Friday, June 25, 2010

A Drop to Cure, an Ounce to Kill: Whoops!

I noticed a powdery mildew outbreak in the Aglianico vines along the shed. I had this coming as the canopy is mismanaged, not allowing good airflow. But, I've learned a few things since last year, when mildew spread across half of the vineyard and I found it difficult to control (and lost 1/2 of the Petit Sirah and 1/2 of the Grenache crops). There's miracle, organic, JMS Stylet oil that arrests mildew outbreaks. The recommended dilution rate with water is 1% to 2%, so I remembered from elementary school there are 16 oz to a pint, 32 oz to a half gallon and 64 ounces to a gallon, right?* So if there are 64 oz to a gallon then I should blend in 6.4 oz of stylet oil per gallon, right? Wrong! The correct amount is .6 oz. What was I thinking?! Alas, I overdosed the vines. Fortunately, light was running out that evening, and I only attacked the worst spots, and I got the dosage correct for the rest of the block. The two pictures above show dead leaves and shriveled grapes as a result of my mistake. I've heard that vines are tough characters, so I think these guys may come back with time. The picture below shows healthyAglianico vines I sprayed with the correct dosage. I wonder when they're going to need some water?

*(Wrong! 128 ounces to a gallon! So the correct dilution is 1.2 oz per gallon + / -)

1 comment:

Kevin said...

Consider using the metric system to measure instead. All based on 100. Very simple. So 1% dillution would be 1l per 100l. You can buy gram scales and ml/dl/l measuring containers at a chemistry shop.

Learned metric when I was in college as a science student. Never use anything else anymore.