Use of fluorescence to determine reduction in Bemisia tabaci (Hemiptera: Aleyrodidae) nymph feeding when exposed to cyantraniliprole and imidacloprid through systemic applications

The Bemisia tabaci whitefly is an important pest of many agricultural crops. Direct feeding by this pest can cause physiological plant symptoms including irregular ripening in tomatoes and silverleaf disorder in squash. In addition, B. tabaci can transmit more than 100 plant viruses that cause severe diseases that affect crop yield and quality. Insecticides are often applied to control this pest and they may be applied to the foliage and/or to the soil. Insecticides that kill quickly or cause feeding cessation reduce the damage caused by B. tabaci on the host plant most effectively. In this study fluorescence was used to assess B. tabaci feeding and to determine the effect of systemically applied insecticides on feeding by the pest. Cyantraniliprole (Verimark™) and imidacloprid (AdmirePro^®) produced a rapid reduction in B. tabaci feeding. At 24 h after a systemic application, the percentage of whitefly nymphs still feeding in plants treated with cyantraniliprole (anthranilic diamide) and imidacloprid (neonicotinoid) were 19% and 33%, respectively. Both products showed a good reduction in insect feeding and since they have different modes of action they should be considered as rotational partners for B. tabaci control in areas where there is no resistance to neonicotinoid insecticides. While the fluorescein sodium salt cannot be used to trace the uptake of insecticides, it has been shown to reliably demonstrate feeding cessation of whitefly nymphs after foliar and systemic applications of insecticides.     

拥挤度和杀虫剂对蚜虫翅型分化和生长繁殖的影响

[目的]为了全面评价田间杀虫剂对害虫的非致死作用,[方法]我们选择了亚致死剂量吡虫啉和种群拥挤作为处理因子,测度了大豆蚜的产蚜量、成蚜寿命、若蚜历期及有翅蚜数量等指标,评价两个因子对蚜虫的寄主植株上种群的增殖力和转移扩散风险的影响性质及大小。[结果]结果表明：亚致死剂量吡虫啉对大豆蚜植株上种群有明显降低繁殖率的作用,从而有效减轻本地危害；另外,用药导致有翅蚜的数量显著降低,能降低蚜虫转移为害的风险。拥挤降低了第一代蚜虫种群的繁殖力,对第二代种群繁殖力没有显著影响。另一方面,拥挤造成有翅蚜数量增加,会增加蚜虫转移为害的风险。药剂和拥挤存在显著交互作用。[结论]研究表明：亚致死剂量的吡虫啉会降低大豆蚜后代的在原植株上的为害和转移为害,拥挤会消减药剂在植株上的控害作用,也会增加蚜虫转移为害的风险。     

Carbendazim resistance in field isolates of Sclerotinia sclerotiorum in China and its management

The ascomycete fungus Sclerotinia sclerotiorum is a devastating necrotrophic plant pathogen with an unusually broad host range and worldwide distribution. The benzimidazole fungicide carbendazim has been widely used to control S. sclerotiorum in China for more than three decades and high levels of carbendazim resistance have been reported in eastern China. In this study, carbendazim sensitivity was assessed in a total of 5042 field isolates of S. sclerotiorum collected from different geographical regions of China from 2008 to 2013. Results showed that no carbendazim resistant isolates could be detected in northwestern and northeastern China. In 2013, 0.77% and 0.72% of the field isolates assayed were highly resistant to carbendazim in Hunan and Hubei provinces of central China, respectively. In Anhui province of eastern China, the frequencies of carbendazim resistance were 18.18%, 7.05% and 7.25% in 2008, 2011 and 2012, respectively. The decrease in frequency of carbendazim resistance in Anhui province from 2008 to 2012 was statistically significant (P = 0.001). Nevertheless, no significant differences (P ≥ 0.16) were found in fitness parameters such as mycelial growth on PDA media, virulence to oilseed rape plants and oxalic acid production between carbendazim resistant and sensitive isolates. A negative cross resistance pattern was detected between carbendazim and diethofencarb. Mixture of carbendazim and diethofencarb (4:1) applied at 200 μg/mL provided 100% and 91.5% preventive efficacy against carbendazim resistant and sensitive isolates, respectively, and 87.1% and 81.7% curative efficacy against resistant and sensitive isolates, respectively.     

多菌灵、三环唑对大丽轮枝菌微菌核、黑色素形成及致病力的影响

 在离体和活体条件下测定了多菌灵、三环唑对大丽轮枝菌的微菌核黑色素形成的影响,以及经2种杀菌剂处理产生的形态变异菌株对棉苗的致病力。结果表明:多菌灵在培养基内含量超过0.1μg/ml时,即可抑制大丽轮枝菌微菌核的形成,随着培养基内多菌灵浓度的增加,微菌核形成时间逐渐延长,形成量逐渐减少;三环唑浓度为0.5μg/ml时,可抑制微菌核的黑色素形成,微菌核从黑色变为浅红至红褐色。三环唑对微菌核黑色素形成呈可逆抑制,变色的微菌核菌落移入不含药的培养基后,大多可恢复形成黑色素。培养基内三环唑浓度的提高,也可抑制大丽轮枝菌微菌核的形成;因2种杀菌剂的抑制而丧失形成微菌核的白色菌丝体移入不含药的培养基,微菌核形成能力也不能恢复。多菌灵和三环唑经棉株吸收后均能抑制植株内大丽轮枝菌微菌核的形成,但对微菌核色素的形成未见有明显影响。2种杀菌剂处理产生的形态变异菌株的致病力与野生型菌株致病力差异不显著。     

Comparison of spinetoram,imidacloprid, thiamethoxam and chlorantraniliprole against life stages of Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) on concrete

Spinetoram, imidacloprid, thiamethoxam and chlorantraniliprole are new insecticides with novel mode of actions, low mammalian toxicity and low impact to environment. In the present study, the efficacy of these insecticides was tested against Tribolium confusum Jacquelin du Val on concrete. Among the tested insecticides, spinetoram proved to be more effective, providing complete control of T. confusum adults and young larvae after 14 days of exposure. For the young larvae, thiamethoxam at the highest dose and chlorantraniliprole at both doses were equally effective with spinetoram. On the other hand, none of the tested insecticides were able to control T. confusum pupae. Moreover, none of the insecticides had ovicidal effect, with the exception of chlorantraniliprole in some combinations. From the mobile life stages, the most tolerant life stages were old larvae and the most susceptible young larvae. The presence of food (flour) moderated T. confusum mortality. From the results of the present study, we can conclude that spinetoram, thiamethoxam and chlorantraniliprole showed potential and need be further evaluated for surface treatments in stored product facilities. Our work underlined the need for good cleaning and sanitation procedures in warehouses and food processing facilities.     

黑龙江省部分稻区稻瘟病菌对多菌灵的敏感性测定

采用生长速率法测定采自黑龙江省部分稻区的稻瘟病菌菌株对多菌灵的敏感性。试验结果表明,供试稻瘟病菌菌株抑制中浓度(EC50)大多数分布在200～300mg/kg之间,最高为405mg/kg,最低为158mg/kg,其EC50值相差2倍以上,说明供试稻瘟病菌对多菌灵的敏感性均较差,且供试菌株对多菌灵已产生不同程度的敏感性差异。     

2种选择性农药刺激稻纵卷叶螟产卵的研究

[目的]探讨选择性农药是否是稻纵卷叶螟再猖獗的诱导因素。[方法]在盆栽和田间试验中,以武运粳7号为供试水稻品种,分别采用不同浓度的25%扑虱灵和10%吡虫啉对稻纵卷叶螟2龄和4龄期的幼虫进行喷雾处理,研究这2种选择性农药对稻纵卷叶螟产卵的影响。[结果]在稻纵卷叶螟幼虫2龄期用扑虱灵300.0、112.5、60.0 g/hm2进行喷雾处理能刺激稻纵卷叶螟成虫产卵;在稻纵卷叶螟幼虫4龄期用吡虫啉60.0 g/hm2喷雾处理也能刺激稻纵卷叶螟成虫产卵,并且其成虫产卵量与对照相比显著增加。[结论]扑虱灵和吡虫啉能刺激稻纵卷叶螟成虫产卵,是稻纵卷叶螟再猖獗的诱导因素之一。     

吡虫啉种衣剂控制水稻灰飞虱及黑条矮缩病等病毒病的效果研究

[目的]评价吡虫啉种衣剂及其与氟虫双酰胺混用对水稻灰飞虱及黑条矮缩病等病毒病的控制效果.[方法]通过田间小区试验研究了吡虫啉种衣剂及其与氟虫双酰胺混用控制水稻灰飞虱及黑条矮缩病等病毒病的效果.[结果]吡虫啉600 FS 83.3 ～125.0ml/hm2及其与氟虫双酰胺混用400 FS150.0 ～ 300.0 ml/hm2在灰飞虱和黑条矮缩病重发生情况下,秧田虫口防效高达45％ ～55％,大田病害防效在28.71％ ～ 56.52％,结合无纺布覆盖育苗以及秧田期防治灰飞虱,可有效控制病毒病的发生.[结论]为吡虫啉种衣剂的应用及水稻病毒病的防治提供了理论依据.     

液相色谱法和液相色谱-串联质谱法测定蔬菜中多菌灵等15种农药残留量的研究

[目的]建立蔬菜中多菌灵等15种农药残留检测方法。[方法]分别采用高效液相色谱法(HPLC)和液相色谱-串联质谱法(LC/MS/MS)对不同蔬菜中多菌灵等15种农药残留进行检测。[结果]2种试验检测方法,多菌灵等部分农药残留量检测结果存在一定差异,这是蔬菜样品基质干扰所致。[结论]LC/MS/MS方法质谱抗干扰能力强、稳定、可靠,使用简便快速、分析时间短;HPLC方法需要更好的方法优化才能得到更可靠的检测结果。     

宁夏枸杞种植区吡虫啉施用情况调查分析

2012年对宁夏枸杞种植区吡虫啉的施用情况进行调查分析表明,枸杞蚜虫是宁夏枸杞种植地区主要的防治对象,而吡虫啉是多年以来防治枸杞蚜虫的最重要药剂之一,枸杞园平均每年施用吡虫啉5~6次,各枸杞种植区吡虫啉施用浓度逐年加大的现象普遍存在。