Effect of different host plants on the development time and parasitization rate of eretmocerus dehachi rose and rosen (hymenoptera: aphelinidae) withparabemisia myricae (Kuwana) (homoptera: aleyrodidae) as insect host

The effect of six citrus and five non-citrus host plants on the developmental time ofEretmocerus dehachi Rose and Rosen (Hymenoptera: Aphelinidae), the parasitoid ofParabemisia myricae (Kuwana) (Homoptera: Aleyrodidae), was studied under laboratory conditions. On citrus host plants, the mean developmental time from egg to adult was shortest on lemon with 14.6 days and longest on trifoliate orange with 26.3 days. On non-citrus host plants the developmental time ranged between 16.3 days on vine and 23.0 days on pomegranate. Among the various host plants tested,E. dehachi preferredP. myricae on sweet orange. A high mortality ofP. myricae due to host feeding and parasitization was observed on sweet orange and grapefruit among citrus host plants and on rose among non-citrus host plants.     

Effect of different host plants on the development time and parasitization rate of eretmocerus dehachi rose and rosen (hymenoptera: aphelinidae) withparabemisia myricae (Kuwana) (homoptera: aleyrodidae) as insect host

The effect of six citrus and five non-citrus host plants on the developmental time ofEretmocerus dehachi Rose and Rosen (Hymenoptera: Aphelinidae), the parasitoid ofParabemisia myricae (Kuwana) (Homoptera: Aleyrodidae), was studied under laboratory conditions. On citrus host plants, the mean developmental time from egg to adult was shortest on lemon with 14.6 days and longest on trifoliate orange with 26.3 days. On non-citrus host plants the developmental time ranged between 16.3 days on vine and 23.0 days on pomegranate. Among the various host plants tested,E. dehachi preferredP. myricae on sweet orange. A high mortality ofP. myricae due to host feeding and parasitization was observed on sweet orange and grapefruit among citrus host plants and on rose among non-citrus host plants.     

广西柑橘衰退病和黄脉病调查及其病原病毒的遗传多样性分析

为明确柑橘衰退病毒(citrus tristeza virus, CTV)和柑橘黄脉病毒(citrus yellow vein clearing virus, CYVCV)在广西柑橘上的发生?分布及其遗传变异情况, 于2020年至2021年对百色?北海?崇左?贵港?桂林?河池?贺州?来宾?柳州?南宁?梧州和玉林等12个柑橘产区进行了病毒病调查?采用RT-PCR对采集样品进行了病毒检测, 并基于病毒分离物外壳蛋白(coat protein, CP)基因的核苷酸序列进行比对分析, 构建系统发育树?结果表明:采集的737份柑橘样品中, CTV的检出率为20.62%, CYVCV检出率为18.32%, CTV的检出率略高于CYVCV?病毒复合侵染的现象在采集的柑橘样品中普遍存在, CTV和CYVCV复合侵染率高达34.50%?对RT-PCR产物测序共获得12个CTV分离物和6个CYVCV分离物的CP基因序列?遗传多样性分析发现, CTV和CYVCV的CP基因序列都较保守, CTV分离物的遗传进化与地理来源?寄主来源均没有明显相关性, 但CYVCV分离物的遗传进化与地理位置具有相关性, 而与寄主来源无明显相关性?上述研究结果可为深入了解CTV和CYVCV在广西的流行情况以及柑橘病毒病的检疫和防控提供参考?     

柑桔溃疡病菌PCR快速检验检疫技术研究

 柑桔溃疡病是严重影响全世界柑桔生产的重大检疫性病害,根据柑桔溃疡病菌(Xanthomonas axonopodis pv. citri)新近公布的全基因组中独有的保守蛋白基因序列,设计筛选出一对种特异性引物(JYF5/JYR5),能专一地扩增检出柑桔组织表面所带溃疡病菌的DNA靶带(413 bp)。而柑桔叶面附生的非致病性黄单胞菌、野油菜黄单胞菌近缘种以及健康柑桔样品都不能扩增;靶细菌DNA检测下限1.56 pg/μL,靶细菌悬浮液检测下限10 cfu/μL;在不同PCR仪及各种控温方式下都能稳定地扩增出特征性靶带。这一特异、准确的柑桔溃疡病菌PCR检验技术和研制的预包被固相化PCR检测试剂盒已开始用于我国非疫生产区建设中柑桔苗木、果实的病害检疫检验。     

柑橘全爪螨种群空间格局的地学统计学分析(英文)

应用地学统计学方法分析了柑橘园主要害螨柑橘全爪螨Panonychus citri(McGregor)种群的空间格局及其动态。结果表明,柑橘全爪螨种群具有空间相关性,变程介于1.10 ～21.0 m,其半变异函数主要符合高斯模型,表现为聚集分布,其中3月、8月和9月的聚集强度较大;种群空间格局动态显示,4月、10月为该种群的两个发生高峰期,柑橘全爪螨种群数量快速上升扩散。地学统计学方法能够应用于柑橘全爪螨种群的空间格局分析,并有助于对该害螨进行发生预测与控制处理。     

安远县大面积应用巴氏钝绥螨防治柑橘全爪螨效果初报

2007年4-5月,安远县在155个柑橘园释放巴氏钝绥螨,应用面积243.5hm2,143个柑橘园的柑橘全爪螨得到了有效控制,占释放柑橘园总量的92%;在柑橘全爪螨密度为百叶100-200头时,每株释放1袋(600头以上)巴氏钝绥螨,释放后30d左右柑橘全爪螨得到控制,持续控制期3个月以上。     

Deterrent effects of some botanical products on oviposition of the cowpea bruchid Callosobruchus maculatus (F.) (Coleoptera: Bruchidae)

Extracts from nine plant materials were tested in choice and no-choice tests as oviposition deterrents for cowpea bruchid, Callosobruchus maculatus (F.) on chickpea, Cicer arietinum L. Seed treatment with 0.1% crude extract of materials resulted in a significant reduction in ovipositional preference of the bruchid. The highest repellency was found in Rhazya stricta leaves (82%), Azadirachta indica seeds (76.8%), Heliotropium bacciferum aerial parts (59.2%) and citrus peels (58.6%). Progeny production was significantly reduced: only 11.5, 11.9, 12.4, 13.4 and 14.8% of the eggs deposited reached adulthood in R. stricta, neem seeds, Piper nigrum, citrus peels and H. bacciferum, respectively. F1 females laid significantly fewer eggs in response to R. stricta, neem seeds, Eugenia caryophyllata cloves, H. bacciferum, citrus peels and P. nigrum. Percentage reduction in F₂ progeny ranged between 71.4% with R. stricta-treated seeds and 24.5% in the P. nigrum treatment.     

Presence of the invasive whitefly Aleurocanthus spiniferus (Hemiptera: Aleyrodidae) in Greece

Aleurocanthus spiniferus (Quaintance) (Hemiptera: Aleyrodidae), commonly known as the citrus (or orange) spiny whitefly, is an important pest of various economic crops such as citrus and tea and causes severe economic losses. It is reported for the first time in Greece, in the island of Corfu (North‐West Greece) on sweet orange trees (Citrus sinensis). Morphological and molecular data has been used for species identification. Sequences of the mitochondrial cytochrome oxidase I (COI) gene from Greek populations have been compared with sequences of the species from Italy and Montenegro, as well as with COI sequences retrieved from GenBank, to examine the genetic diversity of the species. Based on the preliminary results, it appears that the population from Corfu probably arose through several independent introductions.     

Citrus fruit flies of Sichuan Province (China)

The fruit fly pests on Sichuan citrus include Tetradacus citri and T. tsuneonis (Diptera: Trypetidae), regarded as distinct species in China. Special attention has been paid to the former, which is a quarantine pest in China. It is distributed in 18 counties of Sichuan Province and has caused serious losses in citrus orchards. Its hosts are all the citrus fruits, especially orange and pomelo. T. tsuneonis is distributed in only two counties and attacks only tangerine, but it is a potential hazard to all citrus crops in the province. Both species have only one generation per year. The pupae overwinter in soil. Emergence of T. citri begins at the end of April. Before oviposition the adults need supplementary nutrients. Twenty days after emergence, copulation begins and 15 days later the adult begins ovipositing (peak period mid-June to early July). The peak period for hatching is in early September. After three instars, the larva becomes mature in mid-October. The peak period of pupation is from the end of October to mid-November. Emergence of T. tsuneonis is about 15 days later than T. citri. The larvae bore the flesh of citrus fruits, causing great loss to citrus growers every year. Surveys are regularly conducted to check the distribution of the pests in Sichuan Province. Quarantine regulations enacted in 1982 and 1984 regulate the movements of articles that could spread the pests, with specified safeguards. Before female oviposition, spraying with trichlorfon in sugar solution gives satisfactory results in controlling citrus flies in orchards.     

Efficacy of Jordanian Isolates of Bacillus thuringiensis against the citrus leafminer,Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae)

Several laboratory experiments were conducted to test the efficacy of reference and local isolates of Bacillus thuringiensis ( Bt ) against the Middle East strain of citrus leafminer (CLM), Phyllocnistis citrella, on lemon leaves when they were applied to the surface of intact leafminer. Among the six reference strains examined, the strain Bt kurstaki H3a, 3b, 3c ( Bt 4) showed the highest toxicity after 3 days of application. Bt kurstaki also caused additive mortality to the second and third instar larvae of citrus leafminer when the bacteria were combined with Sunspray ® oil. This combination caused significantly higher mortality (63.3%) than did Bt kurstaki alone or Bt kurstaki mixed with the surfactant Surfix ® . Local Bt isolates J6 ( Bt kurstaki ) and J23 ( Bt thuringiensis, H1) showed no significant toxicity differences towards CLM when compared with the reference strain Bt 4. Addition of Bt kurstaki preparation with Vapcocidin ® (pyrethroid insecticide) reduced the required lethal concentration of the pyrethroid pesticide by up to 50%. These results emphasize the value of Bt as part of integrated programmes for controlling citrus leafminer.     

First detection of a virulent strain of Citrus tristeza virus (Closteroviridae) in a citrus orchard of Chlef Valley (Algeria)

A large‐scale survey of Citrus tristeza virus (CTV) was carried out from 2016 to 2018 in the Chlef Valley, one of the main citrus growing areas in Algeria. In this study a total of 1680 citrus trees from 93 commercial orchards were sampled. The collected samples were tested by direct tissue blot immunoassay analysis and by the double antibody sandwich enzyme‐linked immunosorbent assay technique, and 54 trees were identified as being infected with CTV. This result confirmed that 54 trees were infected by the virus, corresponding to an infection rate of 3.21% throughout the studied area. Five of these local CTV sources were chosen for further molecular investigations to determine the genotype associated with the CTV isolates now spreading in the Chlef area. Characterization with multiple molecular markers showed the presence of the T30 and VT genotypes. This result allowed confirmation of the presence of a virulent strain belonging to the VT genotype. The other CTV isolates were similar to those from the Mitidja region, which showed 99% nucleotide identity with the Spanish mild CTV isolate. This early finding of a strain belonging to the VT genotype is an issue for Algerian citrus producers and needs rapid actions to be taken by the National phytosanitary services, extending the surveillance to other citrus production regions and uprooting the infected trees.     

Prolonged exclusion of foraging ants (Hymenoptera: Formicidae) from citrus trees using controlled-release chlorpyrifos trunk bands

Abstract

Controlled-release chlorpyrifos trunk bands excluded foraging ants ( Iridomyrmex spp.) from citrus tree canopies for four growing seasons (182 and 211 weeks in two separate trials). The level of exclusion averaged 92.7% over the full period of the trials. Laboratory bioassays of weathered band material showed the bands were still toxic to ants (98 - 100% mortality) after 200 and 229 weeks. In contrast, trunk applications of lambda-cyhalothrin and a chlorpyrifos 'emulsion' were very short-lived (< 14 weeks) in their activity against foraging ants; levels of exclusion over 15 to 18 weeks averaged 46% for lambda-cyhalothrin and 23% for the chlorpyrifos 'emulsion'. The potential of controlled-release chlorpyrifos trunk bands as a practical management strategy for foraging ants in citrus groves is discussed.     

矢尖蚧生物学特性及其防治研究

矢尖蚧是柑桔主要害虫之一,一年发生三代。各代雌蚧完成一代所需天数依次为64.3、70.6、230天。越冬雌成虫于4月下旬在日平均温度19℃以上开始产卵,10月下旬在日平均温度17℃以下停止产卵繁殖。并证实雌蚧不行孤雌生殖。发现矢尖蚧捕食性和寄生性天敌有7种,其中以日本方头甲、整胸寡节瓢虫、黄金蚜小蜂、矢尖蚧雄蚧体外寄生蜂等四种天敌的发生量较大,似有利用前途。药剂防治以500倍40%氧化乐果及40%水胺硫磷效果最好。     

植物挥发性成分对柑桔潜叶蛾产卵行为的影响

柑桔潜叶蛾成虫对寄主和产卵部位的选择是其生存和种群发展的生物学基础。人工叶片法试验结果表明，寄主植物幼嫩叶中的挥发性化学物质对柑桔潜叶蛾成虫产卵有明显的引导作用，但不同柑桔品种对成虫产卵的影响没有显著差异，显示其含有相同的挥发性物质。用非寄主植物叶片试验发现，其挥发性物质对成虫产卵有明显的驱避干扰作用。马缨丹和印楝叶对成虫产卵的驱避中量(ORD50)分别为13．5和49．4mg鲜叶。     

Thrips (Thysanoptera: Thripidae) in northern Tunisian citrus orchards: population density,damage and insecticide trial for sustainable pest management

Phytoparasitica - Thrips (Thysanoptera: Thripidae) have been considered serious pests infesting a wide range of host plants around the world, which has also been the case for citrus trees in...     

Spread of Paraleyrodes minei Iaccarino (nesting whitefly) in Italian citrus groves

Outbreaks of Paraleyrodes minei Iaccarino have been noted on citrus in a wide area along the whole eastern coast of Sicily (South Italy), in the districts of Catania, Messina and Siracusa. Until this year, the whitefly was only reported in Italy from a few samples collected on a limited number of ornamental sour orange trees in a town park in Portici, in the district of Naples. Findings in 2014 of the insect in Sicily were made not only on ornamental citrus trees in urban areas, but more importantly in orange, lemon and mandarin commercial orchards. This severe and extremely rapid spread of P. minei in Sicily (where more than half of Italian citrus are produced) represents a potential threat for the local citrus industry and requires careful monitoring to define both the actual pest status of the whitefly as well as the occurrence and role of eventual natural enemies. Brief notes on morphology, bio‐ecology and present geographical distribution of P. minei are given in this paper, together with details on the occurrences in Sicily and short considerations on the pest importance and control possibilities for this insect.     

Release and recovery ofMetaphycus spp. (Hymenoptera: Encyrtidae) imported for the control of the mediterranean black scale,Saissetia Oleae (Olivier), in Israel

During 1972–1976 four species of African encyrtid wasps were introduced into Israel and released against the Mediterranean black scale,Saissetia oleae (Olivier), in citrus and olive groves.Metaphycus helvolus (Compere) andM. aff. stanleyi Compere were recovered in small numbers.M. bartletti Annecke and Mynhardt andM. lounsburyi (Howard), which were found in large numbers on citrus during the release season, seem to be promising for the biological control of the black scale.     

The determination of thiabendazole (2-(4-thiazolyl)-benzimidazole) in citrus fruit dips

Methods for analysing the strength of thiabendazole (TBZ) dipping fluids are described. The methods which require only the minimum laboratory facilities and can be used in citrus packing houses, are based upon (i) a titration method utilising the complex formed by TBZ with silver ions, for accurate work, and (ii) a refractive index method after concentration for rapid checking by packing house employees. These methods are compared with a spectrophotometric method.     

Evaluation of effectiveness of Insegar (fenoxycarb 250 g/kg) WP against Phyllocnistis citrella Stainton (Lep., Gracillariidae) and its effect on Cales noacki How. (Hym., Aphelinidae)

Aiming to control the citrus leafminer Phyllocnistis citrella St. while at the same time protecting the biological equilibrium and mainly the beneficial insect Cales noacki, experiments have taken place in the regions of Argolis and Fthiotis, Greece in 1996 and 1997. Insegar (fenoxycarb) 2 5 WP was applied on young citrus trees. During 1996, the compound, applied every 10 days at a rate of 30 g/hI (with or without adjuvant), gave satisfactory protection from P. citrella without substantially harming C. noacki populations. No phytotoxicity symptoms were observed during the experiments.     

Evaluation of effectiveness of Insegar (fenoxycarb 250 g/kg) WP against Phyllocnistis citrella Stainton (Lep., Gracillariidae) and its effect on Cales noacki How. (Hym., Aphelinidae)

Aiming to control the citrus leafminer Phyllocnistis citrella St. while at the same time protecting the biological equilibrium and mainly the beneficial insect Cales noacki, experiments have taken place in the regions of Argolis and Fthiotis, Greece in 1996 and 1997. Insegar (fenoxycarb) 2 5 WP was applied on young citrus trees. During 1996, the compound, applied every 10 days at a rate of 30 g/hI (with or without adjuvant), gave satisfactory protection from P. citrella without substantially harming C. noacki populations. No phytotoxicity symptoms were observed during the experiments.