Residues of brodifacoum and other anticoagulant pesticides in target and non‐target species,Nelson Lakes National Park,New Zealand

Abstract

Cereal‐based bait containing 20 ppm brodifacoum was used in bait stations continuously from December 1997 to August 2000 in the Rotoiti Nature Recovery Project area, for controlling brushtail possum (Trichosurus vulpecula), ship rat (Rattus rattus), and house mouse (Mus musculus) populations. Concurrently (and before and after), baits containing brodifacoum, bromadiolone, flocoumafen, coumatetralyl, or warfarin were also used in St Arnaud village and on farms immediately adjacent to the project area. Brodifacoum residues were detected in the livers of 234 mammals from eight species, and two birds from two species captured alive, and a further seven birds from five species found dead in the project area (cause of death unknown). The highest concentration of brodifacoum residues in mammalian livers was recorded during the period brodifacoum was used in the project area. However, residues were present in the livers of some individuals at least 24 months after brodifacoum use in the project area stopped. These residues may have persisted in animals surviving brodifacoum use in the project area, and/or been transported into the area by animals moving to and from the adjacent village and farms, where brodifacoum use continued. Residues of flocoumafen, coumatetralyl, or warfarin, used only in the village and on farms, were also detected in the livers of animals captured up to at least 8 km from the nearest source. The results concur with other studies cautioning against indiscriminate or prolonged use of persistent anticoagulants for vertebrate pest control. However, the risks from such pesticides must be balanced against the demonstrable benefits of reducing pest abundance.     

四种常用抗凝血灭鼠剂对两种家栖鼠实验室药效比较

比较了几种抗凝血灭鼠剂对家栖鼠的毒效。以常规浓度（溴敌隆０．００５％,杀鼠迷、杀鼠灵和敌鼠钠０．０２５％）的毒饵,对靶标鼠进行单笼饲养无选择和有选择以及围栏群养有选择摄食试验,用毒杀率和摄食系数评价毒效和适口性。结果表明：⑴实验鼠单笼饲养试验：溴敌隆和杀鼠迷对大白鼠适口性好,毒杀率高,敌鼠钠适口性差;对小白鼠的毒效和适口性,溴敌隆最好,敌鼠钠最差;⑵三省四地区的褐家鼠单笼饲养无选择试验,溴敌隆、杀     

The susceptibility of Apodemus agrarius and Rattus losea to the anticoagulant rodenticide,flocoumafen

Flocoumafen had good rodenticidal action against Apodemus agrarius and Rattus losea. The acute oral LD₅₀ for male A. agrarius and R. losea was 1·22 mg kg⁻¹ and 1·36 mg kg⁻¹ respectively. Flocoumafen bait was more toxic to R. losea than to A. agrarius. At bait concentrations of 0·002–0·005%, flocoumafen had a single-feed potency with mortalities of 90–100% for R. losea and 77·8–100% for A. agrarius. Experimental baits prepared using the manufacturing 0·5% master mix of flocoumafen were palatable to both species.     

不同浓度茚虫威对红火蚁的防治效果

为探索适合防治红火蚁的茚虫威浓度,利用丙酮溶解茚虫威原药,使用雾化手段与载体和配方其他试剂充分混合,干燥后保存,进行野外试验测定其防治红火蚁的药效。结果表明,研制的0.025%茚虫威饵剂综合防治效果达85.30%,0.05%茚虫威饵剂达100%,0.1%茚虫威饵剂达100%。3个浓度的茚虫威饵剂拥有良好的防治红火蚁药效,0.05%浓度最适合研制红火蚁饵剂。     

Hepatic microsomal warfarin metabolism in warfarin-resistant and susceptible mouse strains: influence of pretreatment with cytochrome P-450 inducers

In the present paper, the heterogeneity of hepatic cytochrome P-450 isoenzymes in the mouse has been probed, using warfarin as the substrate. Both sex and strain differences in the in vitro microsomal metabolism of warfarin have been investigated in male and female warfarin-resistant HC and warfarin-susceptible LAC-grey mouse strains. Animals were either untreated or treated with the cytochrome P-450 inducers phenobarbitone, beta-napthoflavone or clofibrate. In both sexes and strains of mice, metabolism of warfarin was stereoselective in favour of the R(+) enantiomer. However, regioselectively was different in both strains and sexes of untreated animals. After pretreatment with phenobarbitone, increases in the rate of formation of 4' and 7-hydroxy R(+) and S(-) warfarin metabolites in HC mice were observed, compared with untreated animals. In LAC-grey mice increases in 4'-, 6-, 7- and 8-hydroxy R(+) and S(-) warfarin metabolites were noted, compared with untreated animals. This data indicated that different amounts or forms of cytochrome P-450s were responsible for warfarin metabolism after phenobarbitone treatment in the two strains. Pretreatment of animals with beta-napthoflavone resulted in significant decreases in the rat of R(+) warfarin metabolism in both strains and sexes of mice indicating that the beta-naphthoflavone-inducible cytochrome P-450 isoenzymes were less active in the metabolism of warfarin, as compared to the uninduced isoenzymes. In addition, the cytochrome P-450 isoenzyme composition in the two mouse strains was different after clofibrate pretreatment, as reflected in reduced levels of some warfarin metabolites and a reduced total metabolism of warfarin, consistent with the narrow substrate specificity of clofibrate-induced cytochrome P450IVA1 for fatty acid hydroxylation. Accordingly, it is clear that both the basal and xenobiotic inducible hepatic cytochrome P-450 isoenzymes in warfarin-resistant and susceptible mice are different and therefore have implications for the in vivo disposition of warfarin.     

The effectiveness of poison bait stations at reducing ship rat abundance during an irruption in a Nothofagus forest

Abstract

Ship rats exhibit large increases in abundance (irruptions) following heavy beech seedfall in New Zealand's Nothofagus forests. Predation by rats at high density severely damages native fauna populations. In 2006 the Department of Conservation undertook a management experiment in the Eg‐linton Valley to see if they could protect endangered species during a rat irruption. Poison (0.15% 1080, followed by 0.0375% coumatetralyl, or Racumin®) was laid in bait stations, and the consequences for rat abundance and survival were estimated. All 10 radio‐tagged rats died, suggesting that 1080 had a high impact on the rat population. The two rats that made the smallest daily movements survived longer than the others. Live trapping documented a reduced abundance of rats within the poison area (450 ha) after 1 month of poisoning. However, after 4 months of poisoning, the abundance of rats had begun to recover. Further investigation is needed on acceptance of Racumin® to rats, optimum spacing of bait stations for rats, and bait competition between rats and mice when densities of both species are high.     

The inhibitory effects of the molluscicide metaldehyde on feeding, locomotion and faecal elimination of three pest species of terrestrial slug

Single meals on maize flour pellets containing 0, 0·5, 1, 2, 4, 6, and 8% metaldehyde were analysed in Arion hortensis (agg), Deroceras reticulatum and Deroceras caruanae, by attaching the pellets to a mechanical transducer from which signals were ultimately fed into a BBC microcomputer for on-line analysis. Post-feeding tests were used to investigate toxic effects of metaldehyde and the recovery of slugs was examined daily for 7 days. Bite rates were slightly lower and more irregular on metaldehyde meals especially in A. hortensis. The meal length and number of bites per meal were markedly inhibited by metaldehyde and inversely proportional to the concentration. The size of the bites was also reduced, by about 30%, in meals on 6% pellets compared with 0%. Clear symptoms of poisoning became evident during the meal or normally in the 16-min test period immediately afterwards. In these tests slugs which fed on metaldehyde pellets showed a disruption of their ability to right themselves (after being placed on their side), less activity and a reduced probability of accepting a ‘dummy’ pellet containing no metaldehyde. It is hypothesised that feeding is prematurely terminated primarily because of the toxic effects of the metaldehyde and that aversion also acts to terminate the meal early, by decreasing the probability of continuing to feed as the meal proceeds. At higher concentrations of metaldehyde aversion may be more important than the toxic effects in ending the meal. Faecal elimination is delayed after metaldehyde meals and this contributes to mortality. The estimated lethal doses were about 0·2 mg/g body weight of slug in Deroceras spp. A. hortensis was less susceptible. To increase the likelihood of a lethal dose being ingested the inhibition of feeding needs to be overcome, at least partly, and the results presented indicate the need for a bait formulation which reduces the rate of absorption of the molluscicide from the gut.     

Laboratory tests on mating competition between thiotepa-sterilised and normal males of the potato moth, Phthorimaea operculella (Lepidoptera: Gelechiidae)

Male potato moths less than 24-h-old were sterilised in fumigation chambers in the laboratory with one of three concentrations of thiotepa 0·05, 0·075 and 0·1 g at either 25 or 30°C. Sterile males were associated with untreated virgin males and virgin females in the ratios of 1:1:1, 2:1:1, 4:1:1 and 1:0:1. The sterile and normal male contingents were placed with a single female. The percentage of egg hatch after mating decreased with the increase of concentration and the sterile male ratio. Sterile males were competitive in mating and their longevity was not adversely affected in comparison to the control groups.     

Laboratory and field evaluation of flocoumafen for rodent control

A new anticoagulant rodenticide, flocoumafen, at a concentration of 0·005% in the bait in 24 h no-choice and 48 h choice laboratory feeding tests was found to cause 100% mortality of the Indian bush rat Golunda ellioti, the Indian gerbil Tatera indica and the soft-furred field rat Rattus meltada. In field trials in sugar cane and wheat, where these species and the Indian mole rat Bandicota bengalensis and Mus spp. were present, about 65% rodent control was obtained with a single treatment with 0·005% flucoumafen bait at the rate of 1 kg/ha. The performance of a single treatment with flocoumafen was comparable with that of 2·4% zinc phosphide, a conventional acute rodenticide. Unlike zinc phosphide, however, two treatments with a 10-day interval with flocoumafen resulted in significantly higher rodent control compared with the single treatment, indicating the superiority of flocoumafen over zinc phosphide in repeat baiting treatments.     

Carbon,nitrogen and phosphorus concentrations in aggregates of organic waste-amended soils

This study was undertaken to evaluate the long-term effects of organic wastes on dry aggregate size distribution and on the C, N and available-P concentrations within the different aggregate fractions of some agricultural soils in North-Central Italy. Topsoils (0–20 cm) which had been amended for several years with either pig slurry (PS), cattle slurry (CS) or sewage sludge (SS) were separated into four macro-aggregate classes (4-2, 2-1, 1-0·5, 0·5-0·25 mm) and three micro-aggregate classes (0·25-0·125, 0·125-0·05 and < 0·05 mm) by dry sieving. Compared with the unamended soils, there was generally a slight increase in the proportion of the 4-2 mm macro-aggregate class following waste application. Irrespective of treatment, macro-aggregates (>0·25 mm) constituted > 70% of the total aggregate fractions.Average increases of 17, 13 and 67% (organic C), 18, 13 and 57% (total N) and 430, 372 and 642% (available P) were obtained from additions of PS, CS and SS, respectively, and increases were found in all aggregate fractions following waste application. There was a close positive correlation between the concentrations of C, N and to a lesser extent P, in the aggregates and their silt-plus-clay contents. In terms of total contents, these elements were preferentially concentrated in the macro-aggregates. Only slight differences in the C/N ratios of the aggregates were observed but their C/P and N/P ratios decreased significantly (P ≤ 0·05) following waste application.     

Factors affecting male probing activity of the red bollworm Diparopsis castanea (Hmps.) in relation to sterility induced by tris(1 -aziridinyl) phosphine oxide (tepa)

Assuming that the sex attractant of the female red bollworm, Diparopsis castanea (Hmps.), can be isolated, it might be used at bait stations in combination with chemosterilants for the control of this insect. To ensure success, it is essential that male moths attracted to the bait station should pick up an effective dose of chemosterilant either by brief contact with, or by momentary probing on, chemosterilant-treated surfaces. In Rhodesia, during the dry season, up to 90 % of the moths tested probed on water after 3 days, while 80% probed on 10 %-D-glucose after 2 days. In a laboratory with controlled humidity, 70 % of the moths probed after 18 h at 0–10% R.H.; and 10% probed after 18 h at 40% R.H. The average amount of liquid imbibed by individual moths varied from 15·5 μl after 18 h at 0% R.H. to 7·2 μl after 18 h at 40% R.H. It was estimated, and later confirmed, that thirsted moths probing on a 0·1 % aqueous solution of tris (1-aziridinyl) phosphine oxide (tepa) would take up the equivalent of a sterilizing dose. The treated moths were consistently sterilized with no adverse effects on mating frequency, longevity or competitiveness. As both sexes were found to be sexually mature on emergence, it is probable that little dispersion of the newly emerged adult population occurs before the first mating.     

A comparison of warfarin resistance and liver microsomal vitamin K epoxide reductase activity in rats

Vitamin K-1 epoxide reductase activity was investigated in liver microsomal preparations from warfarin-resistant and -susceptible rats. One rat strain (TAS) is susceptible to the anticoagulant and lethal effects of warfarin and the other two strains are homozygous for warfarin resistance genes from either wild Welsh (HW) or Scottish (HS) rats. The enzyme in microsomal preparations from HW rat livers apparently has a reduced affinity for both warfarin and vitamin K-1 2,3-epoxide. The kinetic parameters for the enzyme activity in HS microsomal preparations indicated, however, that vitamin K-1 epoxide reductase in this warfarin-resistant strain was very similar, in respect of substrate and inhibitor affinities, to that prepared from susceptible (TAS) animals. Analysis of vitamin K-1 epoxide reductase activity in the livers of animals that had been orally treated with sodium warfarin (20 mg/kg body wt.) indicated that enzyme activity was inhibited in all three strains, although this dose is lethal only to animals of the TAS strain.     

Swimming performance and associated ionic disturbance of juvenile pink salmon Oncorhynchus gorbuscha determined using different acceleration profiles

Swimming performance was assessed in juvenile pink salmon Oncorhynchus gorbuscha (body mass <5·0 g) using five different protocols: four constant acceleration tests each with a different acceleration profile (rates of 0·005, 0·011, 0·021 and 0·053 cm s^?2) and a repeated ramped‐critical swimming speed test. Regardless of the swim protocol, the final swimming speeds did not differ significantly (P > 0·05) among swim tests and ranged from 4·54 to 5·20 body lengths s^?1. This result supports the hypothesis that at an early life stage, O. gorbuscha display the same fatigue speeds independent of the swimming test utilized. Whole body and plasma [Na⁺] and [Cl^?] measured at the conclusion of these tests were significantly elevated when compared with control values (P < 0·05) and appear to be predominantly associated with dehydration rather than net ion gain. Given this finding for a small salmonid, estimates of swim performance can be accurately measured with acceleration tests lasting <10 min, allowing a more rapid processing than is possible with a longer critical swim speed test.     

Rôle of single amino acids in phagostimulation,growth, and survival of Acyrthosiphon pisum

Twelve amino acids and amides at 0·1 to 0·75 or 1·0% in 35% sucrose solution were individually tested for their rôle in phagostimulation, growth, and survival in Acyrthosiphon pisum. Leucine and phenylalanine were phagostimulatory at all concentrations tested, tryptophan and valine at 0·1, 0·2, and 0·5%, and threonine at 0·1% only. Methionine was reported earlier by us to be phagostimulatory at 0·05 to 0·5%. Histidine and isoleucine had no effect, whereas arginine and lysine HCl reduced uptake when compared to sucrose alone. The non-essential amino acids, canavanine sulphate and glutamine, reduced uptake at all concentrations, whereas homoserine was phagostimulatory at 0·1 and 0·75%.Arginine, canavanine sulphate, glutamine, histidine, homoserine, isoleucine, leucine, and valine increased weight and prolonged survival, whereas lysine HCl, phenylalanine, threonine, and tryptophan neither promoted growth nor increased survival. Radioactive leucine (¹⁴C(U)) was incorporated into the protein fraction of the larval body and exuviae indicating that it took part in protein synthesis. This seems to be the first report in insects where peptide or protein synthesis occurred from single amino acids in sucrose.     

Comparative effect of three rodenticides warfarin,bromadiolone and brodifacoum on the Indian field mouse,Mus booduga gray

Three anticoagulant rodenticides, warfarin, bromadiolone and brodifacoum, were evaluated in the laboratory for their activity against the Indian field mouse, Mus booduga. In oral intubation studies M. booduga was found to be more susceptible to bromadiolone and brodifacoum than warfarin. Feeding studies with 0.005% bromadiolone and brodifacoum baits produced 83% mortality after a single day's feeding while a similar mortality was achieved with 0.025% warfarin only after 6 days of consecutive feeding. The anticoagulant baits were less palatable than the plain (unpoisoned) bait. Laboratory feeding tests confirmed that 0.005% of the active ingredient would be an effective bait concentration for field use of both bromadiolone and brodifacoum. The single-feed potency of bromadiolone and brodifacoum indicate that these rodenticides may be more effective and economical than warfarin in the field.     

The effects of dietary additives on faecal levels of Lactobacillus spp., coliforms,and Escherichia coli,and faecal prevalence of Salmonella spp. and Campylobacter spp. in US production nursery swine1

Aims: In the United States, carbadox and copper sulfate are growth promoters commonly used in combination in nursery swine diets. Our aim was to determine how selected dietary additives affect selected bacterial populations and pathogens in nursery swine, and compare to larch extract, which contains potential antibacterial activities. Methods and Results: Piglets were weaned and sorted into one of the four treatments: (i) basal diet without antimicrobials; (ii) basal diet with carbadox + copper sulfate; (iii) basal diet + 1000 ppm larch extract; or (iv) basal diet + 2000 ppm larch extract. Diets were fed for a 4‐week period after weaning. In both trials, the carbadox + copper sulfate group consumed more feed over the 4‐week period relative to the other three diet groups (P < 0·05), but did not gain significantly more weight. Faecal shedding of Salmonella spp. was not affected by dietary supplement in either trial, but faecal shedding of Campylobacter spp. was the lowest for the carbadox + copper sulfate diet. In faecal samples collected at the end of each trial, Lactobacillus spp. cell counts for the basal and larch extract diets were nearly 1·0 log₁₀ g^?1 faeces greater (P < 0·05) than the carbadox + copper sulfate group, whereas the coliforms and Escherichia coli were nearly 1·0 log₁₀ g^?1 faeces lower (P < 0·05). Conclusions: Compared to basal fed animals, supplementation with carbadox + copper sulfate significantly altered faecal E. coli, coliform bacteria and Lactobacillus spp. Larch extract has no benefit up to 0·2% of diet in regard to pathogen shedding, whereas carbadox + copper sulfate decreased faecal shedding of Campylobacter spp. Significance and Impact of the Study: Current swine management practices in the United States may be beneficial to managing Campylobacter spp. shedding in nursery swine, but also result in significant changes in the resident gastrointestinal microflora.     

Substituted benzoic and picolinic acids as foliar sprays against potato common scab

Glasshouse tests on potato cv. Arran Banner measured the effects of single early foliar sprays of 18 substituted benzoic and two dichloropicolinic acids on the severity of common scab, caused by soil-borne Streptomyces scabies. The monosubstituted benzoic acids tested (25 mM) did not affect scab. However, anti-scab action was shown by some 2,5-disubstituted acids. Decreases in scab severity were about 35% from 1·6 mM 5-bromo-2-chloro- and 2,5-dimethylbenzoic acids, and over 50% from 1·6 mM 2,5-dichloro-, 2,5-dibromo- and 5-chloro-2-nitrobenzoic acids and from 0·05 mM 3,6-dichloropicolinic acid (clopyralid), which is structurally similar to 2,5-dichlorobenzoic acid. None of the spray treatments affected yield or shape of tubers. No visible effects on foliage were caused by two of the benzoic acids active against scab (5-chloro-2-nitro- and 2,5-dimethyl-), but the other active acids caused some distortion. In tests of the six dichlorobenzoic acids against S. scabies in culture, the 2,5-isomer (which was the most effective against the disease in plants) was one of the least toxic. With other 2,5-disubstituted benzoic acids, it probably decreased scab indirectly by altering the response of the host to infection.     

Some effects of the nematodes Ditylenchus myceliophagus and Aphelenchoides composticola on the yield of the cultivated mushroom

The addition of one, ten and fifty Aphelenchoides composticola per ioo g compost at spawning reduced the total yield of sporophores by 26%, 30% and 42% respectively (P= 0·01), demonstrating a significant regression (P= 0·05) of yield on inoculum concentration. In pots inoculated at spawning with ten and fifty A. composticola per 100 g compost, cropping ceased after 12 weeks. The addition of twenty, 100 and 300 Ditylenchus myceliophagus at casing reduced the total yield of sporophores by 50%, 68% and 75 % respectively (P= 0·01). Cropping did not occur in pots inoculated at spawning, but continued for 9 weeks in pots inoculated at casing. The yield from pots inoculated at casing with either nematode was significantly greater (P= 0·05) than that from pots inoculated at spawning. When inoculated at spawning, peak populations of D. myceliophagus and A. composticola were reached 7 and 13 weeks, respectively, after spawning. Then the numbers present were unrelated to the number in the inocula.     

Partial purification and some properties of wineberry latent, a virus obtained from Rubus phoenicolasius

Wineberry latent virus (WLV) was obtained from a single symptomless plant of American wineberry (Rubus phoenicolasius) originally imported from the United States of America. On graft inoculation, WLV infected but induced no distinctive symptoms in several Rubus species including those used as indicators for known Rubus viruses. It was not seed-borne in wineberry. WLV was mechanically transmitted to several herbaceous species but induced local lesions in only a few; it was weakly systemic in some Chenopodium species. Infective C. quinoa sap lost infectivity after diluting to 10^-4, heating for 10 min at 70°C, and storage either for 8 days at 18°C or for 32 days at 4°C. Sap from infected plants contained flexuous filamentous particles c. 510°12 nm. WLV was partially purified by extracting infected C. quinoa leaves in 0·05 M tris-HCl buffer (pH ₇) containing 0·2% thio-glycerol and 10% (v/v) chloroform and concentrating virus by precipitation with 7% (w/v) polyethylene glycol (PEG, mol. wt 6000) and 0·1 NaCl. The virus was then pelleted through a 30% (w/v) sucrose pad containing 7% PEG+0·1 M NaCl and finally sedimented through a sucrose density-gradient. These preparations had A_260/280 ratios of 1·26, contained end to end aggregates of WLV particles and formed a partly polydispersed peak in the analytical ultracentrifuge. WLV did not react with antisera to four potex-viruses, or to apple chlorotic leaf spot or apple stem grooving viruses.     

Laboratory and field performance of an indoxacarb bait against German cockroaches (Dictyoptera: Blattellidae)

Experimental indoxacarb powder and gel baits were evaluated in the laboratory, and a gel bait was evaluated in subsequent field studies against the German cockroach, Blattella germanica (L.). In continuous exposure tests, LT50 values were 1.90 and 1.10 d for 0.25 and 1% indoxacarb powder baits, respectively. However, 0.25% indoxacarb gel bait had an LT50 value of 0.68 d, similar to a 0.05% abamectin gel bait formulated with the same bait base. There was no difference in toxicity between fresh and 7-d-old gel bait deposits. A pyrethroid-resistant strain of German cockroaches was significantly resistant to both abamectin and indoxacarb gel baits. Gel bait contained approximately 40% water, desiccated rapidly at 25-28 degrees C and 30-45% RH, but did not rehydrate when held at 56.7% RH for 3 d. Powder indoxacarb baits contained <1% water and did not desiccate or gain water. Indoxacarb gel bait (0.25%) was relatively nonrepellent (approximately 30%) and had positive maximum performance index values (approximately 100) in Ebeling choice box experiments. In field experiments in cockroach-infested kitchens, the 0.25% indoxacarb gel bait significantly reduced visual counts of German cockroaches approximately 74% at 3 d and >95% at 14 d. Indoxacarb baits are toxic, relatively nonrepellent, and can significantly reduce German cockroach populations.