Meihls Lisa N, Huynh Man P, Ludwick Dalton C, Coudron Thomas A, French B Wade, Shelby Kent S, Hitchon Andrea J, Smith Jocelyn L, Schaafsma Art W, Pereira Adriano E, Hibbard Bruce E
USDA-ARS Plant Genetics Research Unit, Columbia, MO.
Division of Plant Sciences, University of Missouri, Columbia, MO.
J Econ Entomol. 2018 Dec 14;111(6):2727-2733. doi: 10.1093/jee/toy268.
The western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), is considered the most important maize (Zea mays L.) pest in the U.S. Corn Belt. Bioassays testing susceptibility to Bacillus thuringiensis Berliner (Bt) and other toxins of corn rootworm larvae often rely on artificial diet formulations. Successful bioassays on artificial diet for corn rootworm have sometimes been challenging because of microbial contamination. Toward the long-term goal of developing a universal artificial diet for western corn rootworm larvae, we compared larval survival, dry weight, and percentage of molt in 10-d bioassays from six current diets of which we were aware. In addition, as part of longer term rearing efforts, we recorded molting over an extended period of development (60 d). Six different artificial diets, including four proprietary industry diets (A, B, C, and D), the first published artificial diet for western corn rootworm (Pleau), and a new diet (WCRMO-1) were evaluated. Western corn rootworm larval survival was above 90% and contamination was 0% on all diets for 10 d. Diet D resulted in the greatest dry weight and percentage molting when compared with the other diets. Although fourth-instar western corn rootworm larvae have not been documented previously (only three instars have been previously documented), as many as 10% of the larvae from Diet B molted into a fourth instar prior to pupating. Overall, significant differences were found among artificial diets currently used to screen western corn rootworm. In order for data from differing toxins to be compared, a single, reliable and high-quality western corn rootworm artificial diet should eventually be chosen by industry, academia, and the public as a standard for bioassays.
西部玉米根萤叶甲，即 Diabrotica virgifera virgifera LeConte（鞘翅目：叶甲科），被认为是美国玉米带最重要的玉米（Zea mays L.）害虫。检测玉米根萤叶甲幼虫对苏云金芽孢杆菌（Bt）和其他毒素易感性的生物测定通常依赖于人工饲料配方。由于微生物污染，在玉米根萤叶甲人工饲料上进行成功的生物测定有时具有挑战性。为了实现为西部玉米根萤叶甲幼虫开发通用人工饲料的长期目标，我们在10天的生物测定中比较了已知的六种当前饲料中幼虫的存活率、干重和蜕皮率。此外，作为长期饲养工作的一部分，我们记录了较长发育时期（60天）的蜕皮情况。评估了六种不同的人工饲料，包括四种行业专用饲料（A、B、C和D）、第一篇发表的西部玉米根萤叶甲人工饲料（Pleau）以及一种新饲料（WCRMO-1）。在所有饲料上，西部玉米根萤叶甲幼虫10天的存活率均高于90%，污染率为0%。与其他饲料相比，饲料D导致的干重和蜕皮率最高。尽管此前未记录到四龄西部玉米根萤叶甲幼虫（此前仅记录到三龄），但来自饲料B的幼虫中有多达10%在化蛹前蜕变为四龄。总体而言，目前用于筛选西部玉米根萤叶甲的人工饲料之间存在显著差异。为了能够比较不同毒素的数据，行业、学术界和公众最终应选择一种单一、可靠且高质量的西部玉米根萤叶甲人工饲料作为生物测定的标准。
