土壤環境因子對蟲生線蟲（Steinernema abbasi）（Rhabditida: Steinernematidae）殺蟲活性之影響

Effects of Soil Environmental Factors on Insecticidal Activity of the Entomopathogenic Nematode, Steinernema abbasi (Rhabditida: Steinernematide)

白志方(Chih-Fang Pai) ； 侯豐男(Roger F. Hou)

《台灣昆蟲》 26卷4期 (2006/12) Pp. ap6+369-377

https://doi.org/10.6661/TESFE.2006032

摘要

在實驗室內，分別測定土壤質地、溫度、含水量、酸鹼值（pH）等土壤環境因子，對本地產蟲生線蟲（Steinernema abbasi）之感染期幼蟲（infective juveniles；IJs）殺蟲活性之影響。以IJs接種大蠟蛾（Galleria mellonella）末齡幼蟲所引起之罹病死亡率，供作評估其殺蟲活性之依據。S. abbasi在砂土或砂壤土中經32日仍具有高殺蟲活性，但在壤土及黏土中的效力，則隨時間延長而遞減。在25℃下，S. abbasi經32日仍維持高的殺蟲活性；但在15、30或35℃下，此線蟲之殺蟲活性均低於25℃處理組。在4～16%土壤含水量下，S. abbasi均可呈現適當的殺蟲活性至16日，惟幼蟲死亡率在32日略為降低；但在2%含水量，死亡率則自94%降至62%。在土壤pH4～6下，S. abbasi可維持適當的殺蟲活性，但pH10則會降低其效力。因此，若應用S. abbasi進行土壤害蟲之生物防治時，宜慎選各種適宜其感染的土壤環境條件。

關鍵字

蟲生線蟲 ； 大蠟蛾 ； 殺蟲活性 ； 幼蟲死亡率 ； 土壤環境因子

並列摘要

Effects of soil texture, temperature, water content, and pH on insecticidal activity of the entomopathogenic nematode, Steinernema abbasi, were investigated in the laboratory. The larval mortality of the greater wax moth, Galleria mellonella, caused by inoculation of the infective juveniles (IJs) within 32 days was adopted as the criterion for evaluating the insecticidal activity of the nematode. Sand and sandy loam were optimal for S. abbasi to exhibit insecticidal activity, while in loam and clay, the nematode was less insecticidal as the time prolonged. Steinernema abbasi remained virulent when incubated at 20 and 25°C for 32 days; whereas the nematode was less virulent when incubated at 15, 30, or 35°C. Steinernema abbasi was highly insecticidal when incubated in the soil with 4-16% water contents for 16 days, although the larval mortalities were lowered slightly only if incubated for 32 days. However, the larval mortality was reduced from 94% to 62% when incubated with 2% water content for 32 days. The soil at pH 4-6 was optimal for this nematode, but pH 10 was not suitable for the nematode infection. Therefore, it is preferable to select favorable soil environmental conditions, if applied this entomopathogenic nematode as a biocontrol agent for soil insect pests.

並列關鍵字

Steinernema abbasi ； Galleria mellonella ； insecticidal activity ； larval mortality ； soil environmental factor