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1.
The effects of hexaflumuron consumption on the mortality of workers of the Western subterranean termite, Reticulitermes hesperus Banks, were observed following various exposures to a substrate treated with 14C-labeled hexaflumuron at 5 g kg(-1). Uptake of hexaflumuron by workers was rapid, peaking at approximately 280 ng hexaflumuron per termite 12 days after exposure. The onset of mortality began at day 8, with cumulative mortality reaching approximately 96% by day 45. Excretion of hexaflumuron from worker termites was rapid following various exposure periods, half-lives ranging from 2.1 to 4.7 days. Trophallaxis among worker termites was efficient, hexaflumuron levels in recipient termites approaching two-thirds of levels present in donor termites feeding continuously on hexaflumuron-treated filter paper. The effect of donor-to-recipient group ratios was negligible on the amounts of hexaflumuron transferred from donors to recipients. In laboratory tests, hexaflumuron diffused from a feeding source within 7 days. The presence of additional food sources appeared to inhibit movement of hexaflumuron. Movement of hexaflumuron by cannibalism and coprophagy occurred, but was significant only when termites were starved. Hexaflumuron also appeared to adversely affect egg development by preventing hatch. Hexaflumuron was readily transferred through termite groups, effectively suppressing laboratory populations of R hesperus. Variable efficacy in field situations employing baiting with hexaflumuron in southern California may be a consequence of sporadic feeding at bait stations, the rapid clearance of hexaflumuron from individual termites, and the difficulties in bait presentation (low foraging activity, poor bait station foraging fidelity) inherent in the foraging characteristics of the Western subterranean termite.  相似文献   

2.
ABSTRACT

Eastern subterranean termite, Reticulitermes flavipes (Kollar), workers were exposed for 7 days to one of five chitin synthesis inhibitors (CSIs): diflubenzuron, hexaflumuron, lufenuron, noviflumuron, and novaluron in commercially available bait matrices. Following a 7 day exposure period, termite donors (D) were combined with naïve (not exposed) termite recipients (R) at five D:R ratios (20:0, 15:5, 10:10, 5:15, and 1:19) and mortality determined daily for up to 68 days. Lethal time and percent mortality data suggest efficient transfer at all D:R ratios for all CSIs tested, except diflubenzuron at 1:19. Despite the data indicating transfer of lufenuron in bioassay, this material may not be effective in field use based on behavioral observations that include limited movement by donors. We also report frequency of visible evidence of CSI intoxication, including the previously described “jackknife” pose and an additional physical deformity, we term “curled-body”. The implications these data and observations have for laboratory evaluation and field population management using commercial termite baiting systems is discussed.  相似文献   

3.
Termite baiting is now one of the two main management tools in developed countries after 20 years of commercial release. It has two main goals: to use small amounts of active ingredient and ‘colony elimination’, i.e. death of all individuals in the colony. We consider how well baiting has been evaluated from 100 studies in the scientific literature. Studies have included 15 active ingredients, 23 termite species and 16 countries, yet most studies have focused on the chitin synthesis inhibitor hexaflumuron, Reticulitermes and the United States. Baiting has mostly met its goals: typically about 0.5 g of active ingredient was used, and colony elimination achieved, albeit with rates varying from 0 to 100%, and sometimes supplemented with liquid insecticide. Baiting was most successful using chitin synthesis inhibitors against Reticulitermes and Coptotermes (Rhinotermitidae), in temperate locations, although colony elimination was usually inferred indirectly – mostly by termite absence from baits – and was often slow, from 25 to 450 days. Baiting has been less tested and less successful against higher termites in tropical locations, where they are most diverse and abundant. Future research may have to consider greater termite species diversity and other active ingredients to reduce control times in order to fulfil the potential of baiting. © 2014 Society of Chemical Industry  相似文献   

4.
The acute and chronic toxicities of three benzoylphenyl ureas, diflubenzuron, hexaflumuron and teflubenzuron were assessed under laboratory conditions against two-day-old second (II) instar Desert Locust, Schistocerca gregaria (ForskÅl) nymphs. Following exposure by ingestion of a single precise dose applied to short pieces of spring barley, nymphs were monitored for two moults until the fourth (IV) instar. Analysis of acute response data gave three significantly different LD50 statistics (P < 0·05), 68·0, 26·6 and 0·71 μg per nymph respectively for diflubenzuron, hexaflumuron and teflubenzuron. The probit regression slopes also differed significantly, indicating distinct tolerance distributions for the three compounds, the narrowest response being to diflubenzuron and the widest range of response being to teflubenzuron. The timing of death was found to vary between the compounds; most nymphs died during the first moult following treatment with either hexaflumuron or teflubenzuron. However, the majority of nymphs that died after exposure to diflubenzuron did so after completing the first moult after treatment, but before the second. The mean development times of nymphs during the II and especially third (III) instars were significantly longer (P < 0·05) than those of the controls following exposure to diflubenzuron and hexaflumuron. Teflubenzuron had no significant effect (P < 0·05) on the duration of the II instar. The potential of the three compounds to control S. gregaria populations in the field is discussed with particular reference to the timing and nature of acute and chronic responses.  相似文献   

5.
Coptotermes gestroi is a subterranean termite from Asia, introduced accidentally to Brazil, where it is responsible for substantial damage in urban areas. The foraging range of this species frequently overlap with that of Heterotermes tenuis, a native termite also considered to be a severe pest. The greatest challenge in controlling these termites is to develop baits suitable for both species. A critical issue is to select compounds that act as common phagostimulants. We examined whether the feeding preferences of C. gestroi for some nutrients were similar to those already reported for H. tenuis. A double choice design was used. Consumption was evaluated by change in the dry mass of paper discs after termite feeding. C. gestroi fed preferentially on discs treated with a solution of sucrose + yeast. However, insects did not choose urea at 0.015 g/ml, one of the preferred solutions for H. tenuis. These results indicate that the two termites have different feeding preferences, and we suggest future use of sucrose + yeast in baits for management of C. gestroi.  相似文献   

6.

BACKGROUND

RNA interference (RNAi) technology is an environmentally friendly strategy for controlling insect pests. Lipopolysaccharide-binding protein (LBP) recognizes lipopolysaccharides, which are a major outer membrane constituent of Gram-negative bacteria. We propose that the LBP gene is a potential target for termite management; however, to date, no studies have examined this gene in termites.

RESULTS

In this study, we cloned the LBP gene of Coptotermes formosanus (Cf) and found that the mortality rate of termite workers significantly increased, and the repellence of these workers to Gram-negative bacteria was suppressed after knockdown of CfLBP using double-stranded RNA (dsRNA) injection and feeding. Moreover, the mortality rate of termite workers fed with CfLBP dsRNA and three Gram-negative bacteria (provided separately) was over 50%, which was much higher than that of termites treated with either CfLBP dsRNA or Gram-negative bacteria. Finally, we found that CfLBP impacts the IMD pathway to regulate the immune response of C. formosanus to Gram-negative bacteria.

CONCLUSION

CfLBP plays a important role in the immune defense of termites against Gram-negative bacteria. It can be used as an immunosuppressant for RNAi-based termite management and is an ideal target for termite control based on the combined use of RNAi and pathogenic bacteria. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

7.
BACKGROUND: Non-repellent insecticides, including fipronil and indoxacarb, are becoming increasingly important for soil treatments to manage the eastern subterranean termite, Reticulitermes flavipes (Kollar). The effects of these insecticides on termite walking and tunneling behavior could significantly reduce their efficacy against colonies. RESULTS: Groups of R. flavipes were exposed to several concentrations of commercial formulations of fipronil and indoxacarb, and the ability of treated termites to tunnel in soil and walk was assessed. Increasing insecticide concentration resulted in a reduction in the ability of R. flavipes to walk, tunnel and form tunnel branches; the importance of these effects on the use of non-repellent insecticides is discussed. CONCLUSION: Exposure of R. flavipes to 1, 10 or 50 mg L−1 of fipronil or 50, 100 or 200 mg L−1 of indoxacarb significantly reduced termite walking and tunneling and the number of tunnel branches. Distance walked (ca 73 mm) by untreated control termites did not change over time for at least 16 h after treatment; control termites formed ca 150 cm of tunnels with ca 40 branches. Copyright © 2012 Society of Chemical Industry  相似文献   

8.
The chitin synthesis inhibitors diflubenzuron and teflubenzuron have recently become ineffective for the control of Spodoptera exigua in floricultural crops. An extended laboratory test with second-instar larvae of S. exigua on Vicia faba plants was carried out to determine the influence of synergists on the biological activity of three benzoylphenyl ureas (BPUs). The co-application of piperonyl butoxide, an oxidase inhibitor, did not increase the activity of diflubenzuron, teflubenzuron or hexaflumuron. The best results were obtained with diethyl maleate, for suppressing glutathione S-transferase activity, and with dimethoate, as a hydrolase inhibitor. A joint application of diflubenzuron (at a concentration which resulted in 43% survival) with diethyl maleate or dimethoate gave only 6.2 and 8.9% surviving larvae, respectively. In addition, development to fourth-instar larvae was inhibited. The more stable teflubenzuron was synergized by both compounds to a much lesser extent than diflubenzuron. None of the synergists had a significant effect on the activity of hexaflumuron, which was the most potent insecticide of the three BPUs tested against S. exigua.  相似文献   

9.
为探讨昆虫生长调节剂氟铃脲和虱螨脲对黑腹果蝇Drosophila melanogaster和斑翅果蝇D.suzukii的毒性机制,采用室内生测法测定氟铃脲、虱螨脲对2种果蝇2龄幼虫的毒力,以及其在亚致死浓度LC_(10)、LC_(20)下对2种果蝇体内几丁质酶活性的影响。结果显示,经不同浓度的氟铃脲和虱螨脲处理后,随着时间的延长和浓度的增加,2种果蝇的死亡率均明显增加,氟铃脲处理可使2种果蝇的死亡率最高达到83.33%,明显高于虱螨脲处理后黑腹果蝇(65.00%)和斑翅果蝇(66.66%)的死亡率。亚致死浓度LC_(10)和LC_(20)的虱螨脲处理果蝇2龄幼虫24 h后,黑腹果蝇2龄幼虫体内的几丁质酶活性呈下降趋势,而斑翅果蝇2龄幼虫体内的几丁质酶活性则呈上升趋势。另外,亚致死浓度的氟铃脲可明显抑制黑腹果蝇体内几丁质酶的活性。表明昆虫生长调节剂氟铃脲和虱螨脲对果蝇有较强的毒力,氟铃脲的毒力高于虱螨脲,且果蝇体内几丁质酶的活性与氟铃脲和虱螨脲密切相关。  相似文献   

10.
Field experiments have revealed that some species of spiders are more sensitive to insecticides than others. Among many factors influencing their susceptibility, foraging mode seems to play an important role. Aspects of foraging mode that appear to be relevant are whether the spider is diurnal or nocturnal, a hunter or a web-maker. Six spider species, Araniella opisthographa, Clubiona neglecta, Dictyna uncinata, Pardosa agrestis, Philodromus cespitum and Theridion impressum were used in the study. P agrestis and P cespitum are diurnal hunters that may come into direct contact with insecticide. C neglecta is nocturnal and so is exposed to residues only. The remaining three species are web-makers building webs that vary in the extent to which they can protect the spider from direct spray. The effect of sprays was tested under laboratory conditions (Potter tower) with three commercial insecticides, an insect growth regulator (hexaflumuron), a selective organophosphorus (phosalone) and a non-selective pyrethroid insecticide (permethrin) using a four-day exposure period. Data were analysed using bootstrap method and randomization tests. The results obtained showed that hunting spiders were more susceptible to the insecticides tested than web-makers (in their webs). Diurnal hunting spiders (Philodromus and Pardosa) were severely affected only by permethrin. A high mortality was observed for the nocturnal hunter, Clubiona, after application of phosalone and permethrin. This species appears to be very sensitive to residues of both insecticides. Comparing the effect on web-making spiders, with and without webs, it was observed that the sparse orb-web of Araniella did not protect its owner at all, but the dense cribellate and frame-webs of Dictyna and Theridion, respectively, reduced the mortality caused by permethrin significantly in comparison with specimens without webs. Of other factors studied, posture (normal and upside-down position) did not influence the susceptibility. Mortality increased slightly with body size after permethrin application. © 1999 Society of Chemical Industry  相似文献   

11.
In Greece, the damage caused to trees and shrubs by termites has been increasing over the last 10 years. Local government and citizens have become interested in this pest due to frequent accidents caused by trees falling onto pavements, cars and people. This led the authors to carry out a survey to list the termite‐infested plant species, mainly on urban streets and in fields all over the country. The only termite species found was Kalotermes flavicollis (family Kalotermitidae). The present study highlights the current situation in Greece and provides a list of the fruit and ornamental trees and shrubs found to be infested by K. flavicollis, during the survey.  相似文献   

12.
The vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), is one of the main pests in vineyards. At present biological control of the pest is based on the release of hymenopterous parasitoids and coccinellid predators. The effectiveness of an entomopathogenic fungus, Isaria farinosa, as an alternative biological control agent on vine mealybug P. ficus was investigated by using different inoculum densities and different relative humidity levels. The fungus caused more than 80% mortality at 95% relative humidity and at 1 × 108 conidia ml?1 inoculum density. The mortality effects of the fungus decreased in lower humidity levels and lower spore densities. The inhibitory effects of common fungicides, used in vineyards, on I. farinosa were also investigated. Sulphur, copper oxychloride, fosetyl-Al and chlorothalonil did not decrease the effectiveness of I. farinosa as a pathogen of vine mealybug. With the application of tebuconazole, penconazole and mancozeb, the most inhibitory fungicides on the entomopathogen, the mortality rates of mealybugs, inoculated with I. farinosa, decreased from 86% to 42%, 34% and 45%, respectively, in the adult females; from 94% to 51%, 45% and 45%, respectively, in the first nymphal stages; and from 86% to 56%, 49% and 63%, respectively, in ovisacs.  相似文献   

13.
In teflubenzuron and teflubenzuron/chlorfluazuron laboratory-selected sub-populations of a Cameron Highlands (1988) strain of Plutella xylostella L., resistance to teflubenzuron reached much greater levels than chlorfluazuron but declined at a correspondingly greater rate to give similar resistance levels after 10–13 generations. There was little evidence of cross-resistance to flufenoxuron and none to hexaflumuron in these populations. Reselection of a Cameron Highlands population with teflubenzuron after 22 generations resulted in a significant (P < 0.05) increase in resistance after three generations. In two more recently collected strains from lowland Malaysia, Sawi (1991) and Serdang (1992) high levels of resistance to teflubenzuron were found, but only the former showed any apparent resistance to chlorfluazuron. There was also evidence of resistance to diflubenzuron in the Sawi strain (Serdang not examined). Resistance to teflubenzuron appeared to be unstable in unselected sub-populations of both lowland strains. Selection of the Sawi strain with teflubenzuron did not effect cross-resistance to chlorfluazuron, while attempted selection with chlorfluazuron had no effect on resistance to either compound. Selection of the Sawi strain with diflubenzuron increased resistance to teflubenzuron but had no effect on resistance to chlorfluazuron. In contrast to the Sawi strain, selection of the Serdang strain with teflubenzuron resulted in cross-resistance to chlorfluazuron. Synergist experiments with piperonyl butoxide (PB) and S,S,S-tributyl phosphorotrithioate (DEF) suggested that resistance to teflubenzuron in the lowland strains may involve both microsomal monooxygenases and esterases. The ovicidal activity of teflubenzuron, chlorfluazuron, hexaflumuron and flufenoxuron was consistently less than their activity against second-instar larvae, hexaflumuron, followed by teflubenzuron, showing the greatest relative ovicidal activity. Hexaflumuron was markedly more active than teflubenzuron against eggs from acylurea-selected Cameron Highlands populations and there was some evidence that resistance to teflubenzuron may be expressed at a lower level in eggs than in larvae in one such strain.  相似文献   

14.

Within the last decade, there has been an increase in attacks on sugarcane in Chad by the fungus-growing termite Ancistrotermes guineensis Silvestri, with yield losses reaching 25%. Management of termite populations through control of the symbiotic fungus, Termitomyces medius Heim, was investigated using systemic fungicides. Following pre-screening, four products (Bavistin, Calixin, Erpacide and Sumi 8) were selected for field experiments, which evaluated a range of parameters. The mortality rate of the fungal comb reached 30% with a corresponding 20% increase in sugarcane yield.  相似文献   

15.
Soil insecticide barriers have been the single most important tool for subterranean termite control in the last half century, but limitations with current soil termiticides have provided the impetus to look for alternatives in recent years. One such alternative is the monitoring--baiting programme. Monitoring stations to detect termites are placed in the soil surrounding a structure. Once termites are found in the stations, monitoring devices are replaced with slow-acting baits such as the chitin synthesis inhibitor, hexaflumuron. Field studies have indicated that termite colonies were eliminated using less than 1 g of hexaflumuron. After the elimination, monitoring resumes and bait is applied if new termite activity is detected. The monitoring and baiting procedure form the basis for an ongoing programme to protect structures from subterranean termite infestation. Although the cost--benefit model developed for agricultural integrated pest management cannot be applied directly to termite control, the underlying concept for using a cost-effective approach remains the same. The benefits of the monitoring--baiting programme over conventional soil treatment are a reduction in pesticide applied per unit and the elimination of termite populations near structures, resulting in the reduction of liability and damage potential. It is expected that the data management system when used in conjunction with the monitoring--baiting programme will provide a database to improve its cost-effectiveness continuously.  相似文献   

16.
The Cryphonectriaceae includes many important tree pathogens, especially of the Myrtales. Disease surveys on Myrtales in South China revealed a stem canker disease on native Rhodomyrtus tomentosa (Myrtaceae, Myrtales) trees in the proximity of Eucalyptus plantations in GuangXi Province and in a natural forestry area in the Hong Kong Region. Fruiting structures with typical characteristics of the Cryphonectriaceae were observed on the canker surfaces. The fungus was identified based on DNA sequence comparisons and morphological features, and its pathogenicity was tested on R. tomentosa under field conditions. DNA sequence comparisons for the partial large subunit, partial internal transcribed spacer nuclear ribosomal DNA, and two regions of the β‐tubulin gene showed that the fungus represents a previously undescribed genus and species in the Cryphonectriaceae. Based on morphology, the fungus is most similar to species in the genus Chrysoporthe, but can be distinguished from this and the other genera of Cryphonectriaceae. The fungus provided with the name Corticimorbus sinomyrti gen. et sp. nov., is described. Field inoculations showed that it is highly pathogenic to R. tomentosa trees, with the ability to kill inoculated branches within 4 weeks. Pathogenicity tests also showed that C. sinomyrti is pathogenic to a tested Eucalyptus clone. Pathogenicity on both native R. tomentosa and non‐native Eucalyptus suggests that this fungus should be monitored carefully to limit its possible spread to commercially grown Eucalyptus in South China.  相似文献   

17.
The aqueous solubilities and octanol–water partition coefficients (KOW) of the benzoylphenylurea (BPU) insecticides teflubenzuron, chlorfluazuron, flufenoxuron and hexaflumuron were determined in comparison with the more extensively studied diflubenzuron. Both teflubenzuron and hexaflumuron were substantially less water‐soluble (9.4 (± 0.3) µg litre−1 and 16.2 (± 0.5) µg litre−1 in water, respectively) than the value previously reported for diflubenzuron (89 (± 4) µg litre−1 in water). Log KOW values for diflubenzuron, teflubenzuron, hexaflumuron, flufenoxuron and chlorfluazuron were 3.8, 5.4, 5.4, 6.2 and 6.6, respectively, as determined using reverse‐phase HPLC. Photodegradation of hexaflumuron, teflubenzuron and diflubenzuron in water indicated hexaflumuron to be the most rapidly degraded of the three compounds at pH 7.0 (t1/2 = 8.6 (± 0.4) h) and pH 9.0 (t1/2 = 5 (± 1) h); diflubenzuron was the slowest of the three pesticides to degrade in pH 7.0 (17 (± 4) h) and pH 9.0 (8 (± 2) h) buffered water. In a solar simulator using river water buffered to pH 9.0, teflubenzuron, hexaflumuron and diflubenzuron half‐lives were 20 (± 4), 15 (± 2) and 12 (± 1) h, respectively; dark controls showed no loss of parent BPU over similar time periods. © 2000 Society of Chemical Industry  相似文献   

18.
氟铃脲对韭菜迟眼蕈蚊不同虫态的致毒特点及毒力   总被引：1，自引：1，他引：0  
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。  相似文献   

19.

BACKGROUND

The Asian needle ant, Brachyponera chinensis, is an invasive ant currently spreading in urban and natural habitats throughout the eastern United States. Recent studies have documented the negative impact of B. chinensis on native ecosystems and human health, yet effective control strategies are lacking. Control difficulties are, in part, due to the unique biology of B. chinensis, which is a predatory ant and a termite specialist. Given that subterranean termites are an important nutritional resource for B. chinensis, the current study evaluated the potential of termite cuticular extract to improve the target-specificity and efficacy of commercial bait used for B. chinensis control.

RESULTS

The efficacy of bait augmented with termite cuticular extracts was evaluated in laboratory and field trials. In laboratory assays, B. chinensis colonies were offered granular bait treated with termite cuticular extract. Results demonstrated that the acceptance of commercial bait is significantly increased by the addition of termite cuticular extract or synthetic (Z)-9-pentacosene, a major component of termite cuticular extract. Foraging activity of Asian needle ants was significantly greater on baits augmented with termite cuticular extract or (Z)-9-pentacosene relative to standard bait. Furthermore, bait augmented with termite cuticular extract worked substantially faster relative to standard bait. To evaluate population effects, field studies were conducted in forested areas invaded by B. chinensis. Bait treated with termite cuticular extract scattered on the forest floor provided rapid control of B. chinensis and ant densities throughout the treated plots declined by 98% within 14 days.

CONCLUSION

The incorporation of termite cuticular extracts and individual cuticular hydrocarbons such as (Z)-9-pentacosene into traditional baits used for B. chinensis control may offer a novel tool to manage this increasingly problematic invasive ant. © 2023 The Author. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.  相似文献   

20.
Abstract

Damage to tea plants due to a root infection was observed on an estate in southern Malawi. Initial symptoms on plants in the infected areas varied from yellowing of leaves on individual branches followed by dieback to a more frequent rapid wilting of the leaves of entire bushes. The bark surface of superficial roots and collar region was covered by a loose mat of coarse fungal mycelium varying from white or cream to pale or bright yellow in colour. Infection was well developed on a large proportion of roots of affected plants before foliage symptoms appeared. The causal agent was identified as Pseudophaeolus baudonii (Pat.) Ryv.; this is the first record of the fungus in Malawi and the first record of its occurrence anywhere on tea. The fungus is widely distributed in Africa on a range of hosts. It is not yet known how the fungus is transmitted and definite control methods cannot be recommended although it is suggested that entire tea crops in diseased areas be removed and the land used for tobacco production. It is unlikely thatP. baudonii will have serious economic effects on tea crops in the area.  相似文献   

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