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The ladybird Eriopis connexa is an important natural enemy of several pest arthropods in agroecosystems. High population of this predator is frequently observed in strawberry and soybean crops associated with spider mites. We used two-sex life table parameters to evaluate under laboratory conditions, the suitability of three species of spider mites (Tetranychus evansi, Tetranychus urticae, Tetranychus ogmophallos), and a species of aphid (Myzus persicae) as a prey for the predator E. connexa. Eriopis connexa completed immature development on all prey species except on T. evansi, in which all individuals of predator died before reaching the pupal stage. Among prey species that allowed the immature development of E. connexa, T. urticae and M. persicae provided a faster development time to the predator. Oviposition days, longevity and fecundity of E. connexa on T. urticae and M. persicae were substantially longer/higher than on T. ogmophallos. Net reproductive rate (R 0 ), intrinsic rate of increase (r), and finite rate of increase (λ) of E. connexa feeding on T. urticae and M. persicae were also higher than those on T. ogmophallos. Based on the overall performance of the ladybird, the order of suitability of prey species was M. persicae > T. urticae > T. ogmophallos > T. evansi., (© 2022. The Author(s).)

Pesticides are the main tactics for pest control because they reduce the pest population very fast and their efficiency does not depend on abiotic factors. However, the indiscriminate use of these substances can speed up the development of resistant populations and causing environmental contamination. Therefore, alternative methods of pest control are sought, such as the use of botanical compounds. Nanoencapsulation of volatile compounds has been shown to be an important tool that can be used to overcome the lack of stability of these compounds. In this work, we describe the preparation and characterization of chitosan nanoparticles functionalized with β-cyclodextrin containing carvacrol and linalool. The toxicity and biological activity were evaluated. Decreases of toxicity were observed when the compounds were nanoencapsulated. The nanoparticles presented insecticidal activity against the species Helicoverpa armigera (corn earworm) and Tetranychus urticae (spider mite). In addition, repellent activity and reduction in oviposition were observed for the mites.

Carvacrol and linalool are natural compounds extracted from plants and are known for their insecticidal and repellent activities, respectively. However, their low aqueous solubility, high photosensitivity, and high volatility restrict their application in the control of agricultural pests. The encapsulation of volatile compounds can be an effective way of overcoming such problems. Inclusion complexes between beta-cyclodextrin (β-CD) and carvacrol (CVC) or linalool (LNL) were investigated. Inclusion complexes were prepared by the kneading method. Both complexes presented 1:1 host:guest stoichiometry and the highest affinity constants were observed at 20 °C for both molecules. The nanoparticles containing carvacrol and linalool had mean diameters of 175.2 and 245.8 nm, respectively and high encapsulation efficiencies (<90%) were achieved for both compounds. Biological assays with mites (Tetranychus urticae) showed that the nanoparticles possessed repellency, acaricidal, and oviposition activities against this organism. Nanoencapsulated carvacrol and linalool were significantly more effective in terms of acaricidal and oviposition activities, while the unencapsulated compounds showed better repellency activity. The nanoformulations prepared in this study are good candidates for the sustainable and effective use of botanical compounds in agriculture, contributing to the reduction of environmental contamination, as well as promoting the effective control of pests in agriculture.