scholarly journals Relationships between autumn black spot leaf litter and Venturia inaequalis ascospore production in apple orchards

2002 ◽  
Vol 55 ◽  
pp. 121-124
Author(s):  
I.J. Horner ◽  
M.B. Horner

Ascospore production from pseudothecia in apple leaf litter in the spring is a critical step in the disease cycle of Venturia inaequalis Leaf litter management is potentially an important component of an integrated pest and disease management strategy An orchard study was carried out in Hawkes Bay to investigate the relationships between the incidence of black spot on leaves in autumn the density of apple leaf litter on the orchard floor in spring and the number of ascospores produced in spring A total of 22 blocks on eight orchards were surveyed for black spot incidence in autumn 2000 The following spring remaining leaf litter was measured and ascospore production was quantified using spore traps Autumn black spot levels and spring litter levels were accurate predictors of spring ascospore production Management strategies employed on different blocks influenced spring leaf litter and ascospore levels Blocks with high autumn black spot generally had high spring ascospore production Management practices that substantially reduced litter levels resulted in reduced V inaequalis inoculum

Plant Disease ◽  
2019 ◽  
Vol 103 (3) ◽  
pp. 531-537 ◽  
Author(s):  
Janna Beckerman ◽  
Chelsi Abbott

A 2-year study on the use of organic and conventional adjuvants alone, or mixed with urea, was conducted for management of overwintering inoculum of the apple scab pathogen, Venturia inaequalis. Select adjuvants (LI 700, Bond Max, Latron B-1956, and Organic Wet Betty [OWB]) have the potential to hasten urea-driven leaf litter decomposition and reduce V. inaequalis overwintering inoculum comparable to urea, and that one organic surfactant could perform the same level of leaf decomposition as urea. Combinations of adjuvants with urea significantly improved leaf litter degradation compared with urea alone, concomitant with reducing the number of pseudothecia present and pseudothecium fertility. We demonstrate that the combination of urea with Bond Max or OWB reduced pseudothecia fertility and ascospore production to less than 5% in the remaining pseudothecia, a significantly greater reduction than with urea alone. These results suggest that conventional growers combine urea with Bond Max or OWB to more effectively reduce overwintering inoculum, and that the adjuvant OWB can provide organic growers with comparable performance to urea used in conventional orchards for improved sanitation.


2003 ◽  
Vol 56 ◽  
pp. 95-99
Author(s):  
K. Tshomo ◽  
I.J. Horner ◽  
M. Walter ◽  
A. Stewart ◽  
M.V. Jaspers

Field trials were conducted in Hawkes Bay and Lincoln into methods of treating overwintering apple leaves to reduce ascospore production by the apple black spot pathogen Venturia inaequalis The leaf treatments comprised three levels of nutrient amendments (including a water control) and five levels of saprophytic fungal isolates (including a nofungus control) in a factorial design Leaves were left to overwinter on the orchard floor and in spring the V inaequalis ascospores released were trapped on glass slides and counted Ascospore numbers were reduced (Plt;005) by the leaf amendment urea which alone caused 73 reduction but not by the BioStarttrade; product The effect of fungal isolates was not significant (P012) although when combined with the water treatment the isolates Chaetomium Phoma and Epicoccum spp and Trametes versicolor reduced numbers of ascospores by 33 27 15 and 28 respectively compared to the nofungus control When combined with urea the Chaetomium isolate reduced ascospore numbers by 92 and 82 compared to the nil fungus/water control treatments in Hawkes Bay and Lincoln respectively indicating that this treatment has potential for reducing primary inoculum of apple black spot


2000 ◽  
Vol 53 ◽  
pp. 387-392
Author(s):  
R.M Beresford ◽  
I.J. Horner ◽  
P.N. Wood

The effect of urea applied to apple leaves in autumn on production of ascospores of Venturia inaequalis (black spot) was quantified in four studies Autumn urea at concentrations from 020 reduced ascospore production in spring in proportion to the log of the urea concentration A single application of 5 urea sprayed onto fallen leaves gave an 88 decrease in ascospore production Urea applied to apple trees before leaf fall significantly reduced black spot disease on leaves the following spring in cv Fuji but not in cv Royal Gala Ascospore production was reduced by the fungicide cupric hydroxide but was not affected by a low concentration of fish fertilizer Three methods of ascospore assessment were used to detect differences in ascospore production


Author(s):  
Eleonora Rodríguez-Polanco ◽  
Julian Alberto Reina-Noreña ◽  
Pablo Julian Tamayo-Molano ◽  
Luz Astrid Rodríguez-Polanco ◽  
Edgar Herney Varón-Devia

Leaf spot or black spot (BS) in avocado, caused by the fungus Pseudocercospora purpurea (Cooke) Deighton, is one of the main sanitary limitations for the production of avocado, particularly for the Antillean cultivars (Lorena, Choquette, Santana, and Semil 44) in the northern region of the department of Tolima, Colombia. During 2014-2017, different experiments were carried out in the field, aiming to determine the period of higher fruit susceptibility, the effect of pruning on inoculum reduction, and chemical molecules with a high degree of control, adjusting their chronology and frequency of application. The results allow the technical, economic, and environmental implementation and validation of a chemical strategy for management of this disease. The management strategy carried out by Agrosavia reported a 10% lower incidence of BS in fruits, compared to the one carried out by producers, and a 23.75% return, due to the increase in high quality fruits. In the latter, DMI fungicides (demethylation inhibitors), even without resistance reports, and fungicides with a mixture of two active ingredients (DMI and QoI) in interspersed application and sometimes in conjunction with CuOCl during periods of higher susceptibility to BS were used, aiming to reduce the resistance induction risk in P. purpurea.


2021 ◽  
Vol 913 (1) ◽  
pp. 012056
Author(s):  
M R B Boentoro ◽  
Kisworo ◽  
T Wherrett

Abstract Indonesia is a country of immense biodiversity, however the natural environment is under pressure because of competing economic needs of the large population. Limits of Acceptable Change is a management strategy which acknowledges that any use of an area brings environmental change and best outcomes are achieved if all stakeholders are involved in the process. LAC was applied to develop a management strategy for Pelawan Biodiversity Park, Bangka Belitung. This reserve existsfor the preservation of endemic flora and fauna and is also utilised by local communities so there exists the potential for conflict of interests. This research was conducted March - April 2021. Through direct observation and interviews with all stakeholders, the LAC process was used to identify the reserve’s environmental and cultural values, and the goals held by each of the stakeholders. The results obtained indicate that the primary values assigned to the park are culture and economy, ecology and conservation, education and research, as well as tourism and ecotourism. Some activities of the communities both within and in the surrounding area have direct negative impacts on the environment in the park, including horticulture, tin mining, palm oil, poaching, over-exploitation of pelawan mushroom and honey, as well as tourist activities. After analysing the potential zoning for all activities, three usage zones were proposed to maximise conservation and facilitate economic sustainability for local communities. Specific management strategies for each zone are proposed together with indicators and standards of environmental change. Practical next steps are proposed for community wide consultation and implementation of management practices.


2008 ◽  
Vol 61 ◽  
pp. 54-58
Author(s):  
P.N. Wood ◽  
R.M. Beresford ◽  
T.J. Taylor

In autumn 2006 apple leaves with visible scab (black spot) symptoms were collected at the time of leaf fall and dipped in fungicides at concentrations equivalent to field application rates The leaves were overwintered on gravel and ascospore production measured on three dates during the following spring using suction spore traps Of ten fungicides tested myclobutanil trifloxystrobin captan dodine tolyfluanid and cyprodinil either reduced or delayed ascospore production by Venturia inaequalis during the following spring compared with a waterdipped control Metiram dithianon urea and copper hydroxide had a minimal effect on ascospore production Leaves from a separate orchard trial produced significantly fewer ascospores after myclobutanil treatment than after captan treatment Captan and tolyfluanid are recommended for autumn application to control scab because they significantly reduced or delayed ascospore production and have a low risk of selecting resistant strains of V inaequalis Although also effective myclobutanil trifloxystrobin dodine and cyprodinil should not be used for autumn application because of the risk of fungicide resistance


2013 ◽  
Vol 1 (1) ◽  
pp. 83
Author(s):  
Ozan Büyükyılmaz

The development and expansion of knowledge management as an important management philosophy has a significant impact on human resources management as well as on organization as a whole. In this context, knowledge management processes have been used as a strategic tool within human resources management.Therefore, functions of human resources management must adapt itself to this change. The purpose of this study is to determine the role of human resources management in the management of knowledge and to reveal the effects of knowledge management practices on the functions of human resources byexamining the relationship between human resources and knowledge management. In this context, a theoretical investigation was conducted. It has been determined that significant changes occurred on the functions of human resources management such as selection and recruitment, performance management, remuneration and reward, training and development within the framework of the knowledge management strategies.


1992 ◽  
Vol 2 (1) ◽  
pp. 121-125 ◽  
Author(s):  
George J. Hochmuth

Efficient N management practices usually involve many potential strategies, but always involve choosing the correct amount of N and the coupling of N management to efficient water management. Nitrogen management strategies are integral parts of improved production practices recommended by land-grant universities such as the Institute of Food and Agricultural Sciences, Univ. of Florida. This paper, which draws heavily on research and experience in Florida, outlines the concepts and technologies for managing vegetable N fertilization to minimize negative impacts on the environment.


1993 ◽  
Vol 28 (3-5) ◽  
pp. 91-99
Author(s):  
R. A. Wagner ◽  
M. G. Heyl

As part of the Sarasota Bay National Estuary Program (NEP) evaluation of environmental problems, modeling tools were used to estimate pollution loadings from diverse sources, including surface runoff, baseflow, wastewater treatment plant discbarges, septic tanks, and direct deposition of rainfall on the bay surface. After assessing the relative impacts of the pollution sources, alternative management strategies were identified and analyzed. These strategies focused primarily on future development, and included structural and nonstructural best management practices (BMPs), as well as a regional wastewater treatment plan. Loading reductions, along with planning-level cost data and estimates of feasibility and other potential benefits, were used to identify the most promising alternatives.


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