Spatial distribution of Spodoptera frugiperda in the wasteland of southern Pernambuco state, Brazil

Abstract

ABSTRACT:The fall armyworm (Spodoptera frugiperda) causes damage and reduction in maize production and is considered a pest difficult to control, thus determining its spatial distribution pattern contributes to the development of suitable sampling and control strategies. The aim of this study was to evaluate the spatial distribution of Spodoptera frugiperda in maize culture under the conditions of the wasteland of southern Pernambuco state. The experiment was conducted at the Experimental Station of Brejão -'Instituto Agronômico do Pernambuco' (IPA) from April to May 2012. The study area consisted of 100 plots of 60 m 2 , where 10 plants per plot were weekly sampled at random. In each plant, the number of small and large larvae of S. frugiperda was counted on the leaves and the husk of ears. According to the data observed, the aggregation indices (variance/mean ratio, Morisita's index, Green's Index, and Exponential k of a negative binomial distribution) indicated aggregate distribution for both small and large caterpillars, and the negative binomial distribution was the most appropriate model to represent the distribution pattern of small larvae of this pest in the field. In maize crop in the wasteland of southern Pernambuco state, S. frugiperda presents aggregate pattern of distribution and tends to spread from the points of aggregation and colonize form the border into the center of cultures. RESUMO: A lagarta-do-cartucho (Spodoptera frugiperda) causa danos e redução na produção de milho, e é considerada uma praga de difícil controle; portanto, a determinação do padrão de distribuição espacial contribui para a elaboração de amostragens adequadas e estratégias de controle. O objetivo deste trabalho foi avaliar o padrão de distribuição espacial de Spodoptera frugiperda na cultura do milho, nas condições do Agreste Meridional de Pernambuco. O experimento foi conduzido na Estação Experimental de Brejão-PE, do

Statistical methods for identifying anisotropy in the Spodoptera frugiperda spatial distribution

“…To our knowledge, there are no results in the literature about the study of anisotropy for spatial point patterns in agriculture, for this reason it is not possible to make comparisons with other results. However, there are some works which analyze the clustering property of the S. frugiperda (e.g., Farias et al, 2008 andRios et al, 2014). We think that our results on clustering are in general coherent with those of Farias et al (2008) and Rios et al (2014), although in our study we did not take into account the size of the fall armyworm.…”

“…However, there are some works which analyze the clustering property of the S. frugiperda (e.g., Farias et al, 2008 andRios et al, 2014). We think that our results on clustering are in general coherent with those of Farias et al (2008) and Rios et al (2014), although in our study we did not take into account the size of the fall armyworm. In particular, Farias et al (2008) found that the spreading of the S. frugiperda for small larvae present aggregated behavior, and it becomes increasingly random with larval growth.…”

Geostatistical analysis of fall armyworm damage and edaphoclimatic conditions of a mosaic of agroecosystems predominated by push-pull systems

“…These results align with Hernández-Mendoza et al ( 2008): FAW lower den sities present an aggregated spatial distribution, while the higher densities have a random and uniform distribution. This trend does not occur in an absolute way since studies such as those by Ríos et al (2014) reported this aggregate dist ribution pattern, both for small and large fall armyworm larvae, both in early and advanced infestation stages.…”

Distribuição espacial de Metamasius hemipterus (Coleoptera: Curculionidae) em plantio de dendê (Elaeis guineensis Jacq) em Roraima

“…Esse tipo de distribuição, também, foi encontrada por Silva et al (2011), Monteiro et al (2013) e Rios et al (2014) para diferentes pragas, culturas e localidades.…”

“…Os estudos da dependência espacial de pragas, por meio da geoestatística, têm sido bastante utilizados nos últimos anos, permitindo fazer um controle mais adequado dessas pragas (GREGO et al, 2006;SILVA et al, 2011;MONTEIRO et al, 2013;RIOS et al, 2014).…”