Riparian forest fragments in rice fields under different management: differences on hymenopteran parasitoids diversity

Abstract

<jats:p>Abstract Hymenopteran parasitoids are important biological control agents in agroecosystems, and their diversity can be increased with habitat heterogeneity. Thus, the purpose of the study is to evaluate the influence of distance of rice-growing areas from natural fragment, type of crop management (organic and conventional) and crop stages (vegetative and reproductive stages) on parasitoids family diversity. The work took place in two irrigated rice crops, one with organic management (O.M.) and another one with conventional management (C.M.), in the municipality of Nova Santa Rita, RS, Brazil, during the 2013/2014 and 2014/2015 seasons. The parasitoids were collected with Malaise trap arranged at different distances in relation to the native vegetation surrounding the rice crop in both places. Specimens were collected twice a month from seeding until the rice harvest. Average abundance between management, distances and rice development were compared. The most abundant families were Platygastridae, Mymaridae, Encyrtidae, Eulophidae and Trichogrammatidae. Parasitoid average abundance was significantly higher on OM only in the second season. There was a negative correlation between distance from native vegetation and parasitoid abundance in C.M. areas. There were differences in the composition of the parasitoid assembly between the phenological stages of rice.</jats:p>

Diversidad y grupos funcionales de insectos en cultivos de arroz y sus bordes bajo manejo convencional y agroecológico en Santa Fe, Argentina

“…Presenta dos hábitats diferentes: parcelas usualmente rectangulares, inundadas, donde crecen las plantas de arroz, y taipas (bordes elevados o albardones) que contienen y dirigen el agua, donde, en general, crece otro tipo de vegetación (Bambaradeniya 2003). Las taipas constituyen ambientes que se distribuyen dentro del cultivo, aportan heterogeneidad al agroecosistema y permiten la conexión de sus comunidades con las de los remanentes de vegetación natural (Silva et al 2020). Debido a estas características, algunos autores consideran que los cultivos de arroz son ambientes muy estables a largo plazo, lo que favorece la viabilidad de las poblaciones de una gran variedad de organismos (Bambaradeniya 2003;Bambaradeniya and Amerasinghe 2004;Bambaradeniya and Edirisinghe 2009;Edirisinghe and Bambaradeniya 2010).…”

“…Debido a estas características, algunos autores consideran que los cultivos de arroz son ambientes muy estables a largo plazo, lo que favorece la viabilidad de las poblaciones de una gran variedad de organismos (Bambaradeniya 2003;Bambaradeniya and Amerasinghe 2004;Bambaradeniya and Edirisinghe 2009;Edirisinghe and Bambaradeniya 2010). A pesar de esto, la intensificación de labranza para producir arroz de alto rendimiento bajo la forma convencional implica usar fertilizantes y biocidas químicos (e.g., neonicotinoides, diamidas, piretroides, carbamatos, organofosforados y herbicidas como el glifosato) para controlar insectos perjudiciales y malezas, así como para eliminar vegetación no cultivada que crece sobre las taipas (Attademo et al 2007(Attademo et al , 2018Silva et al 2020). Por el contrario, la producción de arroz orgánica se basa en eliminar el uso de agregados químicos sintéticos en forma de fertilizantes y biocidas y promover el uso de técnicas alternativas para controlar insectos y malezas.…”

“…Por el contrario, la producción de arroz orgánica se basa en eliminar el uso de agregados químicos sintéticos en forma de fertilizantes y biocidas y promover el uso de técnicas alternativas para controlar insectos y malezas. Además, las taipas son mantenidas con vegetación espontánea, no cultivada (Silva et al 2020).…”

Use of Parasitoids as a Biocontrol Agent in the Neotropical Region: Challenges and Potential

“…To deepen the knowledge in this respect, another work was developed to evaluate the contribution of the presence of fragments of natural vegetation near rice-growing areas and the influence of different management of the crop on the abundance and diversity of families of hymenopteran parasitoids through distance gradients [76]. The work took place one rice crop with organic management (OM) and another one with conventional management (CM), in RS, Brazil, during two crop seasons.…”

“…Correlation between distances (Samples spots = 0, 100 m, 200 m, 300 m, and 400 m) from native vegetation (OM p > 0.05 and CM p < 0.05; Pearson Test) ( first crop season)[76].…”