Soybean aphid, Aphis glycines (Hemiptera: Aphididae), developmental and reproductive capacity on white clover, Trifolium repens (Rosales: Leguminosae), in northeast China

Soybean aphid, Aphis glycines (Hemiptera: Aphididae), developmental and reproductive capacity on white clover, Trifolium repens (Rosales: Leguminosae), in northeast China Xiaohui Chen 0 1 Yanjie Fan 0 1 Wei Zhang 0 1 Zhenqi Tian 0 1 Jian Liu 0 1 Kuijun Zhao 0 1 0 Department of Statistics, College of Mathematical Science, Harbin Normal University , Harbin 150025 , China 1 Department of Plant Protection, College of Agriculture, Northeast Agricultural University , Harbin 150030 , China Nymphs of Aphis glycines Matsumura were individually reared to adults in the laboratory on detached leaf discs of Trifolium repens L. (white clover) mounted on agar medium. Adults of A. glycines were fed T. repens within small clip cages in the field. Development, reproduction and intrinsic rates of increase of A. glycines were studied. These data were compared to those of controls fed known host plants including cultivated soybean Glycine max (L.) Merr. and the wild soybean species Glycine soja Sieb & Zucc. The results demonstrated that nymphs of A. glycines successfully developed into adults and reproduced efficiently when reared on T. repens in the laboratory. The lower development temperature threshold for nymphs fed T. repens was estimated as 8.27 °C, and the effective cumulative temperature for A. glycines development from nymph to adult was 90.91 degree-days. Adults of A. glycines could also survive on T. repens in the field, but only a few nymphs were produced. Soybean aphid; White clover; Clip cage - The soybean aphid, Aphis glycines Matsumura, is an insect pest commonly found on soybeans in Asia. In 2000, A. glycines became established in North America (Ragsdale et al. 2004, 2011). By 2003, this pest had infested over 21 America states and three Canadian provinces (Venette and Ragsdale 2004). Soybean aphids can cause direct damage to plants by sucking fluids from leaves and stems (Liu and Zhao 2007; Wu et al. 2004). Additionally, they are also capable of transmitting a variety of plant viruses (Davis et al. 2005; Mueller and Grau 2007). Secondary hosts of A. glycines include cultivated soybean Glycine max (L.) Merr., and the wild soybean species Glycine soja Sieb & Zucc (Wang et al. 1962). It was determined that the aphid could likely utilize horsenettle, Solanum carolinense L. (Clark et al. 2006), and Japanese Metaplexis, Metaplexis japonica (Thunb.) Makino (Chen et al. 2015) as hosts. Results from a previous study showed that Trifolium repens L. was a poor host for soybean aphid (Hill et al. 2004). A later study showed that clover variety significantly affected aphid density, and A. glycines could achieve highest population growth on Ladino, a variety of white clover (Swenson et al. 2014). T. repens is a common legume in natural landscapes and cultivated fields and has a wide distribution in northeast China. In this latter region, it is still questionable whether A. glycines can utilize T. repens as a host. Understanding the role of this widely distributed plant as a host for A. glycines is important for the effective management of this insect in northeast China. In the current study, nymphs of A. glycines were individually reared to adults on detached leaves of T. repens in the laboratory. Adults of A. glycines were fed T. repens in the field while contained in small clip cages. Development, reproduction, and intrinsic rates of increase of A. glycines were studied. These data were compared to those of controls fed the species’ known hosts G. max and G. soja. Materials and methods Aphid source and host plants Soybean aphids were taken from a soybean field at the Xiangfang Experiment Station, Northeast Agricultural University (NEAU), Harbin, Heilongjiang Province, northeast China (126.75°E, 45.72°N). The colony was maintained on G. max (variety Heinong 51) in an environmental chamber at 25 ± 1 °C, 70 ± 5% relative humidity (RH), and a photoperiod of 14:10 h (light:dark; L:D) with artificial light of 12,000 lx. G. max was grown in a chamber at 28 ± 1 °C with six to ten seeds per pot in 10 × 10-cm (diameter × height) plastic pots under the same humidity and photoperiod as described above. Seedlings 15–20 cm tall at the V2 growth stage (Fehr and Caviness 1977) were used for experiments. T. repens (variety Rivendel), were collected from a lawn in NEAU (126.75°E, 45.72°N) and were transplanted into a 50-m2 experiment plot. These plants were used for experiments when they were at a vegetative or generative growth phase. Seeds of G. soja were collected from a field near Limin, Harbin (126.61°E, 45.87°N) and were planted in the same plot. These plants were allowed 4–5 weeks to germinate and mature before being used for experiments. Development of nymphs About 200 apterous adult aphids were transferred from the stock colony onto ten pots of soybean plants (approximately 20 aphids per pot). The plants were placed in an environmental chamber at 25 ± 1 °C, 70 ± 5% RH and a 14:10-h (L:D) photoperiod for a 24-h reproduct (...truncated)