Population dynamics and preference of weevils and moths on stored maize with low grain moisture

Twenty four maize varieties whose moisture content in the grain was constant at the moment of being stored (7.6%) were evaluated in this study. Number of weevils and moths living and dead, their total and per gram number, as well as ear appearance at sight, weight and percentage of flour, and percentage of intact grain in 100 grams were recorded. These varieties were grown in the Colegio de Postgraduados experimental fields at Montecillo and Tecamac in the State of Mexico. At each location, a randomized complete block design with three replications for each variety was used. The storage period comprised 204 days in which a sampling was made every 15 days to complete a total of 12. The main species found were Prostephanus truncatus, Sitotroga cerealella and Plodia interpunctella. The maximum number of weevils was in the sampling 6, while moths had maximum numbers in samplings 4 and 8. Insects had preference to feed firstly from the varieties of the group II (Tuxpeno); secondly, they preferred to feed from the varieties of the group III (Conico Norteno, Bolita, y Conico), and finally they attacked the varieties of the group I (Chalqueno). The preference was determined by the number of insects per gram of ear. No one of the studied varieties presented tolerance to insect attack.Original Abstract: En el presente trabajo se evaluaron 24 variedades de maiz con un contenido de humedad constante del grano al momento de almacenarse (7.6%). Las variables evaluadas fueron el numero de insectos (gorgojos y palomillas) vivos, muertos, total y por gramo de mazorca; aspecto visual de mazorca en la escala de 1 a 5, donde 1 es mazorca sin dano y 5 mazorca totalmente danada; peso y porcentaje de harina; y porcentaje de grano sano en 100 gramos. Las variedades fueron sembradas en los campos experimentales del Colegio de Postgraduados de Montecillo y Tecamac en el Estado de Mexico. Se uso un diseno de bloques completes al azar con tres repeticiones por variedad en cada localidad. El periodo de almacenamiento fue de 204 dias, durante los cuales cada 15 dias se hizo un muestreo hasta completar un total de 12. Las principales especies que se presentaron fueron: Prostephanus truncatus, Sitotroga cerealella y Plodia interpunctella. Los gorgojos alcanzaron su numero maximo en el muestreo 6 y las palomillas en los muestreos 4 y 8. La mayor preferencia alimenticia fue por las variedades del grupo II (raza Tuxpefio), seguidas por las que conformaron el grupo III (razas Conico Norteno,