Avocado 'Hass' leaf age affects life table parameters of Oligonychus yothersi (McGregor) (Acari: Tetranychidae) under laboratory conditions

Tommy Rioja1, 2, Víctor Tello1, Miguel Zarzar1, Antonieta Cardemil3, and Ricardo Ceballos3*
The avocado red mite Oligonychus yothersi (McGregor) is the most important avocado (Persea americana Mill.) foliar pest in Chile, infesting ‘Hass’ avocado between mid-summer and late autumn. The post-embryonic development, survival, longevity and life table parameters of O. yothersi were evaluated on both young and mature ‘Hass’ avocado leaves at 25 ± 0.7 °C, 60 ± 5% relative humidity and 16:8 h photoperiod. The time for larvae, protonymphs and deutonymphs to develop was longer on young leaves than on mature leaves. The immature stage of O. yothersi was shorter (9.29 ± 0.22 d) on mature leaves than on young leaves(14.43 ± 0.28 d); O. yothersi also exhibited higher survival rates for larvae, protonymphs, and deutonymphs on mature leaves. The net reproductive rate (R0) 52.756 ± 1.749 individuals female-1; intrinsic rate of increase (rm) 0.241 ± 0.002 female female-1 d-1, and finite rate of increase (λ) 1.273 ± 0.002 female female-1 of O. yothersi were significantly higher on mature avocado leaves than on young leaves (R0 = 2.727 ± 0.271, rm = 0.049 ± 0.004, and λ = 1.051 ± 0.004). The time required to double the O. yothersi population was only 2.872 ± 0.002 d on mature leaves. Therefore, life table parameters of O. yothersi are negatively affected by young avocado leaves, suggesting that constitutive defenses present in young leaves could affect O. yothersi population parameters.
Keywords: Avocado red mite, fecundity, life history, post-embryonic, Tetranychidae.
1Universidad Arturo Prat, Facultad de Recursos Naturales Renovables, Campus Huayquique, Casilla 121, Iquique, Chile.
2Universidad de Tarapacá, Facultad de Ciencias Agronómicas, Campus Azapa, Casilla 6-D, Arica, Chile.
3Instituto de Investigaciones Agropecuarias, INIA Quilamapu, Av. Vicente Méndez 515, Chillán, Chile.
*Corresponding author (rceballos@inia.cl).