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Competition behavior involving agricultural pest species has long been viewed as a powerful selective force that drives ecological and phenotypic diversity. In this context, a Game Theory-based approach may be useful to describe the decision-making dilemma of a competitor with impacts to guarantee its superiority in terms of ecological dominance or sharing of the food resource with its competitor. In an attempt to elucidate the consequences of competitive dynamics for the ecological dominance of these species in refuge areas of Bt cotton, we conducted a study that was divided into two parts. The first study consisted of an evaluation of interactions involving Spodoptera frugiperda (JE Smith, 1797) and Helicoverpa armigera (Hübner, 1808) on non-Bt cotton plants in a field trial. In the second study, we explored the data matrix collected in the field to parameterize a model of Cellular Automata (CA) with update rules inspired by Game Theory. Computer simulations were analyzed in hypothetical scenarios involving the application (or not) of insecticides in the refuge areas in combination with the resistance factor of one or both pest species to the insecticides used in the refuge areas. H. armigera had superior competitive performance in relation to S. frugiperda only at high densities. According to the density-mediated shift in dominance of the species, the resistance of S. frugiperda to insecticides is seen as a risk factor for the production of susceptible individuals of H. armigera on a large scale in the refuge areas. Additionally, S. frugiperda insecticide resistance may potentially impact the resistance evolution of the H. armigera population to Bt cotton. Thus, ecological dominance could diverge by the presence of a resistance allele to insecticides with interspecific competition perhaps subordinate to evolutionary processes.

O sorgo apresenta alta responsividade à aplicação de fertilizantes, principalmente os nitrogenados. Nesse contexto, objetivou-se avaliar as plantas de sorgo (Sorghum bicolor), mediante doses crescentes de bioestimulante, na presença e ausência de nitrogênio. O estudo foi conduzido na Fazenda Experimental Luiz Eduardo de Oliveira Sales, no município de Mineiros-GO. Foi utilizado o delineamento em blocos casualizado em esquema fatorial 5 x 2, correspondentes a cinco doses de bioestimulante no tratamento de sementes (0, 3, 6, 9 e 12 mL ha-1) na presença e ausência de adubação nitrogenada, com 4 repetições, totalizando 40 unidades experimentais. A unidade experimental foi composta por quatro linhas de 4,0 m de comprimento, espaçadas 0,5 m entre si, totalizando uma área de 8,0 m2. Os resultados foram submetidos à análise de variância, onde as descrições das variáveis foram realizadas em função das doses de bioestimulantes com presença e ausência de nitrogênio de liberação gradual, realizando-se a regressão polinomial e testando-se os modelos lineares, quadráticos e, sendo escolhidos os modelos significativos de mais alto grau. Os resultados obtidos mostraram a influência do nitrogênio sobre as plantas de sorgo. O intervalo de 5,5 a 6,0 mL de bioestimulante na presença de adubação nitrogenada com nitrogênio de liberação gradual melhorou o crescimento e o rendimento de plantas de sorgo.Palavras-chave: Sorghum bicolor, reguladores vegetais, adubação nitrogenada. BIOSTIMULANT AND GRADUAL RELEASE NITROGEN IN THE PERFORMANCE OF SORGHUM ABSTRACT: Sorghum presents high responsiveness to the application of fertilizers, mainly nitrogen fertilizers. The objective of this study was to evaluate sorghum plants (Sorghum bicolor), using increasing doses of biostimulant, in the presence and absence of nitrogen. The study was conducted at the Experimental Farm Luiz Eduardo de Oliveira Sales, in the municipality of Mineiros, Brazil. A randomized block design in a 5 x 2 factorial scheme, corresponding to five doses of biostimulant in the treatment of seeds (0, 3, 6, 9 and, 12 mL ha-1) was used in the presence and absence of nitrogen fertilization, with 4 replications, totaling 40 experimental units. The experimental unit was composed by four lines of 4.0 m in length, spaced 0.5 m apart, totaling an area of 8.0 m2. The results were submitted to analysis of variance, where the description of the variables were performed according to the biostimulant doses with the presence and absence of gradual release nitrogen. The polynomial regression was performed by testing the linear and quadratic models, and the significant models were chosen and presented. The results obtained showed the influence of nitrogen on sorghum plants. The range of 5.5 to 6.0 mL of biostimulant in the presence of nitrogen fertilization with gradual release nitrogen improved the growth and yield of sorghum plants.Keywords: Sorghum bicolor, plant regulators, nitrogen fertilization.

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In this work, the effect of different densities (1, 3, 5, 7 and 9)

Insects and algae demonstrate adaptability in hydroponic environments. Algae attract flies, Bradysia spp. (Diptera: Sciaridae) and Scatella stagnalis (Diptera: Ephydridae), called fungus gnats and shore fly, respectively. Flies feed on algae, damaging seedlings radicellae, and may transmit pathogens to lettuce plants. Little information on the management of flies and algae is known. A paradox in the face of the expansion of hydroponics. The objective was to evaluate the potential of hydrogen peroxide (H 2 O 2 ) as an insecticide and algaecide agent. Entomopathogenic fungi were also evaluated as an alternative control to flies. The experiment was conducted in a commercial hydroponic system under a randomized complete block design with 5 treatments and 4 replicates. The treatments, sprayed on the phenolic foam plates, immediately after lettuce seed deposition, were: H 2 O 2 , Beauveria bassiana, Metarhizium anisopliae, Spinosyn and water, as control. The quality of the lettuce seedlings (cv. Brida), the presence of flies and algae evolution in the phenolic foam plates were recorded daily. H 2 O 2 and Spinosyn affected lettuce seed germination, but were able to reduce adult flies on the phenolic foam cells. The highest number of larvae was observed with both fungi, and only water, compared to H 2 O 2 . No larvae were found in Spinosyn sprayed phenolic foam cells. However, lettuce seedlings from Spinosyn sprayed plates were those with lower fresh weight. H 2 O 2 severely retained algae infestation in phenolic foam cells over a 15-day observation period. The present work demonstrates the potential that H 2 O 2 can play as an insecticidal and algaecide agent in hydroponic environments.

New hosts and parasitism notes for the mite Leptus (Acari: Erythraeidae) in Brazil. Larval erythraeid mites are common ectoparasites of harvestmen (Opiliones). Studies describing insects as potential hosts have received little attention. Specimens of an undescribed species of the genus Leptus were collected in association with predatory and phytophagous Heteroptera bugs in a secondary forest in Viçosa, Minas Gerais state, Brazil. New mite-host records and information on seasonality of this mite are presented.Keywords: Heteroptera, host, parasite, predatory bugs.Novos hospedeiros e notas sobre o parasitismo do ácaro Leptus (Acari: Erythraeidae) em fragmento de Mata Atlântica, Brasil ResumoHá novos hospedeiros e notas sobre o parasitismo do ácaro Leptus (Acari: Erythraeidae) no Brasil. As larvas de ácaros da família Erythraeidae são ectoparasitas comuns de opiliões (Opiliones). Estudos de insetos como potenciais hospedeiros de ácaros eritraídeos são escassos. Indivíduos de uma espécie nova do gênero Leptus foram coletados em associação com percevejos fitófagos e predadores (Heteroptera) em uma floresta secundária no município de Viçosa-Minas Gerais, Brasil. São apresentadas informações sobre a sazonalidade e o registro de hospedeiro desse ácaro do gênero Leptus.Palavras-chave: Heteroptera, hospedeiro, parasita, percevejos predadores.