Field effectiveness of fosetyl-AI against citrus foot rot and brown rot1

The effectiveness of fosetyl-A1 against citrus foot rot caused by Phytophthora citrophthora has been evaluated in a 25-year-old orchard of sweet orange cv. Tarocco, showing severe symptoms of the disease and in a 10-year-old orchard of the clementine-type mandarin cv. Monreal, apparently healthy. All the trees were grafted on sour orange. In both orchards, three sprays at 200 g a.i. per 100 1 were applied in May, July and September for 3 years. The results were evaluated on the basis of yield and fruit quality. Trees of cv. Tarocco had yield increased by 25–44% whereas cv. Monreal yielded 3–16% higher than the unsprayed trees. Fruits of orange cv. Tarocco were collected from trees sprayed with fosetyl-A1 and plunged in a water suspension of P. citrophthora. Fruits treated 11 days before inoculation showed an infection rate of 8.7%) whereas those unsprayed were 77% infected. Fruits inoculated 21 days after the treatment with fosetyl-A1 were 32% infected whereas those unsprayed were 91%, infected. In other trials, trees of volkamer lemon were sprayed with a conidial and mycelial suspension of P. citrophthora at different times after application of fosetyl-A1. The number of infected fruits and leaves in the unsprayed trees was very high (up to total leaf drop) and decreased sharply with the number of sprays (1 to 3).     

The phytotoxicity of narrow distillation range petroleum spraying oils to valencia orange trees in South Australia. Part II: The influence of distillation temperature and spray timing on fruit quality

Petroleum oils sprays are used as pesticides on citrus in South Australia to control California red scale (Aonidiella aurantii Maskell), but may have phytotoxic effects on trees and fruit. As part of a programme to establish improved specifications for spray oils for South Australia, three oils with different 50 %-distillation temperatures were applied to trees each month from October to May for two seasons in order to observe their effects on fruit quality. The 50 %-distillation temperatures of the three oils were 211, 224 and 240°C at 10 mmHg (in order of increasing molecular weight) and the oils are subsequently referred to as the 211, 224 and 240 oils. The 224 and 240 oils significantly reduced the amounts of sugar and acid in the juice, and delayed and inhibited colouring. These effects increased in severity, the closer to harvest the trees were sprayed and the higher the distillation temperature of the oil. The 240 oil prevented full colour development, and caused ‘re-greening’ if sprayed later than February. Oil sprays applied to the same trees in the following season caused similar effects. However, if oil sprays were omitted in the following season, there was no residual effect, of the previous season's spray, on the sugar and acid contents or the colour of the fruit. Individual fruit weight was not affected in the first spraying season, but there was an increase in the average individual fruit weight in the second season, regardless of whether a second spray was applied that season or not. The effect was more severe, the closer to harvest the trees were sprayed and the greater the distillation temperature of the oil. The effects on yield resulted from a change in the number of fruit per tree.     

The phytotoxicity of narrow distillation range petroleum spraying oils to valencia orange trees in South Australia. Part I: The influence of distillation temperature and spray timing on yield and alternate cropping

Petroleum oil sprays are used on citrus to control California red scale (Aonidiella aurantii Maskell), but may have phytotoxic effects on trees and fruit. As part of a programme to establish improved specifications for spray oils for South Australia, three oils with various 50%-distillation temperatures were applied to trees each month from October to May to observe their effects on crop yield. Some treatments were applied once in each of three consecutive seasons while others were applied only once in the first season. The 50%-distillation temperatures of the three oils were 211, 224 and 240°C at 10 mmHg. The oils caused significant reductions in yield, and caused or accentuated alternate cropping cycles. The higher the 50%-distillation temperature of the oil, the greater the effect. The time of application was also important. The greatest yield reductions (expressed as two averages) occurred when the oils were sprayed in November; the tendency to alternate cropping increased with the month of application from December to May. For the oil with the highest 50%-distillation temperature, the yield reductions were about 30%, and the yields from trees in a severe alternate cropping cycle, in the ‘light crop’ year, were as low as 25% of those on unsprayed trees.     

The phytotoxicity of narrow distillation range petroleum spraying oils to valencia orange trees in South Australia. Part III: The influence of distillation temperature and spray timing on leaf and fruit drop

Petroleum oil sprays are used as pesticides on citrus to control California red scale (Aonidiella aurantii Maskell), but may have phytotoxic effects on trees and fruit. As part of a programme to establish improved specifications for spray oils for South Australia, three oils with different 50 %-distillation temperatures were applied to trees each month from October to May to observe their effects on leaf and fruit drop. The 50%-distillation temperatures of the three oils were 211, 224 and 240°C at 10 mmHg (in order of increasing molecular weight). The oils caused significant leaf drop. The higher the 50%-distillation temperature of the oil, the greater the leaf drop. Most leaf drop was caused when natural leaf drop was greatest. Oils applied from October to February caused severe leaf drop for periods of about 1–2 months, while oils applied from March to May caused severe leaf drop for up to 6 months or more. There was also a tendency for oils with a lower 50%-distillation temperature to cause leaf drop sooner after spraying than oils with a higher 50%-distillation temperature. Significant fruit drop was caused in only a few treatments, but the maximum fruit drop was less than 5% of the total fruit number and of little consequence when compared with the effects of oils on yield through reduced fruit set. Visually, a significant proportion of the total number of leaves present fell in many of the oil spray treatments, and the rate of disappearance of the oil film was directly related to the 50%-distillation temperature of the oil, and to the spraying date.     

苹果斯氏刺瘿螨发生与危害调查

斯氏刺瘿螨是四川省苹果上新发现的一种危害苹果叶片的害螨，以雌成螨在苹果芽的芽腋两侧越冬，翌年苹果芽萌动时开始出蛰。全年以５月中旬至６月中旬发生数量最多。气候温暖、低湿、少雨发生重，相反则轻。在调查的８个品种中，叶片多茸毛的品种受害重。天敌主要为捕食螨     

叶螨为害苹果树的产量损失估测

1987—1989年研究苹果全爪螨(Panonychus ulmi)与山楂叶螨(Tetranychus viennenses)为害对苹果产量的影响。结果表明:①叶螨为害后,叶片的各项生理指标皆有反应,其中以光合作用强度最敏感;②叶螨为害对果实质量无显著影响,但不同螨量的果实体积之间存在明显差异;③平均累积雌成螨螨日(MDi)与平均减产率(Qi)之间有正相关关系,为害当年表现出果实变小单果重减轻,次年表现出花量减少,果实数下降。1987与1989年以苹果全爪螨为主,减产率分别为3.31%—11.25%与2.89%—10.75%。1988年以山楂叶螨为主,减产率为2.36%—13.48%;④上年受害树次年继续测产,看出叶螨的持续影响更为严重。以苹果全爪螨为主的持续减产率第二年达2.0%—86.2%;第三年的影响又相对减轻。以山楂叶螨为主的减产率第二年为-14.4%—69.4%。     

A comparison of the efficiency of sprays of two drop-size ranges in an apple orchard

A two-season trial of a mist blower-sprayer with improved air-flow characteristics was made to assess the relative efficiency of 120 and 180 μm mass median diameter (MMD) drop-size sprays for the control of apple powdery mildew (Podosphaera leucotricha) and fruit tree red spider mite (Panonychus ulmi Koch) in a hedgerow-type apple orchard. The principal pesticide was binapacryl, applied at two rates for each drop-size. Under typical commercial conditions the smaller drop-size approximately halved the incidence of apple mildew found when the conventional 180 μm MMD drop-size spray was used; there was no conclusive advantage against red spider mite. Unexpectedly large variations occurred in the deposits from the weekly applications and were related to the humidity during spraying.     

柑桔红蜘蛛(Panonychus citri (McG.))的初步研究

柑桔红蜘蛛为柑桔主要害虫之一,据在广东(?)平地区观察,此虫虫口消长与树令,夏、秋梢,有一定的关系,一般结果树受害轻;幼苗受害严重。每当夏、秋梢老熟时,正值红蜘蛛出现高峯。该虫完成一世代的历期,与温度有关:2—5月,完成一世代的历期31—41天;6—10月,历期20.25—27.00天。每头雌成虫产卵7—113粒。药剂防治以600—800倍20% T.D.N 效果最好;2,000—6,000倍乙基1059次之;0.4°波美的石硫合剂、0.4°波美的多硫化钡等残效期较短。     

Addition of Oil to Pesticide Sprays—Downwind Movement of Droplets

Abstract

An investigation of the downwind movement, distribution and distance covered from a spray source of insecticide to which oil is an additive. Vertical targets were placed at distances ranging from 0.25 to 64 m and at three heights, 35, 70 and 150 cm, downwind from the spray source. There was an increase in the number of droplets arriving at the targets when 20% oil was added to the aqueous solution. An even greater increase was seen when oil only was sprayed; these results are compared with sprays containing water and a 5% wetting agent. Droplet size and air turbulence effects are discussed, as is the faster evaporation of water-based sprays. The work was carried out on rhododendron leaves using Saturn yellow fluorescent dye as a tracer using a Micron Mini-ULVA and Ulvapron oil. A comparison is made with the use of Shell oil A and Risella 33 used by pest workers.     

Targeting Cydia pomonella (L.) (Lepidoptera: Tortricidae) adults with low‐volume applications of insecticides alone and in combination with sex pheromone

BACKGROUND: Studies surveyed the toxicity of several insecticides against adult codling moth, Cydia pomonella (L.), and examined the field effectiveness of applying low‐volume (12 L ha^?1) sprays alone or in combination with a microencapsulated (MEC) sex pheromone formulation. RESULTS: Neonicotinyls, organophosphates and synthetic pyrethroids significantly reduced fecundity at concentrations nearly 100‐fold lower than their maximum labeled field rate. Field studies in 2005 demonstrated that six applications of esfenvalerate resulted in > 90% reduction in fruit injury versus the untreated check. The addition of the MEC pheromone formulation did not further improve control. Five sprays of esfenvalerate, phosmet and acetamiprid all significantly reduced levels of fruit injury compared with the untreated control in 2006. Esfenvalerate and acetamiprid mixed with the MEC pheromone significantly reduced fruit injury compared with the MEC‐only treatment. Significant increases in pest and decreases in predator mite densities occurred in plots treated with esfenvalerate in both years. Low‐volume sprays of phosmet and acetamiprid did not disrupt mites. CONCLUSION: Low‐volume insecticide sprays can effectively manage codling moth and are less disruptive of integrated mite management. Developing an effective ‘attract and kill’ technology with this approach will require optimization of the attractant(s) to maximize moth exposure to insecticide residues. Published 2010 by John Wiley & Sons, Ltd.     

我国落叶果树主要害虫及其防治技术60年研究进展

落叶果树是指秋末落叶的一类果树,是我国重要的农林作物之一。近年来,随着果树种植结构的调整和种植面积的扩大,虫害对果树产业的影响越来越严重,越来越多的科研工作者加入到果园害虫防治的队伍中,并在果园害虫绿色防控方面获得了一批新技术,取得了一些新成果。为持续推动果树虫害防治新理念的落实,该文统计了20世纪60年代至今落叶果树虫害防治相关研究论文的发表情况,综述了落叶果树主要害虫的演变,总结了60年来落叶果树害虫防治理念及技术的转变。展望未来,害虫智能化精准识别与种群动态监测、害虫生态调控、害虫遗传调控以及基于纳米材料的RNA杀虫剂等新技术正推动果园害虫监测防控体系的不断创新。     

Aerial electrostatic‐charged sprays for deposition and efficacy against sweet potato whitefly (Bemisia tabaci) on cotton

Background: The efficacy of aerial electrostatic‐charged sprays was evaluated for spray deposit characteristics and season‐long control of sweet potato whitefly (SWF), Bemisia tabaci Genn. biotype B (aka B. argentifolii Bellows & Perring), in an irrigated 24 ha cotton field. Treatments included electrostatic‐charged sprays at full and half active ingredient (AI) label rate, uncharged sprays and conventional sprays applied with CP nozzles at full label rate with several different insecticides. Results: Spray droplet size was significantly smaller for electrostatic‐charged sprays than for conventional sprays in top‐ and mid‐canopy locations. The seasonal mean numbers of viable eggs and live large nymphs on cotton treated with electrostatic‐charged sprays were comparable with those on cotton treated with conventional applications. Lethal concentration (LC₅₀) for adults for electrostatic‐charged sprays was comparable with that for conventional sprays. Conclusion: The amenability of electrostatic‐charged sprays to a wide array of pesticides with different chemistries should be a useful tool in combating insect resistance. Results reported here suggest that the potential exists for obtaining increased efficacy against whiteflies using an electrostatic spray charging system, and that additional research will be required to improve charge‐to‐mass (Q/M) ratio in order to increase deposition of pest control materials to the lower surfaces of cotton leaves where the whiteflies reside. Copyright © 2009 Society of Chemical Industry     

生态因素与钝绥螨种群数量关系及应用于防治桔全爪螨的研究

在柑桔园种植一种菊科杂草——藿香蓟覆盖地面,对桔全爪螨的重要天敌纽氏钝绥螨有明显的助长作用。柑园覆盖藿香蓟后,在夏季高温季节,可使柑桔树冠外围温度从40～45℃降至35℃以下,相对湿度增加;藿香蓟的花粉可供作钝绥螨的食料。这种小生境的改善,有利于钝绥螨种群的稳定和增长。藿香蓟草丛中的生态条件适合钝绥螨的生存繁殖,钝绥螨在藿香蓟叶片上的密度,常比在柑桔叶片上为高。在需要使用化学农药防治其他害虫或病害而引致柑桔树上的钝绥螨数量明显减少时,藿香蓟上的钝绥螨是一个重要的补充源泉。藿香蓟的生长抑制了其他杂草,大大减少用于除草的劳动力。藿香蓟可作绿肥,根系较浅,无明显与柑桔争肥现象。经多年试验,证明上述方法防治桔全爪螨的效果良好,目前这种措施已在广东省的一些柑桔产区应用。对柑桔害虫的综合防治,可利用钝绥螨防治桔全爪螨,对其他重要害虫如桔锈螨、柑桔潜叶蛾和柑桔木虱可通过采取选择性农药防治或农业技术防治而加以控制。     

Further studies of the deposition and persistence of binapacryl,bupirimate and diflubenzuron on apple foliage and fruit

In an extension of previous work, deposits and residues of binapacryl, bupirimate and diflubenzuron on mature foliage and the peel of developing fruit of Worcester and Cox apple trees were monitored throughout the 1980 season following applications by mistblower sprayer. The three compounds were applied as commercial formulations in trials to compare integrated pest management with routine farm spray programmes. In contrast to previous results, all three compounds persisted on foliage until leaf-fall and were detected on the peel of harvested fruit. The mean residue of diflubenzuron on harvested Worcester fruit was 0.05 mg kg^?1 fresh weight and on harvested Cox fruit was 0.02 mg kg^?1 fresh weight. Binapacryl and bupirimate were present on harvested fruit of both cultivars. The unexpectedly long persistence of these chemicals in 1980 remains unexplained, but may be due to climatic factors.     

桔全爪螨的为害对柑桔经济产量影响的进一步研究

本文分析了桔全爪螨Panonychus citri(McG.)的为害对柑桔经济产量的影响。由通径分析发现,该螨对经济产量的影响是通过影响结果枝有效光合面积起作用的。该螨吸食叶片,致使光合作用下降;为害严重时,采果前落叶直接影响叶果比,从而影响果重、果实大小和品质。据此导出叶片受害(X)与果重(Y)的确定性函数关系:Y=7.7567A~(c-0.02041A)-0.9365~S-0.3656~X+0.0006186~(X~2)+11.54式中A为果枝最佳叶面积,S为受害引起落叶百分率。     

Foliar residues of aminocarb at tree canopy and ground levels in an experimental spray operation in conifer forests

Foliar residues of aminocarb were measured at tree canopy and ground levels in conifer forests in New Brunswick, Canada, following aerial application of three spray mixtures of aminocarb, one water-based, one in a volatile oil of low viscosity, and the third in a non-volatile oil of high viscosity. For a given volume rate of application, all three mixtures provided similar foliar residues at tree canopy level, but the aqueous and the volatile-oil based sprays provided significantly lower residues on cut foliage positioned at ground level, than the non-volatile oil spray mixture.     

苹果全爪螨抗药性研究进展

苹果全爪螨是重要的蔷薇科果树害虫之一, 具有体型小、繁殖快、世代周期短等生物学特点。该螨以若螨和成螨取食苹果叶片和嫩芽, 影响果树生长发育, 造成果实品质和产量下降, 自20世纪60年代开始其在我国果园的发生逐年加重。国内外对苹果全爪螨的防治主要采用化学杀螨剂, 由于化学杀螨剂长期不规范的使用, 致使该螨对多种类型的化学杀螨剂产生了抗药性。本文总结了苹果全爪螨的发生、为害、抗药性现状及其抗性机理, 同时结合国内外苹果全爪螨抗药性和防治相关研究, 提出该螨抗药性治理策略, 以期为其防治提供参考。     

从南非鲜橙上截获重要害虫坚果异胫小卷蛾

坚果异胫小卷蛾是南非果树上重要经济害虫。珠海检验检疫局曾在南非鲜橙中截获过该虫。本文对坚果异胫小卷蛾的分布、寄主及成虫形态特征进行了描述,并分析了该虫的DNA条形码检测方法。通过GenBank数据库比对分析,邻接法构建的系统发育树及BOLD数据库查询比对,可最终确定所截获害虫为坚果异胫小卷蛾。     

First record of the citrus red mite <Emphasis Type="Italic">Panonychus citri</Emphasis> in Cyprus

A new phytophagous mite species, Panonychus citri (McGregor) (Acari: Tetranychidae) (the citrus red mite), was found in Cyprus during spring 2008, infesting citrus plantations. Mites occurred in large numbers, mainly in the canopy of orange, lemon and mandarin trees. The adults and larvae preferred the upper surfaces of mature leaves of the above citrus species, although they occurred on both leaf surfaces. Orange, lemon and mandarin trees were greatly affected by this mite, as its high population densities under hot and dry conditions in the spring caused heavy leaf drop (firing) and twig dieback.     

Effects of huanglongbing on fruit quality of sweet orange cultivars in Brazil

Citrus huanglongbing (HLB), associated with Candidatus Liberibacter asiaticus and Ca. L. americanus and transmitted by the Asian psyllid Diaphorina citri, is the most serious disease of citrus worldwide because of crop devastation and difficulty to control. Since 2004, approximately 3 million trees were eliminated in attempts to limit its spread in Brazil. Where HLB becomes endemic, the disease progression in the orchard and the increasing symptom severity throughout the tree canopy can be relatively fast, greatly reducing the economic life of affected orchards because of tree decline and yield reduction. Although the majority of the fruit from symptomatic branches drop before harvest, a significant amount of affected fruit remain attached, are available for harvest, and can affect juice quality. To quantify and compare the effects of HLB on fruit quality of the most important sweet orange cultivars grown in São Paulo State, 4–6 year-old sweet orange trees from 26 blocks (two of ‘Valencia Americana’, eight of ‘Hamlin’, four of ‘Westin’, seven of ‘Pera’, and five of ‘Valencia’) were selected prior to harvest. In each block, 14–21 HLB-symptomatic trees were chosen. In each tree, the quality of 20 fruit normal in appearance from asymptomatic branches and 20 symptomatic fruit from symptomatic branches were assessed. In general, compared to normal fruit, the symptomatic fruit were small, light, more acidic, and had lower juice percentage, Brix, total soluble solids per box, total soluble solids per fruit, and Brix/acidity ratio. These effects of fruit quality were less pronounced on early and mid season sweet orange cultivars than on late season cv. Valencia.