Screening for Rootstock Resistance to Grapevine Phylloxera Genotypes From Australian Vineyards Under Controlled Conditions

Scientific Opinion: Improving the Definition of Grape Phylloxera Biotypes and Standardizing Biotype Screening Protocols

“…An in planta bioassay system uses whole plants, with no induced effects caused by root excision, and is performed within cages to prevent phylloxera spread and migration. This bioassay has been introduced in several variations, of which we suggest either the bottle-system (Forneck et al 2001b) or the potted trial with root enclosures (Korosi et al 2007). To have comparable data, we suggest calibrating the phylloxera population data and plant responses (nodosities, pseudotuberosities, and tuberosities) in relation to the root biomass, which depends on the pot/vessel chosen.…”

“…The advantages of the bottle method include the ability to observe root development/damage without disturbance, limited space requirements, and the ability to easily insect-proof the system to limit migration. The methods we recommend are a modified version of Korosi et al (2007) and Forneck et al (2001b), respectively, that runs the assay at 25 ± 2°C using a 16 hr photoperiod.…”

“…Keep plants under controlled conditions for eight weeks. At harvest, carefully wash root pieces, collect the washing, and examine for phylloxera life stages and assess root damage by counting tuberosities, pseudotuberosities, and nodosities (Korosi et al 2007).…”

Insight into the durability of plant resistance to aphids from a demo‐genetic study of Aphis gossypii in melon crops

“…; Korosi et al. ). Conversely, resistance‐breaking biotypes have emerged in a number of plant–aphid systems reviewed by Smith and Chuang (), but the processes by which plant resistance to aphids is overcome at the population level are poorly understood.…”

“…Aphids, the major arthropod pests of cultivated plants (Dedryver et al 2010), display most of these features (Hales et al 1997). Host plant resistance to some aphid species may be efficient and durable, as observed for resistance to phylloxera (Daktulosphaira vitifoliae) in Vitis (Granett et al 2001;Korosi et al 2007). Conversely, resistance-breaking biotypes have emerged in a number of plant-aphid systems reviewed by Smith and Chuang (2014), but the processes by which plant resistance to aphids is overcome at the population level are poorly understood.…”