Bioinsecticides used against Spodoptera spp. in the cultivation of watermelon (Citrullus lanatus T.) in Los Ríos, Ecuador

Abstract

[Objective] The objective of this work was to analyze the use of organic insecticides from extracts of different plants to control the impact produced by the caterpillar pest Spodoptera spp. on the watermelon (Citrullus lanatus) crop in the province of Los Ríos, Ecuador. [Methodology]  A randomized complete block design (RCBD) was used, consisting of five treatments with four replicates, with different extracts and a control. Treatment T1 consisted of Capsicum sativum chili bell pepper extract plus common soap; treatment T2 consisted of Allium sativum garlic extract with liquid paraffin vegetable oil plus common soap; treatment T3 consisted of Urtica dioica nettle extract; treatment T4 consisted of Ruta graveolens rue extract, and treatment T5 was defined as a control. Differences between results of treatments were compared using Tukey’s test. Results were considered to be statistically significant when p ≤ 0.05. [Results] The T3 treatment was most effective, producing the lowest percentage of pest incidence (an average of 25%), and the lowest percentage of fruit damage (an average of 10%). It was followed by T1 (32.50% pest incidence) and T2 (35.00% pest incidence). The T5 control produced negative results, with 50% pest incidence and 37.50% fruit damage. [Conclusions] The study demonstrated that nettle extract, used as a botanical extract for the potential control of Spodoptera spp. in the watermelon crop produced the lowest incidence of pests (25%), demonstrating the usefulness of botanical extracts in sustainable horticultural production.