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2006 Grape Loss Survey Report

Keith Striegler, Ph.D., Eli Bergmeier and Andy Allen
University of Missouri
Institute for Continental Climate Viticulture and Enology
108 Eckles Hall
Columbia, MO 65211
Telephone: 573-882-6656
FAX: 573-882-0596
November 30, 2006

Background

The Missouri Wine and Grape Board (MWGB) requested that the Institute for Continental Climate Viticulture and Enology (ICCVE) conduct a survey of Missouri grape growers to determine the extent of crop loss during the 2006 season. A draft survey document was developed by R.K. Striegler, R.A. Allen and E.A. Bergmeier. The draft survey document was sent to MWGB members and MWGB Research Committee members for review. The survey document was revised based upon input received. Surveys were mailed to members of the Missouri Grape Growers Association, Missouri wineries and the ICCVE Missouri grape growers mailing list during the week of November 6, 2006. Growers were asked to return completed surveys by November 22, 2006.

Response to Survey

Responses to the survey were characterized as listed below:

62 surveys received.

  • One survey was received from an unplanted vineyard and excluded from the study.
  • Surveys were received from 9 nonbearing vineyards.
    • Surveys representing nonbearing vineyards were excluded from the loss analysis portions of the study, but were included in calculations regarding vineyard acreage receiving irrigation and the percentage of irrigated vineyard acreage.
    • Total acreage reported does include non-bearing acreage.
  • Surveys were received from 52 bearing vineyards (used for majority of figures reported).

Total vineyard acres reported: 794

Survey Results

Grape acreage, production and reported loss data are presented in Table 1. Survey responses represent 794 acres. A very high percentage (83 percent) of growers responding to the survey indicated they had suffered crop loss in 2006. The amount of crop loss was estimated to be 421 tons. This represents a 15 percent loss based upon the information reported by responding growers.

The factors responsible for crop loss are provided in Table 2. The 2006 season was characterized by low precipitation and higher than normal temperatures in many growing regions in Missouri, especially during the April to July period. Approximately 41 percent of losses reported were attributed to these conditions (heat and drought). The factor(s) accounting for the second highest level of reported loss was feeding by vertebrate pests (27 percent - birds, deer and raccoon). Other significant causes of reported loss were disease (16 percent) and frost (14 percent).

The MWGB also asked that certain additional information be collected as part of the survey. This information is presented in Tables 3 and 4. Seventy percent of vineyard acreage represented in the survey was irrigated (Table 3). In addition, growers were asked to report if they sold fruit to out-of-state processors and if they had fruit they were unable to sell. Out-of-state sales were reported by 10 percent of growers responding to the survey. Twenty-one percent of responding growers reported they had fruit they were unable to sell in 2006. Initially, this appears to be an alarming and disturbing result. However, when the unmarketable crop is viewed on a tonnage basis, a different trend is evident. There were 10.3 unmarketable tons reported, which is a small amount when compared to the 2415 tons reported to have been harvested (Table 4).

Table 1. Grape acreage, production, and reported loss. 2006.
Reported acreage 794
Percent of growers reporting crop loss 83
Grape tons harvested 2415
Grape tons lost 421
Total grape tons produced (projected) 2835
Loss - percent of total production 15
 
Table 2. Reported cause of grape loss. 2006.
Cause Tons Lost Percent of Total Grape Loss
Heat 52 12
Drought 121 29
Frost 60 14
Disease 68 16
Insect 2 <1
Birds, deer or raccoon 114 27
Other 4 <1
 
Table 3. Additional information from growers responding to survey. 2006.
Percent of vineyard acres receiving irrigation 70
Percent of growers who sold to non-Missouri processors 10
Percent of growers with unmarketable crop 21
 
Table 4. Unmarketable crop as reported in survey. 2006.
Unmarketable Cultivars No. of Growers Total Tons
Norton 4 4.1
Cayuga White 1 0.5
Chardonel 2 0.6
St. Vincent 1 2.0
Catawba 1 1.0
Chambourcin 2 1.5
Vidal blanc 3 0.6
 
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