Vineyard diseases, Grapevine Moths and Fungus, VÍ vid at DO Utiel-Requena.

One disease and one pest. Both are worrying CRDO Utiel-Requena who held a training session on Wednesday 20 July for vine-growers in an attempt to improve the health of vines in this important comarca.

The pest is a moth which lays its eggs on the young grapes, (polilla del racimo de la vid) or Lobesia Botrana. It is a pest which is prevalent throughout vineyards all over Europe.

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Todays training day began at 08.00am outside the Cooperativa in the hamlet of Los Marcos, between Utiel and Venta del Moro in Valencia Province.

Vine-growers and some technical staff gathered to visit the site of an ecologic treatment which is showing good results in combatting the moth. This treatment involves confusing the male moth whilst he is looking for females to mate with.

70 year old Bobal vine.

70 year old Bobal vine.

In the vineyards we first went to visit a plot with 70-year-old vines which have not yet been included in the trial . In small groups we inspected the bunches of grapes looking for evidence of the moths presence. It did not take long to find it! Not only did we discover eggs we found live caterpillers which can be encouraged to leave the grape by gently squeezing it.

Seaqrching for Moth eggs.

Searching for Moth eggs.

Essentially, the moth arrives in April and lays its eggs. The larvae then enter the baby grapes after flowering and then feed, emerge and go through the chrysalis stage  having done initial damage. The new moths lay further eggs in June and July which go through the same process and cause further damage to the grapes as they grow. A third generation repeat the process in August and September as the grapes mature causing damage which can ruin  the crop or at the very least leave bad quality grapes which have started to rot before harvest.

Moth egg, next to the thumb

Moth egg, white spot  next to the thumb

The process involves sexual confusion, a system discovered in 1973. In 1979 the first vineyard trials were conducted with promising results. The first trial in Valencia took place in an isolated plot of Moscatel.

It works by flooding a vineyard with female pheromones, totally confusing the male so that he cannot find, or mate with a female. This consists of what looks like a short length of electric wire with the plastic coat containing the pheromones. These can just be twisted around a part of the vine and these diffusors are spread throughout the area to be treated. There are more sophisticated and more expensive versions but the method is the same.

Moth caterpiller emerging from grape.

Moth caterpiller emerging from grape.

It was trials conducted between 2001 and 2005 in Font de la Figuera which produced very satisfactory results that made it the preferred treatment. It has several advantages, being ecological and clean, leaving no residues. it does not affect the biological balance, it is specific to one pest and is easy to apply. It also adds value to the crop. On the downside it is difficult in areas where the vines are isolated, less effective at the edges of parcels of vines, does not combat other pests at the same time and is relatively expensive.

Carmen Perez with the cure!

Carmen Cárcel with the cure!

Nonetheless it is proving successful and the DO are encouraging its use to eradicate this pest which whilst the current position is not grave, is potentially bad for the quality of the wines from Utiel-Requena.

Fungus in the wood of vines ( Yesca) is a far bigger problem. It is currently a worldwide problem.  Champagne and Cognac in France and parts of Rioja are facing 30% of their plants being affected. In fact Hennessy, the prestige Cognac house have offered a reward of 600,000€ to anyone who can come up with a cure for it.

Until 2003 it was controlled by Arsenico Clorico but this was banned by the EU when it was identified as one of the most carcinogenic chemicals. Currently there is no short-term cure identified.

Vine affected by Yesca.

Vine affected by Yesca.

It is a disease which causes new wood to die off and can affect the wood on old vines as well. Symptoms do not appear until it is too late.

We know it is not a major problem in Utiel Requena currently although we saw an example at a bodega we visited two years ago. By contrast on our drive from Ontinyent to Fontanares earlier this week we saw many examples in the vineyards beside the road.

Until a new cure is found the culture in the vineyard will need to change. Many people blame the nurseries where new plants come from for the disease. But this does not hold up. It is not just a disease affecting vines, it is present in olives and almonds as well, both of which sit side by side with vineyards. The spoors are blown about and attach themselves to wounds in the plants. The trouble is vines are pruned twice a year, six times in three years. New plants are more susceptible than older vines but these are not exempt from catching the disease.

Seminar begins

Seminar begins.

There is no law requiring nurseries to provide or guarantee the health of plants they sell but many have exemplary practices. They will need to ensure that mother plants which provide the cuttings are all healthy in the future.

In the vineyard it is recommended that pruning takes place by hand, not by machine, that wounds are treated and the cuttings are burned. If this is not possible the cuttings should be shredded as small as possible and buried in the ground as lack of oxygen kills the spoors. The current practice of leaving piles of vine cuttings at the edge of the vineyard will have to stop as spoors continue to be produced for  three years.

Vineyard owners will have to understand which varieties and which of their clones are most susceptible before buying new cuttings or grafts.

Round Table Expert Team.

Round Table Expert Team.

The two presentations were followed by a lively round table-workshop with many intelligent and challenging questions being asked of the experts consisting of  Jose Luis Salón from Pasiego, Carmen Cárcel, Secretary General of the DO and Ximó Fernandez, a professor at the Requena wine school, together with Josep Armengal and Vicent Badia. Some 125 vineyard growers took place in the seminar showing just how seriously the issue is being taken and the effectiveness of the DO´s education programme. This was a very informative day exploring two issues affecting the future of this DO.

 

 

 

 

 

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