In the vine-rows closest to the cellar we have noticed the tell-tale signs of either Panonychus Ulmi Koch or Eotetranycus carpini, nasty little red and yellow spider-mites, visible only through the leaf damage they leave in their wake.
Their presence is a sign that the balance between predators and pathogens is broken and so we are obviously concerned. It may be that these particular rows are more vulnerable due to a nutritional imbalance and the dust from their proximity to the road. It could also be the effect of global warming on the life-cycles of the mites and/or their predators, the long-tail effect of products that were used in the past or a combination of all these factors.
Obviously one immediate solution could be to spray in order to protect this year’s crop. In the short-term damage in the vineyard would automatically decrease. However in the long-term the spiders are bound to reappear because as a species they have a brilliant and proven ability of developing chemical resistance. The enormous negative, quite apart from spoiling our track-record of not using chemicals, is that the natural predators of the mites are also killed indiscriminately by the chemical sprays. The natural balance of the vineyard would be destroyed, and there is a risk of residues in the groundwater and in the wine.
So what to do?
We invested in some tiny envelopes containing Amblyseius andersoni, a beige predatory mite, less than 1mm in diameter. In three years these little beasties should re-balance the mite situation, be it yellow or red.
Let the bug wars commence!