Araceli Vasicek1; Francisco La Rossa y Andrea Paglioni
In the present work, biological and population parameters of aphid Nasonovia ribisnigri on lettuce (Lactuca sativa L.) varieties Divina, Criolla Blanca and Cuatro Estaciones, were obtained and compared. Cohorts were reared at 10± 1ºC; 14:10 L:D cycle and 90% of relative humidity. Nimphal period was longest on Criolla Blanca varying between 31 and 34 days, while on the rest of cultivars the length of this period was 22 to 25 days. Reproductive period and fecundity were also higher on Criolla Blanca. Net reproductive rate (Ro) values were 12.70 to 22.35 female/female on Criolla Blanca. On Cuatro Estaciones and Divina, Ro values were 6.85 to 9.95 and 5.80 to 8.56, respectively. Significant differences among the values of intrinsic rate of increase (rm) calculated for each variety were observed. Cohorts on Criolla Blanca showed the highest values of rm with 0.066 to 0.081, followed by Cuatro Estaciones (0.041-0.049) and Divina (0.046-0.055). Survivorship (lx) and fecundity (mx) curves were also analyzed. Results indicate that Cuatro Estaciones and Divina could have some negative effect on the population increase of N. ribisnigri, compared with Criolla Blanca.
Key words: biology, life tables, intrinsic rate of increase.
1 Universidad Nacional de La Plata, Facultad de Ciencias Agrarias y Forestales, 60 y 119-CC 31 (1900) La Plata,. Buenos Aires, Argentina. E-mail: email@example.com.