Vine health issues: not currently resolved

Syrah disorder
Symptoms:

• Red vine in late summer
• no gophers (mounds), voles (holes around base), tractor damage, or blight
• Swelling above graft union and pitting/grooving on scion (girdle causes red leaves)
• Negative on virus panel.

Variation in symptom expression:
Clone susceptibility generally more important than rootstock.
Rootstock: Most symptomatic (99R, 110R), Least (5BB, Riparia (Gloire), 1103P, 101-14, 420A anecdotal)
rupestris in background may be a factor
Clones: Most symptomatic (73, 99, 301, 381, 382, 383), Intermediate or variably symptomatic (100, 174*, 300, 525, 585, 877**), Least (470, 471, 524, 747)
* Clone 174 was highly variable and was highly symptomatic in some tests.
**Clone 877 has been planted throughout Paso Robles and has been highly impacted by Syrah decline.

References:
Greenspan, Mark. Disorder has Syrah Growers Seeing Red.
Syrah Vine Health Symposium

Pest and disease control: current research in PWV

Current method of choice for powdery mildew control
1. Use IPM method with Gubler-Thomas model
2. Rotate fungicides with different modes of use to prevent selecting for resistant strains.

Further reading:
PM control: Crisp group
Compares alternative methods. Milk is the best for low pressure regions . Also references 2 and 3 in the Greenspan article provide more detail on application rates and methods.
PM detection: Gary Grove
Rod collection with PM spores, not viable method yet due to PCR requirement and rods are cumbersome. A good group to follow.
Mite control (Willamette and Pacific): Zalom group
Compares products. Agri-Mek, Zeal+Dannitol, Envidor, Acramite and Omite best. Did not test stylet.

References: