LERGP Reacts to Winter Damage
February 2015 will go down as one of the coldest on record pushing many vineyards past their hardiness thresholds. On February 16th, early morning temperatures reached damaging levels for most regionally grown grape varieties. NEWA weather stations across the Lake Erie region ranged from -17ᵒF to -29.9ᵒF. These cold temperatures left many grape growers with concerns about freeze damage. In response, the Lake Erie Regional Grape Program (LERGP) personnel combined efforts to determine the effects of the low temperatures. Results helped growers make decision on how to compensate for the damage to ensure a 2015 crop.
The past two years, the Lake Erie region harvested near-record Concord crops, and with exceptional growing conditions in 2014, there were high hopes of another bumper crop this year. Optimism shifted to worry on February 16, when low temperatures fell from -17oF to -30oF throughout the region and to some extent inflicted freeze damage to all grape varieties. The Lake Erie grape region encompasses 30,000 acres of grapes with Concord consisting of 87% of this acreage. The lethal temperature for a concord bud is -22oF and with many areas surpassing this temp.
In response, the Lake Erie Regional Grape Program assessed over 15,000 grape buds for damage and found a large range of primary bud mortality ranging from 10% to 80%. Hardest hit Concord vineyards were either in low line areas that have a tendency to hold excess water or vineyards with health issues. A representative bud assessment for every Concord block within the area is not feasible, therefore efforts were made to educate growers how to examine their own grape buds for freeze damage. Programing for our winter conference was focused on dealing with freeze damage. In addition, we also held ‘bud assessment workshop’ and developed a step-by-step tutorial for out newsletter.
To compensate for this type of damage, many growers left more buds than they typically do contributing to this year average. A survey of 161 growers who attended Coffee Pot meetings in 2015 showed that 63% of growers used Extension information to assess 2015 freeze damage and modify their viticulture plan (adjust pruning levels). And 36% of growers used Extension information to conduct their own on-farm assessment of bud survival. Growers who were able to accurately estimate bud damage adjusted pruning levels accordingly.
- Haggerty, Luke L
- Haggerty, Luke
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