Donna A. Marshall

Effects of Kaolin Clay Application on Flower Bud Development, Fruit Quality and Yield, and Flower Thrips [Frankliniella spp. (Thysanoptera: Thripidae)] Populations of Blueberry Plants

Abstract Three separate studies were conducted to report the effects of kaolin applications (Surround WP) on southern highbush blueberries (Vaccinium corymbosum L.) and rabbiteye (V. ashei Reade) blueberries. When applied to mature blueberry plants, kaolin clay emulsion dried to form a white reflective film that affected bud development, fruit set and development, plant growth, and fruit yield, but had no effect on fruit quality parameters. When kaolin was applied before fruit set, yield was increased with no significant residue left on the fruit. Surround WP consistently reduced the number of flower thrips (Frankliniella spp.) within the canopy of rabbiteye blueberry plants by approximately 50%. Kaolin applications were not phytotoxic to blueberry buds, flowers, leaves, or fruit and were harmless to foraging bees.

Flavor of Fresh Blueberry Juice and the Comparison to Amount of Sugars, Acids, Anthocyanidins, and Physicochemical Measurements

Six cultivars of southern highbush (SHB) and rabbiteye (RE) blueberry samples were harvested on 2 different dates. Each treatment combination was pressed 2 times for repeated measures. Fresh juice was characterized for 18 flavor/taste/feeling factor attributes by a descriptive flavor panel. Each sample was measured for sugars, acids, anthocyanidins, Folin-Ciocalteu, soluble solids (BRIX), titratable acidity (TA), and antioxidant capacity (ORACFL ). Flavors were correlated with the composition and physicochemical data. Blueberry flavor correlated with 3 parameters, and negatively correlated with 2. Strawberry correlated with oxalic acid and negatively correlated with sucrose and quinic acid. Sweet aroma correlated with oxalic and citric acid, but negatively correlated with sucrose, quinic, and total acids. Sweet taste correlated with 11 parameters, including the anthocyanidins; and negatively correlated with 3 parameters. Neither bitter nor astringent correlated with any of the antioxidant parameters, but both correlated with total acids. Sour correlated with total acids and TA, while negatively correlating with pH and BRIX:TA. Throat burn correlated with total acids and TA. Principal component analysis negatively related blueberry, sweet aroma, and sweet to sour, bitter, astringent, tongue tingle, and tongue numbness. The information in this component was related to pH, TA, and BRIX:TA ratio. Another principal component related the nonblueberry fruit flavors to BRIX. This PC, also divided the SHB berries from the RE. This work shows that the impact of juice composition on flavor is very complicated and that estimating flavor with physicochemical parameters is complicated by the composition of the juice.

Erythritol and Lufenuron Detrimentally Alter Age Structure of Wild Drosophila suzukii (Diptera: Drosophilidae) Populations in Blueberry and Blackberry

Abstract We report on the efficacy of 0.5 M (61,000 ppm) erythritol (E) in Truvia Baking Blend, 10 ppm lufenuron (L), and their combination (LE) to reduce egg and larval densities of wild populations of Drosophila suzukii (Matsumura) infesting fields of rabbiteye blueberries (Vaccinium virgatum) and blackberries (Rubus sp.). Formulations included the active ingredients (lufenuron, erythritol, or both), sugar (in control and erythritol treatments), and Dawn hand-soap applied to plants with pressurized 3-gallon garden spray tanks. The three chemical treatments (E, L, and LE) had no effect on D. suzukii ovipositing in blackberry and blueberry fruit, but they did reduce larval infestation by 75%, particularly densities of first and second instars. Erythritol and lufenuron were equally efficacious compounds as a D. suzukii ovicide and larvicide, but they did not display additive or synergistic activity. Extremely high larval mortality in control fruits show an age structure heavily skewed toward egg output.

Splitting severity among rabbiteye (Vaccinium ashei reade) blueberry cultivars in Mississippi and Louisiana

Abstract A survey of blueberry growers determined the extent of rain-related splitting fruit on blueberry production in Mississippi and Louisiana. Growers were asked to approximate (1) the number of acres or plants of each cultivar on their farm (2) the severity rating (1 = No splitting-5 = Severe splitting) of each cultivar, and (3) the percent of berries lost to rain-related splitting. Among the 3 most widely planted cultivars, ‘Premier’ exhibited the least splitting (1.2 rating) followed by ‘Climax’ (2.2) and ‘Tifblue’ (3.1) had the most split fruit.

Biology and Efficacy of Aprostocetus (Eulophidae: Hymenoptera) as a Parasitoid of the Blueberry Gall Midge Complex: Dasineura oxycoccana and Prodiplosis vaccinii (Diptera: Cecidomyiidae)

ABSTRACT In the southeastern United States, bud-infesting larvae of two gall midge species, Dasineura oxycoccana (Johnson) and Prodiplosis vaccinii (Felt), destroy from 20 to 80% of the rabbiteye blueberry crop, Vaccinium virgatum Aiton (syn. V. ashei Reade). These midge larvae are attacked by five species of parasitoid wasps. The most effective of these is the bivoltine eulophid Aprostocetus sp. nr. marylandensis (Eulophidae), whose adults constitute one-third of the gall midge parasitoids, active in both conventional and organic blueberry fields. Broods of Aprostocetus use several reproductive strategies to keep sole possession of their larval hosts. As solitary endoparasitoids as well as facultative hyperparasitoids, precocial larvae of Aprostocetus devour hosts organs along with any younger siblings and rival parasitoid broods. Although larger hosts are preferred, any sized larvae can be parasitized, which reduces brood congestion and infanticide. An Aprostocetus female spends an hour or more in a systematic hunt for hosts, during which time 40 to 100% of midge larvae encountered are parasitized. Aprostocetus females could have located hosts more quickly had they recognized host-feeding scars as cues. Even so, high rates of larval parasitism achieved by Aprostocetus may kill as many midges as insecticides do.

Creating a Community of Practice for Blueberries

The “All about Blueberries” Community of Practice is adapting the best existing extension publications and developing new research-based extension recommendations related to blueberry production and consumption. Our primary goal is to increase blueberry productivity and consumption of blueberries, initially in the southeast and then nationwide. The experts that are members of our Community of Practice are located in the southeastern United States (Alabama, Louisiana, Mississippi, and North Carolina) where both southern highbush and rabbiteye blueberries are grown. Southern states with relatively small blueberry industries and insufficient funds to support active land-grant research and extension programs (Louisiana and Alabama) are benefiting from cooperation with the United States Department of Agriculture, Mississippi State University, and North Carolina State University that have well-developed, robust research/extension programs that support the blueberry industry.

‘Pearl’ Southern Highbush Blueberry

‘Pearl’ is a new southern highbush blueberry (Vaccinium spp. hybrid) developed and released by the United States Department of Agriculture Agricultural Research Service. The new cultivar has several advantages for growers in the Southeastern U.S. over rabbiteye blueberry cultivars, the most widely grown type of blueberry in the region. Among these are an earlier ripening period, high yield potential, and fruit quality. These attributes enable producers to participate in the lucrative early U.S. fresh market where opportunities for marketing rabbiteye blueberries have diminished due to expanding acreage in the region and other states.

Performance of Persimmon (Diospyros kaki) Cultivars in Southern Mississippi

The oriental persimmon is native to China and is best adapted to areas with moderate winters and relatively mild summers. However, because of its low chilling requirement, persimmons will break dormancy during early warm periods only to be damaged by spring frosts later. This study was initiated to determine suitable cultivars for the gulf coast region. ‘Hana Fuyu’ was greatly affected by a freeze event. ‘Fuyu Imoto’ and ‘Matsumoto’ had numerous smaller fruit and were less affected by freeze events. Results indicated that persimmon cultivars are available that would be a good addition to growers who would like to diversify their fruit selection in the southern U.S.

Effects of Kaolin Clay Particle Film on Southern Highbush (Vaccinium corymbosumL.) Blueberry Plants

Abstract Two separate studies were conducted to study the effects of kaolin applications (Surround WP) on southern highbush blueberries (Vaccinium corymbosumL.). When applied to mature blueberry plants, kaolin clay emulsion dried to form a white reflective film and affected bud development, fruit set and development, plant growth, and fruit yield, but had no effect on fruit quality attributes. ‘Cooper’ received a single application of kaolin during flowering (bud stages 3-6) which increased fruit set and reduced the rate of flower bud development. Berry size was reduced with kaolin, perhaps due to increased number of fruit present. ‘Magnolia’ received a single application of kaolin at four different stages of maturity resulting in a linear increase in plant volume with early applications. When kaolin was applied before fruit set, yield was increased with no significant residue left on the fruit.