Grape phylloxera is a small aphid, usually less than 0.5mm long. It has been a major pest in all grape growing countries for at least a century. The immature insects are referred to as crawlers. In Australia they are the main dispersive stage, crawling to adjacent vines either below or above ground or spread by wind. Human-aided dispersal is very important, and entry potential is considered high.
Phylloxera is established in most grape growing regions of the world, including Europe, Asia, Africa, North and South America, Japan and New Zealand. In Australia it occurs in quarantine zones in New South Wales and Victoria.
Wine grapes would be severely affected if phylloxera became established in Western Australia.
It is estimated that phylloxera could cost affected growers $20 000/ha in the first year in lost production and replanting costs, and a total of $42 000 over a five-year period in lost production and additional costs.
Although table grape plantings in Western Australia are mainly on resistant rootstocks, some damage is possible. The extent would depend on the level of rootstock resistance as well as the phylloxera strain present.
The north American grapevine (Vitis rupestris) is affected on roots and leaves, while only the roots are affected on the European grapevine (Vitis vinifera).
Season of occurrence
Phylloxera exists on the roots of vines throughout the year. Populations increase rapidly during spring and early summer, and peak in mid-summer.
Premature yellowing of leaves in autumn, weak shoot growth, and reduced crop are typical symptoms. Phylloxera damage may be difficult to detect initially, due to the lack of obvious above-ground damage which is only visible two to three years after the initial infestation.
Image sets and diagnostic notes are available at http://www.padil.gov.au/pests-and-diseases/Pest/Main/136106.
What to do if I find it?
Phylloxera is a prohibited declared pest for Western Australia. It is important that suspected infestations are reported. Please contact the Pest and Disease Information Service (PADIS) to report this pest on 1800 084 881 or email email@example.com.