The red spider mite (Tetranychus) is an important polyphagous pest in greenhouses, fields and orchard crops worldwide. In Europe and Israel, spider mites infest hundreds of plant species and often remain unnoticed until their presence is revealed by plant damage. In response to spider mite attack, tomato plants (Solanum lycopersicum), produce a blend of volatile molecules, such as terpenoids. The function of this odor class mainly lies at the third trophic level of making the plant more attractive to predators or parasitoids of herbivores. These molecules are highly induced upon pest attack, and their levels dynamically change during plant infestation periods. However, the volatile composition and intensity that attracts the spider mites along the tomato plant development, remains unclear. Our goal is to understand the volatile emission of infested tomatoes during plant development. To address this, we selected two cherry tomato cultivars, Ofir and Shiran, that are regularly grown in nethouses. Along the experiment, nethouses were kept for three months under two regimes: i) a mite-sprayed nethouse, which included all conventual pesticides, and ii) a non-mite-sprayed nethouse, which included all of the pesticides but those against red spider mites. After three months, the pest damage and plant conditions were quantified. Our preliminary results suggested that while the Ofir showed less damage phenotype and the number of adults and young mites were mild, the Shiran cultivars showed susceptible phenotype and a higher number of mites. This might indicate that the mites recognize and are attracted to Shiran more than to Ofir. Our next step is to analyze the volatile blend that spider-mite-infested tomatoes emit during plant development using a GC/MS analytical instrument. The genetic variation between Shiran and Ofir will be utilized to examine the plant-insect interaction that is further triggered to improve predator attraction, with the goal of reducing pesticide use and increasing sustainability.
|State||Published - 25 Jan 2018|