In the never ending quest to produce good quality grapes from disease free vines, preventing pests from damaging the grape crop calls for a combination of techniques, or integrated pest management (IPM). Along with cultural practices, sometimes chemical control, the use of pesticides, can be more effective in controlling pests (in the greater context of a broad IPM strategy). Yesterday evening was the first time Stylet-Oil (SO) was used on the grapevines (with a little Mettle® fungicide thrown in for good effect). SO is a little more effective against powdery mildew (Uncinula necator) (PM) in cooler growing seasons (like the one the Napa Valley is experiencing this year) versus the more conventional use of sulphur. Sulphur needs warmer temperatures to volatize (65°F is the recognised minimum temperature required for sulphur activity against PM), whereas SO is not temperature dependent and so it acts as an eradicant, protectant and, most importantly, an antisporulant 24 hours a day. In layman's terms, SO stops spores from growing, and insects from breathing. And it makes baby-grapes shinier.
