ABSTRACT The parasitoid Telenomus remus Nixon (Hymenoptera: Scelionidae) is a natural enemy of lepidopteran pests, and several studies have been conducted to evaluate its efficiency on eggs of Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae). Functional response is an important parameter for assessing the potential of parasitoids. The objective of this work was to evaluate the harvesting behavior and the functional response of T. remus on eggs of S. frugiperda. We conducted the experiment in an acclimatized chamber at 25 ± 2°C, relative humidity 70% ± 10% and photophase of 12 hours. For harvesting behavior, we observed that a female takes 2.4 minutes, from the placement to the first cleaning, which is 44.7 seconds, to parasite one egg. The value of the quadratic coefficient was negative (P1 < 0.0005), so it can be assumed that the functional response of T. remus to eggs of S. frugiperda was type III. The results of attack rate (a’), handling time (Th ), and number of eggs parasitized at 24 hours by T. remus were, respectively, 0.00664 and 0.5649·h-1. The sex ratio of the parasitoid was influenced by host densities, with a ratio of 0.5 at 10 and 30 egg densities, but values were not differentiated from the density of 15 eggs. Our results can be helpful for developing field studies, enhancing the knowledge and possibilities for integrated pest management.

The black aphid Aphis craccivora (Koch, 1854) stands out between the bugs considered cowpea pests. The objective of this study was to evaluate the effects of silicon application on the resistance induction of cowpea plants to the black aphid A. craccivora. The experiment was conducted in the Entomology Laboratory of the Phytosanitary sector of the Centro de Ciências Agrárias at the Universidade Federal do Piauí. The effects of the application of silicon on biological aspects were evaluated using a completely randomized design, with four treatments and 40 repetitions, being: silicon in soil (T1), silicon in soil + leaf (T2), silicone leaf (T3), and control (T4). The following biological variables were evaluated: generation period, reproductive period, fecundity, and daily average of nymphs per female. The silicon and lignin contents were also evaluated in the plants. The silicic acid was applied in a 1% solution around the stem of the plants (soil), 15 days after emergence, by diluting 2 g of the product in 200 mL of water. However, the leaf application was carried out with sprayer five days after application in soil. The non-preference of A. craccivora on bean was also evaluated. The evaluations were performed after 24, 48 and 72 hours of infestation by counting nymphs at 24, 48 and 72 hours and adults at each leaf session. The application of silicon promotes the reduction of the production of nymphs, interfering in the biological aspects of A. craccivora, and has potential to be used in a cowpea pest management program in cowpea.