The main goal of the present study was to evaluate the hexanoic acid (HEX) and acetic acid (ACET), two active ingredients of the nematicidal Melia azedarach fruits water extract (MWE), for use on root knot nematodes control. We studied the effect of the acids on various growth stages of the phytoparasitic nematode Meloidogyne javanica, along with the phytotoxicity on tomato plants, their fate in soil and ecotoxicology, including non-target soil nematode and microbial communities. The EC_50/4d values established for paralysis activity on second-stage juveniles were 195 and 49 μg mL⁻¹ for HEX and ACET, respectively. Both acids significantly inhibited M. javanica undifferentiated egg hatch and J2 release from free eggs immersed in 100 μg mL⁻¹ solutions, but only HEX achieved activity when egg masses were treated with acids’ concentrations greater than 50 μg mL⁻¹. HEX lasted longer in soil than ACET did and yielded less females of M. javanica per gram of tomato root (EC₅₀ = 112 mg kg⁻¹). Other than efficacy, the two acids had a negative impact on the free-living nematode abundances compared to the control, thus implying an eco-toxic character. MWE is effective for the target nematodes and increases the abundance of free-living nematodes and the microbial biomass.

中文翻译：

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己酸和乙酸对爪蟾根瘤菌的作用方式和生态毒性

本研究的主要目的是评估用于根结线虫防治的杀线Mel子果实水提取物（MWE）的两种活性成分己酸（HEX）和乙酸（ACET）。我们研究了酸对植物寄生线虫Meloidogyne javanica各个生长阶段的影响，以及对番茄植物的植物毒性，其在土壤中的命运和生态毒理学，包括非目标土壤线虫和微生物群落。建立的第二阶段少年麻痹活性的EC _{50 / 4d}值对于HEX和ACET分别为195和49μgmL ^-1。两种酸均显着抑制爪哇分枝杆菌浸没在100μgmL ^-1溶液中的游离卵中未分化的卵孵化和J2释放，但是当用浓度大于50μgmL ^-1的酸处理卵块时，只有HEX才能达到活性。在土壤中，HEX的持续时间比ACET持续的时间长，并且每克番茄根产生的爪哇爪哇雌性数量减少（EC ₅₀  = 112 mg kg ^-1）。除功效外，与对照相比，这两种酸对自由活动线虫的丰度有负面影响，因此暗示了生态毒性。MWE对目标线虫有效，并增加了自由活动线虫和微生物生物量的数量。