Procurou-se verificar a influência da região e da irrigação na cultura do arroz sôbre a suscetibilidade posterior do grão armazenado ao ataque da traça. Amostras de arroz com casca foram plantadas em quatro regiões diferentes do Estado de São Paulo, em culturas de várzea irrigada e de sequeiro. O produto, armazenado por um ano e meio em ambiente uniforme, foi submetido ao ataque da traça Sitotroga cerealella (Olivier). Foi observado que o local de cultivo do arroz influencia sua suscetibilidade à infestação da traça dos cereais durante o armazenamento. Os resultados mostraram que o arroz cultivado em sequeiro na região de Pindorama foi muito mais atacado pela traça que os cultivados nas outras regiões. O teste de Scheffé mostrou que houve um contraste significativo entre o arroz de várzea de Pindamonhangaba, Campinas e Mococa e o de sequeiro de Pindorama e Campinas, mas não houve diferença significativa entre o arroz de várzea e o de sequeiro de Campinas. O período entre a infestação do arroz em casca, em laboratório, e o início da emergência dos primeiros adultos foi de 23 dias.

It was investigated whether or not the local of cultivation of rice affects the posterior susceptibility to Sitotroga cerealella of the grain in storage. Samples of rough rice from the same bulk of seeds, of the variety Dourado Agulha, were planted in four regions of the State of São Paulo, Pindamonhangaba paddy, Pindorama upland, Mococa paddy. Campinas paddy and Campinas upland. The rice, after having been harvested, was taken to Campinas where - after one year and half of storage under uniform conditions for all samples - it was tested for its susceptibility to the insect, by using samples of each local replicated 10 times randomly distributed inside of an insect cage. The progeny of insects of each sample was recorded daily. The trial was repeated twice. The results showed that the local of cultivation has influence upon the posterior susceptibility of the grain in storage. The rice grown in Pindorama was more damaged by the pest than the rice grown in other regions. There was no significant difference in susceptibility between the paddy and upland rice grown in Campinas. Scheffe's test indicated that there was a strong contrast between the paddy rice grown in Pinda-monhangaba, Mococa and Campinas and the upland rice grown in Pindorama and Campinas, the latter being more infested. Although the locality may account for this difference, there was a tendency for the upland rice to be much more infested in storage by S. cerealella. The period between infestation and the beginning of emergence of the first adults was of 23 days, showing that under favorable conditions this pest may give one generation each 25 days, in rough rice.