Characterization of local populations of Pseudapanteles dignus (Hymenoptera: Braconidae), a biological control agent of the South American tomato moth Tuta absoluta (Lepidoptera: Gelechiidae), in Argentina

VALLINA, CONSUELO; PUCH, LILI; AQUINO, DANIEL A.; LUNA, MARÍA G.; SANCHEZ, NORMA

Denver, Colorado

Encuentro; ESA Annual Meetings; 2017

In biological control, agents that are widely distributed commonly show inter-population genotypic and phenotypic differences. Variation in life history attributes may lead to reproductive isolation which, in turn, is responsible of failures in mass rearing or effective biocontrol. The endoparasitoid Pseudapanteles dignus is a major enemy of Tuta absoluta and it is being evaluated as a biological control of this pest in NE Buenos Aires province, a main horticultural region of Argentina. The parasitoid has an American distribution, and particularly for Argentina, its presence in other horticultural areas is scarcely known. To extend the use of P. dignus in this country, we have started characterizing its populations from Northern Province of Salta. Firstly, surveys in tomato farms during 2015 and 2016 yielded significantly lower (< 5%) percentages of parasitism than in Buenos Aires. Secondly, some P. dignus biological traits were assessed in the laboratory, at two temperatures: standard conditions (25ºC) and average maximum registered in Salta (30ºC). Pre-imaginal developmental times for both sexes were 4 days shorter and the proportion of F1 females significantly decreased at the highest temperature. The functional response of P. dignus evaluated at different host densities differed from the type-I determined for the Buenos Aires strain: a type-II at 25ºC and a type-III at 30ºC. Higher proportions of attacked hosts were found in the Salta strain: 0.87 (host density=15) and 0.85 (host density=7) at 25º and 30ºC, respectively. These results on intraspecific variability could help using appropriate P. dignus strains for T. absoluta control in Argentina.