Reducing elasmobranch bycatch: Laboratory investigation of rare earth metal and magnetic deterrents with spiny dogfish and Pacific halibut

Spiny dogfish (Squalus acanthius) comprises a significant unwanted bycatch on demersal longlines set for halibut and cod in shelf waters of the east and west coasts of North America. In this laboratory study, attacks on baits were tested in the presence of two different rare earth materials (neodymium–iron–boride magnets and cerium mischmetal) believed to deter elasmobranch catch. Experiments were made with spiny dogfish and with Pacific halibut (Hippoglossus stenolepis) in pairwise tests of the rare earth materials and inert metal controls. Dogfish attacked and consumed baits tested with cerium mischmetal at a lower frequency than controls. Times to attack the baits were significantly higher in the presence of mischmetal, as were numbers of approaches before first attack. The time differential between mischmetal and control treatments and the number of baits consumed converged with increasing food deprivation (1 h, 2 d, and 4 d), but treatment differences were always significant. Cerium mischmetal appeared to be irritating to dogfish and may disrupt their bait detection and orientation abilities. Magnets also appeared to irritate dogfish but provided no protection for baits in feeding trials. Pacific halibut showed no reaction whatsoever to the rare earth magnets or cerium mischmetal. Mischmetal, therefore, may be useful in reducing spiny dogfish bycatch in the halibut fishery. Disadvantages in using mischmetal in commercial operations are expense, hazardous nature, and relatively rapid hydrolysis in seawater.     

The Control Efficiency of Plant Alcohol Extracts on the Laboratory Populations of Myzus persicae (Sulzer)and Lipaphis erysimi (Kaltenbach)

The effects of semiochemicals extracted from 63 species of plants, on peach aphid (Myzus persicae) and mustard aphid (Lipaphis erysimi), were studied in laboratory. The deterrent rate, reproduction deterrent index and the interferential index of population control (ⅡPC) was used to evaluate the efficiency of semiochemicals on population control of the two target aphids. The results showed that the extracts of 34 species of common plants have noticeable effect on both aphid populations, especially, Xanthium sibiricum Petr.Et Widd. and Syngonium podophyllum Schott. These plant extracts could be used to construct the plant protectant to protect crops.     

Mute swan grazing on winter crops: Evaluation of three grazing deterrents on oilseed rape

The population of mute swans Cygnus olor (Gmelin) in the UK has increased since 1986 to >25 000 birds, leading to increased complaints of damage to winter crops, and the need for cost-effective management measures. Using a randomized block design in a split-field experiment, the effectiveness of three licensed grazing deterrents was evaluated for mute swans feeding on oil-seed rape: (1) a ziram-based chemical repellent (AAprotect TM at 10 kg ha -1 ), (2) white flags (25 flags ha -1 ), and (3) hazard warning tape (1000 m ha -1 ) with twine (400 m ha -1 ). Deterrents and control (no treatment) were assigned to one of four plots (approximately 1 ha) in each of four fields. From 4 December 1998 to 26 March 1999, grazing intensity was estimated by counting mute swan droppings on plots at approximately 2-week intervals. Over the entire study (10 - 15 weeks depending on field), total numbers of droppings did not differ significantly between treatments. Over the initial 8 weeks, however, droppings were significantly lower on tape/twine. Tape/twine may therefore potentially be cost-effective in reducing mute swan grazing, and further work is recommended to refine the technique.     

两种植物根甲醇提取物对桃粉大尾蚜的忌避作用

选用老鸦皮(Litsea populifolia Gamble)以及苦参(Sophora flavescens Ait)根部组织的甲醇提取物对挑粉大尾蚜[Hyalopterus amygdali (Blanchard)]成虫进行了忌避作用的研究。结果表明24 h后,两种植物根甲醇提取物对蚜虫忌避作用显著,1.0 g/L老鸦皮、0.5 g/L苦参甲醇提取物处理的效果最好,忌避指数分别为0.260 0、0.373 3。同时,两种植物根提取物对桃粉大尾蚜在不同时段表现为杀虫活性,苦参提取物24~72 h之间有很好的杀蚜活性,72 h后1.0 g/L、0.5 g/L处理的平均存活指数均为0.153 8。老鸦皮提取物48 h~72 h对蚜虫有致死作用,72 h后,1.0 g/L处理的平均存活指数为0.307 7。     

Effectiveness of solar blinkers as a means of crop protection from wild boar damage

The population density of wild boar (Sus scrofa) in Northern Switzerland has increased dramatically during the last three decades and the species has become a major threat to agriculture, causing severe damage to crops and grassland. Vulnerable fields have to be protected from wild boar incursion, which is in most cases achieved by using electric fences. Alternatively, deterrents basing on optical, acoustical or gustative effect are available. The effectiveness of most of these systems has not previously been scientifically tested in the field. In our study we investigated the effectiveness of solar blinkers at baited luring sites. We conducted field experiments at 4 different sites with free-ranging wild boars from January 2007 to January 2008. Data from 504 inspections of the luring sites indicate that solar blinkers reduced the probability of wild boar visits at the luring sites by 8.1% compared to the control sites. We therefore evaluate deterrence effect of solar blinkers to be insufficient for effective crop protection. Probability of wild boar visits at the luring sites changed throughout the study period, showing seasonal variation of the extent of wild boar activity in the fields.     

苦皮藤乳油对小菜蛾种群的控制作用

通过室内外系统试验探讨了体积分数1％苦皮藤乳油对小菜蛾（Plutella xylostella L.)种群的控制作用，并采用生命表技术进行评价。结果表明，其控制作用主要表现在对成虫产卵的忌避作用、对幼虫的拒食作用以及对生长发育的影响和减少幼虫危害力等方面。体积分数1％苦皮藤乳油10.00mL/L处理对成虫的忌避率为73．2％，对幼虫的选择性和非选择性拒食率分别为94．7％和93．5％，幼虫总取食量是对照的40．1％，使小菜蛾种群趋势指数（I值）由对照的21．954降为0．6684，干扰作用控制指数（IIPC）为0．0304。采用状态空间分析法就苦皮藤乳油施用后小菜蛾种群数量动态的模拟分析亦表明，其显著的控制作用表现在种群发展初期对成虫产卵的忌避作用。     

山西省蚜虫名录

在经过多年野外调查、采集、室内显微鉴定的基础上,本课题组将采自山西省境内已定名的蚜虫种类名录整理于下,共包括11个科74个属的158个种。其中包括2个新属,21个新种,5个新亚种,2个新纪录属,17个新纪录种。     

烟青虫幼虫味觉可塑性行为研究

[目的]研究烟青虫幼虫的可塑性行为,为害虫防治提供参考。[方法]采用行为试验双选法和切除味觉感受器研究了不同取食经历烟青虫5龄幼虫对取食抑制素的味觉可塑性行为。[结果]正常人工饲料饲养幼虫对取食抑制素十分敏感,切除了侧栓锥感受器的幼虫对取食抑制素的反应与正常幼虫相似,切除了中栓锥感受器的幼虫对取食抑制素不敏感。而用含有低浓度取食抑制素的人工饲料饲养的幼虫对取食抑制素不敏感。[结论]中栓锥感受器中含有对取食抑制素敏感的味觉神经元,不同取食经历的烟青虫幼虫对取食抑制素具有行为可塑性。     

Coyote hair as an area repellent for white-tailed deer

Increasing white-tailed deer ( Odocoileus virginianus ) populations create numerous conflicts with agricultural production and transport safety. Lethal control is not always an option and area repellents, such as predator waste products, have generally shown limited effectiveness. We tested coyote ( Canis latrans ) hair as a repellent at feeding stations during the winters of 2000 and 2001 and along established deer trails during the summer of 2000 in northern Ohio. Feeding station experiments were conducted in which five treatment sites received one or three bags containing 17 g of coyote hair placed adjacent to or in front of a trough of whole kernel corn and five control sites received empty bag(s). In all feeding trials, corn consumption decreased at treated sites from 59 to 91%. Intrusions by deer at treated sites decreased by 48-96% in three tests, but did not vary in the first 3-week test when coyote hair was adjacent to the corn. Corn consumption and deer intrusions at control sites generally remained constant or showed an increase over the test period. In the deer trail test, use of trails did not differ between the pre-treatment and treatment periods for the control or treated trails. Coyote hair therefore served as an effective repellent to keep deer from a desired food source and should have use in protecting limited, discrete sites. However, coyote hair did not deter deer from moving along established trails.