Bioinseticida como alternativa sustentável e econômica

Abstract

The increasing concern regarding food quality and the intensive use of pesticides, especially in vegetable crops, has stimulated research on bioinsecticides as an alternative to synthetic insecticides. Neem (Azadirachta indica) is recognized for its insecticidal effects. For smallholder farmers, who often produce primarily for subsistence, the on-farm production of extracts from neem leaves emerges as a viable alternative, given the limited availability of seeds for oil extraction. The present study aimed to evaluate the performance and feasibility of using aqueous and ethanolic extracts of neem leaves for the control of pests in collard greens under field conditions. The experiment was conducted between June 1, 2024, and October 10, 2024, in a completely randomized design, with five replications and five treatments: commercial neem extract (CE), aqueous extract of fresh leaves (AFL), ethanolic extract of fresh leaves (EFL), aqueous extract of dried neem leaves (ADL), and control (CONT). Pest infestations were monitored weekly. Total and marketable yields were evaluated over seven harvests, using three classes: 1 – no damage; 2 – up to 5% leaf loss; and 3 – more than 5% leaf loss or compromised plant structure. Classes 1 and 2 were considered marketable. The commercial extract required a lower number of applications (17), compared to the prepared extracts (19). All extracts showed equivalent results among themselves and relative to the commercial product and were superior to the control treatment in the control of Plutella xylostella, leaf damage reduction, and marketable yield. In the feasibility analysis, the commercial extract showed better performance in terms of cost benefit ratio (1:41) and Net Present Value (US$ 38,428.95). Among the prepared extracts, EFL was the most viable in terms of cost–benefit ratio (1:28.05) and AFL in terms of Net Present Value, while ADL was the least attractive option. The results indicate that neem leaf extracts are effective in controlling Plutella xylostella in collard greens and represent a sustainable alternative, especially for smallholder farmers, as they combine technical efficiency and economic viability.