Abstract

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 degrees 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 (R-0) 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 (lambda) 1.273 +/- 0.002 female female(-1) of O. yothersi were significantly higher on mature avocado leaves than on young leaves (R-0 = 2.727 +/- 0.271, r(m) = 0.049 +/- 0.004, and lambda = 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.