Protection of Grapevine Pruning Wounds against Eutypa lata by Biological and Chemical Methods

Eutypa dieback, caused by the fungus Eutypa lata, is a serious disease of grapevines that infects mainly through pruningwounds. The aim of this study was to evaluate the in vitro efficacy of fungicides from various chemical groups againstE. lata, as well as the in vivo efficacy of the most effective fungicides and selected bacterial and fungal antagonists ofE. lata, in grapevine pruning wound protection trials. In vitro studies revealed that flusilazole, tebuconazole, benomyl,fenarimol and myclobutanil were the most effective fungicides to inhibit mycelial growth of E. lata. Two field trialswere conducted, one subjected to artificial inoculation and the second to natural infection only. In the first, benomyl,flusilazole and commercially available Trichoderma harzianum-containing products and an experimental Bacillussubtilis strain were applied to fresh pruning wounds. Two Cabernet Sauvignon vineyards were pruned in August2001 and 2002 and immediately treated and inoculated with a spore suspension of E. lata one day later. Isolationswere made from the treated pruning wounds after 12 months to assess the effectiveness of the treatments. Thefungicides benomyl and flusilazole were the most effective treatments, although the Trichoderma treatments T77 andTrichoseal spray caused a significant reduction in E. lata infection. In a second trial, pruning wounds of CabernetSauvignon, Sauvignon blanc, Red Globe and Bonheur were treated with the Trichoderma products Vinevax (=Trichoseal spray) and Eco77 (= T77) in August 2005 and 2006, subjected to natural infection only and evaluatedafter seven months. Vinevax and Eco77 not only reduced E. lata, but they also reduced the incidence of othergrapevine trunk disease pathogens

Patterns of distribution and current protection status of the Carnivora, Chiroptera and Insectivora in South Africa

Geographic patterns of species richness and endemism in three mammalian orders (Chiroptera, Insectivora and Carnivora) were studied in relation to the biomes and existing protected areas of greater South Africa (including Lesotho and Swaziland). Locality data for 21500 specimens representing 124 species were analysed with a geographical information system. Species richness of Chiroptera is high in the savanna biome, particularly in the north-east of the country, owing to the marginal intrusion of 14 tropical species. Endemism in Chiroptera is low, however, with only two endemic species in the fynbos and Karoo biomes. The Carnivora display less biome specificity and endemism than the Chiroptera. Whereas the north-eastern savannas have the highest species richness, the transition between the Nama-Karoo and grassland biomes is an important southern African centre of endemism for the Carnivora, particularly the smaller species. In addition to being an important centre for species richness in the Carnivora and Chiroptera, the Kruger National Park is also particularly important for Red Dala Book species in both orders. The Insectivora display both high species richness and endemism. Species richness of the Insectivora is greatest in the mesic south-east of the country, whereas endemism is most pronounced in the forest and grassland biomes. Differences in biome specificity and endemism between these orders reflect not only phylogenetic divergence, but also variation in body size, vagility and life-history strategies. Most of South Africa's endemics are small mammals and many of them are listed in the Red Data Book. Distributions, life-history strategies and trends in man-induced habitat degradation were used to re-evaluale the protection status of the 124 species. We conclude that at least 11 endemic species are not adequately protected by existing publicly owned protected areas and consequently identify several areas which need to be added to the existing protected area system

Prediction of parturition in Holstein dairy cattle using electronic data loggers

The objective of the present study was to assess the effect of parturition on behavioral activity [steps, standing time, lying time, lying bouts (LB), and duration of LB] 4 d before calving using electronic data loggers. Animals (n = 132) from 3 herds were housed in similar freestall barns using a prepartum pen 21 d before the expected calving date and were moved into a contiguous individual maternity pen for parturition. Electronic data loggers were placed on a hind leg of prepartum heifers (heifers, n = 33) and cows (cows, n = 99) at 7 ± 3 d before the expected calving date and removed at 14 ± 3 d in milk. Calving ease (scale 1–4), parity, calving date and time, and stillbirth (born dead or died within 24 h) were recorded. The number of steps (no./d), standing time (min/d), lying time (min/d), number of LB (no./d), and duration of LB (min/b) were recorded. Data were analyzed using MIXED procedures of SAS, adjusting for the herd effect. Only cows experiencing unassisted births (calving ease = 1) were included in the study. An activity index was developed to predict calving time. Heifers and cows with unassisted births had significantly higher number of steps and longer standing time, decreased lying time, and more LB of shorter duration 24 h before calving compared with d −4, −3, and −2. Additionally, the number of LB increased as both heifers and cows approached labor starting on d −2 and peaked at the day of calving. The time since the activity index increased over 50% to parturition did not differ between heifers and cows, and the activity index revealed the shift in activity on average 6 h 14 min (range from 2 h to 14 h 15 min) before calf birth. This study provided evidence that heifers and cows approaching parturition showed a similar, but distinct, behavioral pattern that can be observed on average 6 h before calf birth. The potential benefits of electronic data loggers as predictors of parturition along with proactive management practices should improve the overall survival and welfare of both the dam and calf

Endogenous cytokinin levels of table grape vines during spring budburst as influenced by hydrogen cyanamide application and pruning

Cytokinins play an important role in budburst, flowering and fruit set in table grapes. Rest-breaking treatments with hydrogen cyanamide and pruning practices modify budburst and reproductive development in table grapes, especially in regions with low and often inadequate winter chilling. The effect of these treatments on the xylem sap and bud Zeatin riboside (ZR) content was determined during late winter and budburst in 'Sultanina', 'Sunred Seedless', and 'Alphonse Lavalleé' canes in a total of nine trials conducted between 1997 and 2001. Bud ZR levels of hydrogen cyanamide treated 'Sultanina' canes showed an earlier and increased cytokinin peak, in particular in the distal buds. Large ZR peaks before budburst and noticeable differences between distal and proximal buds were absent on non-sprayed canes. The xylary ZR content of long pruned 'Sultanina', 'Sunred Seedless', and 'Alphonse Lavaleé' canes showed a significantly higher and earlier cytokinin peak than in short pruned spurs. By contrast, the bud ZR content tended to be higher in spurs than canes. Pruning and rest-breaking treatments enhanced budburst and increased endogenous cytokinins in these experiments. Long pruning in 'Sultanina' and 'Sunred Seedless' (both parthenocarpic) is necessary for acceptable fruit set and yields. Possibly, in longer canes more cytokinin is available for reproductive development. 'Alphonse Lavaleé' (seeded) is sufficiently fruitful and produces adequate yields following spur pruning. © 2006 Elsevier B.V. All rights reserved.Articl

The Effect of Ethephon on the Berry Colour of Flame Seedless and Bonheur Table Grapes

Flame Seedless grafted onto Richter 99 situated in the Lower Orange River region and Bonheur grafted onto Ramsey in the Berg River Valley region of South Africa were used to test ethephon treatments for berry colour improvement. The trial was repeated over three seasons. Four ethephon dosages (100, 200, 300 and 400 mg/L) in combination with five application times (weekly intervals starting from acid maximum) were compared to an untreated control. As soon as general minimum maturity for export was reached, pack-out percentage was determined and representative bunch samples harvested and packed as for export. After storage for four weeks at -0.5°C and one week at l0°C, bunch quality was evaluated according to standard industry norms. As a preliminary determination anthocyanin and phenol absorbance levels were determined during one season to possibly complement visual evaluation of berry colour. The best overall result with regard to the timing of application for both Flame Seedless and Bonheur was obtained with an ethephon application two weeks after acid maximum (30 to 40% colour). Significant seasonal differences were observed regarding various quality variables of Bonheur. This timing was not very critical for improved export pack-out or meeting the berry colour quality norm. Treatments closer to harvest increase the risk of quality defects during cold storage, such as berry crack, S02 burn, as well as soft and loose berries. An ethephon dosage of 300 mg/L for Flame Seedless and 200 mg/L for Bonheur gave satisfactory results regarding export pack-out, export-quality berry colour at harvest and post-cold-storage quality. The preliminary evaluation of anthocyanin and total phenol absorbance levels did not correlate well with visual evaluation of berry colour, showing the difficulty of sensory determinations for quality evaluation

A multisliced finite-element model for induction machines incorporating interbar current

This paper initially reviews some previous work with respect to the effect of interbar currents on the performance of a cage induction machine with a skewed rotor. A multisliced nonlinear 2-D finite-element model is then put forward to account for this current. This model uses different circuits to assess how the interbar current should be incorporated into the simulation. It uses different arrangements in both the axial and radial representations. The starting characteristics are focused upon, and the simulation results are compared to measured results. It is verified that the interbar currents do have an effect that is not normally accounted for in standard modeling techniques