Department of Zoology, Hazara University, Mansehra, Pakistan.
National Insect Museum, National Agricultural Research Centre - NARC, Islamabad, Pakistan.
Braz J Biol. 2021 Mar-May;81(2):387-391. doi: 10.1590/1519-6984.226952.
Poor storage conditions provide favorable environment to stored grain pests for their growth. The bio-pesticides are the best alternatives to synthetic pesticides. Present study was conducted to compare toxicity of Rubus fruticosus and Valeriana jatamansi against granary weevil, Sitophilus granarius and subsequent changes in enzyme activity responsible for grain damage. In current research 5 g of R. fruticosus fruit and V. jatamansi rhizome powders were tested separately against S. granarius, in 50 g wheat whole grains for seven days in comparison with the control. The enzymatic activity of malate dehydrogenase and α-amylase was observed in the cellular extracts of S. granarius. The insects were crushed and homogenized in phosphate-buffer solution and centrifuged at 10000 rpm for 5 minutes. For the enzymatic measurement supernatant was tested; the spectrophotometer was adjusted at 340 nm. The reagents were mixed and incubated at 25 °C for five minutes. The cuvettes were placed in the experimental and reference sites of spectrophotometer and recorded the change in absorbance for 3-4 minutes. There was 5.60% and 14.92% reduction in the activity of malate dehydrogenase in R. fruticosus and V. jatamansi, treated insects, respectively. The alpha amylase enzyme activity was 6.82% reduced and 63.63% increase in R. fruticosus and V. jatamansi, treated insects, respectively. Present study addresses that both plant powders are effective against granary weevil by altering enzyme activities so both the plant powders can be used as bio-pesticides against the stored grains pests.
储存条件差为储粮害虫的生长提供了有利环境。生物农药是合成农药的最佳替代品。本研究旨在比较悬钩子和缬草对玉米象（Sitophilus granarius）的毒性，以及随后对导致谷物损伤的酶活性的影响。在目前的研究中，将 5 克悬钩子果实和缬草根粉末分别与对照进行比较，在 50 克小麦全谷物中，在 7 天内对玉米象进行了测试。在玉米象的细胞提取物中观察到苹果酸脱氢酶和α-淀粉酶的酶活性。昆虫被压碎并在磷酸盐缓冲液中匀浆，然后以 10000rpm 的速度离心 5 分钟。用于酶测量的上清液进行了测试；分光光度计在 340nm 处进行调整。将试剂混合并在 25°C 下孵育 5 分钟。将比色杯放入分光光度计的实验和参考位置，并记录 3-4 分钟内吸光度的变化。用悬钩子处理的昆虫中苹果酸脱氢酶的活性分别降低了 5.60%和 14.92%，用缬草处理的昆虫中苹果酸脱氢酶的活性分别降低了 6.82%和 63.63%。本研究表明，两种植物粉末均可通过改变酶活性有效防治玉米象，因此均可作为防治储粮害虫的生物农药。
