Toxicity on Orius insidiosus (Hemiptera: Anthocoridae) and Tupiocoris cucurbitaceus (Hemiptera: Miridae) of homemade botanical and mineral pesticides used in agroecological systems

Abstract

The susceptibility of the predators Orius insidiosus (Hemiptera: Anthocoridae) and Tupiocoris cucurbitaceus (Hemiptera: Miridae) to garlic (Allium sativum L.) bulb extract, chili (Capsicum frutescens L.) fruit extract, onion (Allium cepa L.) infusion and Bordelaise broth was investigated in the laboratory. These products were tested at the rate of application recommended to the farmers in agroecological systems to control vegetable pests and diseases (garlic-chili: 50 ml/1, onion: 100 ml/l, Bordelaise broth: 1 l/25 m2). The concentrations of the extracts were 0.713 ± 0.047 mg/ml for garlic, 0.642 ± 0.055 mg/ml for chili, and 0.858 ± 0.030 mg/ml for onion. The effect of these compounds on the survival and fecundity of exposing nymphs and adults of O. insidiosus and T. cucurbitaceus to the botanical residuals were tested. Mortality was recorded 24 h after the treatment. The homemade botanical insecticides were classified according to the definitions of toxicity given by the International Organization for Biological Control. Chili fruit extract affected the survival of adults of O. insidiosus and onion infusion produced a decrease in T. cucurbitaceus fecundity when females were treated as nymphs. This parameter was also affected by Bordelaise broth regardless of whether it was applied to nymphs and adults of the mirid. The homemade botanical and mineral pesticides were classified as follows: chili fruit extract slightly harmful (Class 2) (O. insidiosus adults), harmless (Class 1) (O. insidiosus nymphs) and garlic bulb extract Class 1 for both O. insidiosus nymphs and adults; Bordelaise broth and onion infusion class 2 for both adults and nymphs of T. cucurbitaceus.