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1.
Experiments with fungicide mixtures used protectively and curatively against apple scab showed no advantage from adding phenylmercury chloride (PMC) to certain protective fungicides. Sulphur fungicides greatly impaired the curative activity of PMC, especially in mixtures applied 24 hr. after infection, but captan showed little and dodine acetate no such effect. PMC, however, contributed appreciably to the curative effectiveness of mixtures with captan or dodine acetate. Commercially prepared mixtures of dispersible sulphur with phenylmercury dimethyldithiocarbamate and of zineb with mancozeb gave promising results, and an experimental mixture of dodine/glyodin acetates at low rates was effective protectively and especially curatively. Dodine acetate, dichlofluanid, lime-sulphur, and isobutyl-o-coumarate showed little translocated activity against scab when applied after infection, and PMC, which earlier showed strong translocated activity when applied in summer before infection, was much less effective when applied in spring 24 hr. after infection. Uncontrolled powdery mildew early in the scab-incubation period greatly reduced the establishment of scab infection on the test plants (clonal root-stocks); methods of mildew control in such experiments are suggested.  相似文献   

2.
Glasshouse experiments on apple scab   总被引:1,自引:0,他引:1  
Dilutions of various fungicides were compared on potted MM 109 clonal rootstocks in the glasshouse for protective (pre-infection) and curative (post-infection) activity against apple scab. The materials, as commercial preparations, included captan, copper (as ‘dry’ Bordeaux mixture), dichlofluanid, didecyldimethylammonium bromide (DDAB), dispersible sulphur, dithianon, dodine acetate, lime-sulphur (LS), phenylmercury chloride (PMC), and thiram; they were assessed on the basis of percentage active ingredient in the dilutions. When acting at normal rates of use, many of the fungicides were much more effective protectively than curatively, but this contrast was less applicable to DDAB, dodine acetate, LS, and dichlofluanid. PMC, however, was an especially notable exception in proving curatively superior at unusually low rates. In addition, it was particularly active in vapour form, and was effectively translocated not only from one leaf surface to the other, but, especially at 0.005%, from sprayed to younger unsprayed leaves on the same shoots. Other standard fungicides showed little or no translocated activity, but isobutyl-o-coumarate was effective at the growing shoot-tips in spring from a spray applied to the lower leaves. PMC reduced infection when applied once at any time during the scab-incubation period, and especially 24 hr. after infection, when the control was almost complete. Longer intervals before spraying reduced the curative action, but not in proportion to the intervals; the infection pattern showed multi-peak fungicidal activity and, after the later sprays, many lesions were practically infertile. The curative properties of PMC were matched by several other formulated phenylmercury salts compared at equivalent percentage mercury content, but the dimethyldithiocarbamate proved rather less effective. A preliminary attempt to supplement the curative properties of PMC with the protective properties of LS, by mixing these fungicides at low rates, showed evidence of fungicidal antagonism, and this needs further investigation. Several fungicides, notably the inorganic sulphurs, thiram, the phenylmercury compounds, dichlofluanid, and DDAB showed incidental activity against natural infection by powdery mildew.  相似文献   

3.
Benomyl (0.025% a.i.) and thiabendazole (0.05 % a.i.) applied in July, August and September to apple trees cvs. Sunset and Cox's Orange Pippin gave slightly better control of Gloeosporium spp. rots in stored fruit than captan (0.1% a.i.) applied at similar intervals. On Cox's Orange Pippin, treatment with captan at 0.1 % a.i. in July and at 0.2% a.i. in August was as effective as three sprays at 0.1 % a.i. in July, August and September in controlling both Gloeosporium spp. and Nectria galligena rots. Benomyl applied in the spring and early summer to control apple scab on orchard trees reduced the incidence of Gloeosporium spp. and Monilia fructigena in stored fruit. Pre-harvest sprays of benomyl and captan gave good control of rotting caused by N. galligena but thiabendazole was ineffective. Post-harvest dips of thiabendazole controlled rotting by Gloeosporium spp. butnot byN. galligena.  相似文献   

4.
Efficacy and phytotoxicity of lime sulphur in organic apple production   总被引:3,自引:0,他引:3  
Curative and preventive efficacy and phytotoxicity of lime sulphur spray schedules, based on a warning system, were evaluated in the Netherlands during two growing seasons under field conditions. In most cases, lime sulphur treatments applied either curatively or preventively resulted in significantly lower scab damage on both the leaves and fruits compared to wettable sulphur treatments. However, all lime sulphur treatments showed high phytotoxicity values, reduced leaf size and had a tendency to a reduced yield quality compared to all other treatments. For curative schedules of lime sulphur on scab control, phytotoxicity and yield did not differ significantly from preventive schedules of lime sulphur. However, the use of a warning system combined with curative schedules of lime sulphur saved one and two lime sulphur sprays in 2000 and 2001, respectively, compared to the preventive treatments of lime sulphur. Our results demonstrated that a curative spray programme with lime sulphur at 0.75–2%, applied 35–45 h after predicted infection periods, can provide effective primary apple scab control, but no benefit in either yield or fruit quality was reached under organic growing conditions. Moreover, research herein clearly showed that organic growers are forced to find a balance between good efficacy and phytotoxic effects of lime sulphur.  相似文献   

5.
In vitro experiments showed that ammonium bicarbonate and aqueous extracts of oregano were effective in inhibiting conidia germination and germ‐tube elongation of Venturia inaequalis. Complete inhibition was achieved by 1% ammonium bicarbonate, 2% oregano extract and 0.01% synthetic fungicide difenoconazole. Two orchard experiments were conducted on the highly susceptible cv. Mutsu to apple scab to investigate the efficacy of ammonium bicarbonate alone or in combination with an aqueous extract of oregano for the control of apple scab. In 2008 and 2009, except for the applications of 1% aqueous extract of oregano, the applications of ammonium bicarbonate (0.5 and 1%) and difenoconazole (0.01%) to trees at 10‐day intervals significantly reduced disease incidence and severity on leaves and fruit compared to the water‐treated control. In both years, the efficacy of 0.5 and 1% ammonium bicarbonate in inhibiting both disease incidence and severity on leaves and fruit was equally effective in all monthly assessments from June to September. Combining 0.5 and 1% ammonium bicarbonate with 1% aqueous extract of oregano did not significantly improve the efficacy of stand‐alone applications of treatments in the final assessment in 2008 and 2009. All treatments were neither phytotoxic to leaves and fruit nor did they adversely affect quality parameters of fruit including physiological disorders and taste both at harvest and after storage. These results indicate that ammonium bicarbonate treatment may be applied as an alternative chemical for the control of apple scab.  相似文献   

6.
A 3‐year field trial was conducted using established apple cv. Crown Gold and English oak (Quercus robur L.) to assess the efficacy of eight fungicides applied via microcapsule trunk injection against the foliar pathogens apple scab (Venturia inaequalis) and powdery mildew (Phyllactinia sp). In both apple cv. Crown Gold and English oak, the fungicide myclobutanil was not taken up when microcapsules were inserted into the tree vascular system at the root flare. Disease severity in injected trees, excluding myclobutanil, was lower over the following two growing seasons compared to water‐injected controls indicating seven of the eight fungicides used in this study provided a significant degree of protection against scab and powdery mildew infection. A difference in the magnitude of pathogen control achieved was recorded between fungicides. Of the fungicides tested, penconazole, pyrifenox and carbendazim significantly reduced disease severity and significantly increased leaf chlorophyll (Fv/Fm) and SPAD values as a measure of tree vitality and chlorophyll content, respectively, in both apple cv. Crown Gold and English oak over two growing seasons after microcapsule injection. Based on the results of this investigation, it is suggested that these three fungicides be used in preference to thiabendazole, fosetyl‐aluminium, triadimefon and propiconazole for the control of apple scab and powdery mildew where outbreaks of these foliar pathogens are problematic.  相似文献   

7.
In a previous study, it was observed that Microsphaeropsis ochracea was less efficacious as a biofungicide for apple scab when applied under field conditions as an unformulated spore suspension with an airblast spray using low water volumes as compared to a ground cover spray using high water volumes. The effect of spore concentration (109 to 1012 spores ha?1), water volume (250–1500 L ha?1), and 20 adjuvants were studied to improve colonization of apple leaves by M. ochracea. Using commercial-type spray equipment, the fungus was applied to excised apple leaves. Higher spores concentrations resulted in greater colonization. Water volume did not have a strong impact on colonization. Only a few adjuvants improved germination (glycerine) and mycelial growth (K-90, Agrimer, Ekol, and Tween 80) in some trials. When tested on apple trees, the adjuvant Assist provided the most consistent improvement in colonization in five out of eight trials. The use of oils, humectants, and surfactants could broaden the opportunities for using this biofungicide.  相似文献   

8.
Breeding for scab-resistant apple cultivars by pyramiding several resistance genes in the same genetic background is a promising way to control apple scab caused by the fungus Venturia inaequalis. To achieve this goal, DNA markers linked to the genes of interest are required in order to select seedlings with the desired resistance allele combinations. For several apple scab resistance genes, molecular markers are already available; but until now, none existed for the apple scab resistance gene Vbj originating from the crab apple Malus baccata jackii. Using bulk segregant analysis, three RAPD markers linked to Vbj were first identified. These markers were transformed into more reliable sequence-characterised amplified region (SCAR) markers that proved to be co-dominant. In addition, three SSR markers and one SCAR were identified by comparing homologous linkage groups of existing genetic maps. Discarding plants showing genotype–phenotype incongruence (GPI plants) plants, a linkage map was calculated. Vbj mapped between the markers CH05e03 (SSR) and T6-SCAR, at 0.6 cM from CH05e03 and at 3.9 cM from T6-SCAR. Without the removal of the GPI plants, Vbj was placed 15 cM away from the closest markers. Problems and pitfalls due to GPI plants and the consequences for mapping the resistance gene accurately are discussed. Finally, the usefulness of co-dominant markers for pedigree analysis is also demonstrated.  相似文献   

9.
In vitro experiments indicated that boric acid, monopotassium phosphate, sodium metabisulfite and synthetic fungicide fluopyram + tebuconazole were effective in inhibiting conidia germination and germ‐tube elongation of Venturia inaequalis. Monopotassium phosphate even at the highest concentration used in the study reduced conidia germination and germ‐tube elongation of V. inaequalis by 22.1% and 28.8%, respectively; however, the difference between two compounds at lower concentrations except 0.05% (for conidia germination) and 0.1% (for germ‐tube elongation) of boric acid was statistically significant (P ≤ 0.05). Complete inhibition was achieved by 0.01% sodium metabisulfite, 0.035% fluopyram + tebuconazole and 0.2% boric acid. Two orchard trials were conducted on the highly susceptible cv. Mutsu to apple scab to ascertain the efficacy of 0.2% boric acid, 0.5% monopotassium phosphate, 0.5% sodium metabisulfite and 0.035% fluopyram + tebuconazole for the control of apple scab. In both 2013 and 2014, except for the applications of monopotassium phosphate and sodium metabisulfite, the applications of boric acid and fluopyram + tebuconazole to trees at 10‐day intervals significantly reduced disease incidence and severity on leaves and fruit compared to the water‐treated control. In both years, the efficacy of boric acid and fluopyram + tebuconazole treatments was similar in reducing both disease incidence and severity on leaves and fruit in all monthly assessments from July to September. All treatments were neither phytotoxic to leaves and fruit nor did they adversely affect quality parameters of harvested fruit. These results show that boric acid treatment may be applied as an alternative chemical for the control of apple scab.  相似文献   

10.
An air assisted tunnel sprayer (the Noric Joco EX2) incorporating CDA rotary atomisers (Volume Median Diameter (VMD) =c. 140 μm, volume rate = 50 litre ha-1 forward speed = 3.9 km h-1) gave at best equal but in some cases significantly poorer control of apple powdery mildew and scab than the standard commercial practice of spraying with an axial fan sprayer with Micron XI rotary atomisers (VMD =c. 90 μm, volume rate = 50 litre ha-1, forward speed = 7.2 km h-1). Approximately 30% of the spray volume applied was collected for recycling with the tunnel sprayer. Increasing spray volumes at approximately constant drop size (c. 140 μm) from 50 to 100 to 200 litre ha-1 with the tunnel sprayer consistently improved efficiency of mildew and scab control. Bulk spray deposits on leaves, and their gross distribution in the tree, was similar with the different spraying methods and volumes. The mean percentage leaf area covered with spray deposit increased with spray volume as did the number of spray deposits per unit area. The tunnel sprayer at 50 litre ha-1 gave a similar though less variable mean level of cover than the axial fan sprayer at the same volume rate. It gave 2–3 times more cover on upper than on lower leaf surfaces. The axial fan sprayer gave approximately equal cover on upper and lower leaf surfaces. The main limitations of the tunnel sprayer were its slow maximum forward speed and the restricted tree size and shape on which it can be used.  相似文献   

11.
For all known major apple scab resistance genes except Vr, molecular markers have been published. However, the precise position of some of these genes, in the apple genome, remains to be identified. Knowledge about the relative position of apple scab resistance genes is necessary to preliminarily evaluate the probability of success of their pyramidization. Pyramidization of different resistance genes into the same genotype is a reliable way to create cultivars with durable apple scab resistance. Applying the genome scanning approach (GSA), we identified the linkage group of the scab resistance gene Vm, derived from Malus micromalus, and we found a new molecular marker tightly associated with the gene. The simple sequence repeat Hi07h02, previously mapped on linkage group 17, cosegregates with the Vm gene (no recombinants in the 95 plants tested). The already published sequence-characterized amplified region Vm marker OPB12(687) was found to be linked at about 5 cM from the resistance gene and, therefore, this marker also maps on linkage group 17 of apple. This is the first report of the discovery of a major apple scab resistance gene on linkage group 17. The advantages of using GSA for the identification of molecular markers for qualitative traits are discussed.  相似文献   

12.
In a 2-year study, micronised (finely ground) and non-micronised sulphur spray programmes were investigated for peach scab control and influence on peach fruit quality variables including fruit colouration, soluble solids content and flesh firmness. Both sulphur programmes, applied six or 11 times at 15 kg ha−1, controlled scab equally well in both years on cultivars (cvs) Contender and Cresthaven. Six applications of a half dosage of both micronised and non-micronised sulphur programmes were significantly less effective ( P  < 0.05) compared with all other programmes when scab incidence was >90% on cv. Contender. None of the sulphur programmes influenced significantly ( P  < 0.05) colouration and flesh firmness of harvested fruits compared with the industry standard (a chlorothalonil–captan programme). Only soluble solids concentrations showed significant differences among fungicide programmes ( P  < 0.05), but these differences were not consistent with either particle sizes of sulphur fungicide or reduced application fungicide programmes. In conclusion, our study showed that (a) micronised sulphur did not control peach scab more effectively compared to non-micronised sulphur; (b) six applications of sulphur were sufficient to control peach scab when disease pressure was low to medium; and (c) neither six nor 11 applications of sulphur-based products applied at 15 kg ha−1 had commercially relevant negative impacts on important peach fruit quality variables.  相似文献   

13.
The wetting behaviour of the spray and the biological efficacy of Cu2+ active ingredients in agrochemical formulations may be enhanced by tank-mix additives. We investigated how three BREAK-THRU® additives (BT301: biodegradable, BT133 and BT420: bio-based and biodegradable) tank-mixed with commercial copper preparations influenced the spray distribution, leaf uptake and biological efficacy of copper additive mixtures against apple scab and apple powdery mildew under controlled conditions. We quantified the synergetic effects of these additives in foliar applications. In addition, we determined the phytotoxic potential and evaluated their impacts on photosynthetic activity, non-photochemical quenching and ROS activity. The additives BT301 and BT420 strongly reduced surface tension and contact angle of copper treatments. The fluorescence observations revealed that BT301 achieved better spreading of copper formulation with more complete coverage of the leaf surface than BT420 and BT133, whereas ‘coffee-ring’ spreading was observed with BT133. The additive BT301 showed an increase in relative fluorescence area, indicating higher ROS production as a signal of intra-cellular tissue activity. The photochemical efficiency of photosystem II (Fv/Fm) was not negatively influenced by copper or additive treatment. Thus, we observed no phytotoxic effects of copper-additive mixtures on apple leaves at treatment doses of 4 g Cu2+ L−1. All copper treatments reduced apple scab infections significantly, by 53%–76%. Interestingly, addition of BT301 to copper preparations showed the strongest biological efficacy (83% reduction) against Venturia inaequalis, whereas addition of BT420 showed the strongest effect against Podosphaera leucotricha (89% infection reduction). The synergetic effects of additives on the biological efficacy without phytotoxic effects on plants may have potential for reducing copper loads in horticultural production systems.  相似文献   

14.
Apple scab, Venturia inaequalis (Cke) Wint., is a major problem in Romanian apple orchards and is responsible for serious economic losses. The purchase of spraying equipment and phytopharmaceutical products is very expensive in comparison to the income of local apple growers. This is one of the reasons why reduced fungicide sprayings are becoming more and more important. That's why a project was started to investigate the influence of West-European control measures and to improve interaction between local apple growers and research facilities. This experiment took place in an orchard of the university of Timisoara (USABT), where occurrence of apple scab was very high, and in a well managed commercial orchard, both in the Banat region. In July 2006, a comparative study between a traditional Romanian management program, a calendar-based program and a computerized weather-based management program was conducted. Four test plots were taken. The sprayments in plot 1 happened according to the integrated computerized model. No sprayings took place in plot 2. In plot 3 were some sprayments done with sulphur according to the traditional Romanian program. The sprayings in plot 4 were done following a calendar-based spraying program. The products that were used for the sprayments were all easy to obtain in Romania such as dodine (Sillit flow), dithianon (Delan flow), difenoconazole (Score), pyrimethanil (Scala), metiram (Polyram), kresoxim-methyl (Stroby). The occurrence of scab in plot 1 was very low in comparison to the other plots. Analysing the data, on average, the treatments done in plot 1 caused about 50% less damage than the traditional sprayings. This indicated that with a relative small amount of well timed sprayings a enormous amount of damage can be prevented. A calendar-based management program seems to be less effective (more sprayings needed and the results are worse). These results also emphasize the importance of the development of an adequate apple scab management program that should be presented to local apple growers.  相似文献   

15.
Scab, caused by the ascomycete fungus Venturia pirina, leads to severe damage on European pear varieties resulting in a loss of commercial value and requiring frequent use of fungicides. Identifying scab resistance genes, developing molecular markers linked to these genes and establishing marker-assisted selection would be an effective way to improve European pear breeding for scab resistance. Most of the European pear cultivars (Pyrus communis) are currently reported to be sensitive. The pear cultivar ‘Navara’ was shown to carry a major scab resistance gene whose phenotypic expression in seedling progenies was a typical stellate necrosis symptom. The resistance gene was called Rvp1, for resistance to V. pirina, and was mapped on linkage group 2 of the pear genome close to microsatellite marker CH02b10. This genomic region is known to carry a cluster of scab resistance genes in apple indicating a first functional synteny for scab resistance between apple and pear.  相似文献   

16.
17.
The efficacy of two insecticide control programs for managing the codling moth, Cydia pomonella (L.), and the apple maggot, Rhagoletis pomonella (Walsh), were compared in the Georgian Bay, London, Niagara, and Quinte apple production areas of Ontario during 1995, 1996, and 1997. In the border spray program, an initial cover spray of organophosphorus insecticide was applied to eradicate codling moths that may have colonized a test plot during the previous growing season. Subsequent sprays were applied only to a four-tree-wide zone (approximately 20 wide) around the perimeter of the plot to control immigrating codling moths or apple maggots. In the cover spray program, all sprays of organophosphorus insecticide were applied to the entire plot. Apple maggot injury was significantly greater in border spray program plots than in cover spray program plots only during 1995 in the London production area. There was no significant difference in codling moth injury between border spray and cover spray plots in the four production areas during the three-year study. The elimination of cover sprays from border spray plots during July and August may have left the apple crop more susceptible to damage by second generation larvae of the obliquebanded leafroller, Choristoneura rosaceana (Harris), in the London production area during 1995. There was a trend of increasing codling moth injury from 1995 to 1997 in two border spray plots, and apple maggot injury was detected in these plots during the third year of the study.  相似文献   

18.
Scab is one of the key parasites in fruit growth. In favourable weather conditions for the pathogen, a complete harvest can be destroyed if no control measurements are undertaken. The scab fungi on pear and apple are two distinct species. They have, however, a similar biological cycle. Despite the similarities, there are also clear differences and these differences are significant for the control of the pathogen. Pear scab does not only infect fruit and leaves as apple scab does, but also infects twigs. Especially in organic fruit growing, twig scab is a big problem. Once twig scab occurs, it seems to be impossible to get rid of scab in these orchards. The only possibility for the fruit grower in this case is a strict spraying schedule to ensure no further spread of the infection. The main goal of the project is a thorough study of the pear scab fungi (biology, sensitivity of different plant parts and cultivars, dispersal of the fungi and infection conditions, the pathogenicity and characterization of different biotypes) to unravel the life of the fungi and to develop a better control strategy. A better control strategy means a reduced fungicide use and a reduction of fungicide residue on the fruits at harvest, without a reduction of the quality of the fruits and cost effectiveness for the fruit grower. Special attention in the project goes to the role and the control of twig scab. The first results of this project will be shown.  相似文献   

19.
A two-season study showed that a calendar-based spray program to manage arthropod pests with kaolin (60 g/liter) applied at the rate of 450 liters/ha was effective against European apple sawfly, Hoplocampa testudinea (Klug) (Hymenoptera: Tenthredinidae); white apple leafhopper, Typhlocyba pomaria McAtee (Homoptera: Cicadellidae); apple red bug, Lygidea mendax Reuter (Heteroptera: Miridae); pear plant bug, Lygocoris communis (Knight) (Heteroptera: Miridae); and the apple rust mite, Aculus schlechtendali (Nalepa) (Acari: Eriophyidae). Although it reduced Curculionidae damage, the level of damage was still too high. It had no effect on apple maggot, Rhagoletis pomonella (Walsh) (Diptera: Tephritidae); codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae); and tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Heteroptera: Miridae). Laboratory studies showed fewer gravid twospotted spider mites, Tetranychus urticae Koch (Acari: Tetranychidae), and fewer eggs laid by these females. The study also showed no effect of kaolin on Neoseiulus fallacis (Garman) (Acari: Phytoseiidae).  相似文献   

20.
Using resistance genes from a crossable donor to obtain cultivars resistant to diseases and the use of such cultivars in production appears an economically and environmentally advantageous approach. In apple, introgression of resistance genes by classical breeding results in new cultivars, while introducing cisgenes by biotechnological methods maintains the original cultivar characteristics. Recently, plants of the popular apple ‘Gala’ were genetically modified by inserting the apple scab resistance gene Rvi6 (formerly HcrVf2) under control of its own regulatory sequences. This gene is derived from the scab‐resistant apple ‘Florina’ (originally from the wild apple accession Malus floribunda 821). The vector used for genetic modification allowed a postselection marker gene elimination to achieve cisgenesis. In this work, three cisgenic lines were analysed to assess copy number, integration site, expression level and resistance to apple scab. For two of these lines, a single insertion was observed and, despite a very low expression of 0.07‐ and 0.002‐fold compared with the natural expression of ‘Florina’, this was sufficient to induce plant reaction and reduce fungal growth by 80% compared with the scab‐susceptible ‘Gala’. Similar results for resistance and expression analysis were obtained also for the third line, although it was impossible to determine the copy number and TDNA integration site–such molecular characterization is requested by the (EC) Regulation No. 1829/2003, but may become unnecessary if cisgenic crops become exempt from GMO regulation.  相似文献   

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