different conditions, and here, the same experimental set-up and method for the EPG data collection were used for both tomato species.…”

“…Briefly, a single female whitefly attached with gold wire to the EPG apparatus was placed on the terminal leaflet of a tomato plant and allowed to feed for 20 h. Four replicates were run simultaneously (with one whitefly per plant for each of four plants). EPG waveforms for L. pimpinellifolium were collected, analysed and compared with waveforms previously collected by Tosh and Brogan (2015) for whiteflies feeding on the commercial S. lycopersicum cultivar 'Elegance' (unpublished data). In total, waveforms from 20 whiteflies feeding on L. pimpinellifolium and 23 whiteflies feeding on 'Elegance' were analysed.…”

Attractiveness of host volatiles combined with background visual cues to the tea leafhopper, Empoasca vitis

“…Plant volatiles play important roles in locating hosts by guiding the insects to food sources and oviposition sites (Bruce et al, 2005;Bruce & Pickett, 2011;Knolhoff & Heckel, 2014;Tosh & Brogan, 2015). Plant volatiles exhibit an immense diversity, both quantitatively and qualitatively, which allows herbivores to distinguish suitable hosts (Dudareva et al, 2006;Beyaert & Hilker, 2014).…”