Abstract

ESCALANTE  and  ARMAS, Carlos. Evaluación epidemiológica y económica en el manejo del tizón tardío de la papa en las playitas, Estado Táchira, Venezuela. Bioagro [online]. 2004, vol.16, n.3, pp.189-196. ISSN 1316-3361.

Potato late blight is one of the most important and economically destructive disease of the world. To evaluate the efficient of four chemical management strategies of this disease, tests in the commercial farms fields were performed through three productive cycles. The strategies were: 1) Control (TA) mancozeb, 2) Fungicide rotation (TB) using zinc dithiocarbamate, copper oxychloride + mancozeb, sulphur, cymoxanil + mancozeb, mancozeb, metalaxil + mancozeb and propineb + mancozeb, 3) TB+ Surfactant (TC) and 4) Applications of azoxystrobin, alternated with cymoxanil + mancozeb and metalaxil (TD). Severity (S) was evaluated and yield (Y) measured. Disease progress curves were plotted and infection rates (K) were calculated. S average and its corresponding Y were related by regression analysis. An economical analysis at each cycle was performed through profitability, partial budget, dominance and marginal return rate. Disease affected on the production according to the model Y= e^{(9.86-0.01*S)}. TD showed Y significantly higher for all cycles. In the same way, the smaller K was registered consistently for TD on the three cycles. In the economical analysis TD reached higher profitability and net benefit; dominating nearly all treatments with a very high marginal return rate. From the productive and economical standpoint, TD showed to be superior under the conditions of this study.

Keywords : Phytophthora infestans; potato; fungicide; epidemiologic; economic analysis.