The introduction of an agricultural pest species into a new environment is a potential threat to agroecosystems of the invaded area. The phytosanitary concern is even greater if the introduced pest’s phenotype expresses traits that will impair the management of that species. The invasive tomato borer, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is one such species and the characterization of the insecticide resistance prevailing in the area of origin is important to guide management efforts in new areas of introduction. The spinosad is one the main insecticides currently used in Brazil for control of the tomato borer; Brazil is the likely source of the introduction of the tomato borer into Europe. For this reason, spinosad resistance in Brazilian populations of this species was characterized. Spinosad resistance has been reported in Brazilian field populations of this pest species, and one resistant population that was used in this study was subjected to an additional seven generations of selection for spinosad resistance reaching levels over 180,000-fold. Inheritance studies indicated that spinosad resistance is monogenic, incompletely recessive and autosomal with high heritability (h² = 0.71). Spinosad resistance was unstable without selection pressure with a negative rate of change in the resistance level ( = −0.51) indicating an associated adaptive cost. Esterases and cytochrome P450-dependent monooxygenases titration decreased with spinosad selection, indicating that these detoxification enzymes are not the underlying resistance mechanism. Furthermore, the cross-resistance spectrum was restricted to the insecticide spinetoram, another spinosyn, suggesting that altered target site may be the mechanism involved. Therefore, the suspension of spinosyn use against the tomato borer would be a useful component in spinosad resistance management for this species. Spinosad use against this species in introduced areas should be carefully monitored to prevent rapid selection of high levels of resistance and the potential for its spread to new areas.

The development of new strategies to control pest insects is required, in combination with conventional pesticides or replacing them. Essential oils produced from botanical extracts used in management programs should be effective against pests and selective to natural enemies. Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) is one of the most destructive pests of solanaceous crops in the world, and a possible management strategy consists of releases of the predator Nesidiocoris tenuis (Hemiptera: Miridae), along with botanical applications. The objective of this study was to evaluate the effects of Prev-am^® oil on T. absoluta offspring, either with or without the predator N. tenuis, as well as the oil’s effects on N. tenuis predatory behavior and longevity. The oil’s effects were compared with distilled water (control) and a synthetic pesticide (lambda-cyhalothrin). The response of populations to lambda-cyhalothrin was similar to that with Prev-am^®, compared to the control, showing that N. tenuis had higher capacity to reduce T. absoluta populations. The survival analysis of predators exposed to Prev-am^® indicates that none of the concentrations differed significantly from the control. In addition, the canonical variate analysis indicated significant overall differences in the predator behavior submitted to different treatments, suggesting that synthetic pesticide treatment affected predator behavior when compared to control and Prev-am^®. Reduction in predatory voracity of N. tenuis adults exposed to leaves treated with pesticide and biopesticide was significant compared to the control treatment. The results obtained could improve IPM programs against T. absoluta through the Prev-am^® applications and N. tenuis releases.

The objective of this work was to screen plants with insecticide activity, in order to isolate, identify and assess the bioactivity of insecticide compounds present in these plants, against Coleoptera pests of stored products: Oryzaephilus surinamensis L. (Silvanidae), Rhyzopertha dominica F. (Bostrichidae) and Sitophilus zeamais Mots. (Curculionidae). The plant species used were: basil (Ocimum selloi Benth.), rue (Ruta graveolens L.), lion's ear (Leonotis nepetifolia (L.) R.Br.), jimson weed (Datura stramonium L.), baleeira herb (Cordia verbenacea L.), mint (Mentha piperita L.), wild balsam apple (Mormodica charantia L.), and billy goat weed or mentrasto (Ageratum conyzoides L.). The insecticide activity of hexane and ethanol extracts from those plants on R. dominica was evaluated. Among them, only hexane extract of A. conyzoides showed insecticide activity; the hexane extract of this species was successively fractionated by silica gel column chromatography, for isolation and purification of the active compounds. Compounds 5,6,7,8,3',4',5'-heptamethoxyflavone; 5,6,7,8,3'-pentamethoxy-4',5'-methilenedioxyflavone and coumarin were identified. However, only coumarin showed insecticide activity against three insect pests (LD50 from 2.72 to 39.71 mg g-1 a.i.). The increasing order of insects susceptibility to coumarin was R. dominica, S. zeamais and O. surinamensis.