Avocado ‘hass’ leaf age affects life table parameters of oligonychus yothersi (Mcgregor) (acari: Tetranychidae) under laboratory conditions

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 (r_m) 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, r_m = 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.