TECHNIQUES AND DIFFERENT INSTRUMENTS FOR AN EFFICIENT IMPLEMENTATION OF AN APPLE SCAB WARNING SYSTEM IN SANTA CATARINA

The present paper evaluates the results of apple scab control by means of a warning system installed at the Research Station of Caçador - EMPASC, and the use of different techniques and instruments since 1982. After an initial testing period, the warning system was introduced into practice and is working since 3 years with the help of the extension service. An average of 57 infection periods for Venturia inaequalis were detected in each growing season using the leaf wetness recorder LUFFT and the electronic scab predictor Biometron. A high throughput spore sampler (Burkard) determines the ascospore projection. Ascospore maturation was studied using the method of Szkolnik.

Ascospore liberation begins before blooming with its highest peaks during green tip and blooming period and ends at the end of November.

With the introduction of the warning system apple growers have gained a new phytossanitary conscience, enabling a reduction of the number of fungicide sprays maintaining a good quality of the fruit.