Survey of Blueberry (Vaccinium spp.) Problems in the Gulf South

Authors: Miller Butler, Melinda; CURRY, KENNETH - UNIV OF SOUTHERN MS; Smith, Barbara; BRASWELL, JOHN - MISS COOPERATIVE EXTENSIO

Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/20/2008
Publication Date: 3/3/2009
Citation: Miller Butler, M.A., Curry, K.J., Smith, B.J., Braswell, J. 2009. Survey of Blueberry (Vaccinium spp.) Problems in the Gulf South. Acta Horticulturae (ISHS) 810:369-378.

Interpretive Summary: Rabbiteye and southern highbush blueberries are grown commercially in the Gulf South. These blueberries are tolerant to heat and drought, can grow on a wide range of soil types, and produce abundant fruit with peak ripening beginning in May and extending into July. Blueberry hectares have increased and so has the concern among growers that as their plants age they are seeing more decline and death of bushes in their fields. Questionnaires were mailed to 146 members of the Gulf South Blueberry Growers Association to determine how many of the growers were having problems in their fields and what these problems might be attributed to. Fifty-eight of the surveys were returned which represented over 202 hectares of blueberries. The average number of plants per hectare was 1523 with the majority of plants being 10-20 years old: 89% of the plants were rabbiteye cultivars; and 79% of the respondents considered the overall condition of their plants as average, healthy, or vigorous. Less than 25% of the growers reported problems with diseases such as mummy berry, leaf spot, and root rot. Environmental was reported as the most common cause of plant death. All of the growers reported weed problems and most used herbicides. Most respondents planned to increase their blueberry acreage. These results will be used by research scientists as they plan future areas of study and by extension agents making recommendations to blueberry growers.

Technical Abstract: Raising blueberries in Mississippi has been a growing industry since the early 1980s, but some plants in older fields are now in decline. The root rot pathogen, Phytophthora cinnamomi, is endemic in the southeastern United States and has caused severe losses to blueberries in North Carolina and Arkansas. Because the warm, humid climate of Mississippi, with periods of high precipitation, provides a favorable environment for Phytophthora root rot disease, it was suspected to be the cause of plant decline in older blueberry fields. Members of the Gulf South Blueberry Growers Association were mailed surveys to determine cultural practices and the extent of losses in their blueberry fields. The survey was written in partial, open-ended question format with 34 questions pertaining to cultivars, number of hectares planted, cultural practices, overall health of the blueberry plants, and losses due to diseases, insects, or other problems. Fifty-eight of 146 surveys (40%) were completed and returned. Seventy-six percent of respondents grew rabbiteye (Vaccinium ashei) cultivars and the balance grew southern highbush (V. corymbosum hybrids) cultivars. The average number of plants per hectare was 1523 with the majority of plants 10 - 20 years old. Seventy-nine percent of the growers described the overall condition of their plants as average, healthy, or vigorous. The most common cause of plant death cited was environmental with damage caused by the 2004 and 2005 hurricanes at the top of the list. No major diseases were reported by 36% of the respondents, while mummy berry, leaf spot, and root rot were noted as problems by 22%, 15%, and 10% of the growers, respectively. Phytophthora species were isolated from root and soil samples collected from symptomatic plants on three farms. Weeds were listed as problems on 100% of the surveys. Fifty-five percent of the respondents plan to increase their blueberry plantings mainly with rabbiteye cultivars.