Generalized recommendations for the southeastern U.S. would typically include soil testing well in advance of establishment. Lime, P, and K should be applied at least 2 weeks before planting. Nitrogen is either broadcast and incorporated before planting or sidedressed 2 to 4 weeks after planting at 30 to 70 kg·ha–1. Additional N at 30 to 65 kg·ha–1 is applied late August to mid-September. A late winter N application at 20 to 30 kg·ha–1 is suggested for sandy soils. On established plantings fertilization takes place at renovation, with P and K being applied based on soil test or foliar analysis results. Nitrogen rates are typically in the range of 35 to 60 kg·ha–1. Later season fertilization generally follows the rates and timings of fall and winter recommendations of the establishment year. Minor nutrients can be limiting on sandy soils and B may be required in a wider range of soil types.
David G. Himelrick and Floyd M. Woods
Louise Ferguson, Harry Shorey, and David L. Wood
Several experimental procedures were used to evaluate the influence of solar radiation on insect infestations in Calimyma and Adriatic variety figs (Ficus carica L.). Direct sunlight eliminated infesting insects and prevented further infestation of ripe figs drying on the ground for at least 10 days. Placement in the shade resulted in 12% insect infestation in figs within 3 days. Figs that fell naturally into sunlit areas contained almost no insects, whereas 31% of figs that fell into dense shade were infested. While ripening figs were still attached to trees, the level of insect infestation was 50% higher on the shady north side than the sunny south south side. The insect pests most frequently encountered in these experiments were nitidulid beetles and their larvae. Disease incidence was not affected by degree of exposure. We propose that cultural techniques to maximize exposure of ripening and drying figs to solar radiation could be developed as important pest management tools.
David C. Annis, Paul T. Gibson, and Terri Woods Starman
The objective of this study was to investigate the influence of photoperiod and 0, 1, 5, or 10 applications at weekly intervals of GA3 foliar sprays at 500 mg·liter–1 on growth and flowering of Craspedia globosa `Drumstick' Benth. Long days (LD) hastened flowering and increased the number of flowers per plant. Short days (SD) increased foliage height and foliage fresh and dry weights. Foliage and total plant heights increased and days to bud and secondary inflorescence width decreased linearly as GA3 application frequency increased. Chemical name used: (1α,2β,4aα,4bβ,10β)-2,4a,7-trihydroxy-1-methyl-8-methylen egibb-3-ene-1,10-dicarboxylic acid 1,4a-lactone (gibberellic acid, GA3).
David G. Himelrick, Robert C. Ebel, and Floyd M. Woods
`Navaho' erect thornless blackberry plants were subjected to a combination of three primocane summer topping heights and two winter lateral length pruning treatments. Plants were topped at 91, 122, 152 cm tall, and laterals were shortened to either 30 or 61 cm in length. Treatment effects on yield and plant structure were examined for four growing seasons. Lateral length had little effect on yield and any pruning height. Yield generally increased with increasing plant height. The 122-cm height appeared to optimize yield while still allowing for manageable floricane architecture.
David G. Himelrick, Floyd M. Woods, and W.A. Dozier Jr.
The use of soil solarization on 20-cm raised beds 30, 60, and 90 days prior to fall planting of `Chandler' strawberries was compared with soil fumigation with 269 kg·ha–1 98/2 methylbromide/choropicrin and with 562 liters·ha–1 metam-sodium (Busan). The clear plastic mulch was painted with white latex paint prior to planting on 15 Oct. Methylbromide/choropicrin treatment gave the best yields, followed by the metam-sodium treatment. Soil solarization on raised beds was complicated by weed growth on the top edges and sides of the bed. Soil solarization is a useful alternative for flat bed culture, but is practically limited on raised beds due to insufficient weed control.
George E. Boyhan, Norman E. Schmidt, Floyd M. Woods, David G. Himelrick, and William M. Randle
A spectrophotometric assay for pyruvic acid in onion has been adapted to a microplate reader. Correlations between the spectrophotometer and microplate reader ranged from 0.991 to 0.997 for sodium pyruvate standards and 0.899 to 0.934 for onion samples. Onion pungency values were slightly higher with the microplate reader for both sample and background compared to the spectrophotometer when both are used in the single wavelength mode. Comparing the spectrophotometer in the single wavelength mode to the microplate reader in the dual wavelength mode resulted in no statistically significant difference between them. Standards for both the microplate reader and spectrophotometer followed a quadratic function.
Xiuren Zhang, David G. Himelrick, Floyd M. Woods, and Robert C. Ebel
`Chandler' strawberry plants (Fragaria Xananassa Duch.) were greenhouse grown under natural lighting and then placed into growth chambers at two constant temperatures of 16 and 26 °C and 2 daylengths of 9 h (SD) and 9-h photoperiod (NI) which was night interrupted with 3 hours of incandescent radiation at 30-45 μmol·s-1·m-2 PAR. Plants were given different numbers of inductive cycles in growth chambers and then moved to the greenhouse. Flowering and growth were monitored. Flowering was completely inhibited at 26 °C, regardless of pretreatment growing conditions such as pot sizes and plant ages, photoperiod, and inductive cycles. At 16 °C, SD promoted floral induction compared to NI under all inductive cycles except a 7-day induction. The minimum number of inductive cycles required at 16 °C for floral induction was dependent on photoperiod and prior greenhouse treatment. Flowering rate was also affected by greenhouse treatment, photoperiod, and inductive cycles. Runner production was affected by photoperiod and temperature × inductive cycle.
Monte L. Nesbitt, Robert C. Ebel, Douglas Findley, Bryan Wilkins, Floyd Woods, and David Himelrick
Containerized `Owari' satsuma mandarin (Citrus unshiu Marc.) on Poncirus trifoliata `Flying Dragon' rootstock were exposed to one of two acclimation regimes (cold acclimated and unacclimated) and frozen in a computer-controlled freezer to five different low temperatures. Whole plant survival was measured and compared to the results of four leaf and stem injury assays. Acclimating plants in growth chambers at 20 °C day and 10 °C night for 14 days, followed by 15 °C day and 4 °C night for 14 to 21 days resulted in an 81% and 80% increase in leaf and stem survival, respectively, when frozen to a low of -8 °C. Electrolyte leakage and phenolic leakage assays effectively detected changes in percent leaf survival, but the TTC stain assay, using leaf disks, did not. Stem survival was best predicted by the TTC assay, using the phloem as the indicator tissue for survival. Electrolyte leakage and phenolic leakage were also reliable assays for predicting stem survival, although survival percentages were different at the same electrolyte leakage values reported in other studies. The callus growth assay accurately predicted survival for cold acclimated satsuma mandarin stems only. Chemical name used: triphenyl tetrazolium chloride (TTC).
Thomas R. Gordon, Dorothy Okamoto, Andrew J. Storer, and David L. Wood
Pitch canker, caused by Fusarium subglutinans f. sp. pini, causes branch dieback and stem cankers in many species of pine. Monterey pine (Pinus radiata D. Don), one of the most widely planted pines in the world, is extremely susceptible to pitch canker. Four other pine species, which might serve as alternatives to Monterey pine in landscape settings, were found to be relatively resistant, based on the size of lesions resulting from branch inoculations under greenhouse conditions. Of these species, Japanese black pine (P. thunbergiana Franco) was the most resistant, followed by Canary Island pine (P. canariensis Sweet ex K. Spreng), Italian stone pine (P. pinea L.), and Aleppo pine (P. halepensis Mill.). Consistent with these findings, a field survey conducted in Alameda County, Calif., revealed Monterey pine to have the highest incidence of infection, with significantly lower levels in Aleppo, Canary Island, and Italian stone pines. Japanese black pine was not observed in the survey area.
Carleton B. Wood, Timothy J. Smalley, Mark Rieger, and David E. Radcliffe
Container-grown Viburnum plicatum Thunb. var. tomentosum (Thunb.) Miq. `Mariesii' were planted in unamended planting holes, tilled plots, and tilled plots amended with aged pine bark. A 36-day drought was initiated 108 days after planting. Amending induced N deficiencies, reduced shoot growth, and increased root growth. Plants harvested from tilled and planting-hole plots at drought initiation had 63% and 68% more dry weight, respectively, than plants from amended plots. Between 8 and 19 days after drought (DAD) initiation, plants from tilled plots maintained higher relative leaf water content (RLWC) than plants from planting holes. Plants in amended plots maintained higher RLWC than both other treatments between 7 and 33 DAD. Amended and tilled treatments had higher relative leaf expansion rates (RLERs) than the planting-hole treatment 8, 11, 13, and 15 DAD. As the drought lengthened, plants in amended plots maintained higher RLERs than plants in tilled plots. While plants in pine bark-amended plots were more drought tolerant than those in tilled plots, it is unclear if increased drought tolerance was caused by the improved rooting environment or N deficiency.