Native and alien microsporidia in Argentine grasshoppers

C. LANGE

Buenos Aires

Congreso; 2012 International Congress on Invertebrate pathology and Microbial Control; 2012

Society for Invertebrate Pathology

Cooperative projects between scientists of the Agricultural Research Service (ARS) of the United States Department of Agriculture (USDA) and La Plata National University (UNLP) in the late 1970´s and early 1980´s initiated the study of microsporidia as potential biocontrol agents of grasshoppers in Argentina, a previously unexplored field of research in the country. As elsewhere in the world, absolute reliance on chemical insecticides against some of the 10-15 pest grasshopper species of the country provided the justification underlying the search for more environmental-friendly alternatives of control. Since then, three native microsporidia have been described (Liebermannia dichroplusae, Liebermannia patagonica, Liebermannia covasacrae), several other Liebermannia-like isolates have been detected, and the fate of the introduced microsporidium Paranosema locustae was monitored for years in the Pampas, and to a lesser extent in two other introduction areas in Patagonia. The presentation will review the state of knowledge on the microsporidia associated with grasshoppers in Argentina. None of the native species so far discovered appear to be useful for control purposes due to constraints in transmission, host range, and pathogenecity. On the contrary, P. locustae, well established in the western Pampas and in Loncopué, Neuquén province, seems to be of value as a long-term control factor. Simultaneously, some non-target grasshopper species may be negatively affected. However, in spite of the apparent usefulness of P. locustae against grasshoppers in Argentina, aside from some incipient interest by organic farmers, what has been called “the chemical paradigm” still prevails and no use of P. locustae is being done.