Evaluation of management practices for corynespora leaf spot of tomato

Abstract

Corynespora leaf spot management alternatives on tomato crop were evaluated in two experiments laid out in randomized complete blocks in a factorial design (2 × 3 × 3), with four and six replications, respectively. The first factor was the soil covering in two levels: soil mulching (dry grass clipping) or bare soil. The second factor was the foliar spraying with three levels: non aerated biofertilizer, fungicide and water. The third factor was the plant management with three levels: selective removal of side shoots, diseased leaf removal or no plant management. The disease severity and disease index (DI) data were assessed twice a week and fruit yield was assessed at the end of the crop cycle. The area under disease progress curves were estimated with severity and DI data and fruit yield data was used to performing statistical analysis. The mulching and the non aerated biofertilizer spraying did not have a significant effect in the disease intensity or in fruit yield. In the plants submitted to selective removal of side shoots and diseased leaf removal, disease severity was significantly lower than in plants not submitted to these treatments. Both plant management practices probably decreased the leaf surface wetness duration in the plant canopy and the diseased leaf removal also significantly reduced (P<0,05) the number of C. cassiicola conidia in the air. These cultural management practices should be used for Corynespora leaf spot management in small production fields. © the Brazilian Phytopathological Society. Printed in Brazil.