Krugner Rodrigo, Groves Russell L, Johnson Marshall W, Flores Arnel P, Hagler James R, Morse Joseph G
Department of Entomology, University of California, 3401 Watkins Dr., Riverside, CA 92521, USA.
J Econ Entomol. 2009 Jun;102(3):960-73. doi: 10.1603/029.102.0315.
A 2-yr study was conducted in a citrus orchard (Citrus sinensis L. Osbeck cultivar Valencia) to determine the influence of plant water stress on the population dynamics of glassy-winged sharpshooter, Homalodisca vitripennis (Germar). Experimental treatments included irrigation at 100% of the crop evapotranspiration rate (ET(c)) and continuous deficit-irrigation regimens at 80 and 60% ET(c). Microclimate and plant conditions monitored included temperature and humidity in the tree canopy, leaf surface temperature, water potential, and fruit quality and yield. Glassy-winged sharpshooter population densities and activity were monitored weekly by a combination of visual inspections, beat net sampling, and trapping. Glassy-winged sharpshooter populations were negatively affected by severe plant water stress; however, population densities were not linearly related to decreasing water availability in plants. Citrus trees irrigated at 60% ET(c) had significantly warmer leaves, lower xylem water potential, and consequently hosted fewer glassy-winged sharpshooter eggs, nymphs, and adults than trees irrigated at 80% ET(c). Citrus trees irrigated at 100% ET(c) hosted similar numbers of glassy-winged sharpshooter stages as trees irrigated at 60% ET(c) and a lower number of glassy-winged sharpshooter nymphs than the 80% ET(c) treatment, specifically during the nymphal density peak in mid-April to early July. Irrigation treatments did not affect populations of monitored natural enemies. Although the adult glassy-winged sharpshooter population was reduced, on average, by 50% in trees under severe water stress, the total number of fruit and number of fruit across several fruit grade categories were significantly lower in the 60% ET(c) than in the 80 and 100% ET(c) irrigation treatments.
在一片柑橘园（柑橘品种为伏令夏橙，Citrus sinensis L. Osbeck cultivar Valencia）中开展了一项为期两年的研究，以确定植物水分胁迫对玻璃翅叶蝉（Homalodisca vitripennis (Germar)）种群动态的影响。试验处理包括按照作物蒸发蒸腾速率（ET(c)）的100%进行灌溉，以及按照ET(c)的80%和60%进行持续亏缺灌溉方案。监测的小气候和植物状况包括树冠内的温度和湿度、叶片表面温度、水势以及果实品质和产量。通过目视检查、拍网采样和诱捕相结合的方式，每周监测玻璃翅叶蝉的种群密度和活动情况。严重的植物水分胁迫对玻璃翅叶蝉种群产生了负面影响；然而，种群密度与植物水分可利用量的降低并非呈线性关系。按照ET(c)的60%进行灌溉的柑橘树叶片温度显著更高，木质部水势更低，因此与按照ET(c)的80%进行灌溉所产生的卵、若虫和成虫数量相比，玻璃翅叶蝉的数量更少。按照ET(c)的100%进行灌溉的柑橘树中玻璃翅叶蝉各虫态数量与按照ET(c)的60%进行灌溉的柑橘树相近，且若虫数量低于按照ET(c)的80%进行灌溉的处理，特别是在4月中旬至7月初若虫密度高峰期。灌溉处理对所监测的天敌种群没有影响。尽管在严重水分胁迫下，成年玻璃翅叶蝉的种群数量平均减少了50%，但按照ET(c)的60%进行灌溉的处理中，果实总数以及几个果实等级类别的果实数量均显著低于按照ET(c)的80%和100%进行灌溉的处理。
