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1.
The effect of high carbon dioxide atmospheres (60% CO2) at different temperatures (20, 25, 30 and 34°C) on adult female mortality in Frankliniella occidentalis (Pergande), Frankliniella intonsa (Trybom), Thrips tabaci Lindeman, Thrips palmi Karny, and Thrips parvispinus Karny were tested. Mortality of the five thrips species increased with CO2 exposure duration at each temperature. Median lethal times (LT50) and times required to achieve 100% mortality due to CO2 exposure decreased with increasing temperature, for all thrips species. Exposure to 60% CO2 atmospheres at 30°C is considered to be 100% lethal within 24 h to most pests of fresh agricultural produce. Our findings suggest that CO2 treatment could be used to propagate thrips-free plants in horticultural nurseries, and as a quarantine tool for controlling insects in/on transported plants.  相似文献   

2.
Postharvest treatments, including insecticidal dips, isopropyl alcohol dips, insecticidal fogs and hot-water immersion, were evaluated to control mixed infestations of Western Flower Thrips (Frankliniella occidentalis) and Melon Thrips (Thrips palmi) on dendrobium orchid blossoms. The limiting factor for all postharvest treatments was phytotoxicity, characterised by a loss of vase life that differed among cultivars. Insecticidal dips and insecticidal fogs were less phytotoxic than hot-water immersion and isopropyl alcohol dips. Insecticidal fogs consisting of abamectin 2.0% e.c. and abamectin tank-mixed with Pyrenone e.c. (6% pyrethrins, 60% piperonyl butoxide) reduced the mean number of thrips per blossom by 93.8% and 92.3%, respectively and were nonphytotoxic. An insecticidal aerosol, Floragas (2% permethrin and 0.1% pyrethrum dissolved in high pressure liquified CO2) reduced thrips by 33% to 54% with no phytotoxicity. Insecticidal dips for 3 min with agitation reduced the mean number of thrips per blossom by 43.7% to 99.1%. Of the 12 insecticides and one surfactant tested, only chlorpyrifos 44.4% e.c., fluvalinate 22.3% f., and chlorpyrifos 50% d.f. were both effective and nonphytotoxic. Immersion in water at 49.5°C for 15 and 20 s reduced the mean number of thrips per blossom by 88.1% and 95.3%, respectively. A 70% solution of isopropyl alcohol applied as a postharvest dip did not kill all thrips and was extremely phytotoxic to blossoms.  相似文献   

3.
Western flower thrips, Frankliniella occidentalis, and onion thrips, Thrips tabaci, are both important polyphagous pests of vegetables and ornamentals in greenhouses. Difficulties in biological control of these pests have prompted a search for new natural enemies. Most recently, the predatory mite Amblyseius swirskii has been commercialised as biological control agent of whiteflies and thrips. However, little is known about the suitability of thrips as prey for A. swirskii. We therefore assessed prey acceptance and life history of A. swirskii when feeding on F. occidentalis and T. tabaci at 25±1°C. Amblyseius swirskii juveniles preyed upon first larval instars of both F. occidentalis and T. tabaci but suffered from high mortality (67 and 78%). Developmental time (egg to adult) of A. swirskii was 7.8 days with either prey species. Adult A. swirskii females readily accepted first larval instars of both thrips species, which were attacked in <20 min on a leaf and <10 min in an artificial cage. Oviposition rates (0.92 and 0.99 eggs/female/day) and offspring sex ratios (63 and 70% females) were similar with F. occidentalis and T. tabaci as prey. Less than one-third of juveniles reaching adulthood and oviposition rates below one egg/female per day resulted in relatively low intrinsic rates of increase (r m) (0.056 and 0.024 per day with F. occidentalis and T. tabaci, respectively). Altogether, our study suggests that the recently reported superiority of A. swirskii to the widely used Neoseiulus cucumeris in suppression of thrips is due to other traits than its population growth capacity with thrips as prey.  相似文献   

4.
《Journal of Asia》2019,22(3):733-736
Thrips are known as cell-feeding sucking pests, but little information is available on which and how much of each subcellular fraction they ingest. In this study, the ingested amounts of nuclei and plastids in two representative thrips species (the western flower thrips, Frankliniella occidentalis, and the garden thrips, Frankliniella intonsa) along with two reference sucking pests (the two-spotted spider mite, Tetranychus urticae, a cell feeder, and the brown planthopper, Nilaparvata lugens, a sap feeder) were quantified by quantitative PCR using phytoene desaturase and rubisco as respective marker genes following feeding. The ingested amounts of plastids were significantly greater than those of nuclei in the thrips and mite species. In the thrips species, however, the fold differences in ingested amount between the two fractions were substantially lower than their original ratio in intact plant cells, suggesting that thrips ingest nuclei more selectively than plastids. Unlike the thrips species, the ratio between nuclei and plastids increased in T. urticae. In contrast to these cell-feeding insects, no subcellular fraction was detected in N. lugens. These findings suggest that transgenic expression of foreign hairpin RNA in the nucleus would deliver a substantial amount of target molecules to cell-feeding sucking pests, but not sap-feeding pests, when employing ingestion RNA interference-based control strategies.  相似文献   

5.
《Journal of Asia》2020,23(4):1255-1263
Thrips constitute several families of slender insects with fringed wings and unique asymmetrical mouthparts. They have become globally important pests, infesting a variety of agriculturally important crops. Species of thrips are difficult to identify due to their small size and similarities in morphology. Recently, in addition to morphology, both molecular and non-molecular taxonomic tools have been used to identify species differences. Insect cuticular hydrocarbons have been widely used in chemotaxonomy. In this study, a Thermal Separation Probe was used to identify the cuticular hydrocarbons of Frankliniella occidentalis, Frankliniella intonsa, Thrips palmi, Thrips hawaiiensis, Haplothrips chinensis and Gynaikothrips ficorum. We analyzed the hydrocarbon composition of adults in all 6 species, and in the larvae of F. occidentalis, T. hawaiiensis and T. palmi. The results showed that the composition of cuticular hydrocarbons differed between species. All 6 species of adults and 3 species of larvae were easily distinguishable by quantitative analysis of hydrocarbon profiles. These results provide a possible method for the identification of thrips.  相似文献   

6.
The life history of Thrips palmi Karny on eggplant (Solanum melongena L.) leaves was studied based on the age stage and two sex-life tables at 16, 19, 22, 25, and 31?°C. The intrinsic rate of increase (r) at these temperatures was 0.0427, 0.0566, 0.0979, 0.1738, and 0.2237?day?1, respectively. The relationship among the gross reproductive rate (GRR), the net reproductive rate (R 0), and the pre-adult survivorship (l a) is consistent with R 0?<?l a?×?GRR?<?GRR for all results at different temperatures. The mean generation time was 47.52, 38.33, 29.52, 19.81, and 13.88?days, respectively. The developments of pre-adult and adult stages were faster in males than in females. The means of developmental periods for each developmental stage decreased with increases of temperature. The maximum life span of female adults was noted at 56.67?days, whereas that of males was 50.66?days at 16?°C. The maximum female fecundity (64.18?eggs/female) was recorded at 25?°C and the lowest (23.38 eggs/female) at 16?°C. Life table data could be used to project population growth, to design mass rearing programs, and to establish management tactics to control insect pests.  相似文献   

7.
【背景】外来入侵害虫西花蓟马于2003年首次在北京郊区被发现,并逐渐扩散蔓延,目前已在我国局部地区暴发成灾。【方法】于2008~2009年通过定点调查的方法对山东省115个地区258个样点的主要花卉上的蓟马种类进行了分析。【结果】山东省主要花卉上发生的蓟马有11种,包括花蓟马、黄胸蓟马、黄蓟马、西花蓟马、棕榈蓟马、烟蓟马、禾花蓟马、横纹蓟马、腹小头蓟马、黑白纹蓟马、油加律带蓟马等,其优势种为花蓟马。外来入侵害虫西花蓟马在山东省18个地区的花卉上被发现。其中,荣成市区发生最重,占蓟马采集总量的51.86%;德州市区和青岛市区发生次之,分别占蓟马采集总量的34.21%和33.88%;其他地区西花蓟马发生量占采集总量的1.39%~18.75%。【结论与意义】西花蓟马已在山东省定殖并广泛分布,相关部门应做好西花蓟马的预防与控制工作。  相似文献   

8.
【背景】外来入侵害虫西花蓟马于2003年首次在北京郊区被发现,并逐渐扩散蔓延,目前已在我国局部地区暴发成灾。【方法】于2008~2009年通过定点调查的方法对山东省115个地区258个样点的主要花卉上的蓟马种类进行了分析。【结果】山东省主要花卉上发生的蓟马有11种,包括花蓟马、黄胸蓟马、黄蓟马、西花蓟马、棕榈蓟马、烟蓟马、禾花蓟马、横纹蓟马、腹小头蓟马、黑白纹蓟马、油加律带蓟马等,其优势种为花蓟马。外来入侵害虫西花蓟马在山东省18个地区的花卉上被发现。其中,荣成市区发生最重,占蓟马采集总量的51.86%;德州市区和青岛市区发生次之,分别占蓟马采集总量的34.21%和33.88%;其他地区西花蓟马发生量占采集总量的1.39%~18.75%。【结论与意义】西花蓟马已在山东省定殖并广泛分布,相关部门应做好西花蓟马的预防与控制工作。  相似文献   

9.
Improved laboratory methods are described in detail for mass rearing of various thrips species, such as Frankliniella occidentalis, Frankliniella intonsa, Thrips palmi, Thrips tabaci (Thysanoptera: Thripidae) and a thrips parasitoid, Ceranisus menes (Hymenoptera: Eulophidae), using various foods. In one method, plant pollen and honey solution are used as food sources. In a second method, germinated broad bean seeds are used. Eggs, produced in large numbers in water, are collected by a suction funnel onto a filter paper and incubated in a Petri dish. Large numbers of larvae that hatch are collected by using food traps (plant pollen). Larvae can be reared on pollen or on germinated broad bean seeds until adult emergence without additional water and food. This method has been found useful for producing even-aged thrips at different densities (up to 500 larvae in a cage of 80 mm diameter) with relatively low mortality rates. Evaluation of this rearing method for F. intonsa, shows that during 2 weeks at 20 °C per 100 females more than 4000 females could be produced in the next generation. About 5 min per day is required to achieve this productivity of mass production. The method is also suitable for producing large numbers of the solitary endoparasitoid of thrips larvae, C. menes.  相似文献   

10.
Thrips palmi Karny has recently been implicated in damage to eggplant fruits. This thrips causes cosmetic scars on and deforms fruits, thus lowering their market value. To investigate the relationship between the density of thrips and the resulting damage, experimental plots with initial release densities of 0, 20, 40, 70, and 100 adults thrips per plot were established under greenhouse conditions. Thrips density (for flower sampling = x 1; for sticky trap = x 2) was monitored using flower sampling and blue sticky trap counts, and was found to be directly related to the proportion of damaged-fruits (y) and the reduction in fruit yield: significant relationships were found for the flower samples (y = 1.2261x 1 ? 0.6232, r 2 = 0.8582) and for the trap catches (y = 11.667 ln(x 2) ? 9.5, r 2 = 0.8896). The proportion of damaged fruits that could be tolerated from an economic perspective, based on the cost of controlling the thrips population chemically and the market value of the fruit, was 6.67–11.76 %; this translated into economic thresholds of 1.05–1.5 adults and/or larvae of T. palmi per flower or 4.91–10.17 adults T. palmi per four-day sticky card count.  相似文献   

11.
L. Hughes  F. A. Bazzaz 《Oecologia》1997,109(2):286-290
We measured the effect of elevated CO2 on populations of the western flower thrips, Frankliniella occidentalis and on the amount of leaf damage inflicted by the thrips to one of its host plants, the common milkweed, Asclepias syriaca. Plants grown at elevated CO2 had significantly greater aboveground biomass and C:N ratios, and significantly reduced percentage nitrogen. The number of thrips per plant was not affected by CO2 treatment, but the density of thrips (numbers per gram aboveground biomass), was significantly reduced at high CO2. Consumption by thrips, expressed as the amount of damaged leaf area per capita, was significantly greater at high CO2, and the amount of leaf area damaged by thrips was increased by 33%. However overall leaf area at elevated CO2 increased by 62%, more than compensating for the increase in thrips consumption. The net outcome was that plants at elevated CO2 had 3.6 times more undamaged leaf area available for photosynthesis than plants at ambient CO2, even though they had only 1.6 times the overall amount of leaf area. This study highlights the need for measuring the effects of herbivory at the whole-plant level and also the importance of taking herbivory into account when predicting plant responses to elevated CO2. Received: 9 January 1996 /Accepted: 30 July 1996  相似文献   

12.
《Journal of Asia》1999,2(1):69-75
Effects of the kind of test leaf and temperature on leaf dip bioassay to the western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), were examined with nine different insecticides. For the test of different leaves, cucumber, pepper and potato leaves were evaluated. The test leaves significantly influenced thrips mortalities on leaf dip bioassay. Generally the mortalities on pepper leaf were higher than on cucumber leaf or filter paper. Temperature effects were determined at 15, 20, 25 and 30°C. Regardless of the test leaf, the mortality was increased with increasing temperature except for the case of imidacloprid. Local variations in mortality of F. occidentalis populations were not observed in this study.  相似文献   

13.
The life cycle of the Western Flower Thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), one of the most important glasshouse pests, includes a soil passage composed of three instars that deserve more attention in terms of biocontrol strategies. It has been repeatedly reported that two polyphagous predatory mites, Stratiolaelaps miles (Berlese) and Hypoaspis (Geolaelaps) aculeifer (Canestrini) (Acari: Laelapidae), also prey on these thrips stages, in addition to several other soil inhabiting prey species. However, the potential thrips consumption rates have never been quantified for these predatory mites. Therefore, an arena experiment was carried out to investigate the potential predation rates of the two mites on second instar larvae, prepupae, and pupae of F. occidentalis. In addition, the fecundity on the thrips diet was assessed and compared to oviposition rate on a nematode prey. All thrips instars were accepted as prey by each mite species. Females of H. aculeifer preyed on 3.5 (± 0.5) thrips instars and laid 2.5 (± 0.87) eggs per day, whereas females of S. miles preyed on 1.64 (± 0.3) thrips and laid 0.8 (± 0.53) eggs. Males of both species killed 0.6 (± 0.3) thrips per day. The fitness of the two predatory mites on F. occidentalis as prey and their suitability as biocontrol agents are elucidated. Reasons for reduced thrips control in the soil environment, in contrast to the results obtained in arena assays are discussed.  相似文献   

14.
Pathogenicity of nematophagous fungus Paecilomyces lilacinus (Thom) Samson in control of the most destructive greenhouse pests such as: greenhouse whitefly, Trialeurodes vaporariorum, glasshouse red spider mite, Tetranychus urticae, the cotton aphid, Aphis gossypii and western flower thrips, Frankliniella occidentalis was examined in laboratory and pot experiments. The fungus showed the greatest efficacy in controlling winged and wingless forms of the cotton aphid. The cotton aphid’s population was almost totally eliminated. In controlling the greenhouse whitefly, P. lilacinus was most successful when applied against nymphal growth stages (L3-L4). Control of the western flower thrips was most efficient against prepupal and pupal stages when the fungus was applied as a water spore suspension to the soil. When the fungus was applied at temperatures below 10 °C, it was able to reduce a glasshouse red spider mite population by 60%.  相似文献   

15.
《Journal of Asia》2019,22(2):537-542
Beauveria bassiana (Balsamo) Vuillemin (Hypocreales: Cordycipitaceae) ERL836 has been commercialized under the name ChongchaeSak to control an agricultural insect pest, the western flower thrips Frankliniella occidentalis Pergande (Thysanoptera: Thripidae), in the Republic of Korea. As soon as it was launched in 2017, it became a popular product and has received a positive response. However, study of the storage stability of the fungus ERL836 has yet to be investigated. To determine the optimum conditions for long-term storage, we assessed conidial viability and insecticidal activity of B. bassiana ERL836 according to storage temperature and culture substrate. Viability of B. bassiana ERL836 conidia from mycotized grains (millet and rice) stored at low (4 °C) and moderate (25 and 30 °C) temperatures was maintained at >85% for 24 and 18 months, respectively, along with insecticidal activity. In contrast, the samples stored at 37 °C showed low germination rate (about 80% germination rate for only 5 months). This result suggests that low and moderate temperatures (4 to 30 °C) conserve B. bassiana ERL836 viability and virulence.  相似文献   

16.
We studied the development of Geocoris varius (Uhler) and Geocoris proteus Distant reared on Ephestia kuehniella Zeller eggs at 20, 24, 26, 30, 33, or 36?°C. The lower developmental thresholds (T 0) and the thermal constants (K) of eggs and nymphs of G. varius were 13.3?°C, 151.1 degree-days and 13.4?°C, 433.0 degree-days, respectively; those of G. proteus were 16.1?°C, 98.3 degree-days and 16.9?°C, 226.9 degree-days, respectively. The hatch rate of G. varius eggs was significantly lower at 33?°C than at ??30?°C, and no eggs hatched at 36?°C. That of G. proteus was lowest at 20?°C and did not decline significantly at 36?°C. The survival rate throughout the nymphal period increased with temperature up to 30?°C in G. varius, and it was lowest at 20?°C in G. proteus. Thus, the optimal rearing temperatures for immature stages appear to be about 24?C30?°C for G. varius and 26?C33?°C for G. proteus. It might be possible to improve the efficiency of their mass production by controlling the rearing temperature in the above ranges. This would also make the developmental stages of nymphs more uniform and so prevent cannibalism in mass rearing.  相似文献   

17.
Abstract

Effect of modified atmospheres (MAs) containing CO2 at 20, 40, 60 and 80% or containing N2 at 97 and 98% on the mortality of Corcyra cephalonica Stainton (Lepidoptera: Pyralidae) sixth instar larvae was studied to determine the LT values at 30?°C. The respiration rates of untreated and treated larvae with 60% CO2 and/or 98% N2 at LT50 were measured using Q-Box RP1LP low range respirometry package. Total protein and triglycerides of treated and untreated larvae were assayed. Complete larval mortality was recorded after 72 and 144?h of treatment with 60% CO2 and 98% N2, respectively. Calculated LT50 values were 39.3 at 60% CO2 and 87.5?h at 98% N2 MAs. Respiration quotient (RQ) in the light of consumed O2 and produced CO2 of untreated larvae was 1.0 while it was 0.85 at 60% CO2 and 0.72 at 98% N2. Duration time necessary for produced CO2 curve to reach the maximum point (2000?ppm) was significantly shorter at untreated larvae (27.64?min) in comparison with that recorded at CO2 (35.48?min) which also significantly less than that obtained at N2 (98.54?min). At all treatments, total protein was decreased while triglycerides were increased in comparison with control.  相似文献   

18.
With respect to the limitations use of methyl bromide and phosphine, employing ionizing radiation to control stored product pests has attracted great attention. The aim of this study is the investigation of the combined effects of gamma irradiation as viable alternatives to synthetic insecticides and environmental management on mortality and sterility of Rhyzopertha dominica (Fabricius) in a wheat cultivar (Gascogen). The effect of doses range from 30 to 2000?Gy gamma irradiation in combination with manipulation of temperature (15, 21, 27 and 32?°C) and relative humidity (20%, 50%, 65% and 85%) on 5–10?days old adults of R. dominica in Gascogen cultivar of wheat were explored. The experiments were repeated three times and conducted in The Nuclear Agriculture Research School in Karaj and laboratory of shahid steki silo in shahre-kord. Probit analysis revealed that both temperature and relative humidity had combined effects when used with gamma irradiation. The lowest doses of gamma ray required to kill 25% (14.2?Gy) and 50% (610.8?Gy) of the population (LD25 and LD50) were recorded at 21?°C and 85% relative humidity respectively. The low dose for 99% mortality (LD99; 2386.7?Gy) was recorded for beetles maintained at 21?°C and 50% relative humidity. The effect of temperature (15, 21, 27 and 32?°C) on sterility caused by gamma irradiation was also investigated. The results showed that the F1 generation emerged only when the beetles were treated with doses of 0–100?Gy at 32?°C and 0–70?Gy at 27?°C. These results indicate that temperature and relative humidity play an important role in the susceptibility of the lesser grain beetle to gamma irradiation. The results suggest that controlling the efficiency of gamma radiation through environmental control allows the use of low doses of gamma radiation that have a less harmful effect on human health, non-target organisms and seed agronomic features.  相似文献   

19.
The susceptibility of the cigarette beetle Lasioderma serricorne (F.) to hypoxia was examined at three different oxygen concentrations (0.5?C0.8, 1.0?C1.3, and 2.0?C2.3?%) and four different temperature/humidity (RH) conditions: 30?°C/75?% RH, 25?°C/75?% RH, 20?°C/43?% RH, and 15?°C/43?% RH. The influence of humidity on mortality was also examined at three humidity levels (21, 43, and 75?% RH) at 1.0?C1.3?% oxygen (O2) and 25?°C. Our results revealed that adult beetles were the most tolerant at 2.0?C2.3?% O2 and that the larvae were the most tolerant at O2 levels <1.0?C1.3?%. Mortality increased with increasing temperatures and decreasing O2 concentrations. At 30?°C, 75?% RH, and 0.5?C0.8?% O2, the 99?% lethality (LT99) of larvae was 6.9?days; however, it increased to 20?days when the temperature was decreased to 25?°C or when O2 levels were increased to 1.0?C1.3?%. Humidity also influenced mortality of both larval and adult beetles. LT99 values for larvae at 25?°C and 1.0?C1.3?% O2 were 24.0, 44.6, and 50.2?days at 21, 43, and 75?% RH, respectively. Results of this study indicate that a controlled atmosphere (CA) with reduced oxygen levels (<0.5?C0.8?% O2) represents an effective measure for disinfesting stored tobacco as an alternative to conventional phosphine fumigation at temperatures >30?°C.  相似文献   

20.
The successful use of the predatory bug Orius spp. (Hemiptera:Anthocoridae) for the biological control of pests, namely western flower thrips Frankliniella occidentalis (Pergande), in greenhouses during winter depends on overcoming the obstacles of short photoperiods and low temperatures which limit the efficacy of the predators through diapause induction, slowed development, reduced survival and reproduction. Thus, research has focused on determining the insect species least vulnerable to these problems. This study investigated the effect of varying day-lengths (9, 11, 13 and 16 h) at 26°C as well as constant (18, 22, 26 and 30°C) and fluctuating (10/22°C) temperatures on biological characteristics of Orius niger (Wolff). Photoperiod did not induce reproductive diapause and did not significantly affect development, survival of eggs and nymphs, longevity, fecundity or sex ratio; with the exception of the 16 h day-length which led to a shorter duration of nymphal development. Fluctuating temperatures and a constant temperature of 18°C increased the incubation period, duration of nymphal development, total developmental time, generation time and longevity, compared to the constant temperatures of 22, 26 and 30°C, but decreased fecundity compared to 22 and 26°C. On the other hand, sex ratio was not influenced by 10/22 and 18°C. Egg hatch rate and nymph survival differed significantly between temperature regimes, being lower at 18 and 10/22°C. These results suggest that O. niger would be able to survive and reproduce under winter conditions in unheated Mediterranean greenhouses and is a candidate for use in the biological control of pests.  相似文献   

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