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1.
The species composition and seasonal cycle ofTetranychus urticae Koch (two-spotted spider mite) andEotetranychus uncatus Garman (garman spider mite; the two species were evaluated together),Amphitetranychus viennensis (Zacher) (hawthom red spider nite),Panonychus ulni (Koch) (European red mite),Bryobia rubrioculus (Scheuten) (brown mite) (Acari Tetranychidae),Cenopalpus pulcher Can and Fanz. (flat scarlet mite) (Tenuipalpidae) and their natural enemies (Phytoseiidae and Stigmaeidae family members) were compared in two apple orchards during the years 2000 to 2002 in Tokat, Turkey. One orchard was pesticide-free, and the other was sprayed. Surveys were carried out once a week from April to November and the differences in the dominant species of spider mites and phytoseiid mites between the two orchards were recorded. In the sprayed orchard, the dominant phytophagous mites wereA. vienensis andP. ulmi whereas in the unsprayed orchardE uncatus andC pulcher were abundant. It was found that the predatory mites were able to control spider mites in the unsprayed orchard, but the population level was not adequate to control them in the sprayed orchard, presumably due to the excessive use of pesticides.  相似文献   

2.
A 2-year survey of mite populations and pesticide use was carried out in Nova Scotia, Canada, in apple orchards where the two-spotted spider mite (Tetranychus urticae Koch) was the dominant phytophagous mite. Fungicides were the only class of pesticides that affected cumulative number ofT. urticae-days per leaf in tree canopies and colonization success — the ratio ofT. urticae-days to number of immigratingT. urticae caught in sticky bands on tree trunks. In 2000, increased numbers ofT. urticae-days in the tree canopy were associated with more frequent applications of ethylene bis-dithiocarbamate (EBDC) fungicides and with higher fungicide toxicity scores, which indicate cumulative level of suppression of the phytoseiid predatorTyphlodromus pyri Scheuten by all fungicide applications. Higher rates of colonization success were also associated with higher toxicity scores. EBDC’s applied in 2000 promotedT. urticae immigration as indicated by their counts on sticky bands. In 2000 and 2001, number ofT. pyri-days in the tree canopies was decreased by more frequent EBDC applications and by higher fungicide toxicity scores. Promotion ofT. urticae in tree canopies by EBDC’s was attributed to their toxicity toT. pyri. BothT. pyri and another phytoseiid,Amblyseius fallacis (Garman), were found in ground cover vegetation. Hence, increased immigration from the ground cover attributed to the toxicity of EBDC’s toT. pyri and, especially, toA. fallacis, which is a specialist predator of spider mites and an effective natural enemy ofT. urticae. http//www.phytoparasitica.org posting Sept. 13, 2006. Formerly, Atlantic Food and Horticulture Research Centre, now retired.  相似文献   

3.
为探寻具有杀螨潜力的生防真菌,采用喷雾法测定分析玫烟色虫草Cordyceps fumosorosea IF-1106菌株和球孢白僵菌Beauveria bassiana BB-1339菌株对朱砂叶螨Tetranychus cinnabarinus和二斑叶螨Tetranychus urticae卵、幼螨及雌成螨的致病力。结果表明,感染玫烟色虫草IF-1106菌株和球孢白僵菌BB-1339菌株后螨类的形态特征不一致,感染IF-1106菌株后形成棉絮状菌丝,而感染BB-1339菌株后则形成羊毛状菌丝。IF-1106菌株和BB-1339菌株对朱砂叶螨和二斑叶螨卵的LC50分别为2.38×107、8.26×107CFU/mL和4.48×107、1.21×108CFU/mL,对朱砂叶螨和二斑叶螨幼螨的LC50分别1.97×107、8.26×107CFU/mL和7.65×106、8.99×105...  相似文献   

4.
The effects of Neemgard, an acaricidal and fungicidal formulation obtained from neem (Azadirachta indica) seed kernels, on the phytophagous miteTetranychus cinnabarinus, the predacious mitePhytoseiulus persimilis, and the predatory spiderChiracanthium mildei, were investigated in laboratory experiments. Neemgard was highly toxic toT. cinnabarinus but had no toxic effect onC. mildei orP. persimilis. Another neem formulation—the insecticidal Neemix 45—caused conspicuous repellency, but no mortality, inT. cinnabarinus.  相似文献   

5.
F. Mansour 《Phytoparasitica》1988,16(3):239-245
Dosage mortality data for 12 pesticides were determined with females of an insecticide-susceptible strain of the carmine spider mite,Tetranychus cinnabarinus (Boisd.), by the slide dip method; for four of the pesticides which are specific acaricides, also the Munger cell method was used. The LC50s ranged from 0.00078% to 0.041%, with the synthetic pyrethroids being more toxic than the specific acaricides. There were no differences in results between the two assay methods. Four synthetic pyrethroids that were very active againstT. cinnabarinus in laboratory tests were examined in an unsprayed apple orchard for their effect on the population density of spider mites. An upsurge of tetranychid mites was noted 4 weeks after a single application  相似文献   

6.
The spider mites Tetranychus urticae Koch and Panonychus ulmi (Koch) (Tetranychidae) cause severe economic losses to vegetable farms and deciduous fruit orchards in Turkey. One of their predators, the ladybird beetle Stethorus gilvifrons (Muls.) (Col., Coccinellidae), aggregates on mite-infested patches of plants. The present study assessed whether there is a role for herbivore-induced plant volatiles (HIPVs) and/or odors emitted directly from these two mite species in the aggregative response of ladybird beetles. The olfactory responses of the predator females to volatiles from T. urticae- and/or P. ulmi-infested sweet pepper (four cultivars, viz. ‘Demre’, ‘Yalova Carliston’, ‘Kandil Dolma’ and ‘Yag Biberi’), kidney bean (cv. ‘Barbunya’) and apple (M9 rootstock) were investigated using a two-choice olfactometer. Our results showed that HIPVs emitted from both T. urticae- and P. ulmi-infested plants significantly attracted S. gilvifrons adults for all plants except the sweet pepper cv. Yag Biberi. In addition, it was found that volatiles from apple plants infested by T. urticae and, especially, P. ulmi are more attractive for S. gilvifrons females than those emitted by other infested plants. The results also suggest that the odors of T. urticae adults and their products might influence the attraction of S. gilvifrons females.  相似文献   

7.
Through incubation of onion (Allium cepa L.) seed samples on potato dextrose agar and moist filter papers at 28±2°C, 32 species and four varieties belonging to 19 genera of fungi were determined as seedborne in this crop. Among them, 23 species are new reports to the mycoflora of onion seeds.Aspergillus (11 species and three varieties, ∼42.1% of the total colony count of fungi) was the most prevalent genus:A. niger (∼19.7%) was found at the highest rate in the seeds, followed byA. parasiticus (∼17.3%,A. oryzae (∼17.3%) andA. flavus (∼14.5%). The genusAspergillus was followed byPenicillium (∼12.4%),Sclerotium (∼7.1%),Fennellia, Rhizopus, Chaetomium, Drechslera andAlternaria (∼12.4%),Fusarium, Emericella andByssochlamys (∼7.1%), whereas the remaining eight genera displayed a low level of infection (∼10%). Twenty-seven species, three varieties and 12 genera represent Hyphomycetes; four genera, three species and one variety — Ascomycotina; one genus and one species — Zygomycotina; two genera and two species — other Deuteromycotina; and one genus — Oomycetes. Some species, which are known to cause devastating pre- and postharvest diseases to onion crops, were recovered from the seeds of this crop, suggesting the high possibility of their transmission by seed. http://www.phytoparasitica.org posting July 14, 2004.  相似文献   

8.
In the present study,Cnaemidophorus rhododactyla (Denis & Schiffermüller) (Lepo Pterophoridae) was noted for the first time as a pest ofRosa spp. in Turkey. The larva ofC. rhododactyla makes a cavity by feeding in the flower-bud and destroys at least 60% of the mass of the flower-bud. There are approximately 12 species ofRosa in Erzurum and Kars provinces, butRosa dumalis Bechst. andR. subcanina L. suffered more damage than the otherRosa species. One species of Tachinidae (Diptera) —Pseudoperichaeta palesoidea (Robineau-Desvoidy), and two species of Ichneumonidae (Hymenoptera) —Sinophorus turionus (Ratz.) andScambus brevicornis Gravenhorst, were reared as larval parasitoids ofC. rhododactyla. C. rhododactyla is a new host record for these parasitoids. Additionally,S. turionus is a new record for the Turkish fauna.  相似文献   

9.
A survey of common and uncommon weed species usually showing Verticillium wilt symptoms was carried out during 1992–2000 in Crete, Greece.Verticillium dahliae was isolated in 48 out of 182 sampled fields, in which several weed species were grown, from several locations in Oropedio, Lasithi. Altogether, 124 isolates ofV. dahliae were recovered from the vascular stem-tissue of 19 weed species, belonging to ten botanical families. Pathogenicity trials with 13 out of 19 weed species that have never been reported as hosts of the fungus, using for inoculation isolates which originated from the same weed species, resulted in infection of all of them, showing various disease symptoms. Seven weed species (Anthemis melanolepis, Cardaria draba, Convolvulus arvensis, Erodium sp.,Euphorbia helioscopia, Helminthotheca echioides andSinapis alba) are new hosts worldwide, and six additional species (Euphorbia sp.,Lactuca serriola, Raphanus raphanistrum, Sinapis arvensis, Sonchus oleraceus andTrifolium sp.) are new hosts for Greece. The most susceptible (isolation frequency: 27.9–52.8%, moderate disease severity) species were:Capsella bursa-pastoris, C. draba, Chenopodium album, Senecio vulgaris andSolanum nigrum. Less susceptible (isolation frequency: 4.8–17.8%, slight disease severity) were:Amaranthus sp.,A. melanolepis, C. arvensis, Erodium sp.,Euphorbia sp.,E. helioscopia, H. echioides, L. serriola, Malva sylvestris, R. raphanistrum, S. alba, S. arvensis, S. oleraceus andTrifolium sp. Some species —C. draba, C. album, L. serriola andS. nigrum L. — that usually showed external and vascular wilt symptoms, occasionally exhibited only reduced growth. Visible symptoms under natural field conditions in all 13 weed species that had never been reported as hosts ofV. dahliae were similar to those observed after their artificial inoculation. The fungus was not isolated fromFoeniculum vulgare ssp.piperitum, Oxalis corniculata andStellaria media, among other species. http://www.phytoparasitica.org posting Sept. 18, 2002.  相似文献   

10.
The research into the side effect of fungicides used in the control of the most serious disease in apples (Venturia inaequalis) i. e. the research into the influence of fungicides on the population of phytophagous mites, was carried out at Nedeliŝće (North-West Croatia) during 1997 and 1998. The study is related to the population of the mites most present in apple orchards, such as red spider mite (Pananychus ulmi) and other mites (Aculus schlechtendali andTetranychus urticae). Fungicides which are known to be effective against scab, i. e.Venturia inaequalis, and used in fruit production in Croatia, were tested in order to investigate their secondary properties which have not yet been studied. The following fungicides were used: cyprodinil, dodine, dichlofluanid + bitertanol (as tank mix), and kresoxim-methyl. The tests were repeated three times; the application time was determined by monitoring the conditions for infection. The treatments were done curatively, i. e. up to 96 h after the onset of infection conditions. The mite population was estimated by the pressing method, which yielded the average number of mites per leaf. All the results were statistically processed by variance analysis and by Duncan’s Multiple Range Test, and are presented graphically and in tables. The paper also presents graphically the climatic conditions, scab infections and application time. The research over two years have shown a pronounced suppressive effect of dichlofluanid + bitertanol on populations of phytophagous mites, while the other fungicides used in the research had a neutral effect on the mite papulation.  相似文献   

11.
In recent years, the spread of Verticillium wilt in olive orchards, caused by the soil-borne pathogen Verticillium dahliae, is often related to intensive modern farming of highly productive cultivars, planted at high densities, usually irrigated, and under a mechanised system. The effects of agricultural factors associated with olive orchards were investigated in an important olive-growing area in southern Spain, as tools in predicting outbreaks of the disease. A stratified double-sampling technique was designed to determine the number of olive orchards needed to survey. A sampling survey was conducted from 2002 to 2005 in 873 olive orchards randomly selected, the owners were interviewed for details of agronomic factors, and orchards were inspected for the presence or absence of the disease. Polymerase chain reaction assays were carried out for identifying V. dahliae pathotypes. Pathogen prevalence showed a significant linear correlation with the mean plant density (r 2 = 0.93), associated predominantly with a less virulent non-defoliating pathotype (r 2 = 0.96). Overall, irrigation × high density caused disease incidence to peak in super-high-density olive-tree-planting systems. Olive orchards that had V. dahliae, however, did not differ in pathogen prevalence regardless of the olive cultivars. Young olive orchards were significantly more affected by V. dahliae than were old ones, particularly orchards with trees 8 to 12 years old. Irrigation increased pathogen prevalence and disease incidence in very young orchards (<7 years old). The prevalence of the non-defoliating pathotype was statistically high in young orchards whereas the prevalence of a highly virulent defoliating pathotype was high in old orchards.  相似文献   

12.
Five field experiments were performed in commercial orchards located in Lleida (Spain) over three growing seasons, 2000–2002, in order to estimate the relationship between the incidence of latent infection caused by Monilinia spp. in peaches and the incidence of post-harvest brown rot. No latent infection was recorded at popcorn and the maximum incidence occurred pre-harvest; in some orchards a second peak was detected during the pit hardening period. Monilinia laxa is the most prevalent species isolated from peaches with brown rot. There was a positive correlation between the incidence of latent infection and that of post-harvest brown rot. The average incidence of latent infection during the crop season explained 55% of the total variation in the incidence of post-harvest brown rot. The effect of temperature (T) and duration of wetness (W) on the incidence of latent infection in peach and nectarine orchards was analysed using multiple regression. The regression analysis indicated that T and W jointly explained 83% of the total variation in the incidence of latent infection. The model predicts no latent infections when T < 8°C, and >22 h wetness are required when T = 8°C but only 5 h at 25°C are necessary for latent infection to occur. The incidence of brown rot and latent infection of peaches caused by M. laxa under controlled experimental conditions were also affected by T and W, as well as by fruit maturity and inoculum concentration. Latent infections were produced in fruit when T was not suitable for the development of brown rot symptoms. In these experiments more than 4–5 h of daily wetness were required after embryo growth in fruit sprayed to run-off with an inoculum concentration higher than 104 conidia ml−1 of M. laxa for brown rot and latent infections to develop. The fitted model obtained from the field data was able to predict the observed data obtained under controlled environmental conditions.  相似文献   

13.
The Hatay population of the predatory mitePhytoseiulus persimilis Athias-Henriot was released into a commercial field of cv. ‘Chandler’ strawberries for the control ofTetranychus cinnabarinus Boisduval (Acari: Phytoseiidae: Tetranychidae) in 2000 and 2001 in Silifke county of Icel on the East Mediterranean coast of Turkey. In 2000, populations ofT. cinnabarinus were recorded in the field from the beginning of March in most plots, and increased gradually until mid-May.T. cinnabarinus populations declined to very low levels in all predator release plots approximately 2 weeks after reaching a peak. In general, predator populations rose linearly as the population densities of spider mites increased until mid-May.P. persimilis numbers peaked during the period 16–23 May. A similar scenario developed in 2001, but because of the relatively high number ofT. cinnabarinus in all plots at the beginning of the experiment, bothT. cinnabarinus andP. persimilis peaked almost one month earlier than in 2000. In both years, the Hatay population ofP. persimilis demonstrated good potential for the control ofT. cinnabarinus in field-grown strawberry in the Silifke region of Icel. http://www.phytoparasitica.org posting Sept. 19, 2002.  相似文献   

14.
Twenty-nine plant extracts of local species were evaluated for their potential as a source of bioactive ingredients with significant acaricidal activity that could lead to the development of new and safe bio-acaricides. The crude extracts (70% ethanol) of these plants were tested for their acaricidal activity against the carmine spider miteTetranychus cinnabarinus in a bioassay under controlled conditions. Mortality, repellency, and the number of eggs laid were measured. Extracts fromEucalyptus camaldulensis andInula viscosa caused more than 25% mortality. Sixteen plant extracts showed significant repellency compared with the control. The six best extracts, resulting in more than 75% repellency, were fromAllium sativum, Capparis spinosa, Cupressus sempervirens, Lupinus pilosus, Rhus coriaria andTamarix aphylla. Extracts from 16 plants were found to cause a significant reduction in the number of eggs laid compared with the control. The greatest reduction was achieved by extracts fromC. spinosa, Cyperus rotundus, E. camaldulensis, L. pilosus, Punica granatum, R. coriaria andT. aphylla. A relatively negative fit was found between the mean number of repelled mites and the number of eggs laid (r=−0.65), which might indicate that most repelled mites were unable to lay eggs before leaving the leaf discs of the bioassay. Our results show that several plant extracts have good potential for acaricidal activity and are worth further investigation. http://www.phytoparasitica.org posting Dec. 16, 2003.  相似文献   

15.
Four spider species and the predacious mitePhytoseiulus persimilis (Athias-Henriot) were examined in the laboratory for their capacity to feed on the carmine spider mite,Tetranychus cinnabarinus (Boisduval). The adult females ofChiracanthium mildei L. Koch showed the highest capacity for feeding onT. cinnabarinus (27.5 mites/day) and differed significantly from all other spider species, including the immatureC. mildei which consumed an average of 18.9 mites/day — nearly equal to that of the Oxyopidae species (16.8 mites/day). The salticid (10.1 mites/day) and theridiid (9.5 mites/day) spider species had the lowest capacity, which was nearly equal to that of the predacious miteP. persimilis (11.3 mites/day). Results indicate that spiders play an important role as mite predators.  相似文献   

16.
The efficacy of oxolinic acid (at 200 and 300 μg a.i./l) and of several antibiotic compounds (streptomycin sulfate at 100 μg a.i./l, glycocide B at 700 μg a.i./l, kasugamycin at 80 μg a.i./l and gentamicin sulfate at 30 and 60 μg a.i./l) againstErwinia amylovora, the causal agent of fire blight in pears, was evaluated in 43 orchard experiments in 1997–2000 in Israel. In addition to the above orchard experiments, the efficacy of the bactericides was tested in live experiments with artificial inoculation. Natural fire blight symptoms were observed in 16 of the 43 experiments; in 13 of them, disease intensity and its distribution among the experimental plots provided a basis for data analysis, leading to reliable conclusions concerning the efficacy of the tested bactericides. Oxolinic acid at 300 μg a.i./l was highly effective againstE. amylovora and reduced disease severity significantly in all experiments, as compared with the untreated plots; however, a concentration of 200 μg a.i./l was not effective in some cases. Among the tested antibiotics, only gentamicin sulfate was as effective as oxolinic acid. Results of the artificial inoculation experiments corroborated those obtained in the naturally infected orchards. The pre-infection activity of oxolinic acid was determined on blossom clusters that were sprayed with the bactericide before inoculation. Control efficacy on blossom clusters sprayed 1–4 days before inoculation ranged from 68% to 80%, a level which did not differ significantly from that observed on blossom clusters sprayed on the day of inoculation (80% control). The postinfection activity of oxolinic acid was determined on blossom clusters that were sprayed with the compound after inoculation. Oxolinic acid was as effective when applied 1 or 2 days after inoculation as when it was applied on the day of inoculation; however, application of the bactericide 3 days after inoculation no longer resulted in significant disease suppression. Oxolinic acid has been used commercially in Israel since 1998 with appreciable success. Contribution No. 533-00 from the Agricultural Research Organization  相似文献   

17.
The present study was carried out in a flat storeroom in central Greece, filled with approximately 60 tons of newly harvested wheat, in order to evaluate the population dynamics of stored-product mites and their predators in connection with horizontal and vertical distribution. At 15-day intervals, from July 2000 until March 2001, three replicates were taken from each sampling point at depths of 0–40, 40–80 and 80–120 cm, with a partitioned grain trier. The sampling points were divided into two zones, namely, central and peripheral. Air temperature, relative humidity, grain moisture and grain temperature were recorded during the sampling period. Twenty-four mite taxa were found, the dominant species beingTyrophagus putrescentiae (Schrank) andAcaropsis docta (Berlese). The numbers of these species varied significantly in the two zones and at the three depths. More individuals were found in the center compared with the periphery of the wheat bulk, and at the surface of the bulk than at greater depths. The highest mite population densities for the total mite species were recorded during October–November and after the middle of January. http://www.phytoparasitica.org posting Nov. 4, 2005.  相似文献   

18.
Several new isolates ofBacillus thuringiensis Berliner have shown significantly higher levels of insecticidal activity than the previous best isolates (Bt24-entomocidus and IH-A-aizawai) against bothSpodoptera littoralis Boisd. andSpodoptera exempta Walker. The best ones, in the following descending order of potency, were: againstS. littoralis — K26–21, MF4B–2, MR1–37, K28–30, K26–8; againstS. exempta — Bt-3, K30–3, HD-133, MR1–37, Bt-17, K26–8, K26–21, MF4B-2, HD-593. Larvae ofS. exempta were considerably more susceptible (4.12–1.25 fold) to some of the isolates (Bt-3, K30–3, HD-133, MR1–37, Bt-17, K26–8, HD-593) thanS. littoralis.  相似文献   

19.
Hawthorn (Crataegus monogyna) is one of the natural hosts of Cacopsylla melanoneura, the acknowledged vector of ‘Candidatus Phytoplasma mali’, the causal agent of Apple Proliferation disease, a serious and growing problem for apple production in Europe, particularly in northern Italy. Wild plants could be important sources of both insects and phytoplasmas, but their role in the epidemiology of phytoplasma diseases and their insect vectors has never been thoroughly examined. Cacopsylla melanoneura’s primary host is hawthorn, a plant closely related to apple which often grows wild near orchards. Other psyllid species feed on hawthorn, but no data are available on their possible role as phytoplasma vectors. We investigated the hawthorn’s psyllid fauna in northwestern Italy using yellow sticky traps, beat trays, and molecular analyses from 2003–2005, to study the relationship between hawthorn, the phytoplasma and the insect vector. Population dynamics were monitored, and insects and hawthorn samples were analysed by polymerase chain reaction (PCR), restriction fragment length polymorphism (RFLP), and DNA sequencing for the presence of phytoplasmas. Cacopsylla melanoneura was the dominant psyllid species, followed by C. peregrina, C. affinis and C. crataegi. PCR and RFLP analyses revealed the presence of different fruit tree phytoplasmas in hawthorn plants, and in all four psyllid species.  相似文献   

20.
Fifty strains of Erwinia amylovora isolated in Bulgaria from different host plants and locations as well as in different years were analysed by RFLP analysis of the pEA29 PstI amplified fragment with HpaII. All the strains formed three well-resolved fragments (large—from 365 to 440 bp, medium—about 341 bp and small—about 180 bp).The strains were classified into three RFLP groups based on the polymorphism in the length of the largest fragment. This fragment was of intermediate size for 63% of the strains, and it was the longest (from 410 to 440 bp) for 29% of the strains. The variable region was sequenced for five strains. The DNA sequence analysis confirmed the different size of the largest fragment. Ten or more than ten SSRs were found for the strains in the group with the largest size of the largest fragment. Some correlation between the RFLP profiles and the origin of the strains was revealed. The RFLP profiles displayed stability in certain strains isolated from the same trees and orchards, but in different years. The number of SSRs was different in strains isolated from one and the same host plant, orchard and year, and also in strains isolated from the same host plant and orchard, but in different years. This could indicate that under natural conditions the fire blight symptoms might be caused by a mixture of E. amylovora strains with different SSR numbers, and so coexistence of distinguishable strains or a change in the population could be assumed.  相似文献   

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