小贯小绿叶蝉的疏水性及其在控制中的潜在应用

发布时间：2017-12-28 00:34

本文关键词：小贯小绿叶蝉的疏水性及其在控制中的潜在应用　出处：《福建农林大学》2017年博士论文　论文类型：学位论文

【摘要】：小贯小绿叶蝉Empoasca onukii Matsuda是我国茶园的重要害虫,目前已对多种农药品种产生抗药性,既增加了防治难度,同时也因农药残留等问题影响茶叶饮用的安全性,急需寻找无害化防治措施替代传统的化学防治。小贯小绿叶蝉具有畏水习性,受降雨等水分胁迫影响较大,另一方面该叶蝉活动性强,受惊扰时善于躲避,农药的喷雾防治效果常受到影响。本试验通过室内人工模拟降雨分别对成若虫进行喷雾刺激,研究成虫和若虫的疏水性行为反应特点,分析成、若虫不同部位的微观结构,并探索喷雾防治该叶蝉可行性,主要研究结果如下:(1)观察发现小贯小绿叶蝉成虫和若虫对清水喷雾刺激存在不同的行为反应。试验首先比较龄期对若虫逃避行为的影响,1龄若虫会被喷雾到叶片的水流冲下,其他龄期若虫则困于叶片水泊中;分析停止喷雾后若虫逃离水滴的时间,发现高龄若虫(4～5龄)的逃离时间17.40±2.78s,显著短于低龄若虫(2～3龄)48.70 ± 3.05 s,叶片正面形成的水滴比叶背水膜更有利于若虫逃离;逃离视频观察发现若虫腹部与水滴间存在较高的粘附力。其次,对成虫群体进行加罩喷雾刺激,成虫可躲避在亚克力板上密集水滴的空隙之间,当罩内加上纱网并喷雾形成水膜后,80%成虫不发生逃避行为而困于叶面水滴中,20%成虫前后翅粘附在纱网水膜上,微距观察发现成虫的双翅与水膜间也存在较高的粘附力。研究主要器官对成虫逃避行为的影响,完好组成虫可在0.29 ± 0.15 s内快速逃离喷雾区域,复眼遮盖组成功逃离的概率最低,67%试虫困于叶片水膜中,触角及双翅对其逃避行为的影响较小。(2)证明小贯小绿叶蝉成虫和若虫前跗节结构不同与其疏水性差异存在必然联系。通过水面法观察小贯小绿叶蝉成、若虫前跗节的疏水性,并与茶二叉蚜和白背飞虱进行对比,结果显示叶蝉成虫可站立于水面,而若虫前跗节则陷入水中,表明成虫前跗节的疏水性高于若虫,相比之下,茶二叉蚜和白背飞虱不同虫态间的疏水性没有差异,茶二叉蚜成、若虫的前附节均陷入水中,白背飞虱成、若虫则均可站立于水面。通过扫描电镜比较分析试虫前跗节微观结构的差异,小贯小绿叶蝉成虫前跗节较为宽扁,爪中垫为两个浅盘结构,上面覆盖大量网粒体,而若虫前跗节较肥厚,宽度和厚度与成虫均存在显著差异,爪中垫为两个中空吸杯,而茶二叉蚜和白背飞虱成、若虫两种虫态的前跗节结构没有显著差异。通过自制简易吸管天平测定小贯小绿叶蝉前跗节与茶叶叶面及水滴的粘附力,结果显示若虫前跗节与茶叶叶面的粘附力达96.7 ± 6.9 μN,与水面的粘附力达108.6±11.9 μN,都显著高于成虫。我们推测若虫前跗节吸杯式爪中垫为若虫与接触界面提供较高的吸附力,使其在喷雾过程中不会被水流冲下,而成虫前跗节的宽扁结构及存在的大量网粒体提高其疏水性,有利于成虫快速逃离喷雾区域。(3)证实小贯小绿叶蝉腹部表皮的显微结构随发育而变化,覆盖的网粒体数量也随之增多,疏水性逐渐增强。试验观察到若虫腹部背面除了 6列感觉毛外,表皮较为光滑,腹面微观结构则随虫龄而变化,低龄若虫(1～2龄)腹部腹面密布着大量的微乳突(0.3～0.8 μm),中高龄若虫(3～5龄)腹部中央的微乳突转变为微刺(0.7～1.6 μm);成虫腹部腹面和背面均有鱼鳞状排列的微刺,腹面微刺长度(0.7～1.6 μm)比背板微刺(0.3～0.6 μm)稍长。成、若虫腹部不同的微观结构与网粒体的覆盖密度有很大关系。SEM图像显示成虫腹部的网粒体数量显著多于若虫,且分布更为均匀。通过测定叶蝉腹部的疏水性,发现网粒体移除前成虫腹部静态接触角CAs值平均值为149.10 ±2.36°,去除网粒体后CAs平均值为125.35 ±3.04°,网粒体移除对成虫腹部的疏水性影响较大,而对若虫影响较小。通过比较小贯小绿叶蝉成虫和若虫腹部与水的粘附力POF值,若虫腹部腹面的POF值最高,网粒体可显著降低虫体表皮与水的粘附力。通过以上结果,我们推测若虫腹部与水的粘附力产生原因与虫体太小及网粒体分布不均匀有关,细小水滴在若虫体表能够形成近球形的状态,表现出较强的疏水性,符合Cassie模型,而较大水滴则浸润到若虫腹部其他部位,呈明显的Wenzel状态,表现出较强的粘附力。(4)揭示小贯小绿叶蝉翅面覆盖的网粒体具有提高翅面疏水性以及导致翅面与水间形成高粘附力的双重作用。小贯小绿叶蝉前后翅经扫描电镜观察显示都均匀覆盖网粒体。前后翅与水的静态接触角经测定CAs150°,表明都具有超疏水性;去除网粒体后,前后翅翅面的疏水性水平显著降低。小贯小绿叶蝉成虫前后翅与水的粘附力达160.3 ± 3.5 μN,接近其自身重力的33倍。这种具超疏水性同时又具有高粘附力的现象属于"花瓣效应",形成原因与覆盖在叶蝉翅面微米级的网粒体以及网粒体表面纳米级的空隙所构成微纳米二级结构有关,与水接触时网粒体内部所截留的空气形成翅面与水间的强粘附力。(5)根据小贯小绿叶蝉若虫和成虫不同的疏水性特点,探索获得了清水喷雾防治若虫的最佳措施,以及加罩喷雾防治成虫对减少杀虫剂用量的具体效果。首先测定小贯小绿叶蝉不同发育阶段对浸泡水滴的耐受力,发现低龄若虫(2～3龄)的耐受力最弱,48h死亡率达到83.3%,而高龄若虫和成虫对浸泡水滴的耐受力都较强,死亡率较低,因此推荐生产上采用喷雾法防控小贯小绿叶蝉若虫。室内试验初步获得当喷雾时间为20 min,喷雾距离为30～40 cm,冲刷次数为2次,72h后可获得若虫较高的致死率75%。其次,在室内采用液滴法和纱网药膜法测定成虫双翅被困于药液的毒力效果,并用浸叶法对比药剂的胃毒毒力,用离心管药膜法对比药剂的触杀毒力,所测3种药剂在浓度较低时即获得较高的致死率,其中印楝素的纱网药膜法LC50值为43.39μg/L,为制剂稀释6.9 × 104倍液的浓度,苏云金杆菌的LC50值为447.2IU/L,浓度为制剂稀释1.7×107倍,标准药剂联苯菊酯的LC50值为0.12 μg/L,为制剂稀释2.0 ×108倍,表明所测药剂采用纱网药膜法和液滴法均具有较强的胃毒及触杀效果。此外,设计可移动式薄膜纱网喷雾罩开展田间试验,添加低浓度印楝素乳油(稀释1500倍)的喷雾防控效果接近50%,但与不加罩的喷雾防效差异不显著,因此加罩减药的实际效益还需筛选其他触杀性更强的药剂进行验证。目前关于昆虫的疏水性研究多应用于仿生学材料,如何利用昆虫的疏水性特点为害虫的农业防治提供有力支撑所见甚少,本试验研究结果将为农业小型害虫的无害化防治提供新的思路。
[Abstract]:Through the small green leafhopper Empoasca onukii Matsuda is an important pest of tea in China, has a variety of pesticide resistance, which increased the difficulty of safety control, but also because of the problem of pesticide residues of tea drinking, the urgent need to find harmless prevention measures instead of the traditional chemical control. The small green leafhopper has the fear of water habits, and is greatly influenced by rainfall and other water stress. On the other hand, the leafhopper is strong in activity and is good at avoiding when disturbed. Pesticide spraying and control effect is often affected. This experiment through the indoor artificial rainfall simulation respectively on nymph spray stimulation, characteristics of hydrophobic behavioral response of adult and nymph, analysis and microstructure of different parts of the nymphs, and explore the feasibility of spray control leafhopper, the main results are as follows: (1) observed through small green leafhopper nymphs and adults on the water spray stimulation has some different behavioral responses. Effect of age on the first nymphal escape behavior, 1 instar nymphs will be sprayed onto the leaves washed down, other nymphs are trapped in the leaves in the spray is stopped after the analysis of water; water nymph escape time, found (4 to 5 instar nymphs of age) from 17.40 + 2.78s, was significantly shorter the nymph (2 ~ 3 years) 48.70 + 3.05 s, the formation of water droplets than leaf blade back water film is more conducive to escape video observation nymphs flee; adhesion exists between water droplets and higher abdominal nymphs. Secondly, the adult population is covered with spray stimulation, adults can escape in acrylic plate water intensive gap between, when the water film is formed in the cover with gauze and spray, 80% adults without escape behavior while trapped in leaf drop, 20% adult wing adhesion in the screen above the water film, macro observation showed that the adhesion force is higher there adults and the water film between the wings. The effects of main organs on adults' escaping behavior were studied. Intact insects could escape quickly from 0.29 to 0.15 s, and the probability of escape was 67%. (2) it is proved that the difference of the structure of the tarsus in the adult and nymph of the small green leafhopper is related to the difference of its hydrophobicity. The surface was observed through small green leafhopper nymphs, pretarsus hydrophobic, and compared with two tea graminum and WBPH, results show that can stand on the surface of adult leafhoppers, and nymphs pretarsus into the water, that the adult hydrophobic tarsi than nymphs, compared with there is no difference between the two, hydrophobic tea graminum and sogatellafurcifera different insect state between the two, tea graminum nymphs of the sections are immersed into water, sogatellafurcifera, nymphs could stand in the water. Through the comparative analysis of differences from scanning electron microscopy pretarsus micro structure, through the small green leafhopper adults pretarsus is wide and flat, two claw pad tray structure, covered a large number of network powders, and nymphs pretarsus than hypertrophy, width and thickness of adults and there are significant differences in jaw mat two hollow suction cup, there is no significant difference between the pretarsus structure and two fork tea aphid and WBPH nymphs, two stages. The adhesion of self-made small tubular Straw balance determination of leafhopper pretarsus and tea leaf surface and water droplets, results show that the adhesion tarsi and nymphs before tea leaves up to 96.7 + 6.9 N 108.6 + and the surface adhesion force of 11.9 N, were significantly higher than that of adults. We hypothesized that provide higher adsorption power nymph pretarsus cup type claw pad for nymph and contact interface, the spray process will not be washed, and improve the hydrophobicity of wide tarsal adult before the flat structure and the existence of a large network of particles, is conducive to adult quickly fled the spray area. (3) the microscopic structure of the abdominal epidermis of the leafhopper was confirmed to change with its development, and the number of the covered net particles increased and the hydrophobicity increased gradually. Experimental observation on the back of the abdomen to nymphs in addition to the 6 column sensory hair, the skin is smooth, ventral microstructure with larval age changes, nymph (1 ~ 2 years) with a large number of abdominal ventral micropapillae (0.3 ~ 0.8 m), middle age (3 to 5 instar nymphs) micro mastoid central abdomen into the micro (0.7 ~ 1.6 m); adult abdomen adaxially and abaxially were arranged slightly scaly, ventral micro length (0.7 ~ 1.6 m) than micro backplane (0.3 ~ 0.6 m) slightly longer. The microstructure of the adult and nymphs has a great relationship with the coverage density of the net particles. SEM images showed that the number of net particles in the abdomen of the adult was more than that of the nymphs, and the distribution was more uniform. Through the determination of hydrophobic leafhoppers in the abdomen, found the net particles removed before the adult abdominal static contact angle the average CAs value of 149.10 plus or minus 2.36 degrees, the removal of net particles after the average value of CAs is 125.35 + 3.04 degrees, affect the particle removal of the hydrophobic network adult abdomen, while smaller influence on the nymphs. By comparing the small green leafhopper nymphs and adults through abdominal adhesion and water POF value, the highest POF value of abdominal ventral nymphs, adhesion of net particles can significantly reduce the body skin with water. According to the above results, we speculate that the adhesion of abdomen and causes water nymphs and worms are too small and uneven distribution of particles, small droplets can form nearly spherical in nymph surface, showed strong hydrophobicity, with the Cassie model, while the larger droplets are infiltrating into other parts of the abdomen showed a nymph, obviously Wenzel, showed strong adhesion. (4) the net particles covered by the wing surface of the small green leafhopper can increase the hydrophobicity of the wing surface and lead to the high adhesion between the wing surface and the water. The scanning electron microscope (SEM) of the front and back wings of the leafhopper of the small intersecting green leafhopper showed that the net particles were evenly covered. The static contact angle between the front and back wings and water is measured CAs150 degrees, indicating that all of them have super hydrophobicity. After removing the net particles, the hydrophobicity of the wing wing surface of the front and back wings
【学位授予单位】：福建农林大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：S435.711

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