EFFECT OF FUNGICIDES ON McINTOSH APPLE TREES

1963 ◽  
Vol 43 (4) ◽  
pp. 497-502 ◽  
Author(s):  
R. G. Ross ◽  
R. P. Longley
Keyword(s):  
Venturia Inaequalis ◽  
Apple Scab ◽  
Good Control ◽  
Fruit Color ◽  
Average Yield ◽  
Apple Trees ◽  
Mercury Acetate ◽  
Excellent Control ◽  
Thinning Effect ◽  
Phenyl Mercury

A 4-year test was carried out on the effect of sprays of captan, dodine, dichlone, and phenyl mercury acetate-captan on the performance of mature McIntosh apple trees. Increases in yield of the same trees over the average yield of the previous 5 years were 40, 31, 18 and 7 per cent, respectively, for captan, dodine, mercury-captan and dichlone. The fungicides had little effect on bloom, tree growth as measured by increase in trunk cross-section, and per cent fruit color. Mercury-captan produced larger apples indicating a thinning effect. The captan sprays produced the most attractive apples. With dichlone, fruit finish was rough. Dodine injured about 3 per cent of the apples in 2 years of the test.Dodine gave the best control of apple scab (Venturia inaequalis). Dichlone was very effective for early fruit scab but did not give good control of late or pin-point scab. Mercury gave excellent control of early scab. Captan allowed some late scab to develop.

VARIATION IN THE SENSITIVITY OF ISOLATES OF VENTURIA INAEQUALIS (CKE.) WINT. TO FUNGICIDES

1961 ◽  
Vol 41 (3) ◽  
pp. 499-502 ◽  
Author(s):  
R. G. Ross ◽  
S. A. Hamlin
Keyword(s):  
Copper Sulphate ◽  
Venturia Inaequalis ◽  
Dosage Range ◽  
Mercury Acetate ◽  
Phenyl Mercury

Fifty isolates of Venturia inaequalis, from diseased apples of several varieties collected in sprayed orchards on various fungicide programs and in unsprayed orchards, were tested for their sensitivity to captan, glyodin, dichlone, phenyl mercury acetate, copper sulphate and sulphur. The isolates were sensitive to a wider dosage range of sulphur than of other fungicides but there was no indication that, in nature, V. inaequalis had developed strains resistant to the fungicides.

THE CONTROL OF THE APPLE APHID ON DWARF APPLE TREES WITH BARK APPLICATIONS OF DIMETHOATE

1961 ◽  
Vol 41 (2) ◽  
pp. 407-412 ◽  
Author(s):  
D. P. Pielou
Keyword(s):  
Active Ingredient ◽  
Good Control ◽  
Basal Part ◽  
Effective Control ◽  
Single Application ◽  
Apple Trees ◽  
Emulsifiable Concentrate ◽  
Aphis Pomi ◽  
Wettable Powder ◽  
Excellent Control

Very effective control of the apple aphid, Aphis pomi DeG., on dwarf apple trees, has been obtained by two paintings of an undiluted emulsifiable concentrate of dimethoate (30 per cent active ingredient) on the basal part of the trunk of the tree. Approximately 2 millilitres are applied per tree, and application is made with a 1-inch paint brush around the trunk over a distance of approximately 12 inches. A single application in early July, at a time when the seasonal upsurge of aphids is beginning, gave excellent control for 3 to 4 weeks, even where conditions for reinfestation were favourable. A second application at the end of that period ensured full seasonal control. Almost equally good control was obtained by diluting the concentrate with an equal volume of water. At greater dilutions less effective control resulted. The use of a slurry made from dimethoate, 50 per cent wettable powder, in place of the emulsion, was reasonably effective but slower in action.

scholarly journals MERCURY RESIDUES IN APPLES IN RELATION TO SPRAY DATE, VARIETY AND CHEMICAL COMPOSITION OF FUNGICIDE

1967 ◽  
Vol 47 (2) ◽  
pp. 169-174 ◽  
Author(s):  
D. K. R. Stewart ◽  
R. G. Ross
Keyword(s):  
Chemical Composition ◽  
Mercuric Chloride ◽  
Ammonium Acetate ◽  
Mercury Chloride ◽  
Apple Trees ◽  
Apple Varieties ◽  
Ammonium Lactate ◽  
Mercury Acetate ◽  
Dimethyl Dithiocarbamate ◽  
Phenyl Mercury

Mercury was readily translocated to growing fruit of apple trees which had received one cover spray of phenyl mercury acetate between June 14 and August 31. The rate of translocation was less with cover sprays applied near the end of this period. Translocation due to a phenyl mercury acetate cover spray occurred to about the same extent in the apple varieties McIntosh, Cortland, Red Delicious and Gravenstein. In addition to phenyl mercury acetate, a cover spray of phenyl mercury chloride, phenyl mercury dimethyl dithiocarbamate, phenyl mercury triethanol ammonium lactate, phenyl mercury monoethanol ammonium acetate, and mercuric chloride resulted in similar translocation of mercury to growing fruit.

Benomyl-marked populations of Chaetomium globosum: survival on apple leaves with and without benomyl and antagonism to the apple scab pathogen, Venturia inaequalis

1985 ◽  
Vol 31 (3) ◽  
pp. 251-255 ◽  
Author(s):  
Daniel Cullen ◽  
John H. Andrews
Keyword(s):  
Resistant Strain ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Chaetomium Globosum ◽  
Wild Type ◽  
Population Densities ◽  
Apple Trees ◽  
Initial Inoculum ◽  
Apple Leaves ◽  
Rate Of Decline

Resistance to the fungicide benomyl (BenR) was induced with N-methyl-N′-nitro-N-nitrosoguanidine in Chaetomium globosum isolated from apple leaves. The population densities of a resistant strain reintroduced to leaves on apple trees in an orchard were determined at 3 h, and 1 and 3 weeks following inoculation. Relative to wild-type parents, BenR populations declined more rapidly on orchard trees, but the rate of decline was reduced by amending initial inoculum with 18.5 ppm benomyl. Survival of BenRC. globosum increased 40–58% relative to BenRC. globosum applied without benomyl. In growth chamber experiments with potted apple seedlings, the BenR strain was as antagonistic as were the wild-type parents to the scab pathogen, Venturia inaequalis. The marked strain alone did not significantly reduce scab infection on saplings in the field; however, when it was applied with benomyl, scab severity was significantly (P = 0.01) less than with benomyl alone.

scholarly journals Seasonal and Cross-Seasonal Timing of Fungicide Trunk Injections in Apple Trees to Optimize Management of Apple Scab

Plant Disease ◽  
2016 ◽  
Vol 100 (8) ◽  
pp. 1606-1616 ◽  
Author(s):  
Srđan G. Aćimović ◽  
Anthony H. VanWoerkom ◽  
Thomas Garavaglia ◽  
Christine Vandervoort ◽  
George W. Sundin ◽  
...  
Keyword(s):  
United States ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
The United States ◽  
Apple Trees ◽  
Seasonal Timing ◽  
Scab Control ◽  
Better Than ◽  
Spray Applications

To optimize the number and timing of trunk injections for season-long control of apple scab (Venturia inaequalis), we evaluated 1 to 2 and 4 seasonal and cross-seasonal injections of potassium phosphites and synthetic fungicides and quantified residues in leaves and fruit. Phosphites accumulated in the canopy at the highest concentrations, aligned well in time with scab suppression, and gave better leaf scab control of 41.8 to 73.5% than propiconazole (16.9 to 51.5%) or cyprodinil + difenoconazole (5.4 to 17.4%). More injections of phosphites controlled leaf scab better than fewer (23.7% versus 48.2%), and more fungicide injections resulted in 21.9 to 51.1% better leaf scab control than fewer. Leaf scab control with phosphites was only 3.2 to 13.9% better with 4 cross-seasonal compared with 4 seasonal injections, while 1 to 2 seasonal compared with 1 to 2 cross-seasonal injections improved scab control only for 4.2 to 22.1%. On shoots, injected phosphites provided comparable or for 4.4 to 10.5% and 22.3 to 41.4% better scab control than spray standards. On fruit, injected phosphites slightly improved control compared with sprayed phosphites or the sprayed fungicide standard (33.4 to 40.8%). Two seasonal injections of phosphites controlled shoot scab 5.7% better than 9 spray applications. Five sprays of cyprodinil + difenoconazole controlled scab better than their injections. Fruit residues of phosphites reached 2.8 ppm and declined in all treatments except in 2 seasonal injections and phosphite sprays. Cyprodinil and difenoconazole fruit residues reached 0.02 and 0.07 ppm and declined sharply toward the end of the season. These were far below the United States, Codex, and EU MRL-s of 1, 0.8, and 0.5 ppm for difenoconazole, and 1.7, 2, and 1 ppm for cyprodinil, respectively.

MOVEMENT AND ACCUMULATION OF MERCURY IN APPLE TREES AND SOIL

1962 ◽  
Vol 42 (2) ◽  
pp. 280-285 ◽  
Author(s):  
R. G. Ross ◽  
D. K. R. Stewart
Keyword(s):  
Apple Orchards ◽  
Apple Trees ◽  
Mercury Acetate ◽  
Phenyl Mercury

When sprays of Erad (phenyl mercury acetate) were applied to apple foliage the mercury moved in and from the foliage mainly by translocation rather than by volatilization. It moved to growing fruit and new foliage but there was no uptake through roots.Residues of mercury were found almost entirely in the top 2 inches of the soil in apple orchards sprayed with Erad.

scholarly journals Study of Venturia inaequalis pseudothecia development and apple scab severity under Polish conditions

2015 ◽  
Vol 27 (2) ◽  
pp. 107-114
Author(s):  
Beata Meszka
Keyword(s):  
Central Region ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Susceptible Cultivar ◽  
Critical Periods ◽  
Apple Trees ◽  
Similar Time ◽  
High Severity ◽  
Apple Cultivars ◽  
Severity Of The Disease

Abstract Studies conducted during 2009-2013 at the Experimental Orchard located in the central region of Poland showed that the highest number of V. inaequalis pseudothecia occurred on ‘McIntosh’ and ‘Cortland’ leaves. A smaller number of pseudothecia was found on the leaves of the Alwa and Jonagold cultivars, but there were no statistical differences. The first discharges of ascospores were noted at a similar time on the leaves of all of the apple cultivars, usually at the end of March or in early April. For the forecasting of ascospore discharges and dates of critical periods, a simulation model by RIMpro was used. The number of critical periods and apple scab severity differed in each season. The most critical periods (above 20) were recorded in 2010 and 2013, which also corresponded with a high severity of apple scab. The number of infected leaves and fruits on the untreated trees of the very susceptible cultivar McIntosh reached nearly 100% during these seasons. In other years, the severity of the disease on the same apple trees was lower and amounted to 30-54% of infected leaves and 23-80% of infected fruits.

Constituents from Morus root bark against Venturia inaequalis – the causal agent of apple scab

Planta Medica ◽  
2007 ◽  
Vol 73 (09) ◽  
Author(s):  
JM Rollinger ◽  
R Spitaler ◽  
M Menz ◽  
P Schneider ◽  
EP Ellmerer ◽  
...  
Keyword(s):  
Venturia Inaequalis ◽  
Apple Scab ◽  
Causal Agent ◽  
Root Bark

Working collection formation of apple-tree (Malus domestica Mill.) gene pool for priority breeding trends

2019 ◽  
pp. 101-108
Author(s):  
T.I. Krasulia
Keyword(s):  
Climatic Factors ◽  
Venturia Inaequalis ◽  
High Water ◽  
Laboratory Method ◽  
Apple Trees ◽  
Growing Period ◽  
Breeding Efficiency ◽  
Abiotic And Biotic Factors ◽  
Distinguished Varieties ◽  
Spring Frosts

Aim. To define the priority trends of apple breeding in the southern steppe of Ukraine and to identify varieties – sources of high valuable-for-breeding indices for building up a working collection. Results and Discussion. Spring frosts and wet weather in May-June contributing to development of the scab pathogen (Venturia inaequalis), high temperature and water deficit in the 2nd half of the growing period, when fruits grow and ripen, are the major stress weather/climatic factors for apple trees in the southern steppe of Ukraine. Therefore, the priority in breeding is given to developing varieties that would be resistant to several unfavorable factors. At the same time, commercial use of new varieties is possible provided high commercial quality indicators of fruits. High resistance of buds to spring frosts was observed in varieties Vechirnia Zoria, Moldavskoye Krasnoye, and Prima. Oligogenic varieties (genes Vm and Vf), including Harant, Skifske Zoloto, and Liberty, showed no signs of scab development. Varieties with polygenic resistance to this disease were identified; they included Vechirnia Zoria, Ornament, Carola. Drought-tolerant varieties with high water-holding capacity of leaves and their turgor restoration after wilting, including Carola, Florina, and Prima, were selected by a laboratory method. Assessment of drought tolerance in the field made it possible to enrich this group with numerous varieties. Varieties giving fruits with high commercial qualities on insufficient water availability, such as Vechirnia Zoria, Harant, Moldavskoye Krasnoye, Ornament and others, were distinguished. Varieties combining resistance to several unfavorable abiotic and biotic factors with high marketability traits of fruits were singled out. Among them. Harant, Delicious Spur, Liberty, and Prima should be mentioned. Conclusions. The development of varieties with complex tolerance to spring frosts, drought, scab pathogen and high qualities of fruits is the priority trend in the breeding of apple trees in the southern steppe of Ukraine. Varieties - sources of individual valuable traits and their various combinations were identified. Varieties Vechirnia Zoria, Moldavskoye Krasnoye, Ornament, and Golden Resistant combine the maximum number of valuable-for-breeding features. It is varieties-sources of several traits that should make up a working collection of apple trees to increase the breeding efficiency.

scholarly journals Apple Autotetraploids with Enhanced Resistance to Apple Scab (Venturia inaequalis) Due to Genome Duplication-Phenotypic and Genetic Evaluation

2021 ◽  
Vol 22 (2) ◽  
pp. 527
Author(s):  
Małgorzata Podwyszyńska ◽  
Monika Markiewicz ◽  
Agata Broniarek-Niemiec ◽  
Bożena Matysiak ◽  
Agnieszka Marasek-Ciolakowska
Keyword(s):  
Venturia Inaequalis ◽  
Leaf Shape ◽  
Apple Scab ◽  
Early Period ◽  
Physiological Parameters ◽  
Aflp Analysis ◽  
Poor Growth ◽  
Enhanced Resistance ◽  
Apple Cultivars ◽  
Old Trees

Among the fungal diseases of apple trees, serious yield losses are due to an apple scab caused by Venturia inaequalis. Protection against this disease is based mainly on chemical treatments, which are currently very limited. Therefore, it is extremely important to introduce cultivars with reduced susceptibility to this pathogen. One of the important sources of variability for breeding is the process of polyploidization. Newly obtained polyploids may acquire new features, including increased resistance to diseases. In our earlier studies, numerous tetraploids have been obtained for several apple cultivars with ‘Free Redstar’ tetraploids manifesting enhanced resistance to apple scab. In the present study, tetraploids of ‘Free Redstar’ were assessed in terms of phenotype and genotype with particular emphasis on the genetic background of their increased resistance to apple scab. Compared to diploid plants, tetraploids (own-rooted plants) were characterized with poor growth, especially during first growing season. They had considerably shorter shoots, fewer branches, smaller stem diameter, and reshaped leaves. In contrast to own-rooted plants, in M9-grafted three-year old trees, no significant differences between diplo- and tetraploids were observed, either in morphological or physiological parameters, with the exceptions of the increased leaf thickness and chlorophyll content recorded in tetraploids. Significant differences between sibling tetraploid clones were recorded, particularly in leaf shape and some physiological parameters. The amplified fragment length polymorphism (AFLP) analysis confirmed genetic polymorphism of tetraploid clones. Methylation-sensitive amplification polymorphism (MSAP) analysis showed that the level of DNA methylation was twice as high in young tetraploid plants as in a diploid donor tree, which may explain the weaker vigour of neotetraploids in the early period of their growth in the juvenile phase. Molecular analysis showed that ‘Free Redstar’ cultivar and their tetraploids bear six Rvi genes (Rvi5, Rvi6, Rvi8, Rvi11, Rvi14 and Rvi17). Transcriptome analysis confirmed enhanced resistance to apple scab of ‘Free Redstar’ tetraploids since the expression levels of genes related to resistance were strongly enhanced in tetraploids compared to their diploid counterparts.

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