Morphophysical and biochemical traits involved in maize grain varietal susceptibility to the maize weevil, Sitophilus zeamais (Coleoptera, Curculionidae)

Abstract

Description of the subject. Maize (Zea mays L.) is a major staple food providing nutrients for humans and animals worldwide. In Sub-Saharan Africa, maize is stored to ensure food resource availability throughout the year. However, stored-product pests such as the maize weevil, Sitophilus zeamais (Motsch.) (Coleoptera; Curculionidae) can cause huge grain losses. Objectives. This study aimed to assess the oviposition preference of Sitophilus zeamais over maize varieties commonly cultivated in Senegal and the effect of grain morphophysical and biochemical characteristics on their susceptibility to the maize weevil. Method. Twenty-five S. zeamais pairs (M/F) were placed in the center of an arena at equal distance of small heaps of maize grains (30 g) from nine maize varieties. Adult abundance, damaged grains, grain weight loss, and progeny were confronted to grain characteristics (phenolics and ferulic acid content, hardness, brightness, color and size of grains). Results. Susceptibility to the maize weevil varied significantly among maize varieties. Synth-9243 was the most susceptible variety with greatest damaged grains (10.5 ± 2.3%), grain weight loss (2.3 ± 0.6%), and progeny (17.3 ± 3.8 adults). The least susceptible varieties were Across-Pool, SWAN, Obatampa, and Tzee-Yellow. Grain characteristics such as phenolics and ferulic acid content were negatively related to susceptibility, but other constituents may have antixenosis or antibiosis effects. In addition, grain brightness may also have a visual effect deterring oviposition. Conclusions. The most repellent and less favorable varieties for S. zeamais were Tzee-Yellow, Across-Pool, Obatampa and SWAN, that presented high content of phenolics and ferulic acid, hardness and brightness of grains.

Resistência de genótipos de milho a densidades de Sitophilus zeamais (Coleoptera: Curculionidae)

“…A baixa emergência de insetos em Milho roxo pode ser explicada pela morte larval, resultado da resistência por antibiose (NHAMUCHO et al, 2017;NGOM et al, 2021). Outros trabalhos mostraram que a resistência de milho a S. zeamais pode ser explicada pelo número de insetos emergidos, em que, genótipos mais resistentes apresentaram menor número de insetos emergidos, ao contrário para genótipos suscetíveis com um maior número de insetos emergidos (MARSARO JÚNIOR et al, 2008;DEMISSIE et al, 2015;NHAMUCHO et al, 2017).…”

“…Como alternativa para minimizar esse problema, trabalhos tem buscado por novos métodos de controle, incluindo o uso de variedades resistentes a praga. Essas variedades podem afetar a biologia do inseto, como na perda de peso, menor longevidade, menor oviposição, ciclo de vida, entre outros fatores relacionados com a biologia do inseto (FRAZÃO et al, 2018;KASOZI et al, 2021;NGOM et al, 2021).…”

Resistência de três genótipos de milho ao ataque de Sitophilus zeamais Motschulsky, 1885 (Coleoptera: Curculionidae) em laboratório

“…A antixenose é caracterizada quando uma planta é menos utilizada pelo inseto para a alimentação, abrigo ou oviposição em igualdade de condições com outras plantas (Ribeiro et al, 2023). Nesse contexto, o uso de variedades resistentes pode afetar o desenvolvimento de S. zeamais, comprometendo parâmetros biológicos do inseto, como perda de peso, menor longevidade e ciclo de vida, além da não preferência para oviposição (Frazão et al, 2018;Ngom et al, 2021).…”

Insect-resistance test of Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae) on several maize hybrid lines

“…Observations include population of S. zeamais F1 and susceptibility index. The susceptibility index is determined by using formula below, [24,25] where A B…”

“…The increase of the population indicates the value of the susceptibility index is higher and causes the varieties/lines to be more sensitive to the powder beetle S. zeamais (positive correlation between the susceptibility index and the population). The susceptibility index was correlated with factors such as reduction in seed weight, number of progenies, seed hardness, and increases of insect population [22,25].…”