Floral volatiles ofTanacetum vulgare L. attractive toLobesia botrana den. et schiff. females

The European grapevine moth (EGVM),Lobesia botrana, is a major pest of grapes in Europe. Females are attracted to a nonhost plant: tansy (Tanacetum vulgare L.), which is a common weed in Slovakian vineyards. A steam distillate extract of tansy flowers was analyzed by means of a GC-EAG technique to screen constituents detected by the olfactory receptors of EGVM females. From more than 200 GC peaks, nine peaks corresponding to monoterpenoids released an EAG response in more than 70% of the females (N=15):p-cymene,d-limonene,-thujene,-thujone,-thujone, thujyl alcohol, terpinene-4-ol, (Z)-verbenol, and piperitone. The steam distillate of tansy as well as a synthetic blend of identified compounds released consistent attraction in a field cage. The use of nonhost plants and host plant odors in integrated pest management is discussed.     

Simple and economic syntheses of some (Z)-7- and (Z)-9-alkenyl acetates,and of (E,Z)-7,9-dodecadien-1-yl acetate,the sex pheromone of the European grapevine moth,using aleuritic acid as a common starting material

Short syntheses of (Z)-7-dodecen-1-yl acetate, (Z)-7-tetradecen-1-yl acetate, (Z)-9-dodecen-1-yl acetate, and (Z)-9-tetradecen-1-yl acetate from 7-hydroxyheptanal and 9-oxononanoic acid precursors obtained by oxidative cleavage of easily available aleuritic acid are reported. The key step in these syntheses is a stereoselective Wittig reaction between aldehyde and alkyl-phosphonium salt. Wittig-Horner type reaction of 7-hydroxyheptanal and diethyl cyanomethylphosphonate gave the ,-unsaturated nitrile derivative which after protection of the hydroxyl group was reduced to the corresponding aldehyde. Wittig reaction of the latter, followed by acetylation, completed the synthesis of (E,Z)-7,9-dodecadien-1-yl acetate, the sex pheromone of the European grapevine mothLobesia botrana Schiff.     

Characterization of Pheromone Blend for Grapevine Moth, Lobesia botrana by Using Flight Track Recording

The behavioral responses of Lobesia botrana males to calling females, pheromone gland extracts, and synthetic sex pheromones were recorded in a wind tunnel. Gland extracts and synthetic pheromones were released from a pheromone evaporator. The numbers of males reaching the source and their flight tracks in response to calling females and pheromone gland extracts were compared to those of synthetic blends. Upwind flights to natural sex pheromone were straighter and faster than to a three-component blend of (E)-7,(Z)-9-dodecadienyl acetate (E7,Z9–12:Ac), (E)-7,(Z)-9-dodecadien-1-ol (E7,Z9–12:OH), and (Z)-9-docecenyl acetate (Z9–12:Ac) (100:20:5). The optimum ratio of E7,Z9–12:OH and Z9–12:Ac to E7,Z9–12:Ac was found to be 5% and 1%, respectively. An additional seven compounds identified in the sex pheromone gland were investigated for their biological activity. Two unsaturated acetates, i.e., (E)-9-dodecenyl acetate (E9–12:Ac) and 11-dodecenyl acetate (11–12:Ac), increased the number of males reaching the source as well as straightness, linear velocity, and decreased the track angle of upwind flight. Optimum response was obtained by releasing 10 pg/min E7,Z9–12:Ac in a mixture with 0.5 pg/min E7,Z9–12:OH, 0.1 pg/min Z9–12:Ac, 0.1 pg/min E9– 12:Ac and 1 pg/min 11-12–Ac. The saturated acetates previously identified in the female glands were biologically inactive.     

Spatial–Spectral Analysis of Hyperspectral Images Reveals Early Detection of Downy Mildew on Grapevine Leaves

Downy mildew is a highly destructive disease of grapevine. Currently, monitoring for its symptoms is time-consuming and requires specialist staff. Therefore, an automated non-destructive method to detect the pathogen before the visible symptoms appear would be beneficial for early targeted treatments. The aim of this study was to detect the disease early in a controlled environment, and to monitor the disease severity evolution in time and space. We used a hyperspectral image database following the development from 0 to 9 days post inoculation (dpi) of three strains of Plasmopara viticola inoculated on grapevine leaves and developed an automatic detection tool based on a Support Vector Machine (SVM) classifier. The SVM obtained promising validation average accuracy scores of 0.96, a test accuracy score of 0.99, and it did not output false positives on the control leaves and detected downy mildew at 2 dpi, 2 days before the clear onset of visual symptoms at 4 dpi. Moreover, the disease area detected over time was higher than that when visually assessed, providing a better evaluation of disease severity. To our knowledge, this is the first study using hyperspectral imaging to automatically detect and show the spatial distribution of downy mildew on grapevine leaves early over time.     

砧木不同嫁接高度对葡萄生物学性状及抗病性的影响初探

本试验以沪培2号、沪-11和粉红亚都蜜为接穗,以华佳8号为砧木,研究葡萄砧木不同高度嫁接对各品种成活率、枝条生长量、结果性能以及抗病性的影响.结果表明:低位嫁接的成活率最高,效果最好;高位嫁接则有利于接穗品种的花芽分化与结果,并能增强接穗品种的抗病能力,霜霉病、黑痘病等病害的发病率较低.     

Impact of node position and bearer length on the yield components in mechanically pruned Cabernet Sauvignon (Vitis vinifera L.)

Background and Aims: Bunch number per node or shoot varies significantly between seasons and is a major cause of yield variation. Varying total node numbers by pruning is the least expensive way to regulate yield. However, there is little information available on how varying bearer length (and thus node number) in a machine‐pruned canopy alters yield components. Methods and Results: The impact of bearer length on yield components was investigated in a mechanically pruned vineyard in Coonawarra, South Australia. Yield components were analysed according to the node position on the bearer at which the shoot arose. Both budburst and inflorescence number per node were highest at the distal node positions regardless of bearer length. When node positions two and three were located in the two most distal nodes made terminal by the pruning, they were significantly more fruitful than equivalent nodes on longer bearers. Shoots that arose from the two most distal node positions had the highest flower number per inflorescence and berry number per bunch. Conclusions: Budburst, and the number and size of the inflorescence and bunch were affected more by the node position at which the shoot occurred relative to the cut end of the bearer, than the position of the node from the base of the bearer. Significance of the Study: Our understanding of how pruning regimes impact on yield and how these pruning regimes may be modified to achieve a target yield has been improved.     

Anthocyanin composition and extractability in berry skin and wine of Vitis vinifera L. cv. Aglianico

BACKGROUND: The present article reports the anthocyanin content in the berry skin and wine of the Italian red grape cultivar Aglianico (clone VCR11 grafted onto 1103 Paulsen), one of the most ancient vines and famous for its deep‐red colour. Anthocyanins were extracted from frozen berry skin in an acidified methanol solution. The extraction mixtures, monitored for 120 h, were analysed by high‐performance liquid chromatography. RESULTS: The extraction from berry skin of delphinidin, petunidin and malvidin appeared to be a time‐independent process, whereas the concentration of peonidin increased linearly with time. Peonidin‐O‐acetyl‐glucoside was transferred from skin more slowly than petunidin‐O‐acetyl‐glucoside and malvidin‐O‐acetyl‐glucoside. The anthocyanin composition of the resulting wine showed that the total anthocyanin content was about one‐tenth of the corresponding berry skin content. The ratio acetyl/coumaroyl anthocyanins in the wine was sharply higher than the value in berry skin (0.85 and 0.10, respectively), indicating an enrichment of acetyl derivatives in the wine. CONCLUSION: Levels of single anthocyanins in wine were not always correlated with those detected in grapes, as they were affected by winemaking. The high values of some anthocyanins in Aglianico wine could ameliorate its quality, increasing the chromatic properties, aging stability and product acceptance. Copyright © 2011 Society of Chemical Industry     

Biosynthesis of flavour compounds in Muscat Gordo Blanco grape berries

Inflorescences of the floral grapevine cv Muscat Gordo Blanco (syn. Muscat of Alexandria) were grown on their own shoots until maturity or, after approach-grafting before flowering, on the shoots of the non-floral cv Shiraz (in the glasshouse) or Sultana (in the field). The flavour compounds of their berries were compared with those in the berries of the non-floral cultivars, grown either on their own shoots or, by grafting, on the shoots of the Muscat cultivar. For this, monoterpene glycosides were isolated from the fruits, enzymatically hydrolysed and the released monoterpene aglycons were liquid-liquid extracted and analysed by GC-MS. The Muscat Gordo Blanco berries of ungrafted bunches and of bunches grafted onto Shiraz or Sultana vines yielded fruit with monoterpenes at levels and types typical of this floral grape variety. The berries of Shiraz and Sultana bunches contained only low levels of monoterpene glycosides both on their own shoots or grafted onto Muscat shoots. The lack of difference between flavour compounds in grafted and non-grafted fruit indicate that aroma compounds are synthesised in the berries and that their presence is determined by the genotype of the grape bunch rather than by the genotype of the vine.