Exploring Alternative Products for Tomato Septoria lycopersici Control

The septoriose (Septoria lycopersici) is an important disease in tomato production and can lead to significant losses. Although there are active ingredients registered for the control of this disease, there is little study about products with alternatives for the control of the fungus S. lycopersici. Thus, the objective of this work was to study the effect of alternative products in controlling the septoriose. The rationale for the study was to find efficient products that are less harmful to the environment. The study was conducted at the experimental station of EPAGRI in the state of Santa Catarina, Brazil. Twelve products were tested to control Septoria: Bacillus subtilis QST 713 (274 mg/L a.i.), Bacillus subtilis QST 713 autoclaved (274 mg/L a.i.), lime sulfur (10,000 mg/L c.p.), benzalkonium chloride (250 mg/L a.i.), mixed mineral fertilizer ( 2,000 mg/L c.p.), sodium hypochlorite (320 mg/L a.i.), peracetic acid (5,440 mg/L a.i.), Bordeaux mixture (3,000 mg/L c.p.), Viçosa mixture (3,000 mg/L c.p.), Trichoderma harzianum Rifai ESALQ-1306 (600 mg/L a.i.), acibenzolar-S-methyl (25 mg/L a.i.), potassium phosphite (2,000 mg/L a.i. with 1,340 mg/L phosphorous acid) and biostimulant (200 mg/L c.p.). The doses used were based on label, previous tests in vitro and in phytotoxicity events in tomato plants. In the in vitro experiments, the products that were not able to promote the formation of an inhibition halo were: biostimulant, potassium phosphite, acibenzolar-S-methyl, Trichoderma harzianum, Viçosa mixture and Bordeaux mixture. The products B. subtilis, lime sulfur, benzalkonium chloride, mixed mineral fertilizer, peracetic acid, sodium hypochlorite and autoclaved B. subtilis were able to inhibit fungal growth in vitro, forming a halo of inhibition. The chemical fungicides mancozeb + pyraclostrobin + fluxapyroxad were used as a positive control. In vivo, the positive control was able to control 100% of the incidence and severity of Septoria and no symptoms were observed in the plants. For incidence, the products that controlled at least 80% of the disease were lime sulfur and mixed mineral fertilizer. When considering the disease severity, the products that controlled at least 80% of the disease were: lime sulfur, mixed mineral fertilizer, Bacillus subtilis QST713 and benzalkonium chloride. The products Bordeaux mixture, Viçosa mixture, sodium hypochlorite and peracetic acid caused phytotoxicity when applied to tomato plants. Although lime sulfur has shown promise, its successive application can lead to a decrease in the photosynthetic rate.