Natural mortality factors are responsible for regulating pest populations in the field. However, plant attributes such as the variety and phenological stage can influence the performance of these factors. Therefore, we investigated the performance of the natural mortality factors of Aphis gossypii (Glover; Hemiptera: Aphididae) as a function of the plant variety and phenology. To investigate the performance of these factors, we evaluated the mortality of A. gossypii caused by natural mortality factors for 2 yr in field conditions in transgenic (Bacillus thuringiensis/Roundup Ready) and non-transgenic cotton crops during vegetative, flowering, and fruiting stages. The natural mortality factors were affected similarly between the transgenic and non-transgenic plants; however, differences were observed in their performance, depending on the phenological stage of the cotton plant. Compared with other stages, predation was higher in the flowering stage, whereas the mortality caused by rainfall was higher in the vegetative stage. Coccinellid beetles were primarily responsible for the predation on A. gossypii. These findings highlight that the performance of the natural mortality factors of A. gossypii varied more as a function of the phenological stage of cotton than of the variety.

Studies on the natural factors contributing to pest regulation are fundamental to developing efficient integrated pest management programs. Chemical control is the main management method used for pests [e.g., Aphis gossypii (Glover)]. The studies of pest management with chemical control provide information that can be incorporated into integrated pest management programs to promote more sustainable pest control approaches. Here, we report the critical stages of A. gossypii and its abiotic and biotic natural mortality factors in cotton crops as a function of plant phenology using a life table. The critical stages of A. gossypii were the first and fourth instars. Together, the abiotic and biotic factors caused 94.31% of the mortality in the A. gossypii populations in cotton crops with plants in the vegetative, flowering, and fruiting stages. The key mortality factors were rainfall and predation. Syrphidae Allograpta exotica (Wiedemann) (Diptera: Syrphidae) and Chrysopidae Chrysoperla externa (Hagen) (Neuroptera: Chrysopidae) larvae, many Coccinellidae species Cycloneda sanguinea (L.) (Coleoptera: Coccinellidae), Eriopsis connexa (Germar) (Coleoptera: Coccinellidae), Harmonia axyridis (Pallas) (Coleoptera: Coccinellidae), Hippodamia convergens (Guérin-Meneville) (Coleoptera: Coccinellidae), Scymnus rubicundus (Erichson) (Coleoptera: Coccinellidae) and Stethorus punctillum (Weise) (Coleoptera: Coccinellidae), one Anthocoridae species Orius insidiosus (Say) (Hemiptera: Anthocoridae), and individuals from the Araneidae family were responsible for the predation of A. gossypii. The results obtained in this study provide support for the idea that efforts to preserve natural enemies (e.g., predators) and rainfall monitoring should be adapted due to their importance for the regulation of A. gossypii populations in all the phenological stages of cotton in tropical regions.

A semeadura de leguminosas em Moçambique é feita maioritariamente por mulheres utilizando enxada, paus e outros instrumentos, que demandam muito tempo e esforço humano. A avaliação das tecnologias de semeadora manual de leguminosas em agricultores de feijão nhemba no distrito de Mogovolas com o objectivo de aumentar a produtividade, rendimento, redução do esforço físico, tempo gasto na plantação, mão-deobra no campo dos pequenos produtores e a integração do gênero nas atividades é uma das soluções. A semeadora é leve e fácil de transportar. Um teste foi montado usando o Randomized Complete Block Design e cinco demonstrativos em testes agrícolas da tecnologia com produtores. O perfil do agricultor foi estudado para determinar os fatores que determinam a adoção de tecnologias que também foram analisados por meio de entrevistas semiestruturadas. A análise de dados estatísticos para os ensaios foi realizada usando GenStat 12ª Edição e Stata 14.0 para análise do perfil dos agricultores de dados. Os resultados mostraram diferenças significativas entre os locais para as variáveis altura de planta, produtividade e época de semeadura. Os métodos de plantio apresentaram diferenças significativas para a variável densidade de plantas. A época de plantio teve diferenças significativas com menor tempo para a tecnologia semeadora manual de leguminosas. O custo-benefício mostrou-se favorável para o uso da semeadora manual de leguminosas.

Strip intercropping in crops can influence insect population activity, increasing or decreasing the population number of pests and natural enemies. For this purpose, the effect of intercropping in strips in the crops of (Maize with nhemba beans, Holoco beans and Crotalaria Juncea) on the management of the funnel caterpillar (Spodoptera Frungiperda) on the corn crop (Zea mays L.) was evaluated. received no chemical treatment. A field trial was established in four different agro-ecological zones with a randomized complete block design (DBCC), with four replicates, and in each replicate with four treatments for a total of 16 treatments, each plot had intercropped legumes and maize where the maize was in the two central rows and the various legumes served as a barrier, four cuts, one of each repetition being pure maize. After corn emergence, all treatments were monitored weekly, counting the funnel caterpillar population and other pests and natural enemies. However, the natural enemies were found more in the plots with the intercropped crop than in pure corn. Pure corn was the most attacked by the caterpillar in relation to intercropped corn, which had the highest yield. There were no significant differences in yield between pure maize (control) and maize intercropped with cowpea, holoco bean and Crotalaria juncea in the three locations only in Gurué.