We evaluated relationships between floral traits of 23 genotypes of southern blueberries and indices of pollination efficiency (fruit set, fruit abortion, seed number, and berry size) for Osmia ribifloris Cockerell, a manageable solitary bee. Flower size in Vaccinium and presumably ovary size were proportional to berry size, except for the tiny blooms of one V. tenellum clone (NC7808), which produce large commercial-sized berries of ≈2 g. Longer-styled blueberry flowers visited by O. ribifloris produced the heaviest berries with the most seeds. Osmia ribifloris reliably pollinated ‘Climax’ and ‘Tifblue’ rabbiteye blueberries. However, the peculiarly misshapen blooms of ‘Premier’ rabbiteye blueberry receive less pollination from O. ribifloris and yield berries containing 25% fewer seeds. Fruit set for these misshapen ‘Premier’ flowers was equivalent to that of intact flowers indicating that this floral polymorphism would not greatly alter cultivar performance. For seven Vaccinium species, wild and cultivated alike, 80% to 100% of a plant’s fruit production depends on efficient cross-pollination by bees such as O. ribifloris.
Blair J. Sampson, Stephen J. Stringer and Donna A. Marshall
Stephen J. Stringer, Arlen D. Draper, Donna Marshall-Shaw, Blair J. Sampson and John J. Adamczyk Jr.
Christopher T. Werle, Karla M. Addesso, Blair J. Sampson, Jason B. Oliver and John J. Adamczyk
Invasive ambrosia beetles (Coleoptera: Curculionidae) are an important pest problem at ornamental tree nurseries. Available chemical treatments are not completely effective and, due to the length of the beetle dispersal period and insecticide breakdown, repeated treatments can become costly in terms of application expense and nontarget impacts. Additional options are needed to reduce application frequency and to provide an acceptable level of crop protection. Four treatments were tested using ethanol-injected eastern redbud trees at research sites in Mississippi (MS) and Tennessee (TN) over 2 years (2014–15), with the number of new ambrosia beetle galleries compared over time on 1) nontreated control trees, 2) kaolin-treated trees, 3) bifenthrin-treated trees, and 4) kaolin + bifenthrin (k + b)-treated trees. Kaolin-treated trees rapidly lost their coating after rain events and, at 6 days after treatment (DAT) in TN, no differences were detected in the number of beetle galleries between kaolin and nontreated control trees. Kaolin + bifenthrin-treated trees appeared to retain treatment residue longer, but were not better-protected than bifenthrin-treated trees at any time. Further research is needed to determine whether an adjuvant, such as a surfactant, spreader, or sticker, may enhance the modest impact offered by kaolin in our test, or if a reduction in rates of bifenthrin may be allowable.
Stephen J. Stringer, Donna A. Marshall, Blair J. Sampson and James M. Spiers
A study was conducted at the Mississippi State University Agricultural and Forestry Experiment Station (MAFES) McNeil Unit in southern Mississippi to identify promising muscadine grape (Vitis rotundifolia) germplasm for use as parents in the breeding and genetics research program and to develop information on performance for use by growers in the region for cultivar selection decisions. The vineyard was first established in 1992 and was expanded in 1994. Cultivars were evaluated in 2001, 2002, and 2006 for their performance and were found to differ in vigor, resistance to diseases, yield, and fruit quality. Cultivars suitable for winemaking that performed well included Carlos, Doreen, Magnolia, Noble, Regale, Sterling, and Welder. Cultivars intended for the fresh market that produced high yields and high-quality fruit included Alachua, Black Beauty, Darlene, Fry, Ison, Janebell, Nesbit, Polyanna, Sweet Jenny, Summit, and Tara. ‘Dixie’, a multipurpose cultivar, ‘Eudora’, a newly released fresh-market cultivar, and ‘Southern Home’, a multipurpose cultivar with enhanced ornamental value, also performed well at this location.
Stephen J. Stringer, Donna A. Marshall, James M. Spiers and Blair J. Sampson
Muscadines are grapes indigenous to the Southeastern United States, and they are highly prized for their unique fruity flavors. Factors including skin color, berry size, skin thickness, flower type, productivity, etc., vary among muscadine grape cultivars, making some cultivars more desirable for fresh market while others are better suited for processing and prodction of juice, jelly, and wine. A muscadine grape research vineyard was established in McNeil, Miss., in 1992 containing 37 named cultivars and numerous breeding lines. Performance of these cultivars was evaluated in 2001–2003 and results of these trials are presented.
Grant T. Kirker, Blair J. Sampson, Cecil T. Pounders, James M. Spiers and David W. Boyd Jr
Azalea lace bug (ALB), Stephanitis pyrioides (Scott), is an important economic pest of azaleas in the southeastern United States. In this study, 33 commercially available cultivars of evergreen azalea, Rhododendron spp., were evaluated for S. pyrioides feeding preference in both choice and no-choice feeding bioassays. Mean stomatal length and area, which were hypothesized to affect ALB feeding preference, were also measured for each of 33 cultivars and results were correlated with indices of ALB feeding (mean feces) and fecundity (mean eggs). An azalea cultivar, Fourth of July, was least preferred by ALB in both no-choice and choice tests, whereas ‘Watchet’ was most preferred. Cultivars Fourth of July and Delaware Valley White had the smallest mean stomatal areas despite their disparate susceptibilities to ALB feeding. Although stomates through which ALB insert their proboscides vary in size among azalea cultivars, they confer no obvious resistance to ALB feeding preference. Therefore, the mechanism for lace bug resistance in azalea remains elusive.