Aqueous extract of chili pepper in the management of the pink hibiscus mealybug (Hemiptera: Pseudococcidae)

Abstract

Maconellicoccus hirsutus (Hemiptera: Pseudococcidae) is a polyphagous pest, attacks several crops of economic importance, including cocoa and coffee. Due to its rapid dissemination, studies are needed to develop management programs to combat this pest, as few studies seek the effectiveness of alternative products such as plant extracts, which can be promising in its control. Therefore, this work aimed to evaluate the efficiency of the aqueous extract of the fruits of chili pepper Capsicum frutescens (Solanaceae) in the management of the pink hibiscus mealybug. The tests were carried out in acclimatized chambers regulated at a temperature of 25 ± 1 ºC, relative humidity of 70 ± 10%, and a 12-hour photophase. The treatments consisted of five extract concentrations: 0.0, 2.5, 5.0, 7.5, and 10% (weight/volume). Coffee leaves were submerged in the aqueous solution of pepper extract and mounted in Petri dishes with agar solution to transfer the mealybugs. Each treatment consisted of 10 repetitions with 10 young mealybugs each. The experiment was evaluated 24, 48, and 72 h after the procedure. Data were submitted for analysis of variance and regression test (p≤0.05). Lethal concentration (LC50) was estimated using Probit analysis. The mortality of mealybugs increased with the increase in extract concentrations, with mortalities greater than 70% from the lowest concentration. The data fit the Probit model, with χ² of 1.0478 (p > 0.05) and a curve slope of 1.7799. The LC50 was estimated at 0.96%. Thus, the aqueous extract of Capsicum frutescens fruits is promising for the management of M. hirsutus.