Field evaluation of a supervised control system forBotrytis leaf blight in spring sown onions in the Netherlands

Abstract

Between 1988 and 1992 two existing weather based advisory models to control leaf blight in onions, were evaluated in the Netherlands. The first model, BOTCAST, can be used to time the initial spray while the second model, SIV, can be used to advise on every subsequent spraying. The evaluation based on field trials showed that application of both BOTCAST and SIV can reduce the number of sprays by 54% compared to a weekly spraying program without any yield loss or a higher disease severity. There was no relation between yield losses of untreated plots and disease severity expressed as lesion counts or leaf dieback. Relative disease growth rate was significantly but not closely related to weather based model characteristics or the observed crop micro-climate using linear regression analysis. The model characteristics did not yield better regressions than the climatological characteristics. Two changes to improve BOTCAST are proposed. Introduction of a supervised control system based on BOTCAST and SIV seems only economically feasible when the system is used as a regional warning system.

Survey of Fungicide Resistance for Chemical Control of Botrytis cinerea on Paprika

“…The gray mold pathogen B. cinerea develops mainly on fruits, leaves or petals (Dik & Elad, 1999), threatens the greenhouse paprika productivity throughout the world, and is usually managed by frequent use of prophylactic fungicides (Braun and Sutton, 1984;Bulger et al, 1987;de Visser, 1996;Raposo et al, 1996), which may lead to the development of multiple resistant pathogen population (Moorman and Lease, 1992;Raposo et al, 1996). While the new generation of fungicides like azoles and strobilurins showed limited effectiveness against this pathogen (Vermeulen et al, 2001), many fungicides have been applied routinely on glasshouse crops to control gray mold disease caused by B. cinerea.…”

A new risk indicator for botrytis leaf blight of onion caused by Botrytis squamosa based on infection efficiency of airborne inoculum

“…, 2005). Recent reports on evaluations of these management systems undertaken in the Netherlands, France and Canada indicate that the estimation of infection is the weakest part of these systems (De Visser, 1996; Huchette et al. , 2005; Carisse et al.…”

“…This research has given rise to monitoring-and weather-based control systems aimed at rationalizing onion protection (Shoemaker & Lorbeer, 1977b;Lorbeer & Jares, 1981;Lacy & Pontius, 1983;Sutton et al, 1986;Vincelli & Lorbeer, 1989;Carisse et al, 2005). Recent reports on evaluations of these management systems undertaken in the Netherlands, France and Canada indicate that the estimation of infection is the weakest part of these systems (De Visser, 1996;Huchette et al, 2005;Carisse et al, 2008a). Hence, in this study the objective was to refine the prediction of infection based on weather conditions.…”

Decision support systems used in the Netherlands for reduction in the input of active substances in agriculture

“…SIV is a sporulation-forecasting model that can be used to time subsequent sprays (Lacy & Ontius, 1983). Evaluation trials between 1988 and 1992 showed on average a 54% reduction in the number of sprays compared with a weekly spraying schedule (de Visser, 1996). The DOWNCAST system is also available for the other main serious leaf of onion, downy mildew caused by Peronospora destructor .…”