Natural enemies and seasonal abundance of the blackmargined aphid (Monellia caryella) in pecan orchards in Israel

The blackmargined aphid,Monellia caryella (Fitch), exhibited a seasonal pattern with early and late peaks of the population in pecan orchards at Newe Ya’ar in the Yizre’el Valley. A similar pattern was not observed at Kibbutz Sede Eliyyahu in the Bet She’an Valley, where there was a single peak, late in the season. The occurrence of natural enemies indicated that spiders and lacewing eggs were the predators most commonly associated with population fluctuations of the aphid. In most cases the rate of increase of the blackmargined aphid was highest late in the season.     

Assessment of viable conidia of Monilinia fructicola in flower and stone fruit combining propidium monoazide (PMA) and qPCR

Brown rot is the most economically important fungal disease of stone fruits and is primarily caused by Monilinia laxa and M. fructicola. Conventional methods used to identify M. fructicola are mainly based on phenotypic characteristics and pathogen quantification is not always accurate. In contrast, methodologies based on molecular tools improve pathogen characterization and identification but are not able to differentiate between live and dead conidia. In this study the PMA‐qPCR methodology was optimized, validated and applied to quantify viable cells of M. fructicola in artificially and naturally infected samples. qPCR methodology showed good primer efficiency and sensitivity with quantification limits lower than obtained using a plate count method. The conditions of propidium monoazide (PMA) pretreatment were 60 μm PMA for 20 min incubation and 30 min of light‐emitting diode (LED) exposure that, combined with qPCR, measured live cells accurately without overestimation of dead cells. Using this methodology in naturally infected samples, M. fructicola live cells were quantified specifically, in contrast to other traditional methodologies that cannot distinguish among Monilinia spp. The developed methodology based on combined PMA‐qPCR will be a new tool to quantify viable M. fructicola in further epidemiological and ecological studies of this fungus.     

烟田6种常用杀虫剂对烟蚜茧蜂影响的研究

为了评估烟田常用杀虫剂对烟蚜茧蜂的安全性,本文在实验室条件下采用药膜法和浸虫法测定了6种烟田常用杀虫剂对烟蚜茧蜂（Aphidiusgifuensis）的影响。结果表明：吡虫啉、啶虫脒、噻虫嗪对烟蚜茧蜂成蜂有明显的触杀毒力,噻虫嗪和吡虫啉显著降低了烟蚜茧蜂的羽化率,且这3种杀虫剂处理僵蚜后可导致羽化出的成蜂双翅畸形; 而甲氨基阿维菌素苯甲酸盐、高效氯氟氰菊酯、吡蚜酮对烟蚜茧蜂成蜂和僵蚜均相对安全,处理1 h后成蜂死亡率为0～5.56%,僵蚜羽化率达70%以上。研究结果可为烟蚜综合防治时合理选用杀虫剂提供依据。