Canadian Forest Service, Natural Resources Canada, 1219 Queen St. East, Sault Ste. Marie, Ontario, Canada P6A 2E5.
Ecotoxicol Environ Saf. 2011 Sep;74(6):1734-41. doi: 10.1016/j.ecoenv.2011.04.021. Epub 2011 Apr 29.
The non-target effects of an azadirachtin-based systemic insecticide used for control of wood-boring insect pests in trees were assessed on litter-dwelling earthworms, leaf-shredding aquatic insects, and microbial communities in terrestrial and aquatic microcosms. The insecticide was injected into the trunks of ash trees at a rate of 0.2 gazadirachtin cm(-1) tree diameter in early summer. At the time of senescence, foliar concentrations in most (65%) leaves where at or below detection (<0.01 mg kg(-1) total azadirachtin) and the average concentration among leaves overall at senescence was 0.19 mg kg(-1). Leaves from the azadirachtin-treated trees at senescence were added to microcosms and responses by test organisms were compared to those in microcosms containing leaves from non-treated ash trees (controls). No significant reductions were detected among earthworm survival, leaf consumption rates, growth rates, or cocoon production, aquatic insect survival and leaf consumption rates, and among terrestrial and aquatic microbial decomposition of leaf material in comparison to controls. In a further set of microcosm tests containing leaves from intentional high-dose trees, the only significant, adverse effect detected was a reduction in microbial decomposition of leaf material, and only at the highest test concentration (∼6 mg kg(-1)). Results indicated no significant adverse effects on litter-dwelling earthworms or leaf-shredding aquatic insects at concentrations up to at least 30 × the expected field concentrations at operational rates, and at 6 × expected field concentrations for adverse effects on microbial decomposition. We conclude that when azadirachtin is used as a systemic insecticide in trees for control of insect pests such as the invasive wood-boring beetle, emerald ash borer, resultant foliar concentrations in senescent leaf material are likely to pose little risk of harm to decomposer invertebrates.
基于印楝素的系统性杀虫剂用于控制树木蛀干害虫，评估其对凋落叶土壤动物、碎屑食性水生昆虫和陆地及水生微生物群落的非靶标效应。该杀虫剂于初夏以 0.2g 印楝素 cm(-1) 树径的剂量注入到白蜡树树干中。在衰老时，大多数（65%）叶片中的叶内浓度处于或低于检测限（<0.01mg kg(-1) 总印楝素），衰老时叶片的平均总浓度为 0.19mg kg(-1)。从印楝素处理的白蜡树衰老叶片添加到微宇宙中，并与未处理的白蜡树叶（对照）微宇宙中的测试生物进行比较。与对照相比，在蚯蚓存活率、叶片消耗量、增长率或茧产量、水生昆虫存活率和叶片消耗量以及陆地和水生微生物对叶片物质的分解方面，未检测到显著减少。在另一组含有高剂量叶片的微宇宙试验中，仅检测到微生物对叶片物质分解的显著负面影响，且仅在最高测试浓度（约 6mg kg(-1)）时。结果表明，在操作浓度下，浓度高达至少 30 倍预期田间浓度，以及在 6 倍预期田间浓度下，对微生物分解的不利影响，对凋落叶土壤动物或碎屑食性水生昆虫均无显著不利影响。我们的结论是，当印楝素作为树木中的系统性杀虫剂用于控制入侵性蛀干甲虫如翡翠灰蝶等害虫时，衰老叶片中的叶内浓度可能对分解无脊椎动物的危害很小。
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