Silva E A, Reis P R, Carvalho T M B, Altoé B F
Departamento de Fitossanidade, Centro de Ciências Agrárias, Universidade Estadual do Maranhão, São Luís, MA, Brazil.
Braz J Biol. 2009 Nov;69(4):1121-5. doi: 10.1590/s1519-69842009000500016.
Gerbera (Gerbera jamesonii Bolus and Hook,) is an ornamental Asteraceae of great commercial value, and pests can affect adversely its cultivation. More than 20 species of arthropods cause economic damage on gerbera, among them the two spotted mite, Tetranychus urticae Koch, 1836 (Acari: Tetranychidae), considered a key pest for this and other ornamental plants. In this work, some life-cycle aspects of T. urticae on gerbera, considered important for the knowledge of its population dynamics and for pest management programs, were studied. Mites were reared on 3-cm diameter arenas of gerbera leaf discs maintained on distilled water in Petri dishes, under laboratory conditions of 25 masculineC, 70 +/- 10% RU and 14-hour photophase, with only one egg left per arena, in a total of 262 arenas. Egg viability was 96.5% and 97.1% for unmated and mated females, respectively. Unmated females originated larvae which lived for 3.2 days and the stages of protonymph and deutonymph, 1.9 and 1.6 days, respectively; those from mated females lived 3.5 days and for protonymphs and deutonymphs, 2.0 and 1.6 days, respectively. Except for the duration of one generation (T), with similar values, 18.6 and 19.7 days, respectively for unmated and mated females, the net reproductive rate of increase (R masculine), the innate capacity to increase in number (r m) and the finite rate of growth (lambda) were different for mated and unmated females, respectively 11.5 and 24.6 for R0; 0.12 and 0.17 for r m and 1.13 and 1.19 for lambda.
非洲菊（Gerbera jamesonii Bolus和Hook）是一种具有重要商业价值的观赏性菊科植物，害虫会对其种植产生不利影响。20多种节肢动物对非洲菊造成经济损害，其中二斑叶螨（Tetranychus urticae Koch，1836年，蜱螨目：叶螨科）被认为是这种植物和其他观赏植物的主要害虫。在这项研究中，我们研究了二斑叶螨在非洲菊上的一些生命周期特征，这些特征对于了解其种群动态和害虫管理计划非常重要。在实验室条件下，将叶螨饲养在直径3厘米的非洲菊叶片圆片上，这些叶片圆片放在培养皿中的蒸馏水上，温度为25℃，相对湿度为70±1０%，光周期为14小时，每个培养皿中只留一个卵，总共262个培养皿。未交配雌螨和交配雌螨的卵孵化率分别为96.5%和97.1%。未交配雌螨产生的幼虫存活3.2天，若螨前期和若螨期分别存活1.9天和1.6天；交配雌螨产生的幼虫存活3.5天，若螨前期和若螨期分别存活2.0天和1.6天。除了一代的持续时间（T），未交配雌螨和交配雌螨的值相似，分别为18.6天和19.7天，净增殖率（R0）、内禀增长率（rm）和有限增长率（λ）在交配雌螨和未交配雌螨中有所不同，R0分别为11.5和24.6；rm分别为0.12和0.17；λ分别为1.13和1.19。
