The dynamics of grape leafhopper Empoasca vitis Göthe populations in southern Switzerland and the implications for habitat management

The life cycle of Empoasca vitis and its most important parasitoid Anagrus atomus in southern Switzerland can be divided into three phases. In phase I the adults of E. vitis move from overwintering sites, i.e. primarily conifers, over deciduous plants into the vineyards. The parasitoid A. atomus on the other hand, appears to overwinter in leafhopper eggs, mainly on roses and blackberries. It subsequently completes one generation in leafhopper eggs primarily on blackberries and hazelnuts, before it attacks E. vitis eggs in the vineyards. For phase II, a population model with time‐varying age structures and stochastic properties was constructed for E. vitis. For this purpose a time‐varying distributed delay model with attrition was constructed. Given the calibrated initial density of overwintering females, the model predicts an unacceptable number of E. vitis for the growing season. However, if egg parasitism of A. atomus and Stethynium triclavatum is introduced into the model as an external variable E. vitis densities are predicted which are economically irrelevant. Inphase III E. vitis adults leave the vineyards for the overwintering sites. The model shows the importance of the parasitoid A. atomus during phase II. A. atomus should be favoured by surrounding the vineyards with host plants carrying leafhoppers’ eggs. Consequently, habitat management measures for E. vitis control could be applied to the surroundings of the vineyards.     

茶假眼小绿叶蝉对不同茶香精和寄主植物的趋性反应

利用"T"形室观察了茶假眼小绿叶蝉Empoasca vitis Gthe对4种茶香精和3种寄主植物的趋性反应。结果表明,假眼小绿叶蝉对不同茶香精粉和寄主植物的趋性反应不同。叶蝉对绿茶和乌龙茶A香精有明显的趋向反应,而对乌龙茶B香精即铁观音茶香精则有明显的忌避反应,对红茶香精则无反应。假眼小绿叶蝉对茶梢和青菜的趋性反应无显著差异,而对茶梢和大豆的趋性反应有差异,表现出更喜好趋向茶梢。     

不同砧穗组合葡萄植株对部分根区干旱的生理生化响应

利用自制木箱对嫁接在3309C、420A和110R砧木上的玛瓦斯亚葡萄（M）进行双侧根区交替灌溉（AI）和单侧灌溉（UI）两种水分胁迫处理,以探讨不同葡萄砧穗组合对干旱的适应能力.结果表明：水分胁迫导致葡萄叶片ABA浓度大幅度增加,AI和UI的3种组合平均分别提高了267.5％和394.7％,而气孔导度和蒸腾速率显著下降.UI处理的3种组合叶片SOD和CAT活性显著增加,脯氨酸（Pro）含量极显著增加,且均以M/110R增幅较大,M/3309C增幅较小;而AI处理的SOD和CAT活性增加较小,但Pro含量显著增加.干旱胁迫导致葡萄叶片质膜透性、MDA和H₂O₂含量极显著增加,以M/3309C增加最多,M/110R增加较少.不同砧穗组合适应干旱逆境的能力主要取决于砧木品种,110R适应干旱逆境的能力强于420A和3309C,其对应的嫁接植株的生长量亦呈同样趋势.与根区单侧灌溉相比,双侧根区交替灌溉对植株造成的伤害较小,是可推广的节水灌溉方式.     

The seven NAD(H)-glutamate dehydrogenase isoenzymes exhibit similar anabolic and catabolic activities

The specific activities of aminating NADH- and deaminating NAD⁺-glutamate dehydrogenase (GDH, EC 1.4.1.2) varied considerably in crude extracts of grapevine ( Vitis vinifera L. cv. Sultanina) callus and were dependent on the nitrogen source of the culture medium. However, dialysis of the enzyme preparations resulted in a significant decrease in the deaminating GDH specific activity while the aminating activity was not affected. The presence of malate in the crude extract resulted in erroneous overestimation of the NAD⁺-GDH activity through the malate dehydrogenase reaction. Thus, in dialysed extracts, the ratio of the NADH-GDH/NAD⁺-GDH specific activities remained relatively constant irrespective of the nitrogen source. In view of this evidence, we now have modified methods for staining both the NADH-GDH and NAD⁺-GDH activities on gels in order to compare the aminating and deaminating activities of each of the 7 GDH isoenzymes. The results from the staining of NADH-GDH and NAD⁺-GDH activity of enzyme preparations from calluses revealed the same isoenzyme profile. Furthermore, separated leaf isoenzymes showed similar activity ratios and kinetic properties. These results may suggest that each one of the 7 isoenzymes have similar in vitro anabolic and catabolic activities.     

Bacterial rhamnolipids are novel MAMPs conferring resistance to Botrytis cinerea in grapevine

Rhamnolipids produced by the bacteria Pseudomonas aeruginosa are known as very efficient biosurfactant molecules. They are used for a wide range of industrial applications, especially in food, cosmetics and pharmaceutical formulations as well as in bioremediation of pollutants. In this paper, the role of rhamnolipids as novel molecules triggering defence responses and protection against the fungus Botrytis cinerea in grapevine is presented. The effect of rhamnolipids was assessed in grapevine using cell suspension cultures and vitro-plantlets. Ca²⁺ influx, mitogen-activated protein kinase activation and reactive oxygen species production form part of early signalling events leading from perception of rhamnolipids to the induction of plant defences that include expression of a wide range of defence genes and a hypersensitive response (HR)-like response. In addition, rhamnolipids potentiated defence responses induced by the chitosan elicitor and by the culture filtrate of B. cinerea . We also demonstrated that rhamnolipids have direct antifungal properties by inhibiting spore germination and mycelium growth of B. cinerea . Ultimately, rhamnolipids efficiently protected grapevine against the fungus. We propose that rhamnolipids are acting as microbe-associated molecular patterns (MAMPs) in grapevine and that the combination of rhamnolipid effects could participate in grapevine protection against grey mould disease.     

葡萄实生树阶段转变过程中的内源多胺含量变化

用高效液相色谱法测定二年生巨峰葡萄自然实生树不同节位叶片、芽、韧皮部中内源多胺含量的结果表明,随着节位的升高,在3种组织中的腐胺(Put)和亚精胺(Spd)含量增加,21～25节腐胺增加幅度最大,自21节起亚精胺含量陡增;21～25节叶片中的精胺(Spm)含量出现高峰.说明21节左右可能是童性消失进入生殖生长期的临界点.     

Uwe Joachim Nebert ‐ 70 Jahre

Esca is a very important and destructive disease of grapevine in many grapevine producing countries. Several groups of fungi have been reported from grapevines with esca disease symptoms; however, Phaeoacremonium species are the main hyphomycete fungi involved in this disease. In recent years, esca disease symptoms with consequent decline disease have frequently been observed in vineyards of north-western Iran. Nevertheless, the involvement of Phaeoacremonium spp. with esca disease symptoms in this region remains unknown. During 2008–2010 growing seasons, wood samples were collected from vines showing typical esca disease symptoms such as interveinal leaf chlorosis with subsequent necrosis and various types of internal wood deterioration in north-western parts of Iran. A total of 44 Phaeoacremonium-like hyphomycetes were recovered from sampled materials. Fungal isolates were subjected to tentative morphological identification and were further characterised by using sequenced data from ITS-rDNA and β-tublin gene. Phylogeny inferred using sequence data from ITS-rDNA region and β-tublin gene revealed that Phaeoacremonium aleophilum and P. mortoniae together with Sarocladium strictum (syn. Acremonium strictum) are associated with esca disease symptoms in this region. The pathogenicity of Phaeoacremonium spp. and Sarocladium strictum were verified by the inoculation of cutting root and stems under greenhouse conditions. Isolates of P. aleophilum and P. mortoniae were the most virulent based on the length of vascular necrosis on woody stems that followed by Sarocladium strictum. This is first study on the pathogenicity of Sarocladium strictum on grapevine worldwide and the first report on the occurrence of P. mortoniae on grapevines in north-western Iran.     

假眼小绿叶蝉自然天敌控制作用的评价

对假眼小绿叶蝉的卵期寄生蜂－缨小蜂进行了初步调查观察,并应用生命表方法对假眼小绿叶蝉的寄生性和捕食性天敌作用作了评价,提出了卵期寄生是一种重要的天敌控制因子,通过高峰期世代自然园与化防轩绿叶蝉生命表比较,结果表明,自然园种群趋势指数为１．０９,化防园为２．７１,模拟采摘试验,下一世代种群趋势指数均小于１,数量将下降。     

Habitat diversification tactic for improving biological control: parasitism of the western grape leafhopper

In a previous study we demonstrated greater abundance of the parasitoid Anagrus epos (Girault) in grape vineyards located downwind of prune trees that function as overwintering habitats. This study examines whether these higher A. epos numbers translated into higher egg parasitism rates of the grape leafhopper, Erythroneura elegantula (Osborn). Paired commercial wine-grape vineyard plots, one with and one without adjacent prune trees, were studied within a complete block design in northern and central California. A. epos was the key mortality factor affecting E. elegantula eggs. Point estimates of A. epos parasitism rates were significantly greater in vineyards associated with prune trees during the first E. elegantula generation in both 1991 and 1992. No consistent differences in parasitism rates were observed during the second or third generations. The results indicated that prune trees enhance early season parasitism rates. Cumulative estimates of egg parasitism across E. elegantula generations demonstrated that enhanced early-season parasitism resulted in a net season-long increase in the degree of mortality imposed by A. epos on E. elegantula eggs. Two factors were found to influence parasitism rates: the abundance of early-season A. epos adults moving into vineyards and the density of E. elegantula eggs in vineyards. Our results indicate that diversification of vineyards using prune trees supports overwintering populations of a specialist parasitoid and thereby alters host-parasitoid interactions to favor enhanced parasitism in vineyards.