Real‐time PCR assay for the identification of Thrips palmi*

Since Thrips palmi became a regulated pest for most European countries, inspections at points of entry into Europe and monitoring in Europe have intensified not only for T. palmi but also for thrips as a whole. Morphological identification of thrips is performed on adults and to a lesser extent on second‐stage larvae only, because no adequate identification keys for the separation of species based on the characteristics of eggs, first‐stage larvae, pre‐pupae or pupae are available. We have developed a real‐time PCR assay based on TaqMan. A T. palmi‐specific set of primers and probe were selected within the mitochondrial cytochrome oxidase I (COI) gene. The specificity of the assay was assessed using 15 specimens of Thrips palmi and 61 specimens of 23 other thrips species commonly occuring in Europe. All T. palmi specimens were detected, and no cross reactions with other thrips were observed. The method was tested on single larvae and adults and proved to be applicable for both those stages of T. palmi.     

Wheat Disease Situation in Madhya Pradesh,India

Leafminter of the genus Liriomyza are important pests of agricultural crops. In the mid-1990s three polyphagous new world species have been accidently introduced into South-East Asia. Different aspects of the biology of one species, Liriomyza sativae Blanchard, were studied during the period May 2000?–?July 2001 in Hanoi province in northern Vietnam on longbean, soybean, tomato, potato and cucumber. Trapping of adults and counting of larvae in mines showed that in May?–?June the generation time was approximately 15 days. This was supported by laboratory studies at constant temperature. The generation time was about 25?–?30 days in October?–?November and about 20 days in the spring season (February?–?May), based on adult trapping. In an unsprayed field, more than 50% of all mines contained parasitized larvae about 2 months after transplanting. Use of insecticides had little effect, indicating resistance in the leafminers.     

A decade of leafminer invasion in China: lessons learned

Liriomyza trifolii (Burgess) is a highly invasive species that has become established in agricultural and ornamental crops throughout the world. L. trifolii was first recorded in China in 2005 in Guangdong Province. Subsequently, its known distribution in China has rapidly expanded to another 11 provinces (Zhejiang, Jiangsu, Shanghai, Fujian, Guangxi, Shandong, Hainan, Hebei, Henan, Hubei and Anhui), where it is currently causing considerable damage and economic losses. Experimental research and field surveys have contributed to our understanding of the ecology of L. trifolii and particularly the process of invasion and its interactions with other established, exotic Liriomyza leafminer species. A number of factors have contributed to the successful establishment of L. trifolii and displacement of interspecific competitors. In China, L. trifolii has become a particularly devastating pest in areas with intensive farming with extensive monocultures and a reliance on insecticide use. Integrated pest management incorporating judicious applications of insecticide combined with biological and cultural controls is likely to provide the best long‐term management strategy for L. trifolii. We provide information regarding 10 years of L. trifolii invasion in China and discuss areas of future research to enhance our overall understanding of the biology and ecology of L. trifolii and to improve management programmes for this widespread invasive insect pest. © 2017 Society of Chemical Industry     

In-transit control of Liriomyza trifolii in chrysanthemum cuttings1

Individual cuttings and leaves of chrysanthemum infested with eggs and larvae of the alien leaf miner Liriomyza trifolii (Burgess) and batches of pupae, were treated in the laboratory in order to find an effective quarantine treatment to control the pest in imported cuttings. Cold treatment for 2 days at 1–2°C followed by methyl bromide fumigation at 15°C with a range of concentration time products (CTPs) was used to obtain accurate dose-response lines and estimate the LD99 and LD99.9 for each stage of the insect. The largest estimates of the LD99 for eggs, larvae and pupae up to 3 days old were less than the CTP specified in the existing (as at September 1983) United Kingdom statutory fumigation treatment designed to prevent the entry of Spodoptera littoralis (Boisd.). This statutory schedule for unrooted cuttings consists of cold storage for 2 days at 1–2°C and then fumigation with methyl bromide at a CTP of not less than 54 g·h/m³ with a minimum treatment period of 4 h at a minimum air temperature of 15°C. Our results indicate that the Spodoptera treatment should give high levels of kill for most stages of L. trifolii provided a CTP of 54 g·h/m³ and a temperature of 15°C (throughout the fumigation) arc achieved uniformly within packs of cuttings when they are fumigated in their transit boxes in commercial practice. The practicality of the technique will depend on whether it is possible to achieve this without causing unacceptable phytotoxicity. The LD99 values for pupae more than 3 days old were greater than those for eggs, larvae and young pupae. Therefore, if this treatment were adopted as a quarantine measure against L. trifolii, good prophylactic treatments and rigorous prc-packing inspections in exporting countries would still need to be maintained, to minimize any risk of importing pupae. The results are presented in full by Mortimer E.A. & Powell, D.F. (1984). Development of a combined cold storage and methyl bromide fumigation treatment to control the American serpentine leaf miner Liriomyza trifolii (Diptera: Agromyzidae) in imported chrysanthemum cuttings. Annals of Applied Biology 105 , (3), 443–454.     

Note: Systemic effects of a spinosad insecticide onLiriomyza huidobrensis Larvae

In an effort to expand the spectrum of larvicides effective againstLiriomyza huidobrensis (Blanchard), the effect of spinosad was studied on the mortality of the leafminer under laboratory conditions. Bean plants infested with various leafminer stages (egg through third instar) were treated by dipping leaves in a liter of water containing 24, 48 or 96 mg a.i. spinosad or by drenching the soil of plants with 200 ml of water containing 12 mg, 24 mg or 48 mg a.i. spinosad. In general, leaf dipping was more efficacious and adverse effects were observed sooner than with soil drench. All concentrations of spinosad significantly reduced the number of adults that emerged except leaf dip of third instar; only the highest concentration caused significant reduction of pupae and adults. Spinosad would likely be a valuable insecticide for control of the pea leafminer,L. huidobrensis. http://www.phytoparasitica.org posting Nov. 4, 2005.     

氟铃脲对韭菜迟眼蕈蚊不同虫态的致毒特点及毒力

为明确氟铃脲对韭菜迟眼蕈蚊不同虫态的致毒特点及毒力,采用胃毒触杀联合毒力法、药液定量滴加法及药膜法分别对韭菜迟眼蕈蚊卵、幼虫、蛹、成虫进行了生物测定。结果表明,经氟铃脲处理的0.5~1、1.5~2和2.5~3日龄韭菜迟眼蕈蚊卵至孵化24 h后,LC_(50)依次为2.27、1.60和0.64 mg/L,对1.5~3日龄卵的毒力高于对0.5~1日龄卵;经氟铃脲处理的2日龄卵、2龄幼虫、4龄幼虫、1日龄和3日龄蛹至羽化时LC_(50)分别为0.06、0.30、0.34、24.05和27.42 mg/L,毒力程度随韭菜迟眼蕈蚊发育而逐步下降;对蛹和成虫毒力较低,100 mg/L氟铃脲染毒1、3日龄蛹的羽化率分别高于10%和20%;药膜法100、1 000 mg/L氟铃脲处理成虫24 h,校正死亡率低于20%。研究表明,氟铃脲对韭菜迟眼蕈蚊各虫态的生长发育均有不利影响,抑制卵的孵化并导致初孵幼虫存活率降低;对幼虫毒杀作用较慢,对蛹及成虫阶段毒力较低。     

The newest leafminer pest in Israel,Liriomyza huidobrensis

The pea leafminer,Liriomyza huidobrensis (Blanchard), recently introduced into Israel, has proven to be extremely proliferous and difficult to control. It is a much more serious pest of vegetable and flower crops than the previously introducedLiriomyza trifolii (Burgess). Photosynthesis is reduced and cosmetic damage is incurred when adult flies stipple plant leaves with feeding punctures and larvae mine the leaves. This paper will review briefly the history, biology and potential control measures of the pea leafminer.     

Dipteran leafminers in the vicinity of glasshouses and plant markets in Lithuania*

Areas surrounding the glasshouses of 60 growers, and 16 plant markets, were surveyed in 2001/2003 to determine the distribution of dipterous leafminers in Lithuania, including regulated species. In total, 152 species belonging to 7 families were discovered, and the infested host plants represented 46 families. The relative frequency of Liriomyza bryoniae was 32% in the vicinity of glasshouses and 19% in market places. This species attacked plant genera such as: Amaranthus, Beta, Bryonia, Chenopodium, Cucumis, Datura, Gypsophila, Lycopersicon, Nicandra, Nicotiana, Physalis, Petunia, Sisymbrium, Solanum, Spinacia and Viola. The same plant genera also potentially provide sites for the survival of economically important species, Liriomyza huidobrensis and Liriomyza trifolii, in Lithuania.     

Cloning,characterisation and expression profiling of the cDNA encoding the ryanodine receptor in diamondback moth,Plutella xylostella (L.) (Lepidoptera: Plutellidae)

BACKGROUND: The rynodine receptors (RyRs) are the main targets of diamide insecticides such as chlorantraniliprole. To provide the basis for a good understanding of the molecular mechanisms of diamide insecticide resistance, an RyR gene from Plutella xylostella was cloned and characterised in the present paper. RESULTS: A full‐length cDNA sequence of RyR was cloned from P. xylostella through RT‐PCR and rapid amplification of cDNA ends (RACE). The gene (named PxRyR1) is 15 753 bp long, with an open reading frame of 15 354 bp, encoding a predicted RyR of 5117 amino acids. An alternative splicing of the PxRyR1 was also cloned and named PxRyR2. The PxRyR1 shares 77–93% identity with other insect RyRs. Quantitative real‐time PCR analysis showed that the PxRyR was expressed at a high level in second‐instar larvae and adults, at a low level in prepupae and pupae and abundantly in the body wall muscle and head (respectively 6.00 and 3.12 times the expression in the gut). Western blot analysis with anti‐RyR antibodies showed that the RyR was mainly present in the body wall muscle and head, but barely present in the haemocyte and gut. CONCLUSIONS: There are at least two alternative splices of PxRyR expressed in all developmental stages and tissues in P. xylostella at various levels. The results provided the basis for further understanding of the mechanisms of resistance to diamide insecticides in P. xylostella. Copyright © 2012 Society of Chemical Industry     

Identification of the Beet Cyst Nematode Heterodera schachtii by PCR

PCR-RFLPs of ITS-rDNA and PCR with species-specific primers were developed for identification of cysts and juveniles of the beet cyst nematode Heterodera schachtii. Restrictions of PCR product by MvaI or ScrFI distinguish H. schachtii, H. betae, H. trifolii and H. medicaginis. RFLP profiles with eight restriction enzymes for these four nematode species are presented. Based on Internal Transcribed Spacer sequences of populations from several Schachtii group species, a specific primer for H. schachtii was designed, permitting amplification of the target sequence from juveniles and cysts of the beet cyst nematode. A duplex PCR protocol tested with a wide range of nematode samples is described.     

Molecular characterization and diagnostics of stubby root and virus vector nematodes of the family Trichodoridae (Nematoda: Triplonchida) using ribosomal RNA genes

Plant parasitic nematodes of the family Trichodoridae cause substantial yield losses in many agricultural crops. Rapid and accurate identification of trichodorids to the species level is critical for selection of appropriate measures for control. This study analysed 99 sequences of the D2–D3 expansion segments of the 28S rRNA gene and 131 sequences of the 18S rRNA gene from the stubby nematodes belonging to the genera Nanidorus, Paratrichodorus and Trichodorus. Species delimiting was based on the integration of morphological identification, which is not provided in the present article, and molecular‐based phylogenetic inference and sequence analysis. Twenty‐two valid species and several species complexes were identified among nematodes included in the analysis. PCR‐RFLPs of the partial 18S rDNA and the D2–D3 expansion segments of the 28S rDNA were tested and proposed for identification of these nematodes. Gel PCR‐RFLP profiles and tables with restriction fragment lengths for several diagnostic enzymes are provided for identification. Some problems of taxonomy and phylogeny of nematodes of the family Trichodoridae are also discussed.     

柳毒蛾幼虫和蛹的空间分布的地统计学分析

为有效控制柳毒蛾Leucoma salicis对沙柳Salix psammophila的为害,深入了解柳毒蛾幼虫和蛹的种群空间结构,利用地统计学方法分析了不同立地条件下不同年龄沙柳林地中柳毒蛾幼虫和蛹的空间分布特性。结果表明:柳毒蛾幼虫和蛹的数量在沙丘顶部最多,每丛沙柳中分别为17.03±5.15和15.24±5.26头,与在沙丘底部的数量分布差异不显著;在多年生沙柳林地内的数量分布最多,每丛分别为20.31±2.39和18.02±3.19头,与2年生沙柳林地内的数量分布差异极显著。沙丘顶部多年生沙柳、沙丘顶部和底部2年生沙柳上柳毒蛾幼虫和蛹的空间分布均呈聚集条带状分布,聚集斑块由聚集中心区域向四周逐渐减小;沙丘底部多年生沙柳上幼虫和蛹的空间分布为随机分布;不同样地内,柳毒蛾蛹和幼虫在沙柳上的空间分布相同。     

Gummy stem blight of balsam pear caused by <Emphasis Type="Italic">Didymella bryoniae</Emphasis> and its anamorph <Emphasis Type="Italic">Phoma cucurbitacearum</Emphasis>

Gummy stem blight of balsam pear found in the Kanto district and in the Hokkaido Prefecture was demonstrated to be caused by Didymella bryoniae (Auerswald) Rehm based on inoculation experiments, molecular analysis, and morphological identification of the pathogenic fungus. This fungus was also pathogenic to related plants belonging to Cucurbitaceae. The imperfect stage of the fungus was identified as Phoma cucurbitacearum (Fr.: Fr.) Sacc. based on morphological similarities.     

Effects of gamma radiation on the immature stages ofLiriomyza Trifolii

The effects of γ-radiation on the immature stages ofLiriomyza trifolii Burgess were studied with doses of 2000-25 Gy. The high doses were lethal to all stages. At doses of 750 Gy or less, larvae survived to pupate, but their number was reduced and the majority were either dead or deformed and did not give rise to adults. Eggs and prepupae were more susceptible to radiation than other stages. Larval radiosensitivity decreased with progressing instar, and pupal sensitivity decreased with increasing age. Contribution from the Agricultural Research Organization. No. 2922-E, 1990 series.     

Fumigant toxicity of essential oils fromLaurus nobilis andRosmarinus officinalis against all life stages ofTribolium confusum

The essential oils from rosemary (Rosmarinus officinalis L.) and laurel (Laurus nobilis L.) obtained from Mersin Province in Turkey, were tested for their fumigant toxicity against all life stages of confused flour beetle (Tribolium confusum du Val.). GC-MS analysis showed that 1,8-cineole was found to be the major component of both rosemary and laurel essential oils. Vapors of rosemary and laurel essential oils were toxic to all life stages ofT. confusum. Only 65% mortality of the eggs was achieved when exposed to a dose of 172.6 mgl ⁻¹ air of rosemary essential oil at the longest exposure period (144 h); at the same dose, the pupae were the most resistant stage, with LT₉₀ (lethal time) value of 120.2 h. The adults were the most resistant stage to laurel essential oil, with LT₉₀ value of 77.2 h. On the basis of LT₉₀ values, tolerance of the life stages ofT. confusum to rosemary and laurel essential oils was, in descending order: pupa < larva < adult, and larva < adult < egg < pupa, respectively. Based on the concentration × time (Ct) products (g hl ⁻¹), rosemary essential oil was more toxic than laurel to the adults and larvae ofT. confusum. However, laurel essential oil was more toxic than rosemary to the eggs and pupae. Since these essential oils need such high Ct products to obtain complete mortality ofT. confusum compared with the most commonly used commercial fumigants, it would be impossible to use them on their own as a commercial fumigant against stored-product insects.     

臭氧对韭菜迟眼蕈蚊的室内毒力及其安全性评价

为明确臭氧对韭菜迟眼蕈蚊Bradysia odoriphaga的毒力及对韭菜和土壤环境安全性的影响采用室内生测法测定了臭氧对3龄幼虫、蛹和成虫的毒力,并测定了臭氧水对韭菜种子的影响及对土壤环境的安全性。结果显示,臭氧对韭菜迟眼蕈蚊3龄幼虫和蛹均有较高的毒力,LC_(50)分别为3.79 mg/L和4.95 mg/L;对其成虫的毒力稍弱,LC_(50)为61.52 mg/m~3。臭氧水浓度为4.50 mg/L时对韭菜种子萌发和幼苗生长促进效果最显著,发芽率、根长和芽长较对照分别显著增加了22.29%、14.11%和4.75%。4.50 mg/L臭氧水处理土壤后,细菌、真菌和放线菌数量较对照分别显著下降了91.91%、85.71%和59.99%;土壤pH提高了2.07%,速效钾含量显著上升了313.19%,有效磷、氨态氮、有机质的含量分别下降了4.69%、18.75%、35.44%。表明臭氧对韭菜迟眼蕈蚊3种虫态均有杀伤作用,且对韭菜种子萌发和幼苗生长有良好的安全性,但对土壤环境有一定影响。     

Fumigant toxicity of<Emphasis Type="Italic">Eucalyptus blakelyi</Emphasis> and<Emphasis Type="Italic">Melaleuca fulgens</Emphasis> essential oils and 1,8-cineole against different development stages of the rice weevil<Emphasis Type="Italic">Sitophilus oryzae</Emphasis>

Essential oils extracted fromEucalyptus blakelyi (1,8-cineole, 77.5%),Melaleuca fulgens (1,8-cineole, 56.9%) and 1,8-cineole were shown to have fumigant toxicity against different development stages ofSitophilus oryzae. The eggs ofS. oryzae were the most tolerant, followed by pupae, larvae and adults in that order.M. fulgens oil,E. blakelyi oil and 1,8-cineole at 100 μl per liter of air gave, respectively, LT₅₀ values of 16.2, 17.4 and 9.1 h for adults, 31.1, 19.3 and 17.5 h for larvae, 55.6, 75.2 and 39.7 h for pupae, and required >7 days for eggs. Only 1,8-cineole (200 μl ⁻¹ air) gave a significant egg kill by 7 days and the LT₉₅ was 134.5 h. 1,8-Cineole could be a useful new fumigant. http://www.phytoparasitica.org posting Oct. 3, 2004.     

A new molecular method for the rapid detection of a metamitron‐resistant target site in Chenopodium album

BACKGROUND: Resistance to photosystem II inhibitors—triazines (atrazine) and triazinones (metamitron, metribuzin)—in Chenopodium album L. is caused by the serine 264 to glycine mutation in the D1 protein. This mutation has been detected in C. album collections from Belgium with unsatisfactory metamitron efficacy in the field and was confirmed in greenhouse resistance bioassays. Incomplete herbicide efficacy in practice can also be caused by reduced uptake due to environmental conditions. Hence, for reliable differentiation and resistance identification, a rapid method for mutation detection in the target gene psbA is required. RESULTS: Dose–response curves obtained in herbicide greenhouse assays with metamitron‐resistant and ‐susceptible reference biotypes showed that a dose of 2 L ha^?1 metamitron was suitable for discrimination. A psbA PCR‐RFLP was developed, based on the presence of a FspBI restriction enzyme recognition site, covering D1 codon 264 in susceptible genotypes. A paper‐based DNA extraction allowed direct processing of leaf samples already in the field. In order to detect the mutation even in mixed seed samples, a nested PCR‐RFLP was also developed. CONCLUSION: The method allows exhaustive surveys screening C. album leaf or seed samples for the occurrence of the D1 Ser264Gly mutation to confirm or disprove metamitron resistance in the case of unsatisfactory control. Copyright © 2010 Society of Chemical Industry