Resistência de Variedades de Milho Crioulo a Sitophilus zeamais Mots., 1855 (coleoptera: curculionidae)

Abstract

The mayze crop (Zea mays L.) belonging to the Poacea Family, is of great importance in rural settlements and in different forms of social organization of production, including family, indigenous and quilombola agriculture, which are considered maintainers and guardians of the variability and natural biodiversity of cultivated crops with the maintenance and multiplication of creole seeds, characterized by local varieties, cultivated through generations. Among the phytosanitary problems faced in the storage of mayze seeds, the corn weevil, Sitophilus zeamais Mots., 1855 (Coleoptera: Curculionidae), is considered a key pest of corn in all producing regions, causing several quantitative and qualitative damage. Thus, the evaluation of the resistance of creole mayze varieties to S. zeamais attack was carried out through host preference bioassays, susceptibility index (SI), instantaneous population growth rate (ri), weight loss (g), in addition to determining moisture (%) and ash (%) contentes, were the objectives of this study. The results obtained demonstrated greater host preference for the creole variety Palha Roxa and lower preference of S. zeamais for the commercial BRS Caatingueiro. The state of use of the corn grains in the bioassays, (i) unattacked and intact grains, (ii) unattacked and broken grains, (iii) attacked and intact or (iv) attacked and broken grains also influenced the choice of S. zeamais. In general, susceptibility indices ranged from 0.01 for the Caatingueiro variety to 0.034 for the Jabotão creole variety, corroborating the instantaneous population growth rates, varying between 0.026 for the commercial Caatingueiro and 0.046 for the Palha Roxa creole variety. The Caatingueiro variety also showed lower weight loss (35.98g), while Palha Roxa (188.76g) showed significantly greater weight loss, in addition to high moisture (%) and ash (%) content.

Keywords: Zea mays L., antixenosis, antibiosis, biochemical composition.