Definition - What does Aphid mean?
In the context of wine vine diseases and pests, aphids are small insects that feed on wine vines. There are over 4,000 different species of aphids, with the most harmful numbering around 300 for agricultural plants growing in temperate climates, and about 10 of those harmful to wine vines. Some aphids can destroy vines and vineyards as they can feed in large numbers on wine vines, attacking the roots, vine, leaves and fruit.
While they can be invisible to the naked eye, they can be observed by the appearance of sap on the leaves, wilted leaves and weakened vines.
WineFrog explains Aphid
Vineyards are full of many different kinds of bugs and insects, and not all are harmful to wine vines, however, tiny aphids, can damage vines from feeding on the vine and by carrying disease. An example of this occurred in France; it was called The Great French Wine Blight and was caused by the Phylloxera Aphid, it nearly destroyed the French Wine Industry.
As the aphids can be invisible to the naked eye, it is important that growers and vineyards take very pro-active measures to avoid infestation of aphids in the vineyard. Almost all vineyards and growing regions adhere to strict guidelines when importing rootstock and vines from new areas and submit to regular inspections to ensure that imported vines are not infected, which was the case with The Great French Wine Blight - the French vines were affected by imported american rootstocks which were resistant to Phyllorexa, however, the French vines were not. Aphids can be resistant to chemical treatment, so it is important for growers to ensure that their vines are strong and healthy.