Karanja Josephine, Poehling Hans-Michael, Pallmann Philip
Institute of Horticultural Production Systems, Department Phytomedicine, Leibniz University, Herrenhäuser Strasse 2, 30419 Hannover, Germany.
Institute of Biostatistics, Leibniz University, Herrenhäuser Strasse 2, 30419 Hannover, Germany.
J Econ Entomol. 2015 Jun;108(3):1182-90. doi: 10.1093/jee/tov047. Epub 2015 Mar 21.
Neem products have been used frequently as an alternative to synthetic pesticides, because of their insecticidal, insect antifeedant, and growth-regulating effects. Moreover, new formulations are continually being developed and therefore, they have to be evaluated for their efficacy and persistence. In this regard, two soil-applied products-a liquid-based drenching solution NeemAzal-T and NeemAzal granules-were evaluated against two whitefly species, Aleyrodes proletella L. and Trialeurodes vaporariorum (West) on Brussels sprout and tomatoes, respectively. The plants were grown in two substrates: one was a commercial substrate (CS) composed of 15% humus, 35% clay, and 50% peat, and the other was a commercial substrate and sand mixture in 1:1 ratio. The main objective of the study was to evaluate the efficacy, persistence, and dose response of the two soil-applied NeemAzal formulations in substrates with different amount of organic matter. The results show that the efficacy of neem formulations was dose dependent, with the highest doses of NeemAzal granules (300 mg/kg=21 mg azadirachtin [AZA]/kg of substrate) and NeemAzal T (2 ml/kg=20 mg AZA/kg of substrate) achieving up to 100% mortality of immature stages of whiteflies. NeemAzal caused significantly higher mortality in immature stages of both whitefly species with CS + sand mixture than with pure CS. Persistence of the NeemAzal formulations was not influenced by the substrate type but rather by time span between treatment application and infestation, with significant decrease in efficacy when whiteflies were exposed 10 d after treatments.
印楝产品因其杀虫、拒食和生长调节作用，常被用作合成农药的替代品。此外，新配方不断被研发出来，因此必须对其功效和持久性进行评估。在这方面，分别在抱子甘蓝和番茄上，对两种土壤施用产品——一种基于液体的浇灌溶液印楝素 - T和印楝素颗粒，针对两种粉虱物种，即温室粉虱和烟粉虱进行了评估。植株种植在两种基质中：一种是由15%腐殖质、35%粘土和50%泥炭组成的商业基质（CS），另一种是商业基质与沙子按1:1比例混合的基质。该研究的主要目的是评估两种土壤施用的印楝素配方在不同有机质含量基质中的功效、持久性和剂量反应。结果表明，印楝配方的功效取决于剂量，印楝素颗粒的最高剂量（300毫克/千克 = 21毫克印楝素 [AZA]/千克基质）和印楝素 - T（2毫升/千克 = 20毫克AZA/千克基质）可使粉虱未成熟阶段的死亡率高达100%。与纯CS相比，印楝素在CS + 沙子混合物中对两种粉虱物种的未成熟阶段均导致显著更高的死亡率。印楝素配方的持久性不受基质类型影响，而是受处理施用与侵染之间的时间跨度影响，当粉虱在处理后10天暴露时，功效显著降低。
