Quantification of imidacloprid toxicity to avocado thrips, Scirtothrips perseae Nakahara (Thysanoptera: Thripidae), using a combined bioassay and ELISA approach

A competitive ELISA (enzyme-linked immunosorbent assay) technique was evaluated for quantifying titres of imidacloprid in homogenates of leaf discs sampled from avocado plants treated with systemic applications of imidacloprid 240 g litre(-1) SC (Admire). Matrix effects were evident with undiluted leaf tissue homogenates, but these were effectively eliminated by dilution of homogenates in water. In a field trial conducted in a commercial nursery, there was an excellent correlation between imidacloprid residues within leaves and avocado thrips (Scirtothrips perseae Nakahara) mortality. However, with subsequent sampling over a 2-month period, the relationship between mortality and apparent imidacloprid concentration became less robust, suggesting that the material was being degraded within the plant to non-toxic metabolites. Nevertheless, assessments of thrips mortality on leaves that had been recently treated with imidacloprid established a lower threshold of activity for imidacloprid residues of 6 ng cm(-2) leaf. Limitations on the use of ELISA to quantify the impact of systemic insecticides on pest populations are discussed.     

上虞绿色防控试点茶园虫害发生情况调研

在浙江上虞地区天香茶园设置吸入式太阳能杀虫灯和黄色诱虫板开展茶园绿色防控工作,并以当地无特殊管理措施的金家茶园作为自然条件下茶树虫害发生模式参照,调查2018年6月-2020年8月期间两处茶园的茶小绿叶蝉、螨类、茶尺蠖、蓟马、蚜虫的发生情况.调查结果显示,天香茶园和金家茶园茶小绿叶蝉、螨类、蓟马和蚜虫的虫口高峰期均出现...     

22%氟啶虫胺腈SC对柑桔矢尖蚧和桔二叉蚜的防治效果

氟啶虫胺腈是一种专门防治刺吸式口器害虫的全新杀虫剂。本文以柑桔矢尖蚧和桔二叉蚜为防治对象,开展了22%氟啶虫胺腈SC田间药效试验。结果表明：药后14d,22%氟啶虫胺腈SC各处理对柑桔矢尖蚧防治效果为67.71~80.73%;药后28d,防治效果可达83.29%以上,其中高浓度处理防治效果可达92.08%。药后1d,22%氟啶虫胺腈SC各处理对桔二叉蚜防治效果达93.36~96.93%;药后7d,防治效果达到最高,其防治效果为97.26%~100%;药后14d,防治效果仍然可达92.04%以上。22%氟啶虫胺腈SC对柑桔矢尖蚧和桔二叉蚜具有优异防治效果和良好的安全性,可大面积在柑桔上使用,推荐使用浓度为3000~4000倍液喷雾。     

黄皮种子甲醇提取物对茶黄蓟马的生物活性

研究了黄皮种子甲醇提取物对茶黄蓟马（Scirtothrips dorsalis Hood）的驱避和触杀作用。结果表明：黄皮种子甲醇提取物对茶黄蓟马有较强的驱避活性,在浓度为20 g/L时,12 h和24 h对茶黄蓟马的驱避率分别为92.86%和89.91%;另外,提取物对茶黄蓟马有一定的触杀作用,处理后12 h和24 h对茶黄蓟马的致死中浓度（LC50）分别为16.60 g/L和12.85 g/L。各萃取相中石油醚相的活性最高,质量浓度为5 g/L 时,石油醚萃取物对茶黄蓟马24 h 后的校正死亡率为49.37%。     

基于气候变化的非洲橘硬蓟马分布区预测与分析

非洲橘硬蓟马(Scirtothrips aurantii)是柑橘等植物的重要检疫性害虫。为明确该虫在我国的可能适生范围及检疫重要性,为制定防止其传入和扩散蔓延的预防措施提供理论依据,利用普利斯顿大学开发的最大熵生态位模型(MaxEnt)软件分析并预测非洲橘硬蓟马在全球及我国的适生区。结果表明:非洲南部、南美洲中东部、墨西哥中部、澳大利亚东海南、印度南部、东南亚中部和西亚的也门是非洲橘硬蓟马在全球的主要适生区;该虫在我国的高度适生区为海南大部和云南中部,中度风险区为贵州大部、广西大部、广东大部、福建东南沿海和四川西南部。2050年,温室气体A1b(能源需求平衡)排放情景下,非洲橘硬蓟马的分布面积呈缩减趋势;A2a(能源需求高)和B2a(能源需求低)排放情景下,该虫在全球及我国的高度和中度风险区面积均呈增加趋势,特别在B2a情景下,高风险区的面积增加显著。结论:非洲橘硬蓟马有入侵我国的风险,应加强对该虫的检疫工作,实行严格的风险管理。     

红圆蚧3种寄生蜂的生物学研究

本文研究寄生于红圆蚧的３种寄生蜂生长发育，产卵和寿命。结果表明，印巴黄蚜小蜂发育最快，岭南黄蚜小蜂次之，盾蚧长缨蚜小蜂最慢。前两者偏好寄生较大的３龄蚧虫；而盾蚧长缨蚜小蜂则偏好较小的２龄蚧虫，从不同龄期羽化的该虫生产卵量也不同。建立一个温度与发育速率的模型，模拟结果与试验结果基本相符。     

茶黄蓟马触角的扫描电镜观察

通过采用扫描电镜技术对茶黄蓟马(Scirtothrips dorsalis Hood)成、若虫的触角感器类型与分布进行观察,结果表明茶黄蓟马触角上共有7种感器,分别为Bhm氏鬃毛、钟形感器、毛形感器、刺形感器、锥形感器、U形感器以及腔形感器。若虫与成虫在触角长度、节数、感器类型与分布等方面均有较大差异,其中若虫触角节数比成虫少;但在感器类型方面,U形感器仅见于成虫触角,花蕊刺形感器仅见于若虫触角。雌雄感器类型与分布无性别差异。     

枳实类黄酮体外抗氧化作用研究

用70%乙醇微波中火提取干燥的脱脂枳实粉1.5min,浓缩干燥得枳实粗提物.提取液过D101大孔树脂,将洗脱液浓缩干燥得枳实纯化物,经测定总黄酮达到92.78%,HPLC测其黄烷酮含量,并测定各提取物的抗氧化活性.结果显示,枳实粗提物、纯化物及黄酮单体均对羟自由基(·OH)、2,2-二苯代苦味酰基自由基(DPPH·)有清除效果,并随着浓度的增加,其对自由基的清除作用呈正相关.提取物对超氧阴离子自由基(·O-2)的清除效果在一定范围内上下波动.枳实提取物具有较强的抗氧化作用,单体之间存在协同作用.     

Resistance of avocado thrips (Thysanoptera: Thripidae) to sabadilla, a botanically derived bait

Bioassays were conducted on four avocado thrips (Scirtothrips perseae Nakahara) populations in southern California that had had limited past exposure to the botanical pesticide sabadilla, with the objective of establishing baseline susceptibility levels for the purpose of resistance monitoring. Reports of avocado thrips resistance in a grove that had received six sabadilla sprays over 2 years were confirmed when a bioassay indicated resistance ratios of 7.6 and 18.8 at the LC50 and LC90, respectively. Owing to the availability of other unrelated pesticides, sabadilla sprays were discontinued at this site, and, after 5.5 years, resistance ratios had dropped to near baseline levels. Avocado thrips baseline susceptibility to cyfluthrin was also obtained from one grove for future resistance monitoring studies. Resistance management principles are discussed in relation to the limited future options available for avocado thrips control.