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1.
The carrot fly (Psila rosae) is a major pest of umbelliferous crops, particularly in carrot production. This pest is present in temperate regions of Northern and Western Europe and also in the warm and dry climate of Central and Southern Europe. Currently, control strategies are limited and there may be a bottleneck of pest control solutions in the future. In practice, growers in the Netherlands mainly rely on a commercial, supervised control system which monitors the carrot fly population pressure. Possibilities to control the carrot fly after exceeding an economical threshold are reduced due to a lack of efficient chemical insecticides. Another option is the use of seed treatment to protect the carrots against the larvae developed from the first flight of the carrot flies for 12–14 weeks after sowing. The state of the art of the carrot fly pest and control possibilities are hereby discussed. Bottlenecks in control of carrot flies are highlighted and described.  相似文献   

2.
Carrot fly (Psila rosae) control in Switzerland appears not to have been a major problem during the years 1985–2000. However, reports on crop losses due to increased damage, and yield lots not complying with raised quality standards, have become more frequent in recent years. Carrot fly control has clearly become more difficult because the fly’s population dynamics have changed (3 generations instead of 2) and due to changes in the cropping system. Furthermore, some insecticides with high efficacy, such as soil insecticides, are no longer available. Seed treatments with various insecticides were tested as potential alternatives to no longer approved soil insecticides, but these were not efficient enough when infestation pressure was high. Spraying, mainly with pyrethroids against the flies landing on carrot leaves, proved to be successful in some plots if the flight of adult flies was monitored with sticky traps and the timing of the insecticide treatments was adequate. However, in other cases treatment efficacy was low, presumably due to less precise timing of the applications. In conclusion, current experience on supervised chemical control indicates that strategies can be adapted, but Swiss agricultural research stations are not yet able to provide the growers with validated recommendations.  相似文献   

3.
The application of granules containing 10 % phorate at 1.12,2.24 or 4.48 kg a.i./ha in a narrow slit together with carrot seed significantly reduced seedling emergence in both a mineral and peat soil. When the granules were applied at 2.24 or 4.48 kg a.i./ha in a narrow slit 2.5 cm below the seed, seedling emergence was adversely affected only at the higher rate in the mineral soil. Phorate granules applied with the seed in the peat soil gave a significantly lower plant density than when applied below the seed, but subsequent carrot yields were unaffected because much larger roots were produced. All phorate treatments gave effective reduction of carrot fly larval damage to the roots. On the peat soil, there were significant increases in total phorate residues present in mature carrots with increasing rate of phorate granules placed with the seed. Placement of the granules 2.5 cm below the seed resulted in a 50% reduction in total residues of phorate in whole carrots compared with placing the granules with the seed. Residues resulting from 1.12 kg a.i./ha with the seed or 2.24 kg a.i./ha 2.5 cm below the seed were not significantly greater than residues in untreated carrots.  相似文献   

4.
Partial plant resistance to the carrot fly, Psila rosae, has been identified in several Nantes varieties of carrot, Daucus carota, which reduces larval damage to the roots and the number of pupae remaining in the soil after cropping by 50%. The resistance of the Nantes variety 'Sytan' was found to be consistent at 12 sites in 5 European countries over two seasons. The resistance has been shown to be based on antibiosis and correlated with concentrations of chlorogenic acid in the roots. The resistance complements cultural and chemical methods for controlling P. rosae. Thus, in field experiments over two seasons it was shown that carrots could be left in the ground for a longer period providing a greater sowing/harvesting interval with a resistant variety than a susceptible one because of the reduction in damage and the delayed development of insects on the resistant variety. In two seasons at two sites a partially-resistant variety required only one-third of the dose of insecticide to provide a marketable crop compared with a susceptible carrot variety. In a breeding programme involving the variety 'Sytan', male sterile lines, inbreds and selections with improved levels of resistance were developed. Much higher levels of resistance were identified in certain wild Daucus species and 15 years of crossing and selection produced lines with significantly higher levels of resistance than exists in the variety 'Sytan'. A range of resistant carrot material bred at Horticulture Research International has been released to seed companies for use in the production of improved carrot varieties. The partially-resistant variety 'Flyaway' was made available to amateur gardeners in 1993 and to commercial growers in 1995 as a result of this research.  相似文献   

5.
Occurrence of ‘Candidatus Liberibacter solanacearum’ (CLso) was studied in field‐grown carrots (Daucus carota) in different regions of Finland. In addition, the frequency of CLso in carrots and in field populations of its vector, the carrot psyllid (Trioza apicalis), was studied in southwestern Finland. CLso was detected in six of the seven regions where the main carrot cultivation areas are located. The highest disease incidence was found in southwestern Finland, in the area where this carrot pathogen was originally found. In the Tavastia Proper and Southwest Finland regions, CLso was detected in 26 out of 30 randomly chosen fields inspected in 2013 and 2014, and in a third of those fields more than 10% of plants showed symptoms. Of those carrots showing both psyllid feeding‐associated leaf curling and CLso infection‐associated leaf discolouration symptoms, 77% were CLso positive in the PCR test. Some symptomless carrots from the affected fields also tested positive. Of the carrot psyllid individuals collected from the same area, 60% were CLso positive. Elsewhere, disease incidence was variable in South Ostrobothnia in western Finland and low but established in South Savonia in eastern Finland. CLso was not detected in the North Ostrobothnia region. Sequencing of the amplified DNA fragments confirmed that the bacteria in the carrot samples from different areas within Finland all represented CLso haplotype C. The frequent occurrence and wide distribution of this pathogen, transmitted by a psyllid that does not migrate over long distances, suggest that it is persistent in Finland.  相似文献   

6.
Insecticides have been extensively used for house fly control in China, with dichlorvos and deltamethrin being widely used. Knowledge about the current status of insecticide resistance and the underlying genetic changes is crucial for developing effective fly control strategies. The susceptibility to dichlorvos and deltamethrin, and the frequencies of genetic mutations involved in insecticide resistance were studied in five field populations of the house fly collected across China. Bioassay results show that flies exhibit 14- to 28-fold resistance to dichlorvos and 41- to 94-fold resistance to deltamethrin, indicating that dichlorvos and deltamethrin resistance are common in house fly populations in China. Molecular analysis reveals that flies from the five various locations carry resistance alleles at multiple loci and have diverse allelic types, different relative frequencies and combinations of each allele. Four non-synonymous single nucleotide polymorphisms (SNPs) (i.e. V260L, G342A/V, F407Y) in acetylcholinesterase (Ace) and two mutations (W251L/S) in a carboxylesterase (MdαE7) were commonly present in the field house flies. The L1014H rather than L1014F mutation in the voltage sensitive sodium channel gene (Vssc) was widely distributed in Chinese house flies. CYP6D1v1, which confers pyrethroid resistance, was found in all the five tested populations in China, although its frequency in house fly from Shandong province was very low. Our results suggest that resistance monitoring and management of house flies should be customized for a given location.  相似文献   

7.
Granular formulations of chlorfenvinphos and phorate were applied to sandyloam soil at 2 kg a.i./ha either broadcast and incorporated to 2.5 cm, broadcast and incorporated at 10 cm or by the bow-wave method along the carrot rows. Depth of incorporation did not influence the rates of residue decline in the soil. Bow-wave applications produced the highest residues in root and foliage and also reduced the rate of oxidation of phorate. 30 weeks after sowing the carrots, all treatments gave the highest residue concentrations in the uppermost 6 cm of carrot root. The peel of carrots grown in the soil treated to a depth of 10 cm contained 88 % and 23 % of the total chlorfenvinphos and phorate residues respectively. Significant differences were found in the residue concentrations in five carrot cultivars treated with chlorfenvinphos and phorate by the bow-wave method at 1.5 kg a.i./ha. The concentrations were inversely correlated with root size so that amounts of insecticide (μg/carrot) were similar in all cultivars. Prolonged growth of cv. Norfolk Giant slightly extended the period of uptake of chlorfenvinphos, but the uptake of phorate was ultimately less than its rate of dissipation. Neither the method of application nor the selection of carrot cultivar extended the period of uptake very greatly but differences which were obtained in residue concentrations in the carrot may become significant in the event of regulatory control of residue levels.  相似文献   

8.
Laboratory tests in a fly chamber and field trials in the UK and Australia have shown that permethrin, (3-phenoxybenzyl (1R,1S)-cis,trans-3-(2,2-dichlorovinyl)-2, 2-dime-thylcyclopropanecarboxylate) containing 25: 75 cis: trans isomers, applied as water emulsions to cattle and horses will control biting flies. Satisfactory protection against the stable fly, Stomoxys calcitrans (L.) and excellent control against the horn fly, Haematobia (Lyperosia) irritans (L.) was achieved on cattle. Good control was obtained on horses against the stable fly and the sand fly Culicoides spp. These early results are encouraging and toxicity and residue data suggest that permethrin would be a safe insecticide to use on livestock for the control of biting flies of veterinary importance.  相似文献   

9.
The carrot weevil, Listronotus oregonensis (LeConte) (Coleoptera: Curculionidae) is a major pest of carrots in northeastern North America. The females oviposit in the leaf petiole and the developing larvae make tunnels in the carrot roots. Exclusive reliance on chemical control and the poor control obtained, prompted, in the early 1980s, research on the ecology and physiology of the pest and its natural enemies. Carrot weevil females start their oviposition by 147±9DD7°C but they oviposit only in carrots past the 4 true-leaf-stage. As a result, oviposition is delayed, and damage reduced, in late-sown carrots. Monitoring carrot weevil adults in the spring with either carrot root sections or wooden plate traps enables growers to apply control treatments only if the population density justifies it. Egg parasitoids of the genus Anaphes (Hymenoptera: Mymaridae) are the most important natural enemies and they account, in untreated plots, for up to 80% mortality. Their effectiveness could be improved by managing field borders to establish secondary host species. An IPM programme was developed in the 1980s based on the research results obtained and, through regular monitoring, has achieved a substantial decrease in pesticide use.  相似文献   

10.
Cultivation procedures for the sugar beet crop continue to change considerably in England. The average contract per grower has increased from 3.4 in 1936 to 8.2 ha in 1973. Within the last decade the use of genetic monogerm seed has extended to 65% of the area sown, and pelleted seed to 90%. Seed spacing has doubled and the hand work needed to establish the crop drastically decreased. Much of the crop is now sown in March, instead of April or even May. The average yield of sugar has increased since 1936 from less than 3.6 to over 6 t ha?1. These changes have been associated with routine usage of fungicide and insecticide on seed and chemical weed control on 90% of the crop in recent years; insecticide, mainly organophosphorus, has been used to control aphids and virus on 36 000 to 125 000 ha of crop annually on the basis of spray warnings; sporadic pesticide control has been used against an abundance of seedling, leaf- and root-eating pests and fungi. The changes in cultural practices have been paralleled by changes in the relative importance of the various pests and diseases—for instance, wide seed spacing and the use of herbicide have intensified seedling pest problems. The extent to which crop losses from weeds, pests and diseases have been assessed as a basis for recommendations for control is discussed, as well as the economics of control by pesticides.  相似文献   

11.
A range of formulations of deltamethrin were prepared, some containing an ultraviolet (UV) absorber compound or a combination of the UV absorber and an oil, and applied to blue cotton tsetse fly target samples which were then exposed to the effect of simulated sunlight and water in the laboratory. The residue of insecticide remaining on the targets and the activity of the latter against tsetse flies was determined. Formulations containing the UV absorber and coconut oil or silicone oil remained the most effective against tsetse flies. A coconut oil formulation of the insecticide was selected for field evaluation in comparison with a commercial deltamethrin formulation, Glossinex 200′ S.C., which contains 10% UV absorber. Target samples treated with these formulations were exposed to natural tsetse fly habitat in Ghana for a period of five months and evaluated for deltamethrin residues and activity against four species of tsetse fly. After five months, 4–13 times more deltamethrin remained on the targets treated with the coconut oil formulation than on those treated with ‘Glossinex’, and consequently the former were more active against tsetse flies than the latter. Target samples sequentially dipped in the coconut oil formulation resulted in uniform insecticide concentration on the targets, whereas those dipped in ‘Glossinex’ contained gradually decreasing deltamethrin concentrations.  相似文献   

12.
Evaluation trials should provide a maximum of information with minimal effort. Conventional trials designed as randomised block layouts are simple but not very precise and they do not readily permit dose/response relationships to be explored. Semi-systematic designs, especially in conjunction with log-dose treatments, can largely overcome these problems. The types of information needed and factors influencing the design of machinery to apply granular insecticides to small plots are discussed. Different experiment designs were tested and standardised designs were developed for evaluating insecticides against cabbage root fly and carrot fly. Examples of results for insecticide efficiency against carrot fly and cabbage root fly and effectiveness in terms of cauliflower yield are given and side-effects involving phytotoxicity and non-selectivity are discussed.  相似文献   

13.
Experiments on the control of wheat bulb fly larvae by seed dressings compared four organophosphorus compounds in standard siliceous earth formulations with special formulations of the same compounds in polyvinyl acetate, polypropylene or wax. The special formulations allowed more insecticide to be placed on the seeds without affecting germination. Counting shoots damaged by wheat bulb fly larvae showed that: siliceous earth formulations of diazinon gave good control which was not improved by special formulations; control with siliceous earth formulations of dimethoate was poor and was improved only little by the special formulations; and control with siliceous earth formulations of parathion and dichlofenthion was moderate and was improved by special formulations, especially polyvinyl acetate and polypropylene. The results suggest that special formulations are of most value with compounds that are moderately effective but where the amount of insecticide in standard seed dressings cannot be increased without damaging the plants.  相似文献   

14.
Cavity spot is a major disease of carrots, causing cavities on the surface of the root. Available commercial varieties show a range of susceptibility but no significant resistance. Seed progeny from 46 tissue culture-derived carrot ( Daucus carota ) somaclones were screened for viability, then 19 selected somaclone families were sown under glasshouse conditions, along with commercial cultivars (Bertan, Nandor, Bolero and Vita Longa) as controls. Mature roots were exposed to Pythium violae in a cavity spot bioassay to determine their response as measured by disease incidence and severity. Some somaclones formed fewer lesions than the least susceptible control cultivar, Vita Longa. Seven somaclonal families that showed a range of susceptibility were sown under field conditions and the assessment was repeated. Although there was little relationship between glasshouse and field-trial results, under field conditions one of the somaclones had a mean incidence of disease, as estimated by transformed data, of 1·9 compared with 37·9 for the most susceptible somaclone and 3·5 for Bolero, the most resistant commercial cultivar. The results indicated that significant genetic variation in susceptibility to cavity spot disease was present in the somaclones.  相似文献   

15.
Picrotoxinin, a convulsant in mammals, was nontoxic when topically applied on whole house flies. When synergized with piperonyl butoxide, the topical LD50 of picrotoxinin on house flies was 6.50 μg/g or 260 times less toxic on house flies than the synergized insecticide, carbofuran, a carbamate cholinesterase inhibitor.When perfused on the isolated thoracic ganglion of house fly, picrotoxinin was less potent in producing convulsions than carbofuran; however, when assayed on the desheathed thoracic ganglion, picrotoxin was more potent than carbofuran. This suggested a substantial barrier to picrotoxinin preventing diffusion into the house fly central nervous system.Of several picrotoxinin analogs synthesized the 2-iodo,4-isopropyl, 6-methylenebromidecyclohexane-γ-lactone was the most potent convulsant.  相似文献   

16.
House flies were collected from dairies in New York state and the levels of resistance to commercially available insecticide formulations were measured on painted and unpainted plywood panels. Dimethoate was ineffective on all surfaces. The wettable powder permethrin formulation was more toxic than the emulsifiable concentrate formulation. The wettable powder cyfluthrin formulation was also more toxic than the recently developed liquid formulation. In general, the best house fly control was obtained on flat latex painted plywood panels and the poorest control on gloss latex painted panels. It is highly unlikely that producers obtain adequate control with dimethoate and permethrin.  相似文献   

17.
Resistance to insecticides remains a major problem for the successful control of the horn fly, Haematobia irritans irritans (L.), one of the most important pests of cattle in many countries including the United States. The organophosphate (OP) insecticide diazinon has been used to control pyrethroid-resistant populations of the horn fly. There are only a few reported cases of horn fly resistance to diazinon in the United States and Mexico. Piperonyl butoxide (PBO) has been used successfully as a synergist of pyrethroid insecticides to control horn flies. PBO-synergized diazinon products are also available for horn fly control in the United States, although PBO is known to inhibit the bio-activation of certain OP insecticides including diazinon. A study was conducted to evaluate the effect of PBO on diazinon toxicity to horn flies using a filter paper bioassay technique. These bioassays in both the susceptible and diazinon-resistant horn fly strains revealed a biphasic effect of PBO on diazinon toxicity to horn flies. PBO inhibited diazinon toxicity when the PBO concentration used was high (5%), and no effect was observed when PBO concentration was intermediate (2%). However, at low concentrations (1% and lower), PBO significantly synergized diazinon toxicity. We demonstrated that enhanced esterase activity was associated with survivability of horn flies exposed to diazinon alone. PBO has been shown to inhibit esterase activity in other insect species. However, results of biochemical assays with esterases from this study suggest that PBO did not have significant effect on the overall esterase activity in the horn fly. The observed synergistic effect of PBO at lower concentrations on diazinon toxicity to horn flies could not be explained by reduced esterase activity due to PBO inhibition. It is likely that PBO synergized diazinon toxicity at lower concentrations by facilitating penetration of diazinon through the cuticle and/or inhibiting the oxidative detoxification of diazinon, and reduced diazinon toxicity at high PBO concentration by inhibiting the bio-activation of diazinon.  相似文献   

18.
R. Collier  S. Finch 《EPPO Bulletin》2009,39(2):121-127
Carrot fly (Psila rosae) is a serious pest of umbelliferous crops such as carrot, parsnip, celery and parsley. Carrot fly has been studied in the UK for more than 60 years. Whilst some of these studies have been focused on insecticides, others have demonstrated the potential for non‐insecticidal methods of control that might contribute to an integrated pest management strategy. These include rotation and spatial separation of susceptible crops; carrot varieties with partial resistance to carrot fly; and crop management strategies to avoid oviposition or the development of severe damage. This paper outlines some of the approaches that have been taken and indicates how these are, or might be, used in practice.  相似文献   

19.
Fipronil is a relatively new insecticide with great potential for insect control, however widespread use of cyclodiene insecticides has selected for an A302S mutation in the Rdl (GABA gated chloride channel) allele. This mutation gives resistance to cyclodienes and limited cross-resistance to fipronil. Given the concern over the possible reduction in efficacy and/or lifetime that fipronil might be used for pest control (given the extensive use of cyclodienes in the past), it is important to know the frequency of the A302S Rdl mutation in field populations. To ascertain the relative frequency of the A302S Rdl mutation in house fly populations we used three experimental approaches. First, we attempted to select for fipronil resistance by initially treating 33,100 field collected flies and selecting 14 additional generations. We were unable to produce a highly resistant strain. Second, we directly sequenced field collected flies. Third, we tested field collected house flies with a diagnostic dose of dieldrin and then genotyped the survivors. Out of the 4750 flies tested, there were no Rdl resistance alleles detected. We conclude that the resistant Rdl allele is rare in house flies in the US due to decades without cyclodiene use and a fitness disadvantage (in the absence of cyclodienes) of the 302S Rdl allele. The limited cross-resistance provided by the cyclodiene resistant Rdl allele, combined with the very low frequency of this allele in field populations, suggests that fipronil could be a promising insecticide for house fly control.  相似文献   

20.
BACKGROUND: The housefly, Musca domestica L., and stable fly, Stomoxys calcitrans (L.) are cosmopolitan pests of both farm and home environments. Houseflies have been shown to be resistant to a variety of insecticides, and new chemistries are slow to emerge on the market. Toxicities of selected semiochemicals with molecular structures indicative of insecticidal activity were determined against adults from an insecticide‐susceptible laboratory strain of houseflies. The three most active semiochemicals were also evaluated against recently colonized housefly and stable fly strains. RESULTS: Nineteen semiochemicals classified as aliphatic alcohols, terpenoids, ketones and carboxylic esters showed toxicity to houseflies and stable flies. Rosalva (LC50 = 25.98 µg cm?2) followed by geranyl acetone and citronellol (LC50 = 49.97 and 50.02 µg cm?2) were identified as the most toxic compounds to houseflies. Permethrin was up to 144‐fold more toxic than rosalva on the susceptible strain. However, it was only 35‐fold more toxic to the insecticide‐tolerant field strain. The compounds generated high toxicity to stable flies, with LC50 values ranging from 16.30 to 40.41 µg cm?2. CONCLUSION: Quantification of LC50 values of rosalva, citronellol and geranyl acetone against susceptible housefly and field‐collected housefly and stable fly strains showed that semiochemicals could serve as potent insecticides for fly control programs. Copyright © 2010 Society of Chemical Industry  相似文献   

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