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GRAPE GRO WING 4. Wood-rotting organisms Various cankers and trunk diseases become problematic as vines age and the permanent structure of the vine increases. Eutypa die- back and bot canker (Botryospaeria sp.) are two of the most troublesome groups of wood pathogens. The diseases are easily confused by symptoms. To tell the diseases apart, and some other canker organisms that are closely related, you must use lab techniques including plating on selective media or biotech approaches such as PCR (polymerase chain reaction.) Both diseases are caused by fungal organisms that have alternate hosts commonly found near the vineyards including fruit trees, willows, ceanothus and buckeye trees among others. The infection periods for the disease are in the winter, when the fungi sporulate and enter vines through pruning wounds. Fruit- ing bodies form on old, dead wood on the trunk and cordons, and spores are emitted during wet weather. Bot canker spore re- leases also may occur during sprinkler frost protection. The degree of susceptibility var- ies among winegrape varieties to these dis- eases, with Cabernet Sauvignon, Sauvignon Blanc and Petite Sirah among the most sus- ceptible. Long-term preventative approach- es include cane pruning to minimize the Pierce's disease results when glassy-winged sharpshooters transmit amount of wood in the vine, pruning late and double-pruning where wood is left long until just before bud break to minimize the amount of time that the pruning wounds are available to spores discharged dur- ing wet weather. Research also has shown that lime sulfur applied during winter at the rate of 10-15 gallons per acre will kill over-wintering fruiting bodies of these fungi and others that may be a problem, includ- ing powdery mildew. (This course of ac- tion is recommended for powdery mildew only when you have had severe problems in previous seasons.) Treating wounds with selected fungicides also is possible (refer to UC IPM Guidelines.) to vines. Esca (black measles) and young vine decline (Petri disease) are very perplexing diseases caused by a complex of fungi including Phaeoacremonium sp. and Phaeomoniella sp. When young vines are affected, their vascular tissue is colonized and the vines often grow poorly or die due to lack of water. The vines can come from the nursery already infected, or they might become infected if not properly irrigated or otherwise stressed. Older vines typically show chlorotic and red interveinal areas on the leaves known as "tiger stripes." Severe infections may cause leaf drop and stem dieback. Fruit may show dark spots and shrivel. The fungi act very similar to fungal canker diseases by sporulating from fruiting ON CAYUGA WINE TRAIL 79 ACRES; Hay barn 68x30 with full basement, workshop. Woods, gulley with creek. 3 Bedroom, 1.5 bath, with good set back from road, plus 1 bdrm. Cottage on 70' west shore Cayuga Lake. Soils suitable for grapes. Was a working vineyard for many years. $450,000 Call for our latest inventory! Mel Russo Licensed Real Estate Broker/Owner Office: 315-568-9404 Cell: 315-246-3997 website: www.senecayuga.com e-mail: senecayuga@aol.com 97 Fall Street, PO Box 386 Seneca Falls, NY 13148 Target Wineries By: Size Location Production Details Sales Data New Wineries Since WinesVinesDATA WINESANDVINES.COM/OMS 56 Wines & Vines APRiL 2012 X y l e l l a f a s t i d i o s a OklahOMa StatE uniVErSity