Efficacy of pyriproxyfen for control of stored-product psocids (Psocoptera) on concrete surfaces

The insect growth regulator pyriproxyfen was evaluated as a surface treatment for control of three stored-product psocid pests Liposcelis bostrychophila Badonnel, Liposcelis decolor (Pearman), and Liposcelis paeta Pearman (Psocoptera: Liposcelididae). Nymphs were exposed for 35 d on a concrete surface treated with 2.3 mg of active ingredient/m2 pyriproxyfen. Exposure to pyriproxyfen significantly reduced the numbers of both adults and nymphs in comparison with untreated controls. In adults, the greatest reduction (> 90%) was for L. decolor and L. bostrychophila, whereas for L. paeta it was 49%. Few adults of any species were found in the pyriproxyfen treatments. The greatest numbers of nymphs were recorded for L. bostrychophila for both pyriproxyfen treatments and controls. Few adults of any species were found in the pyriproxyfen treatments. The results indicate that pyriproxyfen is effective for control of L. bostrychophila, L. decolor, and L. paeta on concrete, and although complete control was not achieved, the results warrant further long-term study to determine whether pyriproxyfen can completely eliminate psocid populations over time.     

Synergized bifenthrin plus chlorpyrifos-methyl for control of beetles and psocids in sorghum in Australia

The efficacy of bifenthrin (0.5 mg/kg) + piperonyl butoxide (7 mg/kg) + chlorpyrifosmethyl (10 mg/kg) against beetle and psocid pests of sorghum was evaluated in silo-scale trials in southeast Queensland, Australia. The pyrethroid bifenthrin was evaluated as a potential new protectant in combination with the organophosphate chlorpyrifos-methyl, which is already registered for control of several insect pests of stored cereals. Sorghum (approximately 200 metric tons) was treated after both the 1999 and 2000 harvests and sampled at intervals to assess treatment efficacy and residue decline during up to 7 mo of storage. Generally, test strains of the beetles Rhyzopertha dominica (F.), Tribolium castaneum (Herbst), Oryzaephilus surinamensis (L), and Cryptolestes ferrugineus (Stephens) were prevented from producing live progeny for up to 7 mo. The treatment failed against one strain of R. dominica known to be resistant to bioresmethrin and organophosphates. Two malathion-resistant strains of O. surinamensis were marginally controlled with 94-100% fewer adult progeny produced. For psocids, no strains of Liposcelis bostrychophila Badonnel, Liposcelis decolor (Pearman), or Liposcelis paeta Pearman produced live progeny, although the control of a field strain of Liposcelis entomophila (Enderlein) was generally poor. Results show that this treatment should protect sorghum for at least 7 mo against most prevalent strains of grain insect in eastern Australia, although control may be limited in areas in which L. entomophila or pyrethroid-resistant R. dominica are present.     

Efficacy of ozone fumigation against the major grain pests in stored wheat

Field experiments were conducted in steel bins containing 13,600 kg of hard red winter wheat, Triiticum aestivum L. One bin was treated with ozone and the second bin served as a control. Stored grain insects were placed in bins for 1-, 2-, 3-, and 4-d exposure periods in sampling tubes to test ozone concentrations of 0, 25, 50, and 70 parts per million by volume (ppmv). Ozone treatments on eggs and larvae of Plodia interpunctella (Hübner) were not effective, but pupae were more susceptible. Sitophilus oryzae (L.) adults were the most susceptible species with 100% mortality reached after 2 d in all ozone treatments. However, some progeny were produced at all concentrations and exposure periods. Tribolium castaneum (Herbst) adults had 100% mortality only after 4 d at 50 or 70 ppmv. No T. castaneum progeny were produced after 2-4 d at 70 ppmv. For Rhyzopertha dominica (F.), Cryptolestes ferrugineus (Stephens), and Oryzaephilus surinamensis (L.), 100% mortality was never achieved and progeny were produced at all ozone concentrations. Laboratory experiments, testing the effectiveness of ozone in controlling psocids, were conducted in two polyvinyl chloride cylinders each containing 55 kg of hard red winter wheat. Ozone treatment at a concentration of 70 ppmv was highly effective against adult female Liposcelis bostrychophila Badonnel and Liposcelis paeta Pearman after only 1 d of exposure. However, it was not effective against eggs of both species at all exposure periods. Ozonation has potential for the control of some stored grain insect pests on wheat.     

中国常见仓储书虱PCR-RFLP快速识别

应用PCR-RFLP技术,对我国4种常见仓储书虱即嗜虫书虱Liposcelis entomophila(Enderlein)、嗜卷书虱L.bostrychophila(Badonnel)、无色书虱L.decolor(Pearman)和小眼书虱L.paeta(Pearman)开展快速识别方法的研究。采用CTAB法从上述4种书虱体内提取基因组DNA,选用1对引物扩增16S rDNA基因区域,分别用5种限制性内切酶对PCR产物进行酶切。结果表明,PCR扩增片段大小约为500bp,用限制性内切酶DraI酶切得到的片段可将供试书虱区分开。该方法不受4种供试书虱地理种群、虫态(成虫、若虫)和性别的影响,可用于4种书虱的快速识别。     

Sequence analysis of the ribosomal internal transcribed spacers region in psocids (Psocoptera: Liposcelididae) for phylogenetic inference and species discrimination

Psocids (Psocoptera: Liposcelididae: Liposcelis spp.) are major pests of stored grain and commonly occur on a wide range of stored products. Increasingly, the genus of Liposcelis has gained recognition of their importance due to their feeding on stored grains, contaminating food, and agricultural commodities as well as transmitting harmful microorganisms, including fungi and bacteria. Psocids have close morphological similarities and often commix occur at the same ecosystems. Therefore, a first step necessary to further implement population studies is the accurate identification of species, based on molecular methods. In this study, we determined nucleotide sequences of the nuclear rDNA internal transcribed spacer (ITS)1-5.8S-ITS2 region in 100 individuals of six Liposcelis species (including Liposcelis bostrychophila Badonnel, Liposcelis entomophila (Enderlein), Liposcelis decolor (Pearman), Liposcelis tricolor Badonnel, Liposcelis paeta Pearman, and Liposcelis yunnaniensis Li & Li) from 16 locations of China. We evaluated the suitability of this marker for phylogenetic inference study in the Liposcelis species. We also developed a molecular identification method for six Liposcelis species based on ITS2 sequence. Results demonstrate that ITS1-5.8S-ITS2 sequences are a useful tool for the population genetic study and phylogeny estimation of Liposcelis species. The results of this study indicate that the ITS2 sequences can be a reliable tool for species discrimination of the six species of psocids tested here. In addition, the multiplex method described proved reliable when tested across different geographical populations.     

Population growth and development of psocid Lepinotus reticulatus at constant temperatures and relative humidities

We investigated the effects of temperature and relative humidity on population growth and development of the psocid Lepinotus reticulatus Enderlein. Part of this study assessed the effects of marking psocids by using methylene blue, chalk powder, and fluorescent powder to differentiate nymphal stages during development. We found that marking psocids by using methylene blue increased mortality and took twice as long to accomplish compared with marking by using fluorescent powder. Using chalk powder shortened the duration of third and fourth nymphal instars. Marking psocids by using fluorescent powder had no effect on mortality or duration of nymphal instars. Therefore, we recommend using fluorescent powder for marking psocids. L. reticulatus did not survive at 32, 43, and 55% RH, whereas populations increased from 22.5 to 32.5 degrees C at 75% RH. The largest population growth was recorded at 30 and 32.5 degrees C, whereas only 9% of nymphs developed to adults and populations declined at 35 degrees C. We developed temperature-dependent developmental equations for eggs, individual nymphal, combined nymphal, and combined immature stages. These equations showed predicted optimal temperatures for the development of eggs, combined nymphal, and combined immature stages to be 32.3, 34.5, and 34.4 degrees C, respectively; development at these temperatures was completed in 6.3, 16.7, and 23.3 d, respectively. Our study shows that psocids that consume their exuviae develop faster than those that do not, and this effect is more pronounced at lower temperatures. These data give us better understanding of L. reticulatus population dynamics, and they can be used to develop effective management strategies for this psocid.     

Effects of diet on population growth of psocids Lepinotus reticulatus and Liposcelis entomophila

We investigated the suitability of 11 diets as culture media for the psocids Lepinotus reticulatus Enderlein (Psocoptera: Trogiidae) and Liposcelis entomophila (Enderlein) (Psocoptera: Liposcelididae). The culture media comprised six diets made of plain cereals, namely, wheat (Triticum aestivum L.), corn (Zea mays L.), milo Sorghum bicolor (L.), barley (Hordeum vulgare L.), oats (Avena sativa L.), and rice (Oryza sativa L.), and five artificial diets. We found that, with the exception of corn, L. reticulatus population increase was greater on plain cereal diets than on artificial diets, and the greatest population growth was on oats. There was an inverse relationship between L. reticulatus population growth and diet compactness. L. entomophila populations grew fastest on wheat, barley, and a mixture of cracked wheat, rice krispies, and brewer's yeast (97:2:1, wt:wt). The proportion of females was greater in diets that were less suitable for L. entomophila population growth compared with that in the more suitable diets. Diet compactness had a weak effect on L. entomophila population growth. This study also has established the relative level of suitability of damaged wheat, corn, milo, barley, oats, and rice to L. reticulatus and L. entomophila.     

Residual efficacy of four organophosphate insecticides on concrete and galvanized steel surfaces against three liposcelid psocid species (Psocoptera: Liposcelidae) infesting stored products

Four organophosphate insecticides, azamethiphos, fenitrothion, chlorpyrifos-methyl, and pirimiphos-methyl, were tested as surface treatments on concrete (porous surface) and galvanized steel (nonporous surface) panels (0.3 by 0.3 m) against adults of three Liposcelid psocid spp.--Liposcelis bostrychophila Badonnel, Liposcelis entomophila (Enderlein), and Liposcelis paeta Pearman. Residual efficacy of these chemicals was assessed at 30 +/- 1 degrees C, 70 +/- 2% RH, and a photoperiod of 12:12 (L:D) h from 1 d after treatment (0 wk) and thereafter at weeks 1, 2, 4, 6, and 8, and then every 4 wk up to week 40. Mortality was recorded at exposure periods of 6 h and then every 24 h until end-point was achieved. L. bostrychophila was the most susceptible species to the organophosphates tested, followed by L. paeta and L. entomophila. We conclude that for long-term protection, azamethiphos is the preferred organophosphate against L. bostrychophila (up to 36 wk on steel and 24 wk on concrete storage surfaces) and L. paeta infestations only on steel surface (up to 28 wk). None of the four organophosphates tested, however, would provide long-term protection against L. paeta on concrete surface and against L. entomophila infestations on either concrete or steel storage surfaces.     

Efficacy of heat treatment for disinfestation of concrete grain silos

Field experiments were conducted in 2007 and 2008 to evaluate heat treatment for disinfestations of empty concrete elevator silos. A Mobile Heat Treatment Unit was used to introduce heat into silos to attain target conditions of 50 degrees C for at least 6 h. Ventilated plastic containers with a capacity of 100 g of wheat, Triticum aestivum L., held Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) and Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Polyvinyl chloride containers with a capacity of 300 g of wheat held adults of Liposcelis corrodens (Heymons) (Psocoptera: Liposcelididae) and Liposcelis decolor (Pearman), which were contained in 35-mm Petri dishes within the grain. Containers were fastened to a rope suspended from the top of the silo at depths of 0 m (just under the top manhole), 10 m, 20 m, and 30 m (silo floor). When the highest temperature achieved was approximately 50 degrees C for 6 h, parental mortality ofR. dominica and T. castaneum, and both psocid species was 98-100%. Progeny production of R. dominica occurred when there was parental survival, but in general R. dominica seemed less impacted by the heat treatment than T. castaneum. There was 100% mortality of L. corrodens at all depths in the heat treatments but only 92.5% mortality for L. decolor, with most survivors located in the bioassay containers at the top of the silo. Results show wheat kernels may have an insulating effect and heat treatment might be more effective when used in conjunction with sanitation and cleaning procedures.     

电子束辐照对嗜虫书虱存活与繁殖力的影响

采用电子加速器产生电子束辐照处理嗜虫书虱Liposcelis entomophila(Enderlein),分别以0、50、100、200、300、400、500、1000Gy的剂量处理成虫和若虫,观察受辐照后的存活情况和成虫的繁殖情况;以0、25、50、100、200、300、400、500Gy的剂量辐照卵,观察受辐照后卵的孵化情况。结果表明:经50Gy及以上剂量辐照后嗜虫书虱的卵不能孵化,也不能存活;在300Gy及其以上剂量经过不到8周的时间后成虫和若虫都不能存活,且在300、400、500、1000Gy的剂量范围内,嗜虫书虱成虫和若虫受辐照后的剂量越大,存活率降低幅度越大。嗜虫书虱各虫态对电子束辐照的敏感性由高至低依次为卵、若虫、成虫;经300Gy辐照后的成虫和若虫分别在8周和6周内完全死亡,300Gy的剂量可作为电子束有效防治嗜虫书虱的参考剂量。所有50Gy以上剂量下都可明显降低此种害虫的繁殖力,300Gy以上剂量的处理可导致试虫零产卵。     

Cloning and characterization of acetylcholinesterase 1 genes from insecticide-resistant field populations of Liposcelis paeta Pearman (Psocoptera: Liposcelididae)

The psocid, Liposcelis paeta Pearman, is an increasingly important polyphagous pest of stored products worldwide. Intensive use of organophosphorous insecticides for pest control has facilitated resistance development in psocids in China. Three insecticide-resistant field populations of L. paeta were collected from Nanyang city of Henan Province (NY), and Wuzhou (WZ) and Hezhou (HZ) cities of Guangxi Province, China. Previous studies have shown that psocids have different susceptibilities to insecticides. In addition, their AChE susceptibilities to paraoxon-ethyl and demeton-S-methyl also differed from each other. Acetylcholinesterase 1, which is one of the major targets for organophosphate insecticides, has been fully cloned and sequenced from these populations of L. paeta. Comparison of both nucleotide and deduced amino acid sequences revealed nucleotide polymorphisms among L. paeta ace 1 genes from different populations, but none of these polymorphisms correspond to the active sites in AChE 1 from other insects. The results of comparative quantitative real-time PCR indicated that the relative expression level of HZ ace 1 gene was the highest among three populations, which was 1.20 and 1.02-fold higher than those of NY and WZ populations, respectively. This may due to an epigenetic inheritance phenomenon, which allows organisms to respond to a particular environment through changes in gene expression.     

Purification and partial characterization of glutathione S-transferase from insecticide-resistant field populations of Liposcelis paeta Pearman (Psocoptera: Liposcelididae)

Enzymes that possess glutathione S-transferase (GST) activity were purified to homogeneity by glutathione-agarose affinity chromatography from three field populations of Liposcelis paeta (Pearman). These populations were collected from Nanyang city of Henan Province (NY), Wuzhou (WZ) and Hezhou (HZ) cities of Guangxi Province, China, and had different susceptibilities to dichlorvos [LC₅₀s of the NY (281.48 mg/m²), the WZ (285.07 mg/m²), and the HZ (243.52 mg/m²), respectively]. The specific activities of purified enzymes from these three populations increased 32.24-, 99.81-, and 42.52-fold, respectively. Kinetic analyses showed that the catalytic activity of purified GST from NY population towards GSH was much higher than the others, while WZ population reached the highest in V. SDS–polyacrylamide electrophoresis revealed that the purified GST had two subunits with a molecular mass of 23.31 and 20.43 kDa for NY, 53.14 and 20.13 kDa for WZ, and 50.79 and 19.42 kDa for HZ, respectively. The in vitro inhibition studies of GSTs indicated that three kinds of insecticides (chlorpyrifos, carbosulfan, and cypermethrin) and five metallic ions (Zn²⁺, Ba²⁺, Ca²⁺, Hg²⁺, Mn²⁺, and Mg²⁺) all possessed inhibitory effects on purified GST, and ethacrynic acid (EA, a specific inhibitor of GST) expressed inhibitory effects. In the bioassay, three populations of L. paeta had different susceptibilities to different insecticides, even after they were reared on diets consisting of 25% EA. The GST activities of L. paeta from different areas also showed different temperature and pH stabilities. The differences in GST among the three populations may be attributed partially to the differences in control practices for psocids between Henan and Guangxi Provinces. © 2009 Wiley Periodicals, Inc.     

楼宇蠹虫的发生与防治技术

危害楼宇木地板、家具、木装饰及玻璃胶等的蠹虫均为长蠹科 Bostrychidae的双钩异翅长蠹H eterobostrychus aequalis、双棘长蠹 Sinoxylon anale、黑双棘长囊 S.conigerum、双窝短跗长蠹 Dinoderusbifoveolatus、竹长蠹 D.minutus及粉蠹科 (L yctidae)的鳞毛粉蠹 Minthea rugicollis等。害虫防治 ,采用磷化铝 10 g/m3 ,熏蒸 7天 ;或硫酰氟 50～ 6 0 g/m3 ,熏蒸 2 4小时。玻璃胶内除虫 ,选择中午 1～ 2时用 5# 昆虫针从虫孔斜插入将虫刺死 ;少量家具可用注射器从虫孔注入敌敌畏 10 0倍稀释液 1～ 3m L,并用棉花紧塞洞口 ,或用淋灌热水法将虫消灭。     

杀虫剂胁迫下嗜卷书虱和嗜虫书虱能源物质的代谢比较

采用比色法测定嗜卷书虱（Liposcelis bostrychophila）和嗜虫书虱（L．entomophila）体内甘油三酯、多糖和可溶性蛋白的贮存量。结果表明,嗜虫书虱体内3种物质的贮存量均显著高于嗜卷书虱。在毒死蜱和丁硫克百威的胁迫下,嗜虫书虱体内3种物质的变化幅度均大于嗜卷书虱,其中甘油三酯的含量先增高后降低,整体呈现下口抛物线趋势;多糖和可溶性蛋白的消耗率增加。这些说明在毒死蜱和丁硫克百威的作用下,书虱更多地启动了多糖和可溶性蛋白的代谢,降低了对甘油三酯的利用,以应对杀虫剂的胁迫。     

两种书虱微卫星富集文库的构建及比较

利用链霉亲和素与生物素之间的强亲和性原理,将链霉亲和素偶联的磁珠与微卫星探针(AC)12、(TC)12、(ATC)8、(ATG)8、(AAC)8、(ATAC)6及(GATA)6退火结合后,再亲和捕捉含接头和微卫星序列的单链书虱基因组DNA限制性酶切目的片段,经PCR扩增形成双链后进行克隆、建库。结果表明本研究成功构建了嗜卷书虱和嗜虫书虱共13个微卫星富集文库,包括6个嗜卷书虱文库,7个嗜虫书虱文库,其平均阳性克隆率为71.17%。经检测发现共得到两种书虱260个微卫星位点。这两种书虱微卫星富集文库的建立和高多态性微卫星位点的筛选将为嗜卷书虱和嗜虫书虱的种群遗传与进化、基因连锁图谱构建、分子系统发育研究等提供大量分子遗传标记,对其在实仓中的持续控制提供遗传学信息。     

Effect of d-limonene on three stored-product beetles

d-Limonene was investigated for contact and fumigant toxicity, ovicidal effects, oviposition-deterrent, development inhibition, and feeding-deterrent activities against three stored-product beetles (Coleoptera): lesser grain borer, Rhyzopertha dominica (F.); rice weevil, Sitophilus oryzae (L.); and red flour beetle, Tribolium castaneum (Herbst). Contact and fumigant toxicity decreased as larvae aged. Contact toxicity was similar for adults of the three species tested, but R. dominica was most susceptible to fumigant activity. T. castaneum oviposition decreased as concentration of d-limonene increased and d-limonene reduced oviposition up to 92.3% at the concentration of 2.14 mg/cm2. Hatching of d-limonene-treated eggs of T. castaneum was reduced by 94.5% with no subsequent larval and adult survival at 2.14 mg/cm2 concentration. A flour disc bioassay indicated 87.7 to 96.8% feeding-deterrency by d-limonene toward all three insect species tested at the highest concentration of 60.0 mg/g food. These results suggest that d-limonene can be effectively used to suppress populations of stored-product beetles.     

Monitoring stored-product pests in food processing plants with pheromone trapping,contour mapping,and mark-recapture

Distribution and movement patterns of several species of stored-product pests in a food processing plant were investigated. The objectives of this study were to determine the temporal and spatial variation in abundance of stored-product pests using pheromone traps; assess the effectiveness of trap type, location, and number on monitoring insect populations; and to evaluate the nature of pheromone trap capture hot spots by measuring patterns of insect movement. We determined that the distributions of Trogoderma variabile Ballion, Lasioderina serricorne (F.), Tribolium castaneum (Herbst), and Plodia interpunctella (Hübner) within the facility were typically clumped and that foci of high trap captures, based on visual observation of contour maps, varied among species and over time. Trap type and location influenced the number of T. variabile captured: traps on the floor and along walls captured more individuals than hanging traps and traps next to support pillars. T. variabile was the predominant insect pest at this facility and from mark-recapture studies, we found that individual beetles moved across multiple floors in the facility and from 7 to 216 m though the warehouse.     

Reproductive performance of Tribolium castaneum (Coleoptera: Tenebrionidae) exposed to the minimum heat treatment temperature as pupae and adults

Managing stored-product insect pests by heating the ambient air of a food-processing facility to high temperatures (50-60 degrees C), also referred to as heat treatment, is an effective technology that has been used since the early 1900s. The minimum temperature during heat treatment for effective disinfestation is 50 degrees C. The effect of sublethal exposures to 50 degrees C on the reproductive performance of stored-product insects associated with food-processing facilities is unknown. The red flour beetle, Tribolium castaneum (Herbst), is a pest commonly found in food-processing facilities worldwide. The adverse effects on fecundity, egg-to-adult survival, and progeny production of T. castaneum exposed as 1-d-old pupae and 2-wk-old adults to 50 degrees C for 60 and 39 min, respectively, were determined in the laboratory. Pupae and adults exposed for the same time periods at 28 degrees C served as the control treatment. Four possible reciprocal crosses were carried out among adults from the heat-treated (50 degrees C) and control (28 degrees C) treatments. The number of eggs produced during the first 2 wk of adult life, survival of these eggs to adulthood, and adult progeny production after 2 and 8 wk of oviposition in treatments representing all four reciprocal crosses were determined. Fecundity, egg-to-adult survival, and adult progeny production decreased by 17-63, 52-63, and 66-78%, respectively, when males, females, and both males and females were exposed to 50 degrees C. These effects were relatively more pronounced in treatments in which pupae were exposed to the high temperature compared to adults, and in exposed females than in males. The impaired reproductive performance in T. castaneum pupae and adults surviving sublethal exposures to the minimum heat treatment temperature is valuable for understanding population rebound following a heat treatment intervention.     

Fumigant toxicity of Eucalyptus intertexta, Eucalyptus sargentii and Eucalyptus camaldulensis against stored-product beetles

Abstract:  Three essential oils extracted from the species of the family Myrtaceae found in Kashan (centre regions of Iran) were shown to have potent fumigant toxicity against three major stored-product insects: Callosobruchus maculatus (Fab.), Sitophilus oryzae (L.) and Tribolium castaneum (Herbst). These were the essential oils from Eucalyptus intertexta R.T. Baker, Eucalyptus sargentii Maiden and Eucalyptus camaldulensis Dehnh. The mortality of 1- to 7-day-old adults of the insect pests increased with concentration from 37 to 926  μ l/l air and with exposure time from 3 to 24 h. The LC₅₀ values to the selected essential oils were between 2.55 and 3.97  μ l/l air for C. maculatus , 6.93 and 12.91  μ l/l for S. oryzae and 11.59 and 33.50  μ l/l air for T. castaneum . Fumigant effects of these essential oils were considered to warrant further research into their potential for commercial use.