Hardman J M, Moreau D L, Snyder M, Gaul S O, Bent E D
Agriculture and Agri-Food Canada, Atlantic Food and Horticulture Research Centre, Kentville, NS, Canada.
J Econ Entomol. 2000 Jun;93(3):590-604. doi: 10.1603/0022-0493-93.3.590.
An organophosphate pyrethroid-resistant strain of Typhlodromus pyri Scheuten imported from New Zealand was reared on potted apple trees in an outdoor insectary. From 1988 to 1995, the population was selected one to three times per year with a dilute solution (1.7 ppm) of the pyrethroid cypermethrin. Petri dish bioassays with cypermethrin in 1995 indicated that the insectary-reared T. pyri had an LC50 of 81 ppm versus 0.006 ppm for native T. pyri taken from a research orchard. The bioassays suggested that recommended orchard rates of cypermethrin would cause heavy mortality in native populations of T. pyri but only moderate losses in the imported New Zealand strain. Bioassays in 1996 with the organophosphate insecticide dimethoate indicated both New Zealand and native T. pyri were susceptible and that recommended orchard rates of dimethoate likely would cause high mortality of T. pyri in apple orchards. These findings from bioassays were supported by data from orchard trials. In June and July 1993, insectary-reared New Zealand T. pyri were placed on five apple trees in each of eight 38-tree plots in the research orchard. In late August 1994, New Zealand T. pyri from orchard trees that had been sprayed twice by airblast sprayer with the full recommended rate of 50 g (AI)/ha (83 ppm) cypermethrin were placed on the other 33 trees in each of six plots. In the summers of 1994-1996, plots were treated with one of the following insecticide regimes: (1) conventional integrated pest management (IPM) (registered neurotoxic insecticides considered harmless or slightly toxic to T. pyri); (2) advanced IPM (use of newer, more selective insecticides); (3) pyrethroid (at least one full-rate application of cypermethrin); (4) dimethoate; and (5) dimethoate plus pyrethroid. Densities of European red mite, Panonychus ulmi (Koch), were highest in all plots treated with dimethoate and in pyrethroid plots not yet inoculated with New Zealand T. pyri. Densities of apple rust mite, Aculus schlechtendali (Nalepa), and of the stigmaeid predator Zetzellia mali (Ewing) were highest in plots treated with dimethoate and were nearly absent in the IPM plots. Densities of T. pyri were high enough for effective biocontrol in the IPM plots and in the pyrethroid plots 1-2 yr after release of the New Zealand strain, provided pyrethroid was applied just before the resistant strain was released in the orchard. A recurring theme of this study was the generally negative association between densities of phytophagous mites and those of T. pyri, suggesting the ability of this predator to suppress their prey. In contrast, the positive association between phytophagous mites and Z. mali suggests the inability of this predator to regulate their prey at least under the conditions of this study.
从新西兰引进的抗有机磷拟除虫菊酯的盲走螨（Typhlodromus pyri Scheuten）品系，在室外昆虫饲养室的盆栽苹果树上饲养。1988年至1995年期间，每年用拟除虫菊酯氯氰菊酯的稀释溶液（1.7 ppm）对该种群进行一至三次选育。1995年用氯氰菊酯进行的培养皿生物测定表明，在昆虫饲养室饲养的盲走螨的半数致死浓度（LC50）为81 ppm，而从研究果园采集的本地盲走螨的LC50为0.006 ppm。生物测定表明，推荐的果园氯氰菊酯用量会导致本地盲走螨种群大量死亡，但对引进的新西兰品系只会造成中等程度的损失。1996年用有机磷杀虫剂乐果进行的生物测定表明，新西兰和本地的盲走螨均敏感，推荐的果园乐果用量可能会导致苹果园中的盲走螨大量死亡。生物测定的这些结果得到了果园试验数据的支持。1993年6月和7月，将在昆虫饲养室饲养的新西兰盲走螨放置在研究果园中8个38棵树的小区中，每个小区的5棵苹果树上。1994年8月下旬，将来自果园树木的新西兰盲走螨放置在6个小区中每个小区的另外33棵树上，这些果园树木已用背负式喷雾器以50克（有效成分）/公顷（83 ppm）的全推荐用量喷洒了两次氯氰菊酯。在1994年至1996年的夏季，对小区进行了以下杀虫剂处理方案之一的处理：（1）常规综合虫害管理（IPM）（使用对盲走螨无害或毒性轻微的登记神经毒性杀虫剂）；（2）先进的IPM（使用更新的、更具选择性的杀虫剂）；（3）拟除虫菊酯（至少一次全量施用氯氰菊酯）；（4）乐果；（5）乐果加拟除虫菊酯。在所有用乐果处理的小区以及尚未接种新西兰盲走螨的拟除虫菊酯小区中，苹果全爪螨（Panonychus ulmi (Koch)）的密度最高。在乐果处理的小区中，苹果锈螨（Aculus schlechtendali (Nalepa)）和食螨瓢虫族捕食者马氏钝绥螨（Zetzellia mali (Ewing)）的密度最高，而在IPM小区中几乎没有。在IPM小区以及在释放新西兰品系后1至2年的拟除虫菊酯小区中，盲走螨的密度高到足以进行有效的生物防治，前提是在果园释放抗性品系之前刚好施用拟除虫菊酯。本研究的一个反复出现的主题是植食性螨类密度与盲走螨密度之间通常呈负相关，这表明这种捕食者有抑制其猎物的能力。相反，植食性螨类与马氏钝绥螨之间的正相关表明，至少在本研究的条件下，这种捕食者无法控制其猎物。
