Influence of fungicidal control of cucumber and tomato grey mould (Botrytis cinerea) on fruit yield

The fungicides tebuconazole, tebuconazole + dichlofluanid, fenethanil, diethofencarb + carbendazim, and vinclozolin combined with chlorothalonil were tested for their ability to control grey mould (Botrytis cinerea Pers. ex Fr.) of cucumber and tomato grey mould in greenhouses under commercial conditions. In winter 1987/88 the number of diseased female fruits of cucumber (Cucumis sativus L.) was reduced by diethofencarb + carbendazim (2·5 mg dm^?3 each) by 93% and by tebuconazole (2·5 mg dm^?3)(phytotoxic when alone) or tebuconazole (1 mg dm^?3) + dichlofluanid (4 mg dm^?3) by 54–57%. Vinclozolin (5 mg dm^?3) + chlorothalonil (25 mg dm^?3) significantly reduced disease incidence on fruits by 40%. Infection foci on cucumber stems were significantly decreased by vinclozolin + chlorothalonil. A more pronounced decrease was obtained with diethofencarb + carbendazim, tebuconazole, or tebuconazole + dichlofluanid. During the season of winter 1988/89, tebuconazole + dichlofluanid (1·5 + 6 and 3 + 12 mg dm^?3) and RH7592 (1 mg dm^?3) significantly reduced diseased fruits by 30–71%. Grey mould of tomato (Lycopersicon esculentum Mill.) leaves was reduced by more than 90% and on fruits by 78–87% when tebuconazole + dichlofluanid (1·5 + 6 and 3 + 12 mg dm^?3) or diethofencarb + carbendazim (2·5 mg dm^?3 each) were applied. Yields of cucumber fruits of the common parthenocarpic cv. Kasem 292 were weighed. There was no correlation between disease level and yield in any experiment, plot or date except for two measurements. Compesation in fruit production by the plant may be regarded as the reason for no positive yield response to efficient control. The possibility of reducing fungicide application is discussed. Control of grey mould on tomato resulted in yield increase.     

Evaluation of permethrin for the protection of cattle against mosquitoes (diptera: Culicidae), applied as electrostatic and low pressure sprays

Permethrin was tested for the protection of cattle against field populations of mosquitoes. Permethrin (500 ml of a permethrin 4·0 g liter^?1 aqueous emulsion) applied with a ‘Dual-Cloud’ electrostatic sprayer was effective in providing coverage of the cattle body surface of a group of four animals; 100 ml of a permethrin 5·0 g liter^?1 aqueous emulsion applied with a ‘Dual-Cloud'’ electrostatic sprayer as a total body spray to a yearling heifer provided 70% or better protection from field populations of mosquitoes for at least 72 h; 500 ml of a permethrin 1·0 g liter^?1 aqueous emulsion applied as a low-pressure spray to the body of a yearling heifer provided 70% or better protection from mosquitoes for at least 140 h. Permethrin applied as a total body-spray thus provides adequate protection to cattle from field populations of mosquitoes.     

Acute toxicity of chlorantraniliprole to non‐target crayfish (Procambarus clarkii) associated with rice–crayfish cropping systems

BACKGROUND: Chlorantraniliprole, a novel anthranilic diamide insecticide, was recently introduced into the United States where rice–crayfish crop rotations are practiced to control rice water weevil (Lissorhoptrus oryzophilus Kuschel) infestations. Chlorantraniliprole has high margins of mammalian safety and excellent insecticidal efficacy, but its toxicity to non‐target crayfish is uncertain. In this study, the acute toxicity of chlorantraniliprole to the red swamp crayfish Procambarus clarkii Girard was determined using aquatic and feeding assays. RESULTS: The aquatic 96 h median lethal toxicity (LC₅₀) data indicate that technical‐grade chlorantraniliprole is highly toxic (US EPA category) to crayfish with an LC₅₀ of 951 µg L^?1 (95% CL = 741–1118 µg L^?1). A no observed effect concentration (NOEC) of 480 µg L^?1 was recorded. Neither the 36 day chronic feeding study, where crayfish fed on chlorantraniliprole‐treated rice seed in aquaria, nor the 144 h acute feeding test, where crayfish fed on rice seeds treated with chlorantraniliprole, produced mortality or abnormal behavior. CONCLUSION: Chlorantraniliprole is three orders of magnitude less acutely toxic to P. clarkii than lambda‐cyhalothrin and etofenprox, two pyrethroid insecticides also used in rice, and is less likely to cause acute crayfish toxicity in rice pond ecosystems. Based on acute toxicity data, the use of chlorantraniliprole should be more compatible with rice–crayfish crop rotations than pyrethroids. Copyright © 2010 Society of Chemical Industry     

Elimination of Grapevine rupestris stem pitting-associated virus (GRSPaV) from two Vitis vinifera cultivars by in vitro chemotherapy

The grapevine (Vitis vinifera L.) cultivars ‘Agiorgitiko’ and ‘Malagouzia’, naturally infected with Grapevine rupestris stem pitting-associated virus (GRSPaV), were subjected to in vitro chemotherapy using the antiviral inosine 5′-monophosphate dehydrogenase inhibitors tiazofurin (TR), ribavirin (RBV) and mycophenolic acid (MPA). The chemotherapy lasted 80 days and was carried out as two consecutive treatments. Severe phytotoxicity, estimated after 40 days of culture, was observed in drug-treated explants, especially when high doses of TR were used. Phytotoxicity exhibited a cultivar- and chemical compound-dependent profile. The virus eradication status of the survived plantlets was determined by nested RT-PCR using total RNA templates, after 80 days of drug treatment and one year later, after the passage of one dormancy period, in potted plants grown in a greenhouse. Data indicated that the highest GRSPaV elimination in ‘Agiorgitiko’ was obtained with 10 μg? ml^?1 TR, 30 μg ?ml^?1 RBV and 20 μg? ml^?1 MPA. The eradication rates were lower in the case of ‘Malagouzia’, where the highest ones were achieved after treatments with 15 μg ml^?1 TR and 80 μg ml^?1 MPA. This is the first report on GRSPaV elimination in grapevine following treatment with antiviral compounds, which could provide an alternative to the traditional methods of virus eradication through meristem culture and thermotherapy.     

Response of maize (Zea mays L.) inbred lines and hybrids to chlorsulfuron

Twenty inbred maize lines, raised in a growth chamber, were treated with 0 or 1 ng g^?1 of chlorsulfuron which caused a variable reduction in root-length. In a second experiment, all crosses (reciprocals included) among two tolerant lines (T: Va85 and Mes44) and two susceptible lines (S: B73 and B79) were raised in a growth chamber together with the parental lines and exposed to 0,0×5 or 1 ng g^?1, The interaction of reciprocal effects x rates was not significant for all traits, The T × S hybrids showed an intermediate response between the T × T and S × S responses for root-length and dry weight. Interaction (hybrids vs. parental lines) × rates was not significant for all traits. These results indicate that susceptibility to chlorsulfuron is not controlled by extra-nuclear factors and that additive gene actions prevail. Four crosses (one T × T, two T × S and one S × S) were further investigated at nine rates from 0 to 1 ng g^?1. The responses confirmed the intermediate behaviour of T×S hybrids, resulting in a GR₂₀ of 0×07, 0×55 and 0×94 ng g^?1 for S × S, T × S and T × T, respectively. In a third experiment, the four crosses previously considered were grown in the field with parental lines and treated at five rates from 0 to 1·12 g a.i. ha^?1. Effects on shoot height and dry weight were consistent with root effects found in growth chamber experiments.     

Insecticidal activity of Sikimi extract and its modulation of the GABAA receptor channel

Sikimi plant (also known as Japanese star anise), Illicium anisatium, is toxic to mammals. Extracts of Sikimi were studied for their insecticidal activity against the larvae of mosquito, Culex quinquefasciatus, and for their mechanism of action on ion channels. Crude methanol extract and its ethyl acetate-soluble fractions were insecticidally active, with EC₅₀ values of 63·0 μg ml^-1 and 43·7 μg ml^-1, respectively. The ethyl acetate-soluble fraction was perfused through the bathing solution and the current induced by a brief (10 ms) application of GABA by pressure ejection through pipette electrode was recorded by the whole-cell patch clamp technique. The extract suppressed GABA-induced currents irreversibly with an EC₅₀ value of 0·42 μg ml^-1. The time constant of current fitted to the single exponential function was shortened by the ethyl acetate-soluble fraction at concentrations ranging from 0·1 μg ml^-1 to 10 μg ml^-1 in a concentration-dependent manner. It was concluded that Sikimi extracts decreased the affinity of GABA for its binding site on the GABA receptor, thereby suppressing GABA-induced currents. © 1998 SCI     

Formulation selection,and investigation of azadirachtin-A persistence in some terrestrial and aquatic components of a forest environment

Five commercial formulations of azadirachtin-A (AZ-A) Margosan-O^®, Azatin-EC^®, Neem-EC^®, RH-9999 and Neemix^® 4.5, were investigated for their volatilization and washoff potential in laboratory studies. Prior to the investigation, RH-9999 (a wettable powder) was mixed with water to provide an end-use formulation containing 35·6 g AZ-A kg^-1, while the remaining four formulations were investigated without dilution. Volatilization and washoff of AZ-A occurred more from white spruce foliage than from wax-coated glass plates. Neem-EC provided the lowest amount of loss, whereas Margosan-O provided the highest. Physical properties and atomization behaviour of the five formulations indicated that Azatin-EC was highly viscous and caused phase separation in droplets collected on glass plates after atomization in a rotary atomizer. RH-9999, despite its low viscosity, caused phase separation in droplets because of the heterogeneity of the wettable powder formulation. Based on the minimum loss of AZ-A due to volatilization and washoff from spruce foliage, and on the minimum potential for phase separation in droplets after atomization in a rotary atomizer, Neem-EC was considered to be the most appropriate choice for use in field studies to investigate environmental persistence and fate of AZ-A in terrestrial and aquatic matrices of a forest ecosystem. The Neem-EC formulation was sprayed at 40 and 80 g AI ha^-1 over single spruce trees and on litter and soil plots selected in a mixed-wood boreal forest in Ontario, Canada. In addition, outdoor aquaria containing stream water and sediment were also fortified with the formulation at 400 and 800 g AI ha^-1. Persistence of AZ-A was evaluated using one-year-old spruce needles, current-year shoots, spruce bark, litter, soil, stream water and sediment. The duration of persistence varied from 3 to 6 days in terrestrial matrices, whereas it ranged from 8 to 13 days in water, and 2 to 3 days in sediment. The half-life (DT₅₀) values ranged from 10·7 h (for soil) to 71·6 h (for spruce bark) at the lower dosage rate, and from 18·8 h (for litter) to 76·2 h (for bark) at the higher dosage rate. The DT₅₀ value for stream water was about 35 h regardless of the dosage rate applied. The data indicated that AZ-A was appreciably labile and short-lived in different forestry matrices, with low DT₅₀ values. © 1997 SCI     

Comparative acute toxicity of neonicotinoid and pyrethroid insecticides to non‐target crayfish (Procambarus clarkii) associated with rice–crayfish crop rotations

BACKGROUND: Most insecticides used to control rice water weevil (Lissorhoptrus oryzophilus Kuscel) infestations are pyrethroids. However, pyrethroids are highly toxic to non‐target crayfish associated with rice–crayfish crop rotations. One solution to the near‐exclusive reliance on pyrethroids in a rice–crayfish pest management program is to incorporate neonicotinoid insecticides, which are insect specific and effective against weevils but not extremely toxic to crayfish. This study aimed to take the first step to assess neonicotinoids as alternatives to pyrethroids in rice–crayfish crop rotations by measuring the acute toxicities of three candidate neonicotinoid insecticides, clothianidin, dinotefuran and thiamethoxam, to juvenile Procambarus clarkii (Girard) crayfish and comparing them with the acute toxicities of two currently used pyrethroid insecticides, lambda‐cyhalothrin and etofenprox. RESULTS: Neonicotinoid insecticides are at least 2–3 orders of magnitude less acutely toxic (96 h LC₅₀) than pyrethroids to juvenile Procambarid crayfish: lambda‐cyhalothrin (0.16 µg AI L^?1) = etofenprox (0.29 µg AI L^?1) ? clothianidin (59 µg AI L^?1) > thiamethoxam (967 µg AI L^?1) > dinotefuran (2032 µg AI L^?1). CONCLUSION: Neonicotinoid insecticides appear to be much less hazardous alternatives to pyrethroids in rice–crayfish crop rotations. Further field‐level neonicotinoid acute and chronic toxicity testing with crayfish is needed. Copyright © 2009 Society of Chemical Industry     

Simultaneous determination of benzimidazole fungicides by HPLC on apples,pears and their pulps

The simultaneous HPLC determination of carbendazim, thiabendazole and thiophanate-methyl in apples, pears and their pulps is described. The method is based on a clean-up procedure carried out on an Extrelut 20 cartridge followed by HPLC analysis on a Diol column using hexune+isopropanol as mobile phase. Average recoveries of 83.8% for carbendazim, 82.9% for thiabendazole and 68.8% for thiophanate-methyl on apple matrix were obtained; recoveries on pear matrix were in the same range. Detection limits with UV detection at 285 nm of 100 ng ml^?1 for carbendazim, 140 ng ml^?1 for thiabendazole and 500 ng ml^?1 for thiophanate-methyl were achieved.     

Effect of Glomus mosseae on concentrations of rosmarinic and caffeic acids and essential oil compounds in basil inoculated with Fusarium oxysporum f.sp. basilici

This study investigated the potential of the arbuscular mycorrhizal (AM) fungus Glomus mosseae to protect basil (Ocimum basilicum) against Fusarium oxysporum f.sp. basilici (Fob). It was hypothesised that G. mosseae could confer a bioprotective effect against Fob as a result of increases in leaf rosmarinic (RA) and caffeic acids (CA) or essential oil concentrations. Glomus mosseae conferred a bioprotective effect against Fob by reducing plant mortality to 20% compared to 33% in non‐mycorrhizal (NM) plants. This bioprotective effect was not related to improved phosphorus (P) nutrition, as AM and NM plants treated with Fob had similar shoot P concentrations (6 and 8 mg g^?1 dry weight (DW), respectively). Both AM and NM plants treated with Fob had similar leaf and root RA and CA concentrations. Furthermore, phenolic (40–70 mg CA g^?1 DW) or essential oil concentrations (0·1–0·6 mg g^?1 DW) were not increased in plants treated with the AM fungus and Fob. Therefore, the bioprotective effect conferred by G. mosseae was not a result of increases in the phytochemicals tested in this study. However, under the AM symbiosis, basil plants treated with Fob had lower methyleugenol concentrations in their leaves (0·1 mg g^?1 DW) than NM plants treated with the pathogen (0·6 mg g^?1 DW).     

Effects of the experimental fungicide RH 886 on Mucor piriformis

No registered fungicide controls Mucor piriformis, a cause of severe postharvest storage rot in pears, but the experimental fungicide RH 886 (active ingredients: 77% 5-chloro-2-methylisothiazol-3-(2H)-one and 23% 2-methylisothiazol-3-(2H)-one) has an ED₅₀ of 23.1 μg ml^?1 in 5 min exposure for germination of sporangiospores of M. piriformis and an ED₅₀ of 9.9 μg ml^?1 for mycelial growth. Mixing RH 886 into infested, amended soil at 8 mg g^?1 soil or mixing copper sulfate into soil at 1 mg g^?1 soil prevented sporulation of M. piriformis. Application of RH 886 to pear fruits prior to inoculation, or immersion of fruits in solutions of RH 886 containing sporangiospores of M. piriformis significantly reduced fruit infection.     

Disposition kinetics of cypermethrin and fenvalerate in black bengal lactating goats

Disposition kinetics of cypermethrin and fenvalerate were investigated in lactating black Bengal goats following single dose intravenous administration at 57 and 45 mg kg^?1 respectively. The maximum and minimum blood concentrations of cypermethrin were 18.49 (±3.17) and 0.06 (±0.002) μg ml^?1, while the corresponding values for fenvalerate were 14.58 (±2.37) and 0.04 (±0.005) μg ml^?1 respectively. Both cypermethrin and fenvalerate remained present in blood for 36 h. The mean t1/2β) and Vd_area values were 5.56 (±0.28) h and 10.38 (±2.20) litre kg^?1 for cypermethrin and 5.66 (±0.35) h and 11.31 (±2.20) litre kg^?1 respectively for fenvalerate. Both cypermethrin and fenvalerate persisted in goat milk for 36 h. The t1/2β) and AUC values of fenvalerate were 7.37 (±1.84) h and 122.38 (±11.65) μg h ml^?1 whilst the corresponding values for cypermethrin were 6.66 (±1.54) h and 99.48 (±7.81) μg h ml^?1 in milk respectively.     

Effect of atrazine on growth, production of aflatoxin, and fatty acid and sterol biosynthesis by Aspergillus spp.

The effects of atrazine were studied on growth, production of aflatoxin, and fatty acid and sterol biosynthesis by four isolates of Aspergillus in vitro. There was little effect of atrazine on Aspergillus spp. at concentrations up to 20 μg ml^?1 but at 40 μg ml^?1 or above, growth, production of aflatoxin, and fatty acid and sterol biosynthesis were remarkably reduced. Palmitic, stearic and linoleic acid synthesis were inhibited in three of the isolates tested at 60 μg ml^?1. At 100 μg ml^?1, except ergosterol, the cholesterol and 5, 7-ergostadienol synthesis was totally inhibited in all isolates. Effet de l'atrazine sur la croissance, la production d'aflatoxine, et la biosynthèse d'acides gras et de stérols par Aspergillus spp. Chez quatre isolats d'Aspergillus, les effets de l'atrazine sur la croissance, la production d'aflatoxine, et la biosynthèse d'acides gras et de stérols ont étéétudiés in vitro. Jusqu'à des concentrations de 20 μg ml^?1, l'atrazine n'a eu que peu d'effets, mais à 40 μg ml^?1 et au-dessus, la croissance, la production d'aflatoxine, et la biosynthèse d'acides gras et de stérols ont été nettement réduites. Les synthèses d'acides palmitique, stéarique et linoléique ont été inhibées chez trois des isolats, à 60 μg ml^?1. A 100 μg ml^?1, mis à part l'ergostérol, les synthèses de cholestérol et de 5, 7-ergostanediol ont été totalement inhibées chez tous les isolats. Die Wirkung von Atrazin aufdas Wachslum, die Bildung von Aflatoxin und die Fettsäuren- und Sterol-Biosynthese von Aspergillus spp. Bei vier Isolaten von Aspergillus wurde in vitro die Wirkung auf das Wachstum sowie auf die Bildung von Aflatoxin, Fettsäuren und Sterolen untersucht. Bei Atrazin-Konzentrationen bis zu 20 μg ml^?1 war keine Wirkung zu beobachten, aber ab 40 μg ml^?1 wurden das Wachstum und die Bildung von Aflatoxin, Fettsäuren und Sterolen deutlich herabgesetzt. Bei 60 μg ml^?1 war bei drei Isolaten die Bildung von Palmitin-, Stearin- und Linolensäure gehemmt. Bei 100 μg ml^?1 war bei alien Isolaten die Bildung von Cholesterol und 5, 7-Ergostadienol, aber nicht Ergosterol, unterbunden.     

Toxicity of 1,2-dibromoethane and 1,3-dichloropropene to microsclerotia of Verticillium dahliae

The toxicity of two fumigants to microsclerotia (MS) of Verticillium dahliae in air and in soil was determined in sealed containers. 1, 2-Dibromoethane (DBE, ethylene dibromide) at 470 μ ml^?1 of air, or at 12.5 μ g^?1 of soil, killed 97% of the MS, both after incubation for 16 days. 1, 3-Dichloropropene (1, 3-D) at 20 μ ml^?1 of air, however, killed 100% of the MS after incubation for 30 h, and at 100 μ g^?1 of soil after incubation for 3 days. Higher temperatures increased the toxicity of both DBE and 1, 3-D to the MS. The toxicity of DBE increased with increase in soil moisture between 0–80% of field capacity while the toxicity of 1, 3-D increased between 0–20% of field capacity and was constant between 20–80% of field capacity.     

Impact of ant control technologies on insecticide runoff and efficacy

BACKGROUND: Insecticides are commonly used for ant control around residential homes, but post‐treatment runoff may contribute to contamination of surface water in urban watersheds. This study represents the first instance where runoff of insecticides was directly measured after applications around single family residences. During 2007, houses were treated with bifenthrin or fipronil sprays following standard practices. During 2008, pin stream applicators, spray‐free zones and restricting sprays to the house foundation were considered as management options. RESULTS: During 2007, the resulting runoff from the bifenthrin spray in the irrigation water had a mean concentration of 14.9 µg L^?1 at 1 week post‐treatment and 2.5 µg L^?1 at 8 weeks, both high enough to be toxic to sensitive aquatic organisms. In comparison, treatments with bifenthrin granules resulted in no detectable concentrations in the runoff water after 8 weeks. The mean concentration for fipronil used as a perimeter spray was 4.2 µg L^?1 at 1 week post‐treatment and 0.01 µg L^?1 at 8 weeks, with the first value also suggesting a potential for causing acute aquatic toxicity to sensitive organisms. During 2008, insecticide runoff was reduced by using spray‐free zones and pin stream perimeter applications. CONCLUSIONS: It is shown that insecticide runoff from individual home treatments for ants can be measured and used to improve techniques that minimize runoff. The pin stream application and applications limited to the house foundation should be further evaluated for their potential to reduce pesticide runoff from residential homes. Copyright © 2010 Society of Chemical Industry     

Aquatic dissipation of the herbicide triclopyr in Lake Minnetonka,Minnesota

A study of the aquatic fate of the triethylamine salt of triclopyr (3,5,6‐trichloro‐2‐pyridinyloxyacetic acid) was conducted in three bays of Lake Minnetonka, Minnesota. Triclopyr is under review by the US Environmental Protection Agency as a selective aquatic herbicide. The primary purpose of this study was to determine dissipation rates of the parent active ingredient, triclopyr, and its major metabolites, 3,5,6‐trichloropyridinol (TCP) and 3,5,6‐trichloro‐2‐methoxypyridine (TMP) in selected matrices including water, sediment, plants, finfish and shellfish. Two 6.5‐ha plots dominated by the weedy species Eurasian watermilfoil (Myriophyllum spicatum L) were treated with triclopyr‐triethylammonum at a rate of 2.5 mg AE liter⁻¹ (2.5 ppm) on 21–23 June 1994. A third 6.5‐ha plot was established as an untreated reference. Water and sediment samples were collected from within the plots and at selected locations up to 1600 m outside of the plots through six weeks post‐treatment for chemical residue analysis. In addition, residue samples were collected from the target and non‐target plants and other non‐target matrices, including game and rough fish, clams and crayfish. All test animals were sequestered in cages located in the center of each plot and samples were collected through four weeks post‐treatment. Half‐lives for dissipation of triclopyr and TCP in water ranged from 3.7 to 4.7 days and from 4.2 to 7.9 days, respectively, with trace amounts of TMP found. Peak triclopyr sediment values ranged from 257 to 335 ng gram⁻¹, with a mean half‐life of 5.4 days, while peak TCP sediment levels ranged from 27 to 65 ng gram⁻¹ (mean half−life = 11.0 days). Trace levels of TMP were detected at one treatment site at one sampling event. Triclopyr and TCP accumulated and cleared from animal tissues proportionately to concentrations in the water (triclopyr dissipation half‐lives <11 days, TCP < 14 days). TMP levels were two to three times higher than those of the other compounds, particularly in visceral tissue. In all cases, residues of these compounds were higher in the inedible portions of the animals, and were usually higher in bottom‐feeding fish species. © 2000 Society of Chemical Industry     

The action of insecticides on neurosecretory neurons in the stick insect, Carausius morosus

The action of insecticides on the spontaneous electrical activity of neurohemal tissue in the stick insect, Carausius morosus, has been studied using extracellular electrodes. The pyrethroid, permethrin, causes a massive increase in the frequency of the spontaneously generated action potentials at concentrations between 5 × 10^?5 and 5 × 10^?8M. Concentrations as low as 5 × 10^?11M are still effective in producing bursting activity.DDT, at concentrations between 5 × 10^?5M and 5 × 10^?6M, produces an overall increase in activity although the bursting activity is less violent than that shown with permethrin. DDT, 5 × 10^?7M, is ineffective at altering the resting pattern.Carbaryl and coroxon cause a transitory increase in electrical activity at 1 × 10^?4M, but are ineffective at 1 × 10^?5M.It is concluded that insecticides could have a direct effect upon the neurohormonal balance in insects.     

The determination of abamectin from soil and animal tissue by supercritical fluid extraction and fluorescence detection

The insecticide abamectin is extracted from soil and animal tissue by supercritical fluid extraction. Supercritical carbon dioxide modified with 9% 2-methoxyethanol extracted abamectin from soil samples at levels up to 11 ng g^?1 with greater than 80% efficiency. Recovery at fortification levels of 5 ng g^?1 were obtainable without the need for clean-up. Abamectin was also easily extracted from animal tissue at levels of 22ng g^?1 without interfering coextractives. Extracted abamectin was determined by liquid chromatography of a fluorescent derivative.     

Residues of synthetic pyrethroid insecticides on horticultural crops

Foliar applications of synthetic pyrethroids were made to several crops to determine residue levels at various intervals after application. On onions, residues of cypermethrin, permethrin and fenvalerate were negligible > 0.1 mg kg^?1, 7 days after application. On lettuce, residues of fenvalerate and permethrin were 0.8 mg kg^?1. On celery, residues of fenvalerate did not decline and ranged from 0.12 to 0.25 mg kg^?1 during the 14-day period. On green bush-beans, residues of permethrin and cypermethrin did not decline during the 14-day period and ranged from 0.1 to 0.6 mg kg^?1. By day 7, residues of cyfluthrin, cypermethrin, deltamethrin, fenvalerate and permethrin on strawberries were less than the acceptable maximum tolerance of 0.1 mg kg^?1 with the exception of cypermethrin, applied at the rate of 0.14 kg a.i. ha^?1 which gave a residue of 0.14 mg kg^?1.     

Fate of the benzoylphenyl urea CGA-184699 in the cat flea Ctenocephalides felis

HPLC was used to determine levels of the benzoylphenyl urea, CGA-184699, in cat blood, flea faeces and eggs. Rate constants were determined for the decline of CGA-184699 concentration in flea faeces of fleas that fed on both high (696 ng ml^?1) and low (305 ng ml^?1) host blood concentrations. There were strong correlations between the concentration of the drug in the host's blood and in flea eggs, between egg concentration and egg hatch and between the concentration of CGA-184699 in faeces and mortality to larvae feeding upon faeces.