Sisterson Mark S, Uchima Sean Y
USDA, Agricultural Research Service, San Joaquin Valley Agricultural Sciences Center, 9611 South Riverbend Avenue, Parlier, CA 93648-9757, USA.
J Econ Entomol. 2024 Feb 12;117(1):118-126. doi: 10.1093/jee/toad210.
Planococcus ficus (Signoret) is a worldwide pest of grapevine. Mealybugs overwinter under bark and move into the grape canopy as the season progresses. Because crawlers are more active than later stages, mealybug movement behavior is likely to be stage specific. To quantify P. ficus demography and movement behavior, a series of laboratory experiments were conducted. First, P. ficus populations were monitored on grapevine seedlings to describe survival, change in size, timing of male pupation, and timing of oviposition over a 6-wk period. Subsequently, cohorts of mealybugs were generated by infesting grapevines with crawlers and holding infested grapevines for a specified duration of 0 (crawlers), 1, 2, 3, or 4 wk. Crawlers (0-wk) were more likely to move upwards and towards a light source, than all other age cohorts tested. Further, mealybugs from 4-wk-old cohorts were more likely to move downward than all other age cohorts tested. Results suggest that crawlers are more likely to move to the top of grapevines by moving upwards and orienting towards either the sun or the moon than all other age cohorts tested, whereas older gravid females are more likely to move downward. Passive movement of mealybugs on farm machinery or animals requires surviving a host free period. To quantify risk of passive movement, establishment rates and effects of starvation on each age cohort were quantified. Larger and older mealybugs were more likely to establish on grapevines than smaller and younger mealybugs. Further, mealybug longevity in absence of food was greater for older cohorts compared to younger cohorts. Crawlers survived an average of 2 days without food, whereas females from 4-wk-old cohorts survived for an average of 11 days without food. Further, 70% of starved females from 4-wk-old cohorts deposited fertile eggs. In the absence of food, some mealybugs from cohorts aged 2-, 3-, and 4-wk formed pupa with viable males emerging. Adult males from starved nymphs lived for an average of 3 days post-emergence. Results provide methods for producing cohorts of mealybugs of predictable size and stage and provides insight into P. ficus demography and movement behavior.
无花果臀纹粉蚧（Signoret）是一种危害全球葡萄树的害虫。粉蚧在树皮底下越冬，随着季节推进迁移至葡萄树冠层。由于若虫比后期虫态更活跃，粉蚧的移动行为可能具有虫态特异性。为了量化无花果臀纹粉蚧的种群统计学特征和移动行为，进行了一系列实验室实验。首先，在葡萄幼苗上监测无花果臀纹粉蚧种群，以描述其在6周时间内的存活率、体型变化、雄虫化蛹时间和产卵时间。随后，通过用若虫侵染葡萄树并将受侵染的葡萄树放置特定时长（0周（若虫）、1周、2周、3周或4周）来组建粉蚧群组。与所有其他测试的龄期群组相比，若虫（0周龄）更倾向于向上移动并朝着光源移动。此外，4周龄群组的粉蚧比所有其他测试的龄期群组更倾向于向下移动。结果表明，与所有其他测试的龄期群组相比，若虫通过向上移动并朝着太阳或月亮方向定向，更有可能移动到葡萄树顶部，而老龄孕雌虫更有可能向下移动。粉蚧在农业机械或动物上的被动移动需要在无寄主时期存活下来。为了量化被动移动的风险，对每个龄期群组的定殖率和饥饿影响进行了量化。体型较大和龄期较大的粉蚧比体型较小和龄期较小的粉蚧更有可能在葡萄树上定殖。此外，老龄群组的粉蚧在无食物情况下的寿命比幼龄群组更长。若虫平均在无食物情况下存活2天，而4周龄群组的雌虫平均在无食物情况下存活11天。此外，4周龄群组中70%饥饿的雌虫产下了可育卵。在无食物情况下，2周龄、3周龄和4周龄群组的一些粉蚧形成蛹，有能存活的雄虫羽化。饥饿若虫羽化出的雄成虫羽化后平均存活3天。研究结果提供了产生可预测大小和虫态的粉蚧群组的方法，并深入了解了无花果臀纹粉蚧的种群统计学特征和移动行为。
