Applied Microbiology and Biotechnology Helicoverpa armigera cadherin fragment enhances Cry1Ac insecticidal activity by facilitating toxin-oligomer formation Donghai Peng1, Xiaohui Xu1, Weixing Ye1, Ziniu Yu1 and Ming Sun1 [email protected] State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, People’s Republic of China The interaction between Bacillus thuringiensis insecticidal crystal protein Cry1A and cadherin receptors in lepidopteran insects induces toxin oligomerization, which is essential for membrane insertion and mediates Cry1A toxicity. It has been reported that Manduca sexta cadherin fragment CR12-MPED and Anopheles gambiae cadherin fragment CR11-MPED enhance the insecticidal activity of Cry1Ab and Cry4Ba to certain lepidopteran and dipteran larvae species, respectively. This study reports that a Helicoverpa armigera cadherin fragment (HaCad1) containing its toxin binding region, expressed in Escherichia coli, enhanced Cry1Ac activity against H. armigera larvae. A binding assay showed that HaCad1 was able to bind to Cry1Ac in vitro and that this event did not block toxin binding to the brush border membrane microvilli prepared from H. armigera. When the residues 1423GVLSLNFQ1430 were deleted from the fragment, the subsequent mutation peptide lost its ability to bind Cry1Ac and the toxicity enhancement was also significantly reduced. Oligomerization tests showed that HaCad1 facilitates the formation of a 250-kDa oligomer of Cry1Ac-activated toxin in the midgut fluid environment. Oligomer formation was dependent upon the toxin binding to HaCad1, which was also necessary for the HaCad1-mediated enhancement effect. Our discovery reveals a novel strategy to enhance insecticidal activity or to overcome the resistance of insects to B. thuringiensis toxin-based biopesticides and transgenic crops. Applied Microbiology and Biotechnology Volume 85, Number 4 / January, 2010 1033- 1040 http://www.springerlink.com/content/v1111759150g5131/ Biological Control Host-seeking behavior and parasitism by Spathius agrili Yang (Hymenoptera: Braconidae), a parasitoid of the emerald ash borer Xiao-Yi Wanga, Zhong-Qi Yanga, , , Juli R. Gouldb, Hui Wuc and Jian-Hai Mad aThe Key Laboratory of Forest Protection, State Forestry Administration, Research Institute of Forest Ecology, Environment and Protection, Chinese Academy of Forestry, Beijing 100091, China bAnimal and Plant Health Inspection Service, Department of Agriculture, Otis ANGB, MA 02542 5008, USA cForestry Bureau of Sanming City in Fujian Province, Sanming, Fujian 365000, China dForest Pest Control Station of Qinghai Province, Xining, Qinghai 810000, China Spathius agrili Yang (Hymenoptera: Braconidae) is a newly described and important idiobiont ectoparasitoid of the emerald ash borer (EAB) that has excellent potential as a biological control agent against EAB populations in the USA. In order to understand the ecological factors involved in the search and discovery of concealed hosts by S. agrili, we investigated the behavioral responses of adult female wasps to potential semiochemicals from host plants, hosts, and host frass as well as to vibration signals from host feeding and movement. Using a bioassay, we showed that S. agrili first finds the host’s habitats by detecting the volatile compounds emitted by ash. In the second phase of host location and acceptance, the parasitoids detect the mechanical vibrations produced by host feeding and movement under the surface of the bark and then probe to find the EAB larvae. Contact chemicals seem to play little or no role in short-range host finding. Female wasps avoided laying eggs on EAB larvae already parasitized and thus paralyzed. We hypothesized that female wasps were not attracted to these larvae due to their lack of feeding or movement. While an induced paralysis in the host is instrumental in avoiding superparasitism, we cannot rule out that S. agrili females also use an oviposition pheromone to deter conspecific females. Together, these results suggest that vibration and olfactory cues play significant roles in distinct phases of S. agrili host habitat and host location behaviors. Biological Control Volume 52, Issue 1, January 2010, Pages 24-29 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WBP-4X97CYF- 1&_user=586462&_coverDate=01%2F31%2F2010&_rdoc=5&_fmt=high&_orig=browse&_srch=doc- info(%23toc%236716%232010%23999479998%231565121%23FLA%23display%23Volume)&_cdi=6716&_sort=d&_docanchor=&_ct=13&_acct=C0 00030078&_version=1&_urlVersion=0&_userid=586462&md5=c5e4912e789de704c9cde225ff5ba7ae Potential impact and non-target effects of Gallerucida bifasciata (Coleoptera: Chrysomelidae), a candidate biological control agent for Fallopia japonica Yangzhou Wanga, b, c, John R.U. Wilsond, e, Jun Zhanga, f, Jialiang Zhanga, g and Jianqing Dinga, g, , a Wuhan Botanical Garden/Institute, Chinese Academy of Sciences, Wuhan, Hubei 430074, China b Institute of Plant Protection, Jilin Academy of Agricultural Sciences, Changchun, Jilin, China c Graduate School of the Chinese Academy of Sciences, Beijing 100049, China d South African National Biodiversity Institute, Kirstenbosch National Botanical Gardens, Claremont, South Africa e DST-NRF Centre of Excellence for Invasion Biology, Department of Botany & Zoology, Stellenbosch University, South Africa f Department of Plant Protection, Huazhong Agricultural University, Wuhan, Hubei 430000, China g Key Laboratory of Aquatic Botany and Watershed Ecology, Chinese Academy of Sciences, Wuhan, Hubei 430074, China A pre-release evaluation of a potential biological control agent is designed to estimate the impact the agent will have on the target in the introduced range, and whether the agent poses an acceptable level of risk to biodiversity. Here, we present an evaluation of the Asian leaf-beetle, Gallerucida bifasciata, a potential biological control agent for Japanese knotweed, Fallopia japonica. First we tested the impact of different larval and adult densities on the plant under laboratory conditions. After six weeks, the biomass of F. japonica was 15% or 28% that of control plants if larvae or adults were added, with levels of damage plateauing quickly with increasing insects densities. High fecundity and larval density dependence means that this agent could substantially and quickly suppress plant growth, although this damage only occurs early in the season, allowing F. japonica time to compensate. Second, following on from general host-specificity trials, we investigated potential non-target effects on the commercially important plant buckwheat, Fagopyrum esculentum, in more depth. The leaf-beetle showed some minor adult feeding on F. esculentum in choice trials, and in no-choice trials the leaf-beetle was able to complete its life cycle and sustain a population on F. esculentum, albeit causing lower levels of damage than on F. japonica. This suggests that if the beetle dispersed to areas where F. japonica is not present, it might colonise F. esculentum. Therefore, despite potentially being an effective agent, that the risk of non-target feeding is unacceptably high. Biological Control Volume 53, Issue 3, June 2010, Pages 319-324 http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WBP-4XY4GK8- 1&_user=10&_coverDate=06%2F30%2F2010&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000050221&_version=1 &_urlVersion=0&_userid=10&md5=d91b938ac833980db9ac7178cc680f81 Performance of the biological control agent flea beetle Agasicles hygrophila (Coleoptera: Chrysomelidae), on two plant species Alternanthera philoxeroides (alligatorweed) and A. sessilis (joyweed) Junjiao Lua, Longlong Zhaoa, Ruiyan Maa, , , Pingping Zhanga, Renjun Fanb and Jintong Zhangc a College of Agriculture, Shanxi Agricultural University, Taigu Shanxi 030801, PR China b Institute of Plant Protection, Shanxi Academy of Agricultural Sciences, Taiyuan, Shanxi 030031, PR China c College of Arts and Sciences, Shanxi Agricultural University, Taigu Shanxi 030801, PR China Agasicles hygrophila has been used as a biological control agent on invasive alligatorweed, Alternanthera philoxeroides in China. We conducted tests to determine the impact of A. hygrophila on the non-target species A. sessilis and examined the developmental differences of A. hygrophila raised on these two plant species to assess the ecological and environmental safety of the introduced A. hygrophila in China. No significant differences were detected in the developmental timing of A. hygrophila from larvae to adults, in larval hatching, and in pupal fresh weight in three treatments: A. hygrophila reared on A. philoxeroides through all life stages; A. hygrophila larvae reared on A. sessilis but pupated in the stems of A. philoxeroides; and A. hygrophila reared on A. sessilis through all life stages. However, when A. hygrophila larvae were reared on A. sessilis but pupated in the stems of A. philoxeroides, they had a significantly longer preoviposition period, lower pupation rate, and lower fecundity than those in other two treatments. The demographic parameters examined indicated that lower fecundity (GRR, R0) and intrinsic rate of natural increase (rm = 0.06), but longer doubling time (Td) were found in A. hygrophila larvae reared on A. sessilis but pupated in the stems of A. philoxeroides compared to the other two treatments (rm = 0.11). Ultimately, A. hygrophila has limited effects on the non-target A. sessilis and is considered safe to the ecosystem.