The basic characteristics of forecasting and control of apple scab
Osnovne karakteristike prognoziranja i suzbijanja čađave krastavosti jabuke
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Apple foliar and fruit scab is mostly spread and, concerning the harmful consequences, economically most important apple disease in our country. The causal agent is a phytopathogenous fungus having two developmental phases: saprophytic - teleomorphic (Venturia inaequalis (Cooke) Winter) and parasitic - anamorphic (Spilocaea pomi Fr.). It is the disease that occurs every year, but not at the same time and with the same severity. Cause is the effect of the different factors, among which the most significant are: pseudothecia maturing period and ascospore discharge (beginning and ending), severity and dynamics of ascospore discharge, the beginning of folliation and rate that apple leaf mass increases, distribution of rainfalls and dew, length of wetting period and air temperature. Based on the knowledge of biological and epidemiological characteristics of pathogen and monitoring the meteorological indicators, the conditions required for occurrence and spread of the disease can be register...ed and consequently the deadlines and modes of applications of control measure can be determined. The basic concept in forecasting and controlling infection should be based on making efforts to prevent primary infections in the course of a whole ascospore discharge period, specially pointing to blocking the earliest infections. If these efforts were made successfully, all problems that would be caused by occurrence and spread of secondary infections would be dealt with. From experience and according to the results obtained for many years of the Institute for plant protection and environment from Belgrade, with an aim to successful forecasting occurrence and spread as well as efficient control of this disease, it is necessary to observe the following procedures: Monitoring the saprophytic phase of the causal agent of a disease - Monitoring apple phenology - Monitoring meteorological conditions needed for realization of infections - Determination of method of apple orchard protection (choice, mode and time of fungicide application) - Final phase in forecasting and control of apple scab (evaluation of the exploited measures of protection) Each of above-mentioned procedures is elaborated in detail and its consistent and on-time application is the prerequsitive for making the overall system of for casting and control of apple foliar and fruit scab successful. Under our bioecological conditions (plantation Obrenovac-Ušće), during the last 15 years (1986-2000), hazard from primary infections lasted from 43-98 days (without correction analysis of emtiness of pseudothecia). In the mentioned period 7(1993) up to 27(1999) conditions required for primary infection were realized. On the basis of all previously said, it can be concluded that a continuous monitoring the conditions necessary for occurrence and spread of pathogen is of great importance, which appears to be a base for a successful forecasting and efficient control of this apple disease.
Keywords:apple scab / forecasting / control / primary infections
Source:Biljni lekar, 2000, 28, 6, 443-450
- Poljoprivredni fakultet - Departman za zaštitu bilja i životne sredine "dr Pavla Vukasovića", Novi Sad