Resistance of avocado thrips (Thysanoptera: Thripidae) to sabadilla, a botanically derived bait

Bioassays were conducted on four avocado thrips (Scirtothrips perseae Nakahara) populations in southern California that had had limited past exposure to the botanical pesticide sabadilla, with the objective of establishing baseline susceptibility levels for the purpose of resistance monitoring. Reports of avocado thrips resistance in a grove that had received six sabadilla sprays over 2 years were confirmed when a bioassay indicated resistance ratios of 7.6 and 18.8 at the LC50 and LC90, respectively. Owing to the availability of other unrelated pesticides, sabadilla sprays were discontinued at this site, and, after 5.5 years, resistance ratios had dropped to near baseline levels. Avocado thrips baseline susceptibility to cyfluthrin was also obtained from one grove for future resistance monitoring studies. Resistance management principles are discussed in relation to the limited future options available for avocado thrips control.     

Effectiveness of insecticide-treated and non-treated trap plants for the management of Frankliniella occidentalis (Thysanoptera: Thripidae) in greenhouse ornamentals

The effectiveness of trap cropping as an integrated control strategy against western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), was explored in potted chrysanthemum, Dendranthema grandiflora (Tzvelev), greenhouse crops. The efficacy of flowering chrysanthemum trap plants, either treated with the insecticide spinosad or untreated, to regulate F. occidentalis populations was tested at different spatial scales (small cage, large cage and commercial greenhouse) and for different time periods (1 or 4 weeks). It was demonstrated that flowering chrysanthemums as trap plants lower the number of adult F. occidentalis in a vegetative chrysanthemum crop and, as a result, reduce crop damage. In the 4 week large-cage trial and the commercial trial, significant differences between the control and the trap plant treatments started to appear in the third week of the experiment. Larvae were only significantly reduced by the presence of trap plants in the 1 week small-cage trials. There were no significant differences between treatments with spinosad-treated and untreated trap plants in the number of F. occidentalis on the crop. This suggests that there was minimal movement of adult F. occidentalis back and forth between the trap plants and the crop to feed and oviposit. It is concluded that the trap plant strategy is a useful tool for integrated pest management against F. occidentalis in greenhouses.     

施磷对紫花苜蓿光合作用及抗蓟马的影响

为了明确施磷对苜蓿抗蓟马的影响及其相关的光合机制,本试验以西北广泛种植的感蓟马苜蓿品种‘甘农3号’和抗蓟马苜蓿品种‘甘农9号’为材料,在大田蓟马为害高峰期,调查评价了不同施磷水平下苜蓿的受害指数、生长指标和蓟马虫口数量,测定了不同施磷水平下苜蓿的光合气体交换参数、可溶性糖含量。结果表明:施磷后,‘甘农3号’和‘甘农9号’苜蓿的受害指数均显著降低,株高和产量显著增加,蓟马虫口数量无显著变化;净光合速率(Pn)和水分利用率(WUE)显著升高,蒸腾速率(Tr)和气孔导度(Gs)显著降低;苜蓿心叶可溶性糖含量显著升高,但可溶性糖含量与蓟马虫口密度间无相关性,而与受害指数之间存在极显著的负相关关系。施磷有效地增强了苜蓿的光合作用,进而增强了苜蓿对蓟马的耐害性。在大田条件下,通过增施磷肥来控制苜蓿蓟马的危害是一种经济有效的绿色防控措施。     

Soil application of azadirachtin and 3-tigloyl-azadirachtol to control western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae): translocation and persistence in bean plants

To study the systemic effects of active neem ingredients, the substrate of bean plants was treated with a 170 g kg(-1) azadirachtin (NeemAzal-U; Trifolio-M GmbH, Lahnau, Germany, registration pending). This product was used at a dose rate of 10 mg AZA (azadirachtin a) and 1.2 mg 3-tigloyl-azadirachtol (azadirachtin b) per treated bean plant. Afterwards, the translocation and persistence of AZA and 3-tigloyl-azadirachtol and the effects on western flower thrips, Frankliniella occidentalis (Pergande), were studied. Residues of AZA and 3-tigloyl-azadirachtol from substrates with different contents of organic matter [pure culture substrate (CS), CS-sand mixture] and from various plant parts were quantified by high-performance liquid chromatography-mass spectrometry (HPLC-MS). The dissipation trends of AZA and 3-tigloyl-azadirachtol were similar within the same substrates. A slower decline of both active ingredients was measured with CS than with CS-sand mixture. Residue analysis of the bean plants showed that only small proportions of the initial amounts of AZA and 3-tigloyl-azadirachtol applied to the substrate were present in the plant (0.3-8.1%). Variable amounts of residues of the active components in relation to plant parts and time of analysis indicated a different translocation pattern for the two active ingredients. Higher residues of the active ingredients were found in roots and stems after neem application using CS, whereas higher residues were found in leaves after CS-sand mixture treatments. Mortality of F. occidentalis after NeemAzal-U soil applications reached up to 95% on CS-sand mixture, compared with 86% in CS.     

First record of Thrips hawaiiensis (Morgan, 1913) (Thysanoptera: Thripidae), an Asian pest thrips in Spain

Several permanent populations of Thrips hawaiiensis (Morgan, 1913) were discovered outdoors for the first time in Spain in 2010. Captures were made mainly on Rosa flowers, Nerium oleander and Gerbera sp.     

<Emphasis Type="Italic">Anascirtothrips arorai</Emphasis> bhatti (Thysanoptera: Thripidae): A new thrips for Israel

Anascirtothrips arorai was discovered for the first time in the Palearctic region and in new niches: inside fig fruits and in the galls ofGynaikothrips ficorum. http://www.phytoparasitica.org posting May 4, 2007     

佳多虫情测报灯和普通黑光灯对草地螟种群监测与防治效果比较

2004-2006年连续3年应用佳多自动虫情测报灯和传统普通黑光灯对草地螟种群监测和诱杀结果表明,两种诱虫灯均可有效监测草地螟种群动态,自动虫情测报灯对高密度草地螟种群诱杀效果显著,诱蛾量明显高于普通黑光灯的,而普通黑光灯对低密度种群诱杀较为有效。两种灯光诱捕器监测的草地螟种群动态变化趋势基本一致,每天诱蛾数呈极显著相关（r2004=0.973、r2005=0.990和r2006=0.981,p<0.01),但黑光灯下草地螟种群始见期较早而终见期较晚。两种灯下诱捕的草地螟雌蛾数均大于雄蛾数,但灯光诱捕器之间诱捕的草地螟雌雄性比差别不大。     

Thrips (Thysanoptera: Thripidae) mitigation in seedling cotton using strip tillage and winter cover crops

BACKGROUND: Thrips are the most consistent insect pests of seedling cotton in the southeastern United States, where symptoms can range from leaf curling to stand loss. In a 2 year study, thrips adults and immatures were sampled at 14, 21 and 28 days after planting on cotton planted with a thiamethoxam seed treatment in concert with crimson clover, wheat or rye winter cover crops and conventional or strip tillage to investigate potential differences in thrips infestations. RESULTS: Densities of adult thrips, primarily Frankliniella fusca (Hinds), peaked on the first sampling date, whereas immature densities peaked on the second sampling date. Regardless of winter cover crop, plots that received strip tillage experienced significantly fewer thrips at each sampling interval. In addition, assessment of percentage ground cover 42 days after planting showed that there was more than twice as much ground cover in the strip‐tilled plots compared with conventionally tilled plots. Correlation analyses showed that increased ground cover was inversely related to thrips densities that occurred on all three sampling dates in 2008 and the final sampling date in 2009. CONCLUSIONS: Growers who utilize strip tillage and a winter cover crop can utilize seed treatments for mitigation of early‐season thrips infestation. Copyright © 2010 Society of Chemical Industry     

Pest status of the Hawaiian flower thrips,Thrips hawaiiensis (Morgan) (Thysanoptera: Thripidae) in lemons in the Mediterranean region of Turkey

Phytoparasitica - The Hawaiian flower thrips, Thrips hawaiiensis (Morgan) (Thysanoptera: Thripidae), is a polyphagous and widespread pest in tropical and temperate regions. In 2015, T. hawaiiensis...     

First record of Bregmatothrips dimorphus (Priesner, 1919) (Thysanoptera: Thripidae) in Tunisia

During an inventory study of thrips species carried out in the central‐eastern coastal region of Tunisia in 2010 and 2011, Bregmatothrips dimorphus (Priesner, 1919) (Thysanoptera; Thripidae) was found on two host plants; barley (Hordeum vulgare Linnaeus) and sorghum (Sorghum bicolor Moench). This is the first record of B. dimorphus in Tunisia. Its distribution in other parts of the world and taxonomic characteristics are briefly presented.     

Quantification of imidacloprid toxicity to avocado thrips, Scirtothrips perseae Nakahara (Thysanoptera: Thripidae), using a combined bioassay and ELISA approach

A competitive ELISA (enzyme-linked immunosorbent assay) technique was evaluated for quantifying titres of imidacloprid in homogenates of leaf discs sampled from avocado plants treated with systemic applications of imidacloprid 240 g litre(-1) SC (Admire). Matrix effects were evident with undiluted leaf tissue homogenates, but these were effectively eliminated by dilution of homogenates in water. In a field trial conducted in a commercial nursery, there was an excellent correlation between imidacloprid residues within leaves and avocado thrips (Scirtothrips perseae Nakahara) mortality. However, with subsequent sampling over a 2-month period, the relationship between mortality and apparent imidacloprid concentration became less robust, suggesting that the material was being degraded within the plant to non-toxic metabolites. Nevertheless, assessments of thrips mortality on leaves that had been recently treated with imidacloprid established a lower threshold of activity for imidacloprid residues of 6 ng cm(-2) leaf. Limitations on the use of ELISA to quantify the impact of systemic insecticides on pest populations are discussed.     

Effects of a juvenile hormone analog,pyriproxyfen, on Thrips tabaci (Thysanoptera: Thripidae)

Effects of a juvenile hormone analog, pyriproxyfen, on various developmental stadia of the onion thrips, Thrips tabaci Lindeman, were determined on cabbage leaves in the laboratory. Pyriproxyfen was applied at 0.064 or 0.128 g AI liter(-1) on leaves (residual contact-ingestion), thrips (direct contact) and leaf-thrips (residue contact-ingestion-direct contact). Pyriproxyfen did not have any significant lethal effects on thrips pupae in any treatment. Lethal effects on thrips larvae varied depending on application method and dosage. In the leaf and the leaf-thrips treatments, few larvae and pre-pupae molted to the next stage, and none developed to adults. In contrast, in the thrips-only treatment, pyriproxyfen did not show any significant lethal effects. The developmental times of larvae and pre-pupae were prolonged when larvae were treated with pyriproxyfen, and those of pre-pupae and pupae were shortened when pre-pupae and pupae were treated. The longevity and survival rates of thrips adults were generally shorter when they contacted and ingested pyriproxyfen-treated leaves than those in water control. Significantly fewer progeny (0.22-1.15 larvae per female) were produced by females that had fed on and been in contact with the pyriproxyfen-treated leaves than by those in the water control (11.94 larvae per female). However, the number of progeny produced by the thrips females increased significantly (3.32-7.28 larvae per female) when the females were transferred to untreated leaves after feeding on treated leaves for 5 days; the daily larval hatching pattern was similar to those in water control, indicating that female adults were able to produce viable eggs when untreated food was offered.     

Addition of alarm pheromone to insecticides and the possible improvement of the control of the western flower thrips,Frankliniella occidentalis Pergande (Thysanoptera: Thripidae)

This study represents the first attempt to improve insecticide contact using the dodecyl acetate component of the alarm pheromone of the western flower thrips ( Frankliniella occidentalis Pergande ). Dodecyl acetate dissolved in ethanol was added to both fipronil and maldison and used in three spray applications (7 days apart) against field infestations of F. occidentalis on strawberries in two separate trials. Fipronil alone was highly effective against larvae and to a lesser extent against adults; however, the addition of dodecyl acetate did not significantly enhance thrips mortality. Although maldison was significantly less effective against adults and larvae, the larval mortality rate was significantly increased with the addition of dodecyl acetate. In one trial, dodecyl acetate applied on its own caused a significant reduction in larval numbers. Frequent insecticide applications are recommended for control of F. occidentalis in Australia because of the short-term effectiveness of most insecticides. This may hasten the development of insecticide resistance, which is already evident in F. occidentalis populations across the continent. Hence, either cultural methods, biological control agents or more effective chemicals need to be identified. This study has shown that there is potential for dodecyl acetate to enhance insecticide control of F. occidentalis .     

Potential for a sticky trap monitoring system for the diamondback moth (Lepidoptera: Yponomeutidae) on cabbages in Indonesia

Experiments on the development of a sticky trap monitoring system for the diamondback moth, Plutella xylostella (L.), were carried out in six cabbage fields (two in each of three villages) in North Sulawesi, Indonesia. This region is characterized by small, closely‐situated, fields. Yellow cardboard traps with a sticky upper surface were placed 10 cm below the crop canopy, four traps per field, and were maintained throughout the 1991 growing season. Larvae were sampled weekly in quadrats centred around each trap. One village where continuous cabbage growing occurred had higher P. xylostella populations than the other two villages, where growing is discontinuous. Although the relationship between trap catches and larval populations for individual fields was weak, the relationship between catches in all fields pooled and larval populations 2 weeks later was very strong, suggesting that a region‐wide predictive system would be feasible. An increase in larval numbers as distance from the traps increased further suggests that sticky traps may have potential for use in mass trapping.     

温度对东亚小花蝽捕食美洲棘蓟马的影响

为明确不同温度下东亚小花蝽Orius sauteri雌成虫对美洲棘蓟马Echinothrips americanus雌成虫捕食能力的影响,利用HollingⅡ、HollingⅢ及Flinn’s三种模型研究了辣椒上天敌捕食量、猎物密度和环境温度三者间的关系,并推测了该功能反应和搜索效应的相关参数。结果表明:在16、19、22、25、28、31和34℃各温度条件下,东亚小花蝽雌成虫捕食量随猎物密度增加而增大,且差异显著,寻找效应随之降低。HollingⅡ与HollingⅢ模型均适合拟合不同温度下东亚小花蝽雌成虫的捕食功能反应,且HollingⅡ模型较HollingⅢ模型拟合度更好。在HollingⅡ模型拟合条件下,东亚小花蝽22℃时瞬时攻击率最高,为1.132,34℃时处理单头猎物时间最短,为0.007 d。在HollingⅢ模型拟合条件下,19℃时最佳寻找密度最低,为10.31头,34℃时单日最大捕食量最大,为52.67头。由双因素变量Flinn’s模型拟合得到的东亚小花蝽雌成虫平均瞬时攻击率为4.314,并且在34℃、初始猎物密度45头下,东亚小花蝽雌成虫能发挥最大捕食潜能。表明东亚小花蝽为美洲棘蓟马的有效天敌。     

Catching Ips duplicatus (Sahlberg) (Coleoptera: Scolytidae) with pheromone‐baited traps: optimal trap type,colour, height and distance to infestation

BACKGROUND: Field trapping experiments were carried out to evaluate effective trap characteristics for maximising Ips duplicatus (Sahlberg) catches in pheromone‐baited traps in China. RESULTS: Window‐slot and cross‐barrier traps had significantly higher catches than multiple‐funnel traps. The colour of window‐slot traps showed a significant effect on catches, with dark colours (black and red) being more effective than light colours, especially white and yellow. Window‐slot traps at a 1.5–2.0 m level caught more beetles than those at either ground level (0–0.5 m) or at 3.5–4.0 m. Ips duplicatus can be attracted to pheromone‐baited traps over a distance of > 100 m from the forest edge in an open grassy field. There was a strong diurnal pattern of flight activity, with catches on window‐slot traps occurring during the daytime with one broad peak at mid‐ to late afternoon. The seasonal flight activity of I. duplicatus as monitored by pheromone‐baited window‐slot traps during 2007–2008 indicated that three major flight peaks occurred in early June, late June–early July and late July respectively, suggesting the existence of a potential second generation. CONCLUSION: The optimal trap characteristics will improve the performance of pheromone‐baited traps as a critical monitoring or mass‐trapping tool to combat outbreaks of this pest species. Copyright © 2009 Society of Chemical Industry     

Evaluation of medium treatments for management of Frankliniella occidentalis (Thripidae: Thysanoptera) and Bradysia coprophila (Diptera: Sciaridae)

Two greenhouse experiments, each comprising two trials, were conducted to evaluate medium drenches of insect growth regulators and conventional insecticides to reduce emergence of adult western flower thrips, Frankliniella occidentalis (Pergande), and fungus gnats, Bradysia coprophila (Lintner) from the medium. In the insect growth regulator trials, diflubenzuron and pyriproxyfen provided the greatest reduction in thrips emergence, and fenoxycarb, pyriproxyfen and azadirachtin resulted in the most significant reduction of fungus gnat emergence. Treatments with the contact insecticides, methiocarb and chlorpyrifos, resulted in the greatest reduction of thrips and fungus gnat populations. These data suggest that fungus gnats are susceptible to many compounds used in commercial greenhouse production. Even though medium drenches are not currently used for thrips management, drenches with diflubenzuron, pyriproxyfen, methiocarb and chlorpyrifos could aid in reducing thrips populations in greenhouse management programs. © 2001 Society of Chemical Industry