ABSTRACT
Distribution, frequency, host range and parasitism of two new cereal aphid pests, Sitobion fragariae (Walker) and Metopolophium festucae cerealium Stroyan (Homoptera, Aphididae), in Chile

Petr Stary1, Fernando Rodriguez A.2, Marcos Gerding P.3, Hernán Norambuena M.4 y George Remaudiere5
 

Metopolophium festucae cerealium and Sitobion fragariae were detected in 1991 in Chile. In the course of research undertaken in 1992, both species were found to tend to pest status, apparently occupying the niches of Metopolophium dirhodum (Walker) and Sitobion avenae (F.) which were lowered to acceptable levels through biocontrol. S. fragariae was found to occur in Regions V, Metropolitana, VII, VIII and IX, whereas M. festucaethat in 1991 was found only in region IX, during 1992 was determined in Regions VII, VIII and IX; this situation indicates its dispersing through Chile. A number of parasítoid wasps (Hym., Aphidiidae) were found to attack both new pests, and the biocontrol is believed to keep the populations at economically acceptable levels. The position ofthe newly immigrant pests in the whole aphid-parasitoid community on cereals in Chile is discussed.

Keywords: Sitobion fragariae, Metopolophium festucae cerealium, aphids, parasitoíds, biocontrol, Chile.
1 Institute of Entomology, Academy of Sciences ofthe Czech Republic, Branisoysk a 31, 370 05 Ceske Budejovice, Czech Republic.
2 Centro Nacional de Entomologia La Cruz, Instituto de Investigaciones Agropecuarias (INIA), Casilla 3, La Cruz, Chile.
3 Estación Experimental Quilamapu (INlA). Casilla 426, Chillán, Chile.
4 Estación Experimental Carillanca (INIA), Casilla 58-D, Temuco. Chile.
5 Laboratoire d'Entomologie, Museum National d'Histoire Naturelle. 45 Rue de Bulton, 75005 Paris, Franca.