A‐scab (Apple‐scab), a simulation model for estimating risk of Venturia inaequalis primary infections*

Abstract

A‐scab (Apple‐scab) is a dynamic simulation model for Venturia inaequalis primary infections on apple. It simulates development of pseudothecia, ascospore maturation, discharge, deposition and infection during the season based on hourly data of air temperature, rainfall, relative humidity and leaf wetness. A‐scab produces a risk index for each infection period and forecasts the probable periods of symptoms appearance. The model was validated under different epidemiological conditions: its outputs were successfully compared with daily spore counts and actual onset and severity of the disease under orchard conditions, and neither corrections nor calibrations have been necessary to adapt the model to different apple‐growing areas. Compared to other existing models, A‐scab: (i) combines information from literature and data acquired from specific experiments; (ii) is completely ‘open’ because both model structure and algorithms have been published and are easily accessible; (iii) is not written with a specific computer language but it works on simple‐to‐use electronic sheets. For these reasons the model can be easily implemented in the computerized systems used by warning services.

Disease Decision Support Systems: Their Impact on Disease Management and Durability of Fungicide Effectiveness

“…The structure of DDSS for apple scab management varies from one simple model such as the Mills rules for infections, coupled with simple models such as ascospore maturity models up to more complex simulation models (Rossi et al, 2007). The simple rule-based DDSS may not be sufficient to make proper estimation of risk, while the complexity of some simulation models refrain growers from using them.…”

Occurrence of Venturia inaequalis races in Poland able to overcome specific apple scab resistance genes

“…It causes damage to the leaves and fruits, with negative consequences for fruit quality and yield. Currently, the most common way to protect apple trees against this disease is the application of fungicides (MacHardy 1996;Rossi et al 2007;Holb 2009). In Poland, during years which have had particularly favourable conditions for the development of apple scab, up to 20 fungicide treatments were found to be necessary in order to avoid losses (Meszka and Masny 2006;Masny 2015).…”

Development and Validation of a Weather-Based Model for Predicting Infection of Loquat Fruit by Fusicladium eriobotryae

“…These studies have been used to elaborate epidemiological models for some of these pathogens including V. pyrina [36], V. nashicola [37], V. inaequalis [38], [39], F. oleagineum [40], and F. effusum [41]. For V. inaequalis , the use of epidemiological models to schedule fungicide applications has reduced the number of treatments [42]–[45].…”