Use of Petroleum Derived Spray Oils in Washington Grapevine Powdery Mildew Management Programs

Fig. 2. Primary mildew colonies on abaxial surface of ‘Lemberger’ grape foliage. Note close proximity to cordon.



Image from Plant Health Progress article:
Use of Petroleum Derived Spray Oils in Washington Grapevine Powdery Mildew Management Programs