scholarly journals The effectiveness of potassium phosphite and captan mixture in controlling Venturia inaequalis in apple orchards

2014 ◽  
Vol 29 (2) ◽  
pp. 137-143
Author(s):  
Goran Aleksic ◽  
Tatjana Popovic ◽  
Mira Starovic ◽  
Slobodan Kuzmanovic ◽  
Nenad Dolovac ◽  
...  
Keyword(s):  
Venturia Inaequalis ◽  
Apple Scab ◽  
Weather Conditions ◽  
Meteorological Conditions ◽  
Environmental Damage ◽  
Weather Station ◽  
Apple Orchards ◽  
High Efficacy ◽  
Potassium Phosphite ◽  
Leaf Infection

Venturia inaequalis is a common apple disease in Serbia and its intensity depends on weather conditions. The most successful method of combating apple scab is to use a lower dose of an active ingredient and increase its effectiveness by adding substances that do not cause environmental damage. The effectiveness of a fungicide mixture of captan and potassium phosphite against V. inaequalis was investigated in apple orchards in 2008 and 2009. A relevant EPPO standard method was used in all trials. Captan 50 WP was used as a standard fungicide. In order to determine the exact conditions marking the onset of apple infection, key meteorological conditions were monitored in the orchards using an automated iMetos weather station and a Lufft electronic instrument. The results showed high efficacy of the tested fungicides which remained similar in both years of investigation. The intensity of leaf infection after treatment with the mixture of captan and potassium phosphite was 0.7-2.4%, while fruit infection was 0.5-3.0%. The efficacy of this mixture ranged from 96.3-97.9% on leaves and 87.4-98.7% on fruits. The standard fungicide Captan 50 WP showed an efficacy ranging from 95.3-96.7% on leaves and from 87.8-99.3% on fruits. No statistically significant differences were found between the fungicide tested and the standard fungicide.

Resistance to Myclobutanil in Populations of Venturia inaequalis in Winchester, Virginia

2007 ◽  
Vol 8 (1) ◽  
pp. 3 ◽  
Author(s):  
Sasha C. Marine ◽  
David G. Schmale ◽  
Keith S. Yoder
Keyword(s):  
Fungicide Resistance ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Apple Orchards ◽  
The Mean ◽  
Moderately Resistant

Sterol-inhibiting (SI) fungicides are widely used to manage apple scab, caused by Venturia inaequalis. However, recent observations indicate that populations of V. inaequalis in orchards in Virginia have developed resistance to myclobutanil and other SI fungicides. Little is known about the frequency and distribution of fungicide resistance in apple scab populations in Virginia. Isolates of V. inaequalis were collected from three different apple orchards in Winchester, VA in 2006. Orchards were treated with myclobutanil on 12 April, 19 April, 1 May, 30 May, and 7 July. The sensitivity of 87 single-spored isolates of V. inaequalis to myclobutanil was determined by monitoring their growth on agar dishes amended with 0, 0.1, 0.5, or 1.0 μg/ml myclobutanil. A relative continuum of fungicide resistance was observed: 16 isolates were resistant, 40 isolates were moderately resistant, and 31 isolates were sensitive to myclobutanil. After 28 days, the mean growth of isolates collected from trees treated with myclobutanil was significantly greater than that of isolates collected from non-treated trees at all concentrations of myclobutanil tested in vitro. High levels of fungicide resistance found in populations of V. inaequalis suggest that replacement programs may need to be developed to manage apple scab in Virginia. Accepted for publication 4 September 2007. Published 13 November 2007.

scholarly journals First Report of QoI Resistance in Venturia inaequalis Causing Apple Scab in Apple Orchards in Turkey

Plant Disease ◽  
2016 ◽  
Vol 100 (5) ◽  
pp. 1016-1016 ◽  
Author(s):  
C. Turan ◽  
I. M. Nanni ◽  
N. Tosun ◽  
M. Collina
Keyword(s):  
Venturia Inaequalis ◽  
Apple Scab ◽  
Apple Orchards ◽  
First Report ◽  
Qoi Resistance

scholarly journals Эффективность биостимулятора Реглалг для защиты яблони от парши (Venturia Inaequalis Wint.)

2020 ◽  
Author(s):  
Иван Боубэтрын ◽  
◽  
Алехандру Даскaлюк ◽  
Keyword(s):  
Economic Efficiency ◽  
Negative Impact ◽  
Plant Protection ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Plant Protection Products ◽  
Combined Effect ◽  
Apple Orchards ◽  
The Cost

The scope of the research was to determine the efficiency of the combined effect of fungicides and the biostimulator Reglalag in the protection of apple orchards from apple scab disease. The introduction of a biostimulator into the tank mixture with fungicides allowed us to reduce by half the quantity of synthetic plant protection products. This combination allows us to reduce the cost of plant protection, reduces the negative impact of the fungicides on environment, and increases the economic efficiency of apple cultivation.

The relationship between meteorological changes and daily feed intake or shell strength of eggs of Leghorn hens

1993 ◽  
Vol 73 (2) ◽  
pp. 465-469 ◽  
Author(s):  
B. K. Thompson ◽  
R. M. G. Hamilton
Keyword(s):  
Specific Gravity ◽  
Key Words ◽  
Feed Intake ◽  
Daily Variation ◽  
Weather Conditions ◽  
Meteorological Conditions ◽  
Weather Station ◽  
Regression Analyses ◽  
The Relationship

Feed intake and egg measurements were recorded daily over a 56-d period from Leghorn pullets and force-molted hens, with 36 of each age. Meteorological conditions during the experiment were obtained from a nearby weather station. Regression analyses indicated that the daily variation in flock parameters reported in other studies may be partly due to the flock's response to weather conditions outside the hen house. Key words: Poultry, meteorological conditions, correlations, flock parameters, feed intake, specific gravity, shell strength, temperature

Efficacy of Kaolin-Based Particle Films to Control Apple Diseases

2001 ◽  
Vol 2 (1) ◽  
pp. 4 ◽  
Author(s):  
D. Michael Glenn ◽  
Tom van der Zwet ◽  
Gary Puterka ◽  
Patricia Gundrum ◽  
Eric Brown
Keyword(s):  
Fire Blight ◽  
Erwinia Amylovora ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Field Studies ◽  
Podosphaera Leucotricha ◽  
Malus Domestica Borkh ◽  
Sooty Blotch ◽  
Leaf Infection ◽  
Hydrophilic Particles

Studies were conducted from 1997 to 1999 to evaluate the effect of processed kaolin-based particle film applications on the incidence and severity of apple (Malus domestica Borkh.) diseases. Greenhouse and field studies demonstrated that pre-emptive application of hydrophobic and hydrophilic particles reduced the incidence of fire blight (Erwinia amylovora (Burrill) Winslow et al.) in blossoms and injured shoots. Hydrophobic and hydrophilic particles suppressed sooty blotch (Gloeodes pomigena (Schwein.)) and flyspeck (Schizothyrium pomi (Mont. & Fr.) Arx: anamorph Zygophiala jamaicensis Mason) to levels equivalent to conventional fungicides. In field studies, apple scab (Venturia inaequalis (Cooke) Wint.: anamorph Spilocaea pomi Fr.) was not suppressed by hydrophilic particles. Hydrophilic particles did not interfere with the action of conventional fungicides or the activity of calcium hydroxide to suppress apple scab. Hydrophilic particles did reduce powdery mildew (Podosphaera leucotricha (Ell. & Ev.) E.S. Salmon (anamorph Oidium farinosum Cooke)) russetting on fruit, but leaf infection was extensive. Accepted for publication 27 July 2001. Published 23 August 2001.

scholarly journals Role of urea in the reduction of apple primary infections by Venturia inaequalis (Cooke) Aderh

2013 ◽  
Vol 55 (1) ◽  
pp. 225-231
Author(s):  
Beata Meszka ◽  
Anna Bielenin
Keyword(s):  
Chemical Control ◽  
Primary Infection ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Leaf Fall ◽  
Urea Treatment ◽  
Apple Leaves ◽  
Leaf Infection ◽  
Ascospore Production

The effect of pre-leaf fall of 5% urea treatment on primary infection of apple by <i>Venturia inaequalis</i>, the cause of scab, was investigated in commercial apple orchards of McIntosh cv. in different regions of Poland, at Miłobądz, Sinołęka and Dąbrowice. Additionally, the development of pseudothecia and maturation of ascospores were evaluated in the spring on apple leaves of two cultivars (McIntosh and Gloster) treated with 5% solution of urea. Microscopic observations of leaves showed that urea treatment significantly reduced the number of pseudothecia (by ca. 90%) and ascospore production. Low number of ascospores after urea treatment has strongly affected primary infection of apple by the fungus in all tested orchards. Reduction of leaf infection on control trees was usually more than 30%. Also efficacy of chemical control of apple scab was significantly higher on plots treated with urea.

scholarly journals Application of fungicides during leaf fall to control apple scab (Venturia inaequalis) in the following season

2008 ◽  
Vol 61 ◽  
pp. 59-64 ◽  
Author(s):  
R.M. Beresford ◽  
P.N. Wood ◽  
P.W. Shaw ◽  
T.J. Taylor
Keyword(s):  
Fungicide Resistance ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Fruit Production ◽  
Leaf Fall ◽  
Apple Orchards ◽  
Resistance Risk ◽  
Chemical Residues ◽  
Integrated Fruit Production

Leaf fall applications of fungicides to reduce scab in apple orchards were investigated to reduce reliance on summer fungicides that can cause trace chemical residues on harvested fruit Two applications of fungicides including captan tolyfluanid myclobutanil and urea were made at 1020 and 5060 leaf fall in four orchard trials in Nelson and Hawkes Bay using the cultivars Royal Gala Braeburn Fuji and Sciros/Pacific Rosetrade; Trial orchards received standard spring and summer fungicide programmes that complied with Integrated Fruit Production and were monitored for leaf and fruit scab in December and at harvest Significant reductions in leaf or fruit scab occurred in three out of five comparisons involving different sites years and cultivars suggesting that autumn applications can reduce scab in the following season Captan and tolyfluanid appeared most useful for autumn application Myclobutanil should not be used because of the fungicide resistance risk Results with urea were variable

scholarly journals Comparative Assessment of Phosphite Formulations for Apple Scab (Venturia inaequalis) Control

2014 ◽  
Vol 40 (4) ◽  
Author(s):  
Luke Hailey ◽  
Glynn Percival
Keyword(s):  
Plant Protection ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Protective Properties ◽  
Advantages And Disadvantages ◽  
Scab Control ◽  
Potassium Phosphite ◽  
Foliar Pathogen ◽  
Protection Agent ◽  
Zinc Phosphite

Potassium phosphite is a widely used plant protection agent. However, a suite of phosphite formulations with alternative cation attachments (calcium, copper, silicon, zinc) are commercially available. The plant protective properties of these formulations have received little attention. This study evaluated five phosphite formulations for plant protection purposes against the foliar pathogen apple scab (Venturia inaequalis) under field conditions. In addition, a comparative analysis against the synthetic fungicide penconazole, which is widely used for apple scab control, was conducted. Greatest reductions in leaf and fruit scab severity were achieved by sprays of the synthetic fungicide penconazole. However, all phosphite formulations evaluated significantly reduced leaf and fruit scab severity at the cessation of the growing season. Within the phosphites tested, the greatest reductions in leaf and fruit scab severity were achieved in the order: copper phosphite > silicon phosphite > zinc phosphite > calcium phosphite > potassium phosphite > control. The advantages and disadvantages of these phosphite formulations for scab control are discussed.

scholarly journals Discharge and Dissemination of Ascospores by Venturia inaequalis During Dew

Plant Disease ◽  
1998 ◽  
Vol 82 (7) ◽  
pp. 761-764 ◽  
Author(s):  
Arne Stensvand ◽  
Terje Amundsen ◽  
Lars Semb ◽  
David M. Gadoury ◽  
Robert C. Seem
Keyword(s):  
Venturia Inaequalis ◽  
Apple Scab ◽  
Weather Conditions ◽  
Fair Weather ◽  
Peak Period ◽  
Ascospore Discharge ◽  
Dew Formation ◽  
Spore Release ◽  
Ascospore Release ◽  
Drying Conditions

Abundant airborne ascospores of the apple scab pathogen (Venturia inaequalis) have never before been observed during periods of dew. We studied ascospore release in V. inaequalis in two orchards in southeastern Norway using Burkard 7-day volumetric spore traps. At Ås in 1990, 1992, and 1997, and at Svelvik in 1992, a total of 14.8, 1.4, 0.27, and 26.9%, respectively, of the season's total spore release was trapped during periods of dew. Dew followed by spore release was observed 22 days at the two locations. During one night with dew at Ås in 1990 and two nights with dew at Svelvik in 1992, approximately 13 and 20%, respectively, of the season's total spore numbers were observed. High numbers of spores were trapped prior to sunrise, and on an average, 48.4% of the spores were trapped prior to 0400 in the morning. Episodes in which more than 1% of the season's inoculum was released during dew occurred around bloom of apple, which is the peak period for ascospore discharge, and followed more than 2 days of fair weather (clear, warm days and cool, humid nights). The ordinary suppression of ascospore release in V. inaequalis during darkness has been overcome in previous studies under laboratory conditions when protracted periods favorable for ascospore maturity occur without opportunity for ascospore discharge. This is the first confirmed report of relatively large (>10% of the season's total inoculum) numbers of airborne ascospores in orchards during dew. The sequential occurrence of specific weather conditions, for example (i) fair-weather days, (ii) cool nights with abundant dew formation, (iii) significant release and dispersal of airborne ascospores, and (iv) poor drying conditions or additional hours of leaf wetness due to fog or rain, would be required for dew-released ascospores to constitute a threat of infection. Absent the foregoing, release during dew is more likely to deplete the ascospore supply with no consequent increase in the overall risk of disease.

scholarly journals Role of organosilicone surfactant in apple scab control under scab conducive weather conditions

2008 ◽  
Vol 14 (3) ◽  
Author(s):  
I. J. Holb
Keyword(s):  
Untreated Control ◽  
Venturia Inaequalis ◽  
Apple Scab ◽  
Weather Conditions ◽  
Fruit Production ◽  
Application Of Surfactants ◽  
Fungus Infection ◽  
Scab Control ◽  
Integrated Fruit Production ◽  
Organosilicone Surfactant

Fungicides of integrated fruit production (dithianon, captan, and diclofluanid) and an organosilicone surfactant were compared in spray schedules from green tip until summer in order to control apple scab caused by Venturia inaequalis and to evaluate their phytotoxicity on fruit. Sixteen sprays of 1.8 kg ha-1captan, 0.41 ha-1 dithianon, and 1.8 kg ha-1 diclolfluanid significantly (P=0.05) reduced the incidence of leaf or fruit scab compared to unsprayed products. All fungicides applied with organosilicone at 0.1% resulted in lower incidence of scab on young and older leaves as well as on harvested fruit, but these were not statistically always better than fungicides applied alone. In case of diclofluanid, the fungicide applied with organosilicone at 0.1% resulted in significantly lower (P = 0.001) incidence of scab on young and older leaves. Diclofluanid applied with organosilicone at 0.1% gave the best scab control on leaf and fruit. Treatments applied with fungicides alone had no significant effect on plant phytotoxicity compared to untreated control. All fungicides applied with organosilicone at 0.1% increased (P = 0.05) fruit damage compared to untreated control or fungicide applied alone, though these were not always significantly different. In case of percentage of fruit russet, treatment of dithianon 0.4 1/ha + 0.1% organosilicone significantly increased fruit russet, while fruit russet index significantly increased in the treatment of diclofluanid 1.8 kg/ha + 0.1% organosilicone compared to untreated control. In sum, application of surfactants can help to increase efficacy of scab fungicides; and consequently, to reduce the risk of fungus infection under high scab disease pressure. This fact may also be helpful in fungicide resistance management and reduced-spray programs with accurate scab warning systems.

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