Abstract Herbicides can impact non-target metabolic pathways in natural enemies and lead to the reduction of these populations in the field. Behavioral characteristics, morphology and histology of reproductive structures and reproduction of females of Podisus nigrispinus (Dallas) (Hemiptera: Pentatomidae) were evaluated under the effect of the herbicides atrazine, nicosulfuron and the mixture of both. The number of mature oocytes per ovary was lower in females exposed to the herbicides atrazine, nicosulfuron and the mixture of both. Herbicides did not affect the longevity and mortality of P. nigrispinus, therefore, they are selective for this predator. On the other hand, herbicides can cause sublethal effects by affecting the reproduction of predators.

ABSTRACT The aim of this work was to determine the persistence of auxinic herbicides applied on tropical pasture and toxicity for succeeding crops. The herbicides were applied in an area of dystrophic red‒yellow latosol with pasture infested of weeds. At 40, 80, and 280 days after application of herbicide, the soil samples were collected at depths of 0 to 20 cm. Soil with residues of 2,4-D, 2,4-D + picloram, triclopyr, and a soil without herbicide application were analyzed with six replicates. Seven crops were cultivated in these soils: cucumber (Cucumis sativus L.), velvet bean [Mucuna pruriens (L.) DC.], pigeon pea [Cajanus cajan (L.) Millsp.], alfalfa (Medicago sativa L.), lablab bean [Lablab purpureus (L.) Sweet], corn (Zea mays L.), and sorghum [Sorghum bicolor (L.) Moench]. The plants of cucumber, pigeon pea, and alfalfa were the most susceptible to the auxinic herbicide residues. However, the lablab bean was the only one among the dicot evaluated that showed tolerance to the 2,4-D + picloram residual when cultivated in soils at 280 days after application of herbicide. Corn and sorghum showed lower chlorophyll content in soils with 2,4-D + picloram residual up to 80 days after application of herbicide.

O fenômeno da desertificação na região semi-árida do Nordeste do Brasil é estudado a partir da análise de variáveis representativas do clima, vegetação, solos e aspectos socioeconômicos na bacia hidrográfica do Taperoá, no Estado da Paraíba - Brasil. As séries temporais da precipitação anual de 32 pluviômetros foram examinadas e um mapa de tendência da pluviosidade anual foi traçado. As variáveis mencionadas acima são estimadas para os municípios de São João do Cariri e Cabaceiras, respectivamente. Os resultados mostram, de modo diferenciado para os dois municípios, a susceptibilidade à desertificação. No primeiro município, todas as variáveis analisadas contribuem para afirmar que um processo bastante significativo de desertificação está em curso, inclusive associado a uma diminuição das precipitações anuais.

The phenomenon of desertification in the semi-arid region of Northeast Brazil is studied from the analysis of some variables representative of climate, vegetation, soils and some economic and social aspects in the Taperoá Basin in the State of Paraíba, Brazil. Annual rainfall data from 32 rain gauges was treated by temporal series analysis and a trend map was drawn. All the above listed variables were estimated for São João do Cariri and Cabaceiras districts. Results show a diferent mode of susceptibility to desertification for both districts, especifically, in the São João do Cariri district, all the variables treated in this study contributed to the occurrence of a desertification process including a negative trend in annual rainfall.