Most folks think of vineyard bird netting as a means to stop crop theft by birds.
I look at it differently: as an important – perhaps the most important – component in an integrated disease management system to safeguard wine quality.
You see, the biggest problem with birds is not the grapes they devour completely. The biggest problems with birds are the grapes they peck and leave behind. These bird pecked grapes are the ones I worry about, and the reason growers should use vineyard netting.
A grape’s skin affords a remarkable degree of protection against fungal and bacterial pathogens… but a beak-punctured skin no longer protects the berry from infection.
One of the most common fungal pathogens is Botrytis, a.k.a. bunch rot. Bird and insect damaged grapes are particularly vulnerable. Botrytis can taint the flavor of your wine – and it doesn’t take too many infected grapes to alter the flavor profile.
As I always say, vineyard managers first start using bird netting when crop losses reach an unacceptable level. The keep on using bird netting year after year because:
1) Once they start netting they always realize that crop losses were even worse than they thought
2) After they start using vineyard bird netting they see a dramatic reduction in the amount of bunch rot… so much so that if they had known that would be the case they would have chosen to use netting regardless of the level of outright crop loss!