防治稻纵卷叶螟高毒农药替代药剂的室内筛选

 为筛选高毒农药替代药剂,采用Potter喷雾法测定了8类29种杀虫剂对广西南宁和江苏南京稻纵卷叶螟3龄幼虫的室内毒力。这8类杀虫剂的毒力顺序为：抗生素类杀虫剂≥苯基吡唑类杀虫剂≥噁二嗪类杀虫剂≥昆虫生长调节剂类杀虫剂≥有机磷酸酯类杀虫剂、拟除虫菊酯类杀虫剂≥有机氯类杀虫剂≥沙蚕毒素类杀虫剂。甲氨基阿维菌素苯甲酸盐（甲维盐）对两地区稻纵卷叶螟3龄幼虫的触杀毒力最高,其LC50值介于0.2~0.8 mg/L;氟虫腈、茚虫威、呋喃虫酰肼、丁烯氟虫腈、虫酰肼、氟啶脲和氟铃脲的LC50值介于1.8~53 mg/L。推荐对稻纵卷叶螟毒力最高的10种新型杀虫剂（甲维盐、依维菌素、阿维菌素、氟虫腈、茚虫威、呋喃虫酰肼、丁烯氟虫腈、虫酰肼、氟啶脲、氟铃脲）和一些有机磷杀虫剂（喹硫磷、辛硫磷、丙溴磷、毒死蜱、哒嗪硫磷）作为高毒农药替代的候选药剂进行大田药效试验。此外,还讨论了稻纵卷叶螟的药剂防治措施。     

菊酯类农药在棉田的合理使用对策

菊酯类农药,是以天然除虫菊酯的化学结构为基础,经人工合成的除虫菊酯类似物的杀虫剂,故也称为拟除虫菊酯类农药。目前国内外生产的种类很多,如2.5％溴氰菊酯(敌杀死),10％二氯苯醚菊酯、10％和20％杀灭菊酯、10％氯氰菊酯、20％氰戊菊酯、     

二化螟对氟虫腈抗性初探

 采用点滴测定法，于2001~2004年对江、浙、皖3省12个县市的二化螟进行了氟虫腈的抗性调查。江苏及安徽等地二化螟对氟虫腈仍处于敏感状态，但江苏无锡和浙江慈溪二化螟的敏感性明显下降（抗性倍数RR分别为3.1和3.6倍），浙江苍南二化螟已出现中等水平的抗性（RR为21.2倍）。由此认为，二化螟目前仍处于对氟虫腈抗性发展的早期阶段。解毒酶抑制剂的活体增效实验发现，TPP、DEM能明显提高氟虫腈对抗性二化螟的毒力（增效比SR分别为1.8和1.6），但PBO在敏感性和抗性二化螟中的增效作用均不显著（SR为1.1~1.2）。表明酯酶和谷胱甘肽转移酶与二化螟对氟虫腈抗性的形成有一定关系。不同杀虫剂的比较毒力测定表明，三唑磷和敌百虫由于产生了抗性，对二化螟的毒力很低，乙酰甲胺磷本身对二化螟的毒力也不高，已很难再用来防治抗性二化螟。但哒嗪硫磷、二嗪磷、溴氰菊酯和阿维菌素对二化螟的毒力较高，而且尚没有明显的抗性产生，在二化螟抗性治理中，可以用作氟虫腈的轮换防治药剂。     

多种药剂对螺旋粉虱不同虫态的毒力测定

采用Potter喷雾法,测定30种杀虫剂对螺旋粉虱成虫与15种杀虫剂对螺旋粉虱若虫的毒力。结果表明:杀扑磷、毒死蜱、辛硫磷、溴氰菊酯、马拉硫磷等对成虫、若虫均具有较高活性。对成虫杀扑磷毒力最强,其LC50值为0.9123mg/L,毒死蜱、辛硫磷、马拉硫磷、顺式氯氰菊酯、溴氰菊酯、敌敌畏及丙溴磷对成虫毒力均较高,其LC50值分别为1.571 4、1.673 1、2.248 2、2.5570、3.039 1、3.186 8、4.1895 mg/L。对若虫溴氰菊酯毒力最强,其LC50值为8.5276mg/L,杀扑磷、毒死蜱、高效氯氟氰菊酯、高效氯氰菊酯对若虫同样具有较高毒力,其LC50值分别为11.486 5、12.9503、12.973 8、13.703 6 mg/L。另通过不同龄期若虫对毒死蜱等8种杀虫剂的敏感性测定,发现1~4龄若虫对杀虫剂的敏感性随虫龄增加而降低,1龄若虫最敏感,2龄和3龄若虫的敏感性相当,4龄若虫敏感性最低。     

大螟田间种群对不同杀虫剂敏感性的差异

近年来大螟危害不断加重,成为不少地区水稻螟害的优势虫种,急需筛选药剂进行针对性防治。本研究连续2年用新建的饲料涂药法测定了10种常用杀虫剂对江苏南京和浙江温岭地区大螟的毒力状况,通过对比分析发现,除杀虫单和三唑磷外,大螟对多数杀虫剂没有产生明显的抗药性,地区和年度之间敏感性变化不大。不同药剂对大螟的毒力顺序为：甲维盐〉〉阿维菌素〉〉稻丰散≈氯虫苯甲酰胺〉〉氟铃脲≈虫酰肼〉茚虫威〉醚菊酯〉杀螟硫磷≈丙溴磷〉三唑磷≈丁烯氟虫腈≈毒死蜱〉〉杀虫单。讨论认为,近些年大量使用阿维菌素和毒死蜱防治水稻螟虫和飞虱,不利于对大螟的兼治;可以充分发挥稻丰散和丙溴磷等低毒廉价有机磷杀虫剂的作用来针对性防治大螟。     

几种新型杀虫剂对棉盲蝽的防治效果

 研究了6种杀虫剂对棉盲蝽的田间防治效果。结果表明：50%氟啶虫胺腈水分散粒剂（WDG）按照75 g·hm^-2（有效成分）、20%呋虫胺可溶粒剂（SG）按照60 g·hm^-2和40%稻丰散·高效氯氟氰菊酯乳油（EC）按照450 g·hm^-2使用后,综合防效较好,不仅速效性快,而且持效期较长,优于常用杀虫剂97%乙酰甲胺磷WDG、45%马拉硫磷EC和2.5%高效氯氟氰菊酯EC。由于50%氟啶虫胺腈WDG、20%呋虫胺SG和40%稻丰散·高效氯氟氰菊酯EC均具有高效低毒安全等特点,对环境影响小,可作为综合防治棉盲蝽的理想药剂。     

花生花蓟马室内药剂筛选及田间药效试验

采用浸叶法在室内对花蓟马进行了药剂筛选试验,并对毒效较高的3种药剂开展了进一步毒力测定和田间药效试验。结果表明,有机磷类的三唑磷和乐斯本,拟除虫菊酯类的高效氯氰菊酯、溴氰菊酯和高效氯氟氰菊酯,以及氨基甲酸酯类的丁硫克百威等药剂对花蓟马的毒效很低,致死率均在37．6％以下。阿维菌素、啶虫脒和吡虫啉对花蓟马的致死作用明显,致死率分别为98．3％、98．7％和66．8％,它们的LC50分别为0．97mg·L^-1、15．4mg·L^-1和42．4mg·L^-1,以阿维菌素的毒力最高,是吡虫啉的43．71倍。田间药效试验结果与室内毒力测定结果相符合,以阿维菌素的防效最高,达93．3％以上,且持效期较长,施药后12d的防效仍在90％以上,是防治花生花蓟马的首选药剂。     

杀虫剂对小菜蛾幼虫的毒力研究

采用浸叶法测定10种杀虫剂对海南省海口、三亚、儋州小菜蛾田间种群的毒力。结果表明：10种药剂对海口地区小菜蛾3龄幼虫的毒力LC50大小顺序为：Bt＞氟啶脲＞多杀菌素＞茚虫威＞虫螨腈＞阿维菌素＞丁醚脲＞虫酰肼＞杀螟丹＞高效氯氰菊酯;三亚地区小菜蛾3龄幼虫的毒力LC50大小顺序为：Bt＞多杀菌素＞氟啶脲＞茚虫威＞虫螨腈＞阿维菌素＞虫酰肼＞丁醚脲＞杀螟丹＞高效氯氰菊酯;儋州地区小菜蛾3龄幼虫的毒力LC50大小顺序为：Bt＞多杀菌素＞茚虫威＞氟啶脲＞虫螨腈＞阿维菌素＞丁醚脲＞虫酰肼＞杀螟丹＞高效氯氰菊酯。3个地区     

取食香根草后水稻螟虫对杀虫剂敏感度变化

【目的】香根草能有效诱集水稻螟虫产卵,且孵化的幼虫取食香根草一定时间后死亡,可用于水稻螟虫的田间防控。但田间防治往往是多种防治措施相结合。为了研究取食香根草后的幼虫对常用杀虫剂的敏感度,【方法】利用稻苗浸渍法测定了茚虫威、氯虫苯甲酰胺、多杀菌素、甲氨基阿维菌素、氟虫胺、氰氟虫腙、阿维菌素、毒死蜱8种常用杀虫剂对水稻大螟和二化螟的毒力作用,以及取食香根草后螟虫对这些药剂的敏感度变化。【结果】8种杀虫剂(氰氟虫腙,甲氨基阿维菌素,氯虫苯甲酰胺,氟虫胺,多杀菌素,阿维菌素,茚虫威,毒死蜱)对大螟的LC₅₀依次为1.04,1.40,2.67,3.48,7.59,13.03,16.57,23.28 mg/L;对二化螟的LC₅₀依次为1.94,2.07,4.20,8.93,9.72,17.63,9.51,64.68mg/L。与取食水稻的螟虫比较,香根草饲喂3d后,大螟幼虫对8种药剂的敏感性均有所提高,致死率提高13.3～22.2个百分点,其中,对氯虫苯甲酰胺、多杀菌素、氟虫胺、氰氟虫腙、毒死蜱的敏感度显著提高;而香根草饲喂后的二化螟幼虫对所有测定药剂敏感度均显著提高,致死率提高26.7～33.3个百分点。二化螟幼虫对所有测定药剂敏感度升高更为明显。【结论】初步明确了水稻螟虫取食香根草后对杀虫剂的敏感度有不同程度提高。     

湖南省市售茶叶中24种农药残留的检测与分析

为了解湖南省市售的茶叶中农药残留的状况,利用气相色谱（GC）对湖南省市售的189份茶叶中24种农药残留情况进行定量检测并对测定结果进行整理和分析。结果显示,189份茶叶样品中有95份被检出有农药残留,检出率50.3%,所有样品均符合国家标准要求,合格率100%;在监测的24种农药残留中,仅检出毒死蜱1项有机磷类农药,而拟除虫菊酯类农药有联苯菊酯、甲氰菊酯、氯氟氰菊酯和高效氯氟氰菊酯3项被检出。检出率分析中,检出率最高的茶叶种类为绿茶,农药种类为氯氟氰菊酯和高效氯氟氰菊酯的检出率最高;检出值分析中,产自福建的茶叶中甲氰菊酯的残留存在超限量值的风险。     

杀虫剂对二化螟卵寄生性天敌稻螟赤眼蜂室内安全性评价

在实验室条件下测定了6类13种杀虫剂对二化螟卵寄生性天敌稻螟赤眼蜂的直接和间接影响。喷雾法处理稻株不同时间后,噻嗪酮、虫酰肼、呋喃虫酰肼、氟铃脲对稻螟赤眼蜂成蜂存活和雌蜂产卵寄生基本没有不利影响,氟虫腈、噻虫嗪、毒死蜱、三唑磷对稻螟赤眼蜂成蜂存活有极明显不利影响,成蜂接触用药处理2 d和7 d稻叶的死亡率分别为100％和800%~98.9%。用氟虫腈、三唑磷处理7 d的稻叶对稻螟赤眼蜂成蜂寄生能力无不利影响,而噻虫嗪处理有显著影响。采用卵卡浸渍法测定药剂对稻螟赤眼蜂成蜂影响的结果表明,吡虫啉、三唑磷、氟虫腈、毒死蜱能显著影响F0代成蜂存活、寄生及F1代成蜂羽化。采用浸渍法处理内含卵期、幼虫期、预蛹期、蛹期稻螟赤眼蜂的寄生卵时,噻嗪酮、虫酰肼、呋喃虫酰肼对成蜂羽化没有不利影响,羽化率达81.4%~91.8%;氟铃脲对蛹、甲维盐对卵和蛹、噻虫嗪对卵也基本没有不利影响,这些药剂对其他虫态有不同程度的影响;甲胺磷、吡虫啉、三唑磷、氟虫腈、毒死蜱、异丙威、敌敌畏等对稻螟赤眼蜂成蜂羽化有极明显不利影响。说明昆虫生长调节剂噻嗪酮、虫酰肼、呋喃虫酰肼对稻螟赤眼蜂没有直接和间接的不利影响,因而使用这些药剂防治水稻害虫时,它们对起自然控制作用的稻螟赤眼蜂是友好的。     

Monitoring of insecticide resistance in Spodoptera litura (Lepidoptera: Noctuidae) from four districts of Punjab,Pakistan to conventional and new chemistry insecticides

Studies were carried out to evaluate the resistance of Pakistani populations of the beet armyworm, Spodoptera litura (F) to several commonly used insecticides. Different field populations of S. litura from four districts of the Punjab were monitored from 2009 to 2011 for resistance to insecticides using a standard leaf dip bioassay method. For organophosphates and pyrethroids, resistance ratios compared with a susceptible Lab-Pk population were in the range of 8–109 fold for deltamethrin, 11–139 fold for cypermethrin, 19–143 fold for chlorpyrifos and 39–162 fold for profenofos. For new chemistry insecticides, resistance levels were 2–74 fold for spinosad, 4–216 fold for abamectin, 7–87 fold for indoxacarb, 2–77 fold for emamectin benzoate, 1.9–58 fold for lufenuron and 4–43 fold for methoxyfenozide. Pairwise correlation coefficients of LC₅₀ values showed a positive correlation with cross-resistance among deltamethrin, cypermethrin and chlorpyrifos, while resistance to profenofos showed correlations with resistances to other insecticides except chlorpyrifos. New chemistry insecticides showed no correlations between any of the tested insecticides. There were high to very high levels of resistance to organophosphates in most of the population, which suggested that the use of these should be avoided against this pest. Selective use of pyrethroids in several areas, including Bahawalpur and Lodhran, where the pest showed a low level of resistance, would appear to be acceptable, the new chemistry insecticides, lufenuron, methoxyfenozide, emamectin and indoxacarb had no, very low, low and moderate resistance levels against populations, respectively. These are considered to be safe to the environment and safer to natural enemies.     

7种杀虫剂对扁喙叶蝉的防效试验

扁喙叶蝉是我国芒果树的主要害虫之一。针对生产上存在的不科学用药现象，作者选择了7种常规药剂对扁喙叶蝉进行室内及田间筛选试验，以期为生产上防治该虫提供参考。结果表明：20%啶虫脒EC 1 500倍、70%吡虫啉WDG 1 000倍、25 g/L高效氯氰菊酯EW 1 000倍及25 g/L溴氰菊酯EC 1 000倍是防治扁喙叶蝉的良好药剂。     

A New and Simple Method for Collecting Eggs of the Striped Stemborer,Chilo suppressalis

The method for collecting eggs of the striped stem borer, Chilo suppressalis using plastic bags was studied in comparison with using caged rice plants. There was no significant difference in fecundity of C. suppressalis at 279 eggs/moth and in percentage of hatched eggs at 95% between in plastic bags and on rice plants. More egg masses were collected on plastic bags than on rice plants, whereas more smaller egg masses (less than 100 eggs per mass) in plastic bags than on rice plants. The advantages in collecting eggs of C. suppressalis and other insects by using plastic bags were also discussed.     

A New and Simple Method for Collecting Eggs of the Striped Stemborer,Chilo suppressalis

The method for collecting eggs of the striped stem borer, Chilo suppressalis using plastic bags was studied in comparison with using caged rice plants. There was no significant difference in fecundity of C. suppressalis at 279 eggs/moth and in percentage of hatched eggs at 95% between in plastic bags and on rice plants. More egg masses were collected on plastic bags than on rice plants, whereas more smaller egg masses (less than 100 eggs per mass) in plastic bags than on rice plants. The advantages in collecting eggs of C. suppressalis and other insects by using plastic bags were also discussed.     

Resistance in the mealybug Phenacoccus solenopsis Tinsley (Homoptera: Pseudococcidae) in Pakistan to selected organophosphate and pyrethroid insecticides

The mealybug Phenacoccus solenopsis is a destructive pest of cotton with the potential to develop resistance to most chemical classes of insecticides. Six populations of P. solenopsis from cotton crops at six different locations in Pakistan were evaluated for resistance to selected organophosphate and pyrethroid insecticides. Resistance ratios (RRs) at LC₅₀ were in the range of 2.7–13.3 fold for chlorpyrifos, 11.6–30.2 fold for profenofos and for the three pyrethroids tested were 10.6–46.4 for bifenthrin, 5.8–25.2 for deltamethrin and 4.1–25.0 for lambda-cyhalothrin. This is the first report of resistance to organophosphate and pyrethroid insecticides in Pakistani populations of P. solenopsis. Regular insecticide resistance monitoring programs are needed to prevent field control failures. Moreover, integrated approaches including the judicious use of insecticides and rotation of insecticides with different modes of action are needed to delay the development of insecticide resistance in P. solenopsis.     

Resistance of beet armyworm Spodoptera exigua (Lepidoptera: Noctuidae) to endosulfan,organophosphorus and pyrethroid insecticides in Pakistan

Field populations of beet armyworm, Spodoptera exigua (Lepidoptera: Noctuidae), from Pakistan were assessed for their resistance to the chlorinated hydrocarbon endosulfan, the organophosphates chlorpyrifos and quinalphos, and the pyrethroids cypermethrin, deltamethrin, bifenthrin and fenpropathrin. Using a leaf-dip bioassay, resistance to endosulfan was high during 1998–2000 but declined to very low, to low levels during 2001–2007, following a reduced use of the insecticide. Organophosphates and pyrethroids were consistently used over the past three decades, and the resistance had been increasing to these insecticide classes. Generally, the resistance to chlorpyrifos and pyrethroids remained low from 1998 to 2002–2003, but resistance increased to moderate to high levels from 2003–2004 to 2006–2007. For deltamethrin, resistance was very high during 2004–2007. Quinalphos resistance remained low during 1998–2006. Correlation analysis of LC₅₀ and LC₉₀ values showed a positive correlation between organophosphates and pyrethroids, but no correlation between endosulfan and organophosphates or pyrethroids tested herein. These results suggest that the conventional chemistries should be replaced with new chemistries for the successful management of S. exigua.     

Development of resistance to insecticides in the invasive mealybug Phenacoccus solenopsis (Hemiptera: Pseudococcidae) in Pakistan

The mealybug Phenacoccus solenopsis has been a serious pest of cotton, vegetables, ornamentals and other plants since its invasion into Pakistan in 2005. Its susceptibility to commonly-used insecticides was monitored during 2005–2013 by a nymphal dip bioassay. Initially, P. solenopsis was found susceptible to a range of insecticide classes. Lethal concentration values were particularly low for organophosphates and pyrethroids. After a year of its exposure to insecticides, P. solenopsis developed moderate to high levels of resistance to pyrethroids. After two years, resistance to organophosphates methidathion and chlorpyrifos also rose to moderate to high levels. After five years of use, resistance to pyrethroids, organophosphates, neonicotinoids, endosulfan, carbosulfan, and thiocyclam was generally high to very high. Acetamiprid resistance was slow to develop, as it reached moderate level of resistance after seven years of its extensive applications. Insecticide resistance in P. solenopsis could have been managed in Pakistan if the effective and diverse insecticides were used in rotation, along with other integrated pest management tactics, at the initial stages of resistance development.