Abstract

LAZO, José Vicente; MUNOZ, José Alfredo  and  ESCALONA, Aníbal. Experimental assessment of chlorothalonil for controlling Black Sigatoka (Mycosphaerella fijiensis) in plantain (Musa spp AAB). Bioagro [online]. 2012, vol.24, n.2, pp.127-134. ISSN 1316-3361.

To evaluate the efficacy and selectivity of the fungicide chlorothalonil in the control of Black Sigatoka (Mycosphaerella fijiensis), two experimental field trials located in commercial crops of plantain in Merida State, were performed. Each experiment consisted on a randomized block design with 4 replications and 5 treatments: Chlorothalonil (experimental formulation) at rates of 1.0, 1.5 and 2.0 kg·ha^{-1, a commercial check (Bravo 500: 2 L·ha-1}), and an untreated check. A single application was made when the first symptoms of the disease appeared in the plantain leaves. The quantitation of effectiveness of control was based on the calculation of the following variables: weighted average of infection (PPI), the youngest leaf affected (HMJE), the percentage of healthy leaves (% HS) and the number of leaves per plant (H/P), all of which were established based on the method of Stover, as amended by Gauhl, to assess the incidence and severity of damage caused by the disease. Results showed that effectiveness of all fungicide treatments were statistically significant with respect to absolute check, according to the performance of the variables, PPI, HMJE, % HS and HP. All fungicide treatments were highly selective to the crop.

Keywords : Efficacy and selectivity of fungicides; and severity of the disease; Musaceae.