2007 Grape Loss Survey Report
Jackie Harris, Andy Allen, Eli Bergmeier and Keith Striegler, Ph.D.
University of Missouri
Institute for Continental Climate Viticulture and Enology
108 Eckles Hall
Columbia, MO 65211
Telephone: 573-882-6656
FAX: 573-884-8212
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 2007 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 5, 2007. Growers were asked to return the survey by November 30, 2007.
Response to Survey
Responses to the survey were characterized as listed below:
- 50 surveys received.
- Total bearing vineyard acres reported 931.
- This represents 78 percent of the 1200 Missouri vineyard acres reported by NASS for 2005.
Survey Results
Grape acreage, production, and reported loss data are presented in Table 1. Survey responses represent 931 bearing vineyard acres. All of the growers responding to the survey indicated they suffered crop loss in 2007. The amount of crop loss was estimated to be 2304 tons. This represents a 61 percent loss based upon the information reported by responding growers. The adoption of cutting edge vineyard technology may be influenced by vineyard size (Noguera et al., 2005). We decided to examine whether vineyard size had an influence on percentage of crop loss. We viewed this as potentially important information due to the influence it might have on future extension/research efforts. Figure 1 breaks the survey responses down by vineyard size category and shows the percentage of reported acreage represented by each category. It is important to note that 64 percent of reported acreage is from only five growers.
Figure 1: Number of respondents by vineyard acreage category and percentage of acreage within each. The value above the lighter bars represent the number of respondents within that acreage category while the value above the darker bars represents the percentage of acreage corresponding to each acreage category.
Figure 2 shows the average percentage crop loss within each of the vineyard size categories. While the averages are similar for most categories, it is important to note that average crop loss was lowest in vineyard operations over 50 acres in size. This suggests that there might be value in having different extension/research activities for small- and medium-sized versus larger growers.
Figure 2: Comparison of the number of respondents, percentage of acreage, and average percentage loss by acreage ranges.
The factors responsible for crop loss are provided in Table 2. The 2007 season was characterized by an early spring with record warmth in March followed by a record breaking freeze event during the April 4-9, 2007 period (Guinan, 2007a). This resulted in early bud burst and shoot development that was extremely susceptible to the following freeze. A vast majority, 91 percent, of losses reported were attributed to freeze injury. Additionally, the 2007 summer was hot with the majority of Missouri counties seeing below normal precipitation between June 7 and November 7 (Guinan, 2007b). The factor accounting for the second highest level of reported loss was feeding by vertebrate pests (5.6 percent - birds, deer, etc). Other significant causes of reported loss were heat/drought (1.8 percent), diseases (1 percent), and insects (0.2 percent).
The MWGB also asked that certain additional information be collected as part of the survey. This information is presented in Table 3. Nearly 68 percent of vineyard acreage represented in the survey was irrigated. 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 8 percent of growers responding to the survey. No growers reported being unable to sell their crop. However, 11 percent of responding growers reported they did not harvest likely due to extremely low yields or other damage resulting from the April freeze.
References
Guinan, P., 2007a. The Easter freeze of 2007 – what happened? In Understanding and Preventing Freeze Damage in Vineyards: Workshop Proceedings. Dec 5-6. Columbia, MO., pp 7-12.
Guinan, P., 2007b. Missouri county precipitation departure from normal. agebb.missouri.edu/drought/accurain6.htm
Noguera, E., Morris, J., Striegler, K., and Thomsen, M. 2005. Production Budgets for Arkansas Wine and Juice Grapes. Arkansas Agricultural Experiment Station Research Report 976.
USDA, National Agricultural Statistics Service (NASS), 2005. Grape facts. www.nass.usda.gov/Statistics_by_State/Missouri/Publications/Brochures/Grape_Facts.pdf
| Table 1. Grape acreage, production and reported loss. 2007. | |
| Reported acreage | 931 |
| Percent of growers reporting crop loss | 100 |
| Grape tons harvested | 1465 |
| Grape tons lost | 2304 |
| Total grape tons produced (projected) | 3769 |
| Loss - percent of total production | 61 |
| Table 2. Reported cause of grape loss. 2007. | ||
| Cause | Tons Lost | Percent of Total Grape Loss |
| Heat/Drought | 42 | 1.8 |
| Freeze/Frost | 2092 | 91.0 |
| Disease | 22 | 1.0 |
| Insect | 5 | 0.2 |
| Birds, deer, etc. | 130 | 5.6 |
| Other/Unknown | * | * |
| *One respondent reported losing an entire vineyard to Nepovirus. The number of tons of grapes lost to this cause was not given. | ||
| Table 3. Additional information from growers responding to survey. 2007. | ||
| Percent of vineyard acres receiving irrigation | 68 | |
| Percent of growers who sold to non-Missouri processors | 8 | |
| Percent of growers with unmarketable crop | 0 | |
| Percent of growers choosing not to harvest | 11 | |
