scholarly journals Integrated control strategy of apple scab according to warning equipment

2017 ◽  
Vol 38 (SI 2 - 6th Conf EFPP 2002) ◽  
pp. 700-703
Author(s):  
L. Raudonis

In 1999–2001 in field trials two different apple scab control strategies were compared: (i) the current strategy – conventional disease management (CDM) and (ii) integrated disease management (IDM), according to scab infection periods. A new scab warning equipment METOS<sup>R</sup>-D was used for detection of infection periods and forecast of disease intensity at three levels: light, moderate and severe. According to CDM apple-trees were sprayed 9 times a season. Scab warning equipment gave a possibility to optimize the use of fungicides against scab and to reduce the total spray applications per season in average till 6.3 in very susceptible cultivars and 5 in moderately susceptible ones. This is 30 and 44% less spray applications comparing with CDM. Annual spray program ranged from 5 till 8 spray applications of very susceptible cultivars. CDM and IDM gave high scab control in apple-trees and there was not found any essential difference in scab incidence between two control strategies.

Plant Disease ◽  
2016 ◽  
Vol 100 (8) ◽  
pp. 1606-1616 ◽  
Author(s):  
Srđan G. Aćimović ◽  
Anthony H. VanWoerkom ◽  
Thomas Garavaglia ◽  
Christine Vandervoort ◽  
George W. Sundin ◽  
...  

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.


Plant Disease ◽  
2010 ◽  
Vol 94 (6) ◽  
pp. 676-682 ◽  
Author(s):  
J. Augusto ◽  
T. B. Brenneman ◽  
A. K. Culbreath ◽  
P. Sumner

The efficacy of chemical control of stem rot (caused by Sclerotium rolfsii) of peanut (Arachis hypogaea) relies partially on increasing deposition and residual activity in the lower canopy. Tebuconazole (0.21 kg a.i./ha, four applications) and azoxystrobin (0.31 kg a.i./ha, two applications) were each applied on peanut plants in daylight or at night, when leaves were folded, in two Tifton, GA, field trials in 2007. Both timings of each fungicide provided similar control of early leaf spot (caused by Cercospora arachidicola). Night applications of azoxystrobin and tebuconazole reduced stem rot at digging and increased yield compared with day applications. Night applications of tebuconazole were also tested in Nicaragua from 2005 to 2007. Peanut plants had less stem rot, similar levels of rust (caused by Puccinia arachidis), and higher yield with night applications than with day applications. Residual activity of azoxystrobin and tebuconazole were improved on the bottom shaded leaves (on which fungicides would be better deposited with night application) compared with top, sun-exposed leaves (where most fungicide would be deposited with a day application) according to a bioassay with S. rolfsii. Increased fungicide residual activity within the bottom canopy may increase fungicide efficacy on stem rot and augment peanut yield.


2005 ◽  
Vol 71 (1) ◽  
pp. 1-8 ◽  
Author(s):  
J. Warner

Several sterol-biosynthesis-inhibiting (SBI) fungicides were tested alone and in combination with a broad-spectrum protectant material in field trials for control of Venturia inaequalis. When used in a 10-day spray schedule, SBI fungicides, whether used alone or in a mixture, provided improved scab control as compared to the protectant material used alone. With bitertanol, diniconazole, and penconazole, the mixture also provided better scab control than when the SBI fungicide was used alone. However, with flusilazole and myclobutanil, no improvement in disease control occurred with the mixture as compared to the SBI fungicide alone. Fruit russeting was observed after a post-bloom application of hexaconazole and growth-regulating effects on the foliage were observed following cyproconazole and hexaconazole use. The use of SBI fungicides in mixtures to avoid or delay the development of fungus resistance is discussed.


Plant Disease ◽  
2016 ◽  
Vol 100 (9) ◽  
pp. 1894-1905 ◽  
Author(s):  
Imre J. Holb ◽  
Stefan Kunz

In a 4-year study in a whole-field sanitized organic apple orchard, the effectiveness of nine fungicide treatments, including potassium mono- and bicarbonate and their combinations with wettable sulfur, were evaluated for scab and powdery mildew control on two cultivars with different susceptibility to scab and powdery mildew, under two pruning treatments. The whole-field sanitation practice was performed by removal of infected fallen leaves. Treatment effects on phytotoxicity and yield were also determined. Pruning significantly reduced leaf scab incidence but only on the more scab-susceptible Idared. Pruning significantly reduced mildew incidence in most years and on both cultivars but the more mildew-susceptible Jonathan showed significantly higher mildew incidence than Idared. Among products approved for organic production, the best scab control was achieved with a potassium mono- or bicarbonate treatment combined with wettable sulfur, except for Jonathan in 2011 on leaf and in 2014 on both leaf and fruit, and for Idared in 2013 on fruit. The best mildew control was also achieved with potassium mono- or bicarbonate treatments combined with wettable sulfur, with exceptions on shoots of Idared in 2011 and 2013 and on fruit of Idared in 2012. Leaf phytotoxicity was significantly higher in all potassium carbonate treatments compared with untreated plots, except for Idared in 2012, while fruit russet in these treatments did not differ significantly from the untreated plots. However, phytotoxicity values of all carbonate treatments were significantly lower than the lime sulfur treatment in most years on both cultivars. Yield of the potassium mono- or bicarbonate treatments combined with wettable sulfur was significantly higher than the untreated plots in the pruned treatments for both cultivars in all years. The integrated control approach designed for organic disease management against the two pathogens is discussed.


Plant Disease ◽  
2000 ◽  
Vol 84 (8) ◽  
pp. 863-870 ◽  
Author(s):  
W. Köller ◽  
W. F. Wilcox

Interactive effects of a mixture of fenarimol and dodine in the inhibition of Venturi inaequalis populations and the risk that resistance will develop when the mixture is used for control of apple scab were investigated. Interactive mixture effects were determined for a composite population (n = 1007) representative of the Great Lakes apple-growing region and for a population (n = 1,295) sampled over three years from a single experimental orchard subjected to various fungicide treatments. Several interactive effects were identified: (i) subpopulations of V. inaequalis isolates resistant to dodine contained a higher proportion of isolates also resistant to fenarimol, (ii) synergistic effects were apparent for a large proportion of dodine- or fenarimol-resistant isolates when tested in mixture, and (iii) the level of fenarimol resistance was higher in the subpopulation resisting the mixture than in the subpopulation resisting fenarimol alone. Interactive effects determined under in vivo test conditions were of low relevance in the control of apple scab. The partly pleiotropic resistance of dodine and fenarimol had no apparent impact on the fenarimol sensitivities of dodine-resistant populations, and expression of synergistic mixture effects were of low or no significance under orchard conditions of scab control. Treatments of apple trees with a half-rate mixture of fenarimol and dodine selected V. inaequalis isolates resistant to the mixture. Such isolates were poorly controlled by the mixture and by each component applied alone at twice their mixture rates; therefore, mixture-resistant isolates will be selected and must be controlled by other means. The level of fenarimol resistance was high for the mixture-resistant subpopulation; therefore, increasing the mixture rate of fenarimol is unlikely to significantly improve control of these isolates. The advantage of a half-rate mixture of fenarimol and dodine in scab management resides in a substantially lower frequency of selectable isolates compared to the frequencies encountered by fenarimol and dodine applied alone.


Agronomy ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1982
Author(s):  
Miguel A. Dionisio ◽  
Estrella Hernández-Suárez ◽  
Felipe Siverio ◽  
Juan M. Arjona-López ◽  
Aurea Hervalejo ◽  
...  

Trioza erytreae (Del Guercio) is one of the psyllid insect vectors of the causal agents of huanglongbing. This paper proposes an assessment of the effectiveness of several pesticides with and without a pine oil-based organic adjuvant, in order to contain the spread and population of this pest and reduce the side effects on the Tamarixia dryi parasitoid. Five insecticides and their combinations with pine oil were sprayed against T. erytreae on citrus trees under semi-field and field conditions. The effect of the same treatments was assessed on T. dryi under laboratory conditions. All insecticides, except for acetamiprid, increased their effectiveness when combined with pine oil under both conditions. Cyantraniliprole, dimethoate, and their respective combinations with the organic adjuvant showed the highest efficacies against T. erytreae. Under laboratory conditions, dimethoate reported the most negative effect on T. dryi activity whereas cyantraniliprole and its combination with pine oil yielded a low toxicity effect on this parasitoid. Our results recommend the development of an integrated control approach for citrus growers based on an insecticide rotation program, preventing the emergence of pest resistance to one substance. In this sense, other insecticides, such as lambda-cyhalothrin with pine oil adjuvant or acetamiprid, could be considered.


Plant Disease ◽  
2011 ◽  
Vol 95 (8) ◽  
pp. 927-934 ◽  
Author(s):  
Kimberley E. Lesniak ◽  
Tyre J. Proffer ◽  
Janna L. Beckerman ◽  
George W. Sundin

Control strategies for Venturia inaequalis rely heavily on chemical fungicides. Single-site fungicides such as the quinone-outside inhibitors (QoI) have been used in Michigan apple orchards for more than 11 years. In 2008, we sampled eight commercial orchards in the Fruit Ridge growing region of Michigan in which apple scab control failures were observed on ‘McIntosh’ apple following applications of kresoxim-methyl or trifloxystrobin. QoI resistance was assessed in 210 total isolates (a total of 17 orchards) using a spore germination assay and in 319 isolates using a polymerase chain reaction (PCR) assay to detect the G143A mutation located within the V. inaequalis cytochrome b gene (CYTB). The G143A mutation is known to confer high-level QoI resistance in plant-pathogenic fungi. QoI resistance was confirmed in 50 and 64% of the isolates tested with the spore germination and PCR assays, respectively, and there was a 97% concordance observed between the assays. In 2009, we sampled and examined an additional 1,201 V. inaequalis isolates from 64 orchards in Michigan and 86 isolates from four baseline sites in Ohio. All of these isolates were assayed for the G143A mutation and it was detected within 67 and 0% of the Michigan and Ohio isolates, respectively. Our results indicate the widespread occurrence of QoI resistance in Michigan commercial orchard populations of V. inaequalis. Loss of QoI fungicides further limits the arsenal of fungicides available to commercial apple growers for successful scab management.


2020 ◽  
Author(s):  
Ibrahim Elkhalil Benzohra ◽  
Hakima Belaidi ◽  
Boualem Boumaaza ◽  
Mohamed Mégateli

Grain legumes have an important role in Algerian agriculture contributing towards food, nutritional security and sustainable farming systems. This kind of culture has a several diseases can reduce the global production and yield. Causes of these major diseases we have to propose the integrated disease management for minimize the damage caused by these diseases. The term Integrated Pest Management was first based on the concept of ‘integrated control’ given by the entomologists from University of California, who defined it as “applied pest control” which combines and integrates cultural, biological and chemical control. Chemical control was used only if necessary and in a way which was least disruptive to cultural and biological control. 


Plant Disease ◽  
2015 ◽  
Vol 99 (4) ◽  
pp. 535-543 ◽  
Author(s):  
Jürgen Köhl ◽  
Christian Scheer ◽  
Imre J. Holb ◽  
Sylwester Masny ◽  
Wilma Molhoek

Apple scab, caused by Venturia inaequalis, is the most important disease in apple production, reducing yield and quality of fruit. Control of apple scab in commercial orchards currently depends on multiple applications of fungicides. The potential of the antagonistic isolate Cladosporium cladosporioides H39, originating from a sporulating colony of V. inaequalis, to control apple scab development was tested in eight trials during 2 years in orchards in Eperjeske (Hungary), Dabrowice (Poland), and Bavendorf (Germany) planted with different cultivars. Treatments were conducted as calendar sprays or after infection periods. Additional trials in an orchard in Randwijk (The Netherlands) focused on the effect of timing of antagonist application before or after infection periods. The overall results of the field trials consistently showed—for the first time—that stand-alone applications of the antagonist C. cladosporioides H39 can reduce apple scab in leaves and fruit. This was demonstrated in an organic growing system as well as in conventional orchards by spray schedules applied during the primary or the summer season. In both systems, the same control levels could be reached as with common fungicide schedules. Efficacies reached 42 to 98% on leaf scab incidence and 41 to 94% on fruit scab. The antagonist was also effective if applied one or even several days (equivalent to approximately 300 to 2,000 degree h) after infection events in several field trials and a trial conducted in Randwijk with single-spray applications at different intervals before or after infection events. Better understanding of the biology of the antagonist will help to further exploit its use in apple scab control.


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