Khathwayo Zanele, Ramakuwela Tshimangadzo, Hatting Justin, Shapiro-Ilan David I, Cochrane Nicolene
ARC-Small Grain, P/Bag X29, Bethlehem, 9700, South Africa.
USDA-ARS, Southeastern Fruit and Tree Nut Research Station, Byron, GA, 31008.
J Nematol. 2021 Jul 8;53. doi: 10.21307/jofnem-2021-062. eCollection 2021.
Soil pH affects the availability of nutrients, which impacts plant growth and development. Similarly, soil pH may also influence microorganisms in the soil, either beneficial or nonbeneficial. One such group of beneficial microorganisms is entomopathogenic nematodes (EPN), parasites of soil-inhabiting insects. Entomopathogenic nematodes have a number of attributes that make them good alternatives to chemical insecticides. The objective of this study was to investigate pH tolerance of 11 steinernematids and six heterorhabditids post exposure to different pH levels. Entomopathogenic nematode populations were exposed to varying pH levels (pH2 to pH11) made up from two different chemical solutions (ammonium-acetate and citrate-phosphate). Entomopathogenic nematode populations are expected to have varying tolerance to different pH levels. The highest infective juvenile survival was obtained from pH3 to pH10 in citrate-phosphate, where all populations displayed >50% survival. populations had >90% survival at pH3 to pH11 in citrate-phosphate solutions. Overall, the steinernematids had a higher survival range in ammonium-acetate pH solutions compared with the heterorhabditids. Moreover, spp., (ScCxrd, ScAll, and ScItalian) and showed consistently higher survival in both acidic and alkaline solutions, when compared to the other steinernematids, suggesting that they may be applied in both acidic and alkaline soils. These findings can be of use when selecting EPNs for biological control purposes in the two countries, respectively.
土壤pH值会影响养分的有效性，进而影响植物的生长和发育。同样，土壤pH值也可能影响土壤中的微生物，无论是有益微生物还是有害微生物。一类有益微生物是昆虫病原线虫（EPN），它是土壤栖息昆虫的寄生虫。昆虫病原线虫具有许多特性，使其成为化学杀虫剂的良好替代品。本研究的目的是调查11种斯氏线虫和6种异小杆线虫在暴露于不同pH水平后的耐pH值能力。将昆虫病原线虫种群暴露于由两种不同化学溶液（醋酸铵和柠檬酸磷酸盐）配制的不同pH水平（pH2至pH11）下。预计昆虫病原线虫种群对不同pH水平具有不同的耐受性。在柠檬酸磷酸盐中，pH3至pH10时获得了最高的感染性幼虫存活率，所有种群的存活率均>50%。在柠檬酸磷酸盐溶液中，pH3至pH11时种群存活率>90%。总体而言，与异小杆线虫相比，斯氏线虫在醋酸铵pH溶液中的存活范围更高。此外，与其他斯氏线虫相比，斯氏线虫属的某些种（ScCxrd、ScAll和ScItalian）在酸性和碱性溶液中均表现出较高的存活率，这表明它们可应用于酸性和碱性土壤中。这些研究结果在分别为两国选择用于生物防治目的的昆虫病原线虫时可能会有所帮助。
