夹竹桃水浸液与化学试剂对沼蛤防控技术比较

Comparison of Oleander Extracts and Chemical Reagents on the Prevention and Control of Limnoperna fortunei

化学试剂灭杀沼蛤(Limnopernafortunei)容易对水质产生二次污染,物理防控方法操作困难,利用植物的化感作用防控沼蛤效果好、生物毒性低、不会对水质造成二次污染。基于预实验筛选出对沼蛤具有化感作用的植物—夹竹桃(Nerium indicum),比较夹竹桃水浸液与化学试剂的防治效果,为沼蛤的防控技术提供理论依据。比较了5种常用试剂草甘膦、丹宁酸、高锰酸钾、次氯酸钠和氯胺对沼蛤的防治效果,观察沼蛤的死亡率、开壳率、粘附率和移动距离,筛选出防治效果较好的化学试剂,然后与前期筛选出夹竹桃水浸液进行沼蛤防治效果比较实验,确定他感植物对淡水壳菜的灭杀能力。结果表明,通过不同化学试剂防治效果比较实验,初步筛选出3种对沼蛤灭杀效果较好的次氯酸钠、高锰酸钾和氯胺,其沼蛤最高死亡率均大于50%,开壳率均在30%以下,而粘附率在50%以下且沼蛤基本未移动;通过夹竹桃水浸液与化学试剂的防治效果比较,次氯酸钠、高锰酸钾、氯胺和夹竹桃水浸液均具有较好的防控效果,其最佳投放浓度分别11mg/L、4mg/L、4mg/L和4mg/L,半致死时间分别为111h、109h、122h和82h。

Limnoperna fortunei(golden mussel)is a typical invasive organism.Preventing and controlling L.fortunei is difficult and,at present,the primary means is application of chemicals,resulting in serious secondary pollution of water.Based on our previous study of plant poisons and the physiological and behavioral characteristics of L.fortunei,we found that Neriumindicum(oleander)contained toxic substances that could potentially control L.fortunei with less secondary pollution.In this paper,we compared the effect of oleander extracts on L.fortunei with the effect of chemical reagents,aiming to provide a theoretical basis for controlling L.fortunei with a plant extract.The test L.fortunei were collected in the Yangtze River at Wuhan in September 2016 and divided into four groups according to body length(L≤5mm,5mm25mm).We first compared the effects of five chemical reagents(glyphosate,tannic acid,sodium hypochlorite,permanganate and chloramine)on L.fortunei and identified the most effective chemical reagents,based on mortality,shell opening rate,adhesion rate and movement.Four concentrations(0mg/L,5mg/L,50mg/L,100mg/L)of each chemical were used for comparison,and each treatment was run in triplicate with 12 L.fortunei per trial(3individuals of each body length).The three most effective chemical reagents were permanganate,sodium hypochlorite and chloramine,all three chemicals gave L.fortunei mortality rates>50%,open shell rates<30%,adhesion rates<50%,and no movement.These three chemicals were then compared with oleander extract under the same conditions,based on the same response parameters,using seven concentrations(0mg/L,1.0mg/L,2.0mg/L,4.0 mg/L,6.0 mg/L and 8.0 mg/L).In all treatments death of L.fortunei occurred after 20 hexposure.The highest mortality of L.fortunei was>90%in the permanganate and oleander treatments and>60%in the sodium hypochlorite and chloramine treatments.The optimal concentration of sodium hypochlorite,permanganate,chloramine and oleander extracts were respectively11mg/L,4mg/L,4mg/L,4mg/L,and the median lethal times were 111 h,109h,122 h,82h.