What's slowing down your grapevines this spring?

摘要

The spring 2000 growing season brought many challenges to San Joaquin Valley grape growers, one of which was delayed spring growth (DSG). Although DSG has occurred in the past, it was experienced in numerous vineyards from Madera to Kern Counties. Valley growers complained of poor budbreak and shoot vigor throughout their entire vineyards. Many of the vineyards that displayed erratic growth patterns were Thompson Seedless, but other varieties also exhibited a reduction in spring vigor. Much of whatwe know about this phenomenon is from comparing cultural practices, such as irrigation, nutrient analysis, and site evaluation - which includes soils and pests - in areas displaying symptoms with non-symptomatic sites. Our own surveys and those by an Australian viticulturist - concerning what the Australians refer to as "restricted spring growth - have helped us understand and determine what factors are most important in defining DSG.