ECOLOGICAL ZONING OF THE FALL ARMYWORM IN THE STATE OF RIO GRANDE DO SUL, BRAZIL

ABSTRACT

The fall armyworm is a polyphagous pest that causes major damage to rice and maize crops in the state of Rio Grande do Sul, Brazil. Various studies have been conducted to minimize the damage caused by the larvae. The observation of biotypes of S. frugiperda in the state of Rio Grande do Sul, associated to higher temperature, has created new scenarios and implications in the management of this pest. The objective of the present study was to define the ecological zoning of S. frugiperda biotypes for “rice” and “corn” in the state, based on thermal requirements of the insect in order to estimate the number of generations, according to the increase in the minimum temperatures predicted by the IPCC. In the current ecological conditions, the biotype “rice” may reach 5 to 9 generations per year, however, with increases of 1, 3 and 5.8° C, it could reach up to 5 to 10, 6 to 12 and 9 to 14 generations, respectively. The biotype “maize,” which today may reach 2 to 8 generations per year, with these increases in temperature would reach 3 to 8, 6 to 10 and 8 to 13 generations, respectively.

KEY WORDS  Spodoptera frugiperda ; temperature; pest distribution