Phytotoxicity to table grapes cv. Thompson seedless of the fungicide sumisclex

Mario Alvarez A.1

Two experiments were conducted on grapes trained in a pergola system, in the Province of San Felipe, V Region, Chile. One experiment consisted of 15 treatments: 12 received liquid applications diluted in four volumes of water (500; 700; 1,000 and 1,500 It/hectare), with three rates of Sumisclex (0; 1; and 1.5 kg/hectare); three treatments received dust applications, where Sumisclex in the same three rates, was mixed wíth 30 kg/hectare of sulphur. Another experiment included three treatments: Sumisclex (WP) formulated in Japan; in France; and dry flowable (D.F.) formulation. Each formulation wastested in fourconcentrations: 0; 50; 100; and 200 g/100 It of water. In both experiments, plants were sprayed or dusted when the shoots were 5 cm or 10 cm long, followed by two flower applications. The trials were evaluated before and after the flower app)ications, rating the phytotoxic severity of the fungicide according to the degree of symptoms produced on leaves. Phytotoxicity increased with increased concentration of sprayed Sumisclex, while dusting did not produce any symptoms. No influence of the water volume used as carrier was found. Symptoms of phytotoxicity of plants which received Sumisclex when the shoots were 10 cm long were more severe. No effect of the phytotoxicity in the number or quality of exportable grape bunches was found.

1 Estación Experimental La Platina (INIA), Casilla 439, Correo 3. Santiago, Chile.