Table 2.

Phylloxera risk considering combined effects of soil sand content and soil temperature, and the explanation of risk assessment for the event of phylloxera introduction to a site.

Risk			Explanation
Sand-based	Temperature-based	Overall
Low	Low	Low	Sand content and temperature are not conducive for phylloxera development.
Low	High	Low	While sand content is not conducive, temperature is. The temperature will have an effect only if the sand content is reduced (e.g., by addition of organic matter).
Moderate	Low	Moderate-low	Sand content is moderately conducive for phylloxera development, but the temperature is not. This combination will reduce the overall risk of rapid phylloxera development.
Moderate	High	Moderate	Sand content is moderately conducive for phylloxera development, and temperatures are optimal. Phylloxera could survive and could potentially thrive if soil sand content is reduced further.
High	Low	High-moderate	Sand content is ideal for rapid phylloxera development, but soil temperature is not. Phylloxera development is possible, albeit at a slightly lower rate.
High	High	High	Soil sand content and temperatures are ideal for the rapid development of phylloxera.