福建省葡萄病毒病的调查和研究

１９９０～１９９２年作者对福建省葡萄产区进行了抽样调查，发现该省约３１％的果园有葡萄扇叶病（ＧＦＬＶ）和葡萄卷叶病（ＧＬＲＶ）。在调查的１１３００株葡萄中（６０２亩），ＧＦＬＤ株发病率为１３．２７％，造成葡萄减产２７．２％；ＧＬＲＶ株发病率为７．３％，减产２１．５％。病株表现为不同程度的种性退化，生长赢弱、停滞，果实品质下降，果粒成熟不齐。     

应用酶联免疫吸附监测1994～1995年BYDV株系

１９９４～１９９５年从我国南北主要冬、春麦区黄矮病发病田块采集ＢＹＤＶ标样，进行酶联免疫测定。１９９４年测定标样１５９株，其中ＧＡＶ株系１１２株，占测定总数的７０．４４％；ＰＡＶ株系８株，占测定总数的５．０３％；与ＰＡＶ抗体和ＭＡＶ抗体都不发生免疫反应的共３９株，占２４．５３％。１９９５年测定了１８７株ＢＹＤＶ标样，ＧＡＶ株系８４株，占４４．９２％；ＰＡＶ株系１８株，占９．６３％；ＰＡＶ与ＧＡＶ混合感染９株，占４．８１％；阴性反应的７６株，占４０．６４％     

甘蔗黑穗病及其防治

甘蔗黑穗病及其防治（海南省白沙县植保植检站５７２８００）龚标勋五月上旬本县的七坊镇的高地、才棉蔗区发现有甘蔗黑穗病发生。平均每１０ｍ２有病株４株，亩发病率１３．３％，重的达１５％。并有发展趋势。病株失去经济价值，病田会造成减产甚至绝收。一、病状：病株...     

胚轴切断法诱导棉花抗棉铃虫及其生化机制研究

诱导抗虫棉株对棉铃虫营养代谢功能的影响表明,胚轴切断法结合假单胞杆菌（Ｄ－２２５１）诱导处理的棉株可使棉铃虫相对生长率（ＲＧＲ）、相对取食量（ＲＣＲ）和近似消化率（ＡＤ）明显降低,分别降低２２．９５％、２６．１２％和２７．２３％,仅用胚轴切断法处理的棉株可使ＧＲＧ、ＲＣＲ和ＡＤ分别降低１７．２５％、２１．４４％和４．０９％。对诱导处理棉株体内植物多元酚和抗虫萜烯类的测定结果表明,经过胚轴切断法后,     

茶蚕颗粒体病毒液剂与复合液剂的田间应用

本文报道茶蚕颗粒体病毒（ＡｂＧＶ）液剂与ＡｂＧＶ杀虫双复合液剂田间防治茶蚕的效果。ＡｂＧＶ液剂６００ｍｌ／ｈｍ ２ 防治卵盛孵期至低龄幼虫期的效果可达８０．４％ ～９１．１％ ,并有明显的持效,施药后１～３ 年,茶蚕的自然感病率仍达４７．６％ ～６２．３％ ;ＡｂＧＶ杀虫双复合液剂（３００ｍ ｌ／ｈｍ ２）防治卵盛孵期至幼虫３龄前幼虫的效果可达８６．２％ ～９７．５％ 。９～１０月以应用复合液剂较好,能加快死亡速度,但持效较ＡｂＧＶ液剂差     

临夏地区春蚕豆根腐病发生与为害调查

对甘肃临夏地区的３４０块春蚕豆田根腐病的调查，明确了该区蚕豆根腐病死亡率为１％～９０％，平均为１５．３３％；死亡率小于１０％的地块占调查地块总数５９．７％，大于３０％地块占１７．３５％，随着海拔梯度的增高，蚕豆死亡率逐渐下降。病原真菌主要有腐皮镰刀菌（Ｆｕｓａｒｉｕｍｓｏｌａｎｉ）、燕麦镰刀菌（Ｆ．ａｖｅ－ｎａｃｅｕｍ）、粘帚霉（Ｇｌｉｏｃｌａｄｉｕｍｒｏｓｅｕｍ）和尖孢镰刀菌（Ｆ．ｏｘｙｓｐｏｒｕｍ）     

速克灵防治葡萄灰霉病

速克灵防治葡萄灰霉病张茂伟，于培贞，薛克富（青岛市植保站，２６６０７１）（山东省植保站）葡萄灰霉病（ＢｏｔｒｙｔｓｃｉｎｒｅａＰｅｒｓ．）是青岛地区的一种新病害，它主要为害叶片，使叶片变黄枯死，造成大量落果，一般减产５０％以上，严重的约８０％。应用波...     

麦田几种主要杂草复合危害损失研究

麦田几种主要杂草复合危害损失研究李复宁（湖北省襄北农场植保站襄阳４４１１２３）野燕麦ＡｖｅｎａｆａｔｕａＬ，、猪殃殃Ｇａｌｉｕｍａ－ｐａｒｉｎｅＬ．和小巢菜Ｖｉｃｉａｈｉｒｓｕｔａ（Ｌ．）Ｓ．Ｆ．Ｇｒａｙ．是鄂北岗地麦田３大恶性杂草，在田间常混合发生...     

不同类型的稻田中镰刀菌对螟虫的感染率调查

不同类型的稻田中镰刀菌对螟虫的感染率调查黄运霞，李华，黄荣瑞（广西农科院植保所，南宁５３０００７）ＩＮＶＥＳＴＩＧＡＴＩＯＮＯＮＴＨＥＰＡＴＨＯＧＥＮＥＣＩＴＹＯＦＦＵＳＡＲＩＵＭＳＰＰ．ＯＮＴＨＥＯＶＥＲＷＩＮＴＥＲＩＮＧＲＩＣＥＢＯＲＥＲＩＮＴＨ...     

杆状病毒表达猪传染性胃肠炎病毒钉状蛋白在血清学诊断上的应用

用从猪传染性胃炎病毒（ＴＧＥＶ）强毒Ｍｉｌｌｅｒ株（Ｍ５Ｃ）克隆建立的一株的重组杆状病毒（Ｒ２－２）表达的重组ＴＧＥＶ钉状糖蛋白（Ｓｐｉｋｅ，Ｓ）建立了一种阻断酶联免疫吸附试验（ＥＬＩＳＡ）来检测猪群中抗ＴＧＥＶ抗体。实验表明，用重组病毒Ｒ２－２接种昆虫传代细胞系Ｓｐｏｄｏｐｔｅｒａ ｆｒｕｇｉｐｅｒｄａ（ｓｆ９），所表达的重组蛋白量在接种后第７２小明达到最高值；该重组蛋白能与抗ＴＧＥＶ Ｓ蛋白Ａ     

TuMV在心叶烟上的症状反应与苗龄和温度的关系

 在心叶烟(Nicotana glutnosa)上接种芜菁花叶病毒(TuMV)的一个分离物,随接种的苗龄和培养温度不同,出现枯斑的类型和数量不同。3叶期接种,在20℃和25℃条件下培养,全部出现典型系统枯斑。6叶期接种后遮光24小时,培养在30℃下,则全部出现系统轮纹枯斑。3叶或6叶期接种,培养在35℃下,接种后25天内,多数植株出现系统枯环,而无其他类型枯斑。试验反映了不同条件下出现不同枯斑类型的趋势及其演变。从而为利用心叶烟鉴别植物病毒病的毒原种群明确了接种和培养条件,有助于鉴定的准确性。同时也反映出应当寻找其他指示植物代替心叶烟来做TuMV株系鉴定的指示植物。     

莴苣花叶病毒病的研究Ⅱ病害的分布、损失、寄主和传播

 莴苣花叶病在山东普遍发生,其中以泰安等地比较严重。苗期和发棵前期发病的损失最大;人工接种证明,3叶期和7叶期感染的病株全无食用价值。在测定的15科63种植物中,有4科14钟植物表现感病。种子带毒率为1-2%,不同品种和不同生育期感染的病株种子带毒率有很大差异,开花后发病的植株种子不带毒。室内测定,萝卜蚜(Rhopalosiphum pseudobrassicae),棉蚜(Aphis gassypii)和大戟长管蚜(Macrosiphum euphorbiae)均可传毒。桃蚜取食15秒钟即可获毒或传毒,单头蚜传毒率为40%左右,获毒1次可连续传毒2-3株。     

香蕉束顶病毒(BBTV)侵染对寄主内源激素的影响

 本试验用ELISA方法测定了香蕉感染束顶病毒(BBTV)后植株体内的3种内源激素,赤霉素(GA₃)、玉米素类(iPAs)和脱落酸(ABA)的变化。结果表明,感株的GA₃水平在侵染过程中虽有微弱增加,但含量和增长速度显著低于健株对照;iPAs在接种BBTV第14天后明显下降,并维持较低水平;ABA在BBTV侵染后被大量诱导增加并不断积累,在接种后第35天测定含量最高,为对照的3.34倍。试验还同时检测了BBTV在侵染过程中的运转。用间接ELISA测定的接种叶和顶叶的BBTV含量显示:接种21天后BBTV在接种叶和顶叶中还大量增殖,呈系统性分布。但寄主的症状在接种35天后才逐渐在顶叶表现。以上结果表明:香蕉束顶病的症状表现似乎主要与病株中的内源激素的失调有关,而与BBTV在体内的运转并不直接相关     

Goat horns: Platforms for viroid transmission to fruit trees?

Mechanical inoculations with contaminating tools and propagation of infected budwood were considered the main causes for the omnipresence of multiple viroid species among citrus and other Middle Eastern and Mediterranean fruit trees and grapevines. However, neither means could explain viroid infections of wild trees — scattered on terrains inaccessible to humans — nor the finding of similar viroids among graft-incompatible plants. Northern hybridization of RNA extracts made of scrapings from the surfaces of goat (Capra hircus) horns that were rubbed against etrog (Citrus medica) stems infected with a citrus viroids complex, revealed accumulation of considerable amounts ofCitrus exocortis viroids (CEVd) andHop stunt viroids (HSVd). Experimental transmission of both CEVd and HSVd was obtained by rubbing healthy citrus plants with goat horns that had been rubbed 24 h earlier on infected etrog stems. These results implicate goats as possible vectors of viroids. Transmissionvia goats could have facilitated the long-range spread of viroids among cultivated and wild plants andvice versa and also among graft-incompatible plants.     

Growth- and leaf-temperature effects on photosynthesis of sweet orange seedlings infected with Xylella fastidiosa

The effects of growth and leaf temperature on photosynthesis were evaluated in sweet orange seedlings ( Citrus sinensis cv. Pera) infected with Xylella fastidiosa (the bacterium that causes citrus variegated chlorosis, CVC). Measurements of leaf gas exchange and chlorophyll  a fluorescence were taken at leaf temperatures of 25, 30, 35 and 40°C in healthy and infected (without visible symptoms) seedlings submitted to two temperature regimes (25/20 or 35/20°C, day/night), not simultaneously. The CO₂ assimilation rates ( A ) and stomatal conductance ( g _s) were higher in healthy plants in both temperature regimes. Values for A and g _s of infected and healthy plants were higher in the 35/20°C regime, decreasing with leaf temperature increase. In addition, differences between healthy and infected plants were higher at 35/20°C, while no differences in chlorophyll  a fluorescence parameters were observed except for potential quantum efficiency of photosystem II, which was higher in infected plants. Low A values in infected plants were caused by low g _s and probably by biochemical damage to photosynthesis. The high alternative electron sink of infected plants was another effect of reduced A . Both high growth and high leaf temperatures increased differences in A between healthy and infected plants. Therefore this feature may be partially responsible for lower growth and/or productivity of CVC-affected plants in regions with high air temperature.     

The distribution of potato spindle tuber viroid in potato plants and tubers1

Potato spindle tuber viroid (PSTV) in potato plants was investigated by ‘return’ gel electrophoresis. The experiments were carried out under quarantine conditions in the greenhouse with primarily and secondarily infected plants. The PSTV content in different plant parts was estimated by the intensity of the viroid band in polyacrylamide gel. The results showed a decrease of viroid content from the upper to the lower parts of the plant. In both primarily and secondarily infected plants, PSTV was reliably detected in the top leaves, but less so in the lower leaves. In four out of ten secondarily infected plants, PSTV was found in the roots. In dormant tubers, the bands were more intense with samples obtained from the rose end and the heel than from those obtained from the medullary tissue. With one exception, all 64 tubers from 26 primarily infected plants were infected with PSTV.     

Transmission by aphids of potato spindle tuber viroid encapsidated by potato leafroll luteovirus particles

Potato spindle tuber viroid (PSTVd) was transmitted by Myzus persicae to Physalis floridana from P. floridana plants that also were infected with potato leafroll luteovirus (PLRV), whereas it was not transmitted by aphids from plants infected with PSTVd alone. Dot-blot hybridisation was used to detect PSTVd. The results indicate that PLRV can assist PSTVd in its transmission by M. persicae. Doubly infected, aphid-inoculated P. floridana plants from the previous experiment were used as the source plants in aphid transmission tests to the tomato cv. Rutgers, P. floridana and Datura stramonium. PSTVd was detected in 17 of 30 plants of tomato. The viroid was not detected by dot-blotting in any plant of P. floridana and D. stramonium in this experiment, but it was recovered from some plants by sap inoculation of the Rutgers plants. Treatment with RNase A of PLRV preparations purified from doubly infected plants indicated that PSTVd was encapsidated by PLRV particles.     

The effect of additional viral infections on garlic plants initially infected with <Emphasis Type="Italic">Allexiviruses</Emphasis>

Yield losses caused by a second viral infection of garlic plants previously infected with either of the isolated Allexiviruses, Garlic virus-A (GarV-A) or Garlic virus-C (GarV-C), were evaluated in a field assay carried out over four consecutive growing seasons. The treatment groups included virus-free plants (VF), plants infected only with GarV-A isolates (A), plants infected only with GarV-C isolates (C), and plants infected with a mixture of viruses that naturally infect garlic, referred to as viral-complex plants (VC). From the first crop cycle the different treatments were infected by other viruses that naturally infect garlic. At the end of the first growth cycle, significant differences in yield were observed among the four treatments. The bulb weight for VF, C, and A treatments was respectively 137%, 116%, and 96% higher than the bulb weight for the VC treatment. After the fourth growth cycle, however, non-significant differences in garlic yield between the VC, C, and A treatments were observed, whereas the yield for the VF treatment was higher than the VC treatment by 22%. Garlic yield decreased more rapidly in plants infected previously with at least one Allexivirus and then infected with other naturally occurring viruses than the plants that were virus-free at the beginning (VF plants).     

Transmission and the role of honeybees in field spread of blueberry shock ilarvirus, a pollen-borne virus of highbush blueberry

ABSTRACT The rapid and random spread of blueberry shock ilarvirus (BlShV) in commercial plantings suggested that insects played a role in transmission. Transmission from infected field plants to trap plants only occurred during bloom, indicating that flowers were the avenue for infection and flower-visiting insects including pollinators were involved. Trap plants readily became infected during bloom when a honeybee hive was included in cages with diseased field plants and trap plants. There was limited transmission in cages without a hive and no transmission when healthy field bushes were caged with trap plants either with or without honeybees. Infective pollen survived within the hive for 1 but not 2 weeks. Western flower thrips did not transmit BlShV when they were allowed to feed on caged flowering trap plants in the presence of a source of infected pollen. Results of pollen washes, cell disruption, and electron microscopy show that particles of BlShV were on, in, and between the cells of the pollen tetrad. Pollen from infected plants germinated as readily as pollen from healthy plants. BlShV was seedborne, but at a low level. All 42 cultivars tested were susceptible to BlShV when inoculated by grafting. The primary mechanism of transmission appears to be the transfer of BlShV-contaminated pollen by honeybees from flowers on infected plants to flowers on healthy plants.