Survivorship, tunneling and feeding behaviors of Coptotermes formosanus (Isoptera: Rhinotermitidae) in response to 2'-acetonaphthone-treated sand

In laboratory tests, 2'-acetonaphthone was incorporated into sand at different concentrations (4.16-200 mg kg(-1)) and evaluated for survivorship, feeding and tunneling effects on the Formosan subterranean termite, Coptotermes formosanus Shiraki. 2'-Acetonaphthone at 8.33 mg kg(-1) sand significantly reduced survivorship (89-94%), tunnel area (68-91%) and food consumption (84-100%) compared with the control. Most of the dead workers were found at the release point and a few had traveled to the surface of the treated sand. Malformed workers (< or =27%) with an unexpected symptom of molting failure were observed, particularly at the lowest concentration tested (4.16 mg kg(-1)). In choice assays, threshold concentration for significant reduction in survivorship, tunnel construction in treated sand and food consumption in the treated-sand side was 8.33mg kg(-1) with termites collected from New Orleans, LA and 35.0 mg kg(-1) for those from Lake Charles, LA. Termites actively fed and tunneled in the untreated sand, whereas 2'-acetonaphthone at 140mg kg(-1) completely inhibited consumption of food placed on the treated sand.     

Structural requirements for repellency: norsesquiterpenes and sesquiterpenoid derivatives of nootkatone against the Formosan subterranean termite (Isoptera: Rhinotermitidae)

BACKGROUND: Research has shown that the family of grapefruit flavors called nootkatones have significant repellant and toxic effects to Formosan subterranean termites (Coptotermes formosanus Shiraki). RESULTS: Nineteen synthetic nootkatone derivatives, along with three commercially available nootkatone derivatives, were tested for repellent activity against C. formosanus by a choice assay in a petri dish with a two‐step triage procedure. Based on the repellency threshold value, the relationships between structure and activity are discussed. CONCLUSION: Four derivatives of nootkatone have very high repellency and toxicity to C. formosanus, 9 times the potency of the primary compound nootkatone. Four other compounds have between 2 and 3 times the repellency of nootkatones, and three compounds are equal in their repellency to nootkatone. Copyright © 2010 Society of Chemical Industry     

Comparative effects of vetiver oil,nootkatone and disodium octaborate tetrahydrate on Coptotermes formosanus and its symbiotic fauna

The potential of vetiver oil and nootkatone as wood treatments against Coptotermes formosanus Shiraki was examined by assessing the effects on termite tunneling, feeding activity and survival, and the consequences on the symbiont protozoa responsible for wood digestion. Comparisons were made with non-treated wood (control), wood treated with the borate compound Tim-Bor (a commonly used lumber preservative) and absence of a food source (starved termites), using choice and no-choice tests. All wood slices were prepared at the same time using a 10 g liter(-1) solution of each substance and were tested in four different sessions over one year to investigate longevity of the effects. Termites had to tunnel through sand to exploit the food sources, consisting of two wood slices, placed on opposite sides of the experimental enclosure. No-choice tests showed that in the presence of vetiver oil or nootkatone, tunneling activity was always the lowest; wood consumption, termite survival and flagellate numbers and species distribution were significantly different from the control and similar to the results obtained for starved termites and with Tim-Bor-treated wood. Nootkatone negatively affected termites for 12 months and was longer lasting than vetiver oil. In choice tests, when vetiver oil or nootkatone were present, termites exhibited a significant preference for non-treated wood. Our results confirmed both the toxicity and absence of repellency of Tim-Bor. Vetiver oil and especially nootkatone affected Formosan subterranean termites and their protozoa, acting as arrestants, repellents and feeding deterrents, and represent a promising natural alternative for the control of this invasive pest.     

木腐菌对台湾乳白蚁取食偏好性的影响

本文测定了经红芝、紫芝、茯苓、黄孢原毛平革菌和密褐褶孔菌5种木腐菌腐蚀的马尾松木屑对台湾乳白蚁行为和取食反应的影响。在双重选择性试验中,与未经木腐菌腐蚀的马尾松木屑相比,台湾乳白蚁嗜好聚集和取食木腐菌腐蚀过的马尾松木屑。在多重选择性试验中,结果显示台湾乳白蚁偏好取食经茯苓、红芝或密褐褶孔菌腐蚀过的马尾松木屑。     

Response of the subterranean termite Coptotermes formosanus (Isoptera: Rhinotermitidae) to soil treated with microencapsulated fenobucarb

BACKGROUND: Treating soil with insecticides is thought to be an effective method for termite control. Speed of action and repellency of insecticides are important factors for discussing their barrier effects as soil-treatment termiticides. The chemical barrier effect of microencapsulated fenobucarb against Coptotermes formosanus Shiraki was examined in the laboratory.RESULTS: Fenobucarb had a significantly faster lethal effect when applied to the mouthparts than to the tergites of worker termites. Soil that had been treated with > or = 50 mg kg(-1) of microencapsulated fenobucarb had a barrier effect within a single day, and could stop or retard the penetration of termites for 7 days. Microencapsulated fenobucarb did not act as a repellent, as indicated by a gradual increase in mortality at > or = 50 mg kg(-1) with slight penetration into the treated soil during the 7 day test.CONCLUSION: The results suggest that microencapsulated fenobucarb is a fast-acting termiticide, with a good barrier effect as a soil treatment, that also acts as a reduced repellent, retarding entry of termites into treated soil.     

Identification of two haplotypes of cytochrome oxidase subunit II (COII) gene of the Formosan subterranean termite,Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae), in southern Mississippi

BACKGROUND: Coptotermes formosanus Shiraki was accidentally introduced into the United States from Asia. The introduction of the pest has brought significant economic consequences. During the past decade, Mississippi has become a significantly infested state, partly due to the proximity to coastal port cities such as New Orleans. This study was initiated to investigate the origin and infestation route of C. formosanus in southern Mississippi. RESULTS: Twenty‐eight colonies (21 colonies from Mississippi, six from Louisiana, one from China) were collected. Sequencing and analysis of 112 sequences revealed 15 haplotypes of cytochrome oxidase subunit II (COII) gene in the world. Two haplotypes of COII were identified in Mississippi. In addition, specific primers were designed and tested differentially to amplify characteristic fragments for verifying and surveying different genotypes of C. formosanus in the future. CONCLUSION: Of the two haplotypes identified in Mississippi, the GA group was identical to those reported previously in Georgia, Louisiana, Alabama and other infested states. The second haplotype, the AT group, was identified for the first time in southeastern United States. Sequence identity of the AT‐group C. formosanus with those reported mainly in southeastern Asian countries provided evidence of at least two introductions of C. formosanus into the United States. Copyright © 2010 Society of Chemical Industry     

Effects of non-repellent termiticides on the tunneling and walking ability of the eastern subterranean termite (Isoptera: Rhinotermitidae)

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     

Group effects on insecticide toxicity in workers of the Formosan subterranean termite,Coptotermes formosanus Shiraki

Coptotermes formosanus workers were treated topically with insecticide and subsequently held individually or in groups to examine possible effects on insecticide toxicity. Chlorpyrifos, cypermethrin and chlordane toxicities were 1.4-, 1.5-, and 1.3-fold greater, respectively, among workers held in groups compared with those held individually after insecticide treatment. Experiments were conducted to examine how enhanced toxicity occurred among termites held in groups after topical insecticide treatment. When workers were treated topically with chlordane and immediately placed with untreated workers, significantly greater numbers of untreated workers were killed compared with controls at all ratios examined (insecticide-treated:untreated). These data indicated that workers treated topically with insecticide were capable of somehow transferring a lethal dose of insecticide to untreated workers confined in the vial. Chlordane was recovered from untreated workers which had been confined with chlordane-treated workers; significantly higher quantities of chlordane were recovered from dead workers exposed to chlordane-treated workers compared with surviving workers exposed to chlordane-treated workers. Possible mechanisms of insecticide transfer from insecticide-treated to untreated termites are discussed.     

二氧化碳对台湾乳白蚁的引诱作用

台湾乳白蚁Coptotermes formosanus Shiraki是华南地区农林树木、木质构件的重要钻蛀性害虫。本文测定分析了二氧化碳(CO2)对台湾乳白蚁的引诱效果。分析结果显示,二氧化碳对台湾乳白蚁具有显著的引诱活性,其中浓度1.5%的二氧化碳对台湾乳白蚁的引诱作用较强,但引诱作用随着二氧化碳浓度的升高而减小。为了便于应用,进一步利用发酵产生的二氧化碳分析,结果显示二氧化碳较常规引诱物松木具有更显著的引诱效果。本研究将为台湾乳白蚁新型引诱剂开发提供参考,有助于提高台湾乳白蚁饵剂的防治效果。     

Antifeedant and toxicity effects of thiophenes from four Echinops species against the Formosan subterranean termite, Coptotermes formosanus

Over 220 crude extracts from repositories generated from plants native to Greece and Kazakhstan were evaluated for termiticidal activity against the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). Emerging from this screening effort were bioactive extracts from two Greek species (Echinops ritro L. and Echinops spinosissimus Turra subsp. spinosissimus) and extracts from two Kazakhstan species (Echinops albicaulis Kar. & Kir. and Echinops transiliensis Golosh.). Fractionation and isolation of constituents from the most active extracts from each of the four species has been completed, resulting in the isolation of eight thiophenes possessing varying degrees of termiticidal activity. 2,2':5',2"-Terthiophene and 5'-(3-buten-1-ynyl)-2,2'-bithiophene demonstrated 100% mortality against C. formosanus within 9 days at 1 and 2 wt% concentrations respectively. In addition, all but two of the eight compounds tested were significantly different from the solvent controls in the filter paper consumption bioassay.     

Distribution of a juvenogen and its metabolites in a laboratory system during juvenogen-induced caste differentiation in a termite, Reticulitermes santonensis (Isoptera: Rhinotermitidae)

BACKGROUND: Juvenoids and juvenogens have been for many years considered promising candidates for control of pest insect species including termites. Their use as termite pest management agents requires the generation of knowledge concerning their degradation and distribution in time and space. Groups of 40 Reticulitermes santonensis de Feytaud workers were provided with wood impregnated with a juvenogen, ethyl cis-N-{2-[4-(2-butyryloxycyclohexylmethyl)phenoxy]ethyl}carbamate, labelled with tritium in the benzene ring (305 GBq mmol(-1)). After 14 days the radioactivity was determined in all elements of the experimental system. RESULTS: The majority of the input activity was detected in the wood, only about 1% in the bodies of surviving termites and 1% in the substrate. A considerable part of the input activity was probably lost as gaseous termite metabolites. The activity in workers was significantly higher than in presoldiers, which had differentiated under the influence of the labelled juvenogen. A stable value of radioactivity was detected on the body surfaces. CONCLUSIONS: The results suggest good stability of the compound in the wooden carrier and low contamination of the environment with non-gaseous residuals, together with the desired biological impact on termite caste differentiation.     

Toxicity and horizontal transfer of chlorantraniliprole against the Asian subterranean termite Coptotermes gestroi (Wasmann): effects of donor:recipient ratio, exposure duration and soil type

BACKGROUND: The effectiveness of chlorantraniliprole and other insecticides (bifenthrin, fipronil, indoxacarb, imidacloprid and chlorfenapyr) were tested against Coptotermes gestroi (Wasmann). Four experiments were conducted: a topical bioassay, a horizontal transfer study, an insecticide bioavailability test and a feeding bioassay. RESULTS: The topical bioassay showed that chlorantraniliprole was significantly less active to C. gestroi at 24 h post‐treatment compared with the other insecticides tested. Nevertheless, it is likely that a lesser amount of chlorantraniliprole was required to cause 50% mortality of C. gestroi at 7 and 14 days post‐treatment. The exposure duration and donor:recipient ratio affect the mortality of recipient termites. Mortality after exposure to chlorantraniliprole in sandy clay was significantly lower than in sand; however, by 14 days, > 90% of donor and recipient termites died in both substrates, irrespective of concentration. Fipronil and imidacloprid showed faster action, and high to moderate toxicity to C. gestroi. Termite workers also ceased to feed after exposure for 1 h to 50 mg kg^?1 chlorantraniliprole‐treated sandy clay. CONCLUSION: Chlorantraniliprole demonstrated delayed toxicity at the lowest label rate (50 mg kg^?1) in sandy clay. Its slow action will enable greater transfer of toxicant between nestmates, while feeding cessation will promote greater social interaction between healthy and exposed termites. Copyright © 2011 Society of Chemical Industry     

Transfer of five commercial termite bait formulations containing benzoylphenyl urea chitin synthesis inhibitors within groups of the subterranean termite Reticulitermes flavipes (Blattodea: Rhinotermitidae)

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.     

Toxicity of indoxacarb and spinosad to the multicolored Asian lady beetle, Harmonia axyridis (Coleoptera: Coccinellidae), via three routes of exposure

The use of selective insecticides may improve conservation of natural enemies and therefore contribute to the success of integrated pest management (IPM) programs. In this study, the toxicity of two commonly used selective insecticides, indoxacarb and spinosad, to the multicolored Asian lady beetle, Harmonia axyridis (Pallas), was evaluated. Third instars and adults of H. axyridis were exposed to indoxacarb at 50 and 100% of the field rate (FR), to spinosad at 100% FR and to water (untreated check) under laboratory conditions via three routes of exposure. Treatments were applied directly on insects (i.e., topical application), on Petri dishes (i.e., residues), or on soybean aphids, Aphis glycines Matsumara (i.e., treated prey). Mortality of exposed individuals in each life stage was recorded 2 and 7 days after treatment. Logistic regression indicated that indoxacarb at 100% FR, followed by indoxacarb at 50% FR, was more insecticidal than spinosad to third instars. Mortality was higher when H. axyridis were exposed to both insecticides via residues followed by treated prey. Indoxacarb at 100 or 50% FR was insecticidal to adults. Adults were tolerant to spinosad via all routes of exposure. The present results suggest that indoxacarb may decrease H. axyridis field populations by causing mortality to larvae and adults via all routes of exposure. Implications of the toxicity of indoxacarb to H. axyridis within an IPM context and possible reasons for the differences in susceptibility of H. axyridis for each route of exposure are discussed.     

Toxicity of a formulation of the insecticide indoxacarb to the tarnished plant bug, Lygus lineolaris (Hemiptera: Miridae), and the big-eyed bug, Geocoris punctipes (Hemiptera: Lygaeidae)

Indoxacarb is a new oxadiazine insecticide that has shown outstanding field insecticidal activity. The toxicity of a 145 g litre-1 indoxacarb SC formulation (Steward) was studied on the tarnished plant bug Lygus lineolaris and the big-eyed bug Geocoris punctipes. Both insect species responded very similarly to indoxacarb in topical, tarsal contact and plant feeding toxicity studies. The topical LD50 of the formulation was c 35 ng AI per insect for both species. Prolonged tarsal contact with dry indoxacarb residues did not result in mortality for either insect species. However, both species were susceptible to feeding through dried residues of indoxacarb after spraying on young cotton plants. Feeding on water-washed plants resulted in lower mortality than that observed with unwashed plants, and toxicity declined even more dramatically after a, detergent rinse, indicating that much of the indoxacarb probably resides on the cotton leaf surface or in the waxy cuticle. These results were corroborated by HPLC-mass spectrometry measurements of indoxacarb residues on the plants. Greater mortality for both species was observed in a higher relative humidity environment. Higher levels of accumulated indoxacarb and its active metabolite were detected in dead G punctipes than in L lineolaris after feeding on sprayed, unwashed plants. When female G punctipes ate indoxacarb-treated Heliothis zea eggs, there was significant toxicity. However, only c 15% of the females consumed indoxacarb-treated eggs, and the rest of the females showed a significant diminution of feeding in response to the insecticide. Cotton field studies have shown that indoxacarb treatments at labelled rates lead to a dramatic decline in L lineolaris, with negligible declines in beneficial populations. A major route of intoxication of L lineolaris in indoxacarb-treated cotton fields thus appears to be via oral, and not cuticular, uptake of residues from treated cotton plants. The mechanisms for selectivity/safety for G punctipes are currently under investigation and may be a combination of differential feeding behavior and diminution of feeding by females exposed to indoxacarb-treated eggs.