Evaluation of the Francome MkII exhaust nozzle sprayer to apply oil-based formulations of Metarhizium flavoviride for locust control

Conidia of the fungus Metarhizium flavoviride were formulated in a paraffinic oil, ‘Shellsol’ T, and sprayed using the Francome MkII exhaust nozzle sprayer. Germination of the conidia collected from the spray was reduced by 30% as compared to unsprayed conidia. However, in bioassays, there was no detectable difference in virulence with conidia collected from the spray samples and unsprayed formulation. This indicated that, despite the recorded reduction in the concentration of active conidia, the efficacy of the formulation remained unchanged after passing through the exhaust nozzle sprayer. The droplet size spectra produced by the sprayer were investigated using the Malvern series 2600cc particle size analyser. The optimum droplets for locust control produced by this sprayer were generated by the number 1 nozzle (internal diameter 2·5 mm) with the number 1 restrictor ring (internal diameter 12.5 mm) sprayed at a pressure of 0·2 bar. The droplets thus produced had a volume median diameter of 58 μm when the nozzle protruded between 1 and 2 mm above the level of the restrictor ring. Of the droplets in the spray plume created by these conditions, 33% were between 50 and 100 μm, a range recommended as an achievable optimum for the ultra-low-volume application of Metarhizium flavoviride. The role of the exhaust nozzle sprayer as a tool for the application of M. flavoviride for locust control is discussed with reference to other vehicle-mounted ultra-low-volume sprayers. © 1997 SCI     

冠层推拨装置对喷杆喷雾机雾滴飘失与沉积特性的影响

喷杆喷雾机具有作业效率高、雾滴覆盖率高、沉积分布均匀、防治效果好等优点,是目前大田作物最主要的施药机具.但受作物冠层遮挡和侧风等气象条件的影响,导致喷杆喷雾机作业时雾滴难以穿透到植株中下部并伴随飘失.为改善喷杆喷雾机喷雾雾滴在作物冠层的穿透性并降低飘移量,本文优化设计了一种适用于大田作物的喷杆喷雾机冠层推拨装置.并分别...     

不同助剂、喷头及喷雾压力对自走式喷杆喷雾机稻田喷雾效果的影响

以亿丰丸山3WP-500CN型号自走式喷杆喷雾机为研究对象,以诱惑红85作为指示剂,测定了6种喷雾助剂 (红太阳、倍力、迈丝、融透、印楝油和哈速腾)、3种喷头 (TEEJET-VP80015、ASJ-VP110015和LICHENG-VP11003) 以及3种喷雾压力 (0.2、0.4 和0.6 MPa) 对农药沉积利用率、药液雾化性能 (D₅₀值雾滴密度等)、雾滴分布均匀性等喷雾参数的影响,以及240 g/L噻呋酰胺悬浮剂对水稻纹枯病防治效果及水稻产量的影响。结果表明:采用TEEJET-VP80015喷头,在0.4 MPa喷雾压力条件下,助剂哈速腾雾滴分布均匀性显著高于其他助剂,变异系数为0.11,同时对雾滴估计沉积量 (45.74 μL/cm2) 与分布跨度 (1.29) 的影响显著高于其他助剂;助剂迈丝对雾滴密度 (103.78个/cm2) 和农药沉积利用率 (83.88%) 的影响均显著高于其他助剂。采用TEEJET-VP80015喷头,在未添加助剂条件下,不同喷雾压力对雾滴分布跨度、雾滴附着率和农药沉积利用率影响差异显著,其中在0.6 MPa压力下,分布跨度为1.18,雾滴附着率为33.32%,农药沉积利用率为78.19%。在未添加助剂、0.4 MPa喷雾压力条件下,喷头LICHENG-VP11003对雾滴分布均匀性的影响显著高于另外两种喷头,变异系数为0.12,同时对雾滴覆盖率 (69.37%)、雾滴估计沉积量 (42.77 μL/cm2) 和农药沉积利用率 (75.79%) 的影响也显著高于另外两种喷头。各测定条件下,240 g/L噻呋酰胺悬浮剂对水稻纹枯病的防治效果与雾化性能和雾化参数结果一致,其中添加助剂迈丝后防治效果达到89.27%,显著高于添加其他助剂,增大喷雾压力到0.6 MPa,防治效果达到88.67%,显著高于其他压力条件;采用TEEJET-VP80015喷头,在0.4 MPa喷雾压力下,水稻产量为8301 kg/hm2,显著高于人工喷雾。因此,助剂与喷头类型均对自走式喷杆喷雾机施药时的农药沉积利用率、雾滴分布均匀性以及雾滴参数和雾化效果有显著的影响,在适当的喷雾压力下添加助剂可提高农药的防治效果。     

离心雾化低容量喷杆喷雾与常量喷雾对比研究

为探究装配离心雾化喷头的喷杆喷雾机在小麦田植保作业中的适用性,研发了一种基于低容量离心雾化技术的喷杆喷雾机(BSC),以添加诱惑红示踪剂的3种药剂（5%己唑醇悬浮剂、40%氧乐果乳油和50%吡蚜酮水分散粒剂）的混合复配制剂为供试药液,与装配液力式喷头的背负式喷雾器(KSH)、喷杆喷雾机(BSH)以及装配离心雾化喷头的背负式喷雾器(KSC)进行田间施药对比试验,分析了4种机具的主要作业效果指标——雾滴沉积分布均匀性、小麦冠层药液穿透性、作业效率以及防治效果。结果表明:对于沉积均匀性,离心雾化低容量喷杆喷雾与常量喷雾无显著性差异,而装配离心雾化喷头的背负式喷雾器的沉积均匀性低于其他3种机具;与常量喷雾相比,离心雾化方式有效提高了药液的冠层穿透性,最多可提高2.9倍;与常量喷杆、低容量离心背负和常量背负式喷雾器相比,低容量离心喷杆喷雾机的作业效率分别提高0.5倍、5.6倍和18.6倍;对比空白处理,低容量离心喷雾和常量喷雾方式防治效果显著,但两者之间无显著性差异。该研究可为低容量施药技术、超低容量施药技术和离心雾化技术在喷杆喷雾机上的应用提供参考。     

不同植保器械在水稻不同生育期喷施农药的沉积率及雾滴参数

评估不同植保器械的农药喷施效率为水稻上农药减量控害和统防统治工作提供理论技术支撑.本研究参照NY/T 2677—2015《农药沉积率测定方法》,在广东省南雄市全安镇晚造直播水稻田开展农药喷施试验,分析了分别采用手动喷雾器、电动喷雾器和植保无人飞机喷施的农药沉积率及雾滴参数.结果表明:在同一水稻生育期使用不同植保器械喷施...     

Neem oil (Azadirachta indica) nanoemulsion--a potent larvicidal agent against Culex quinquefasciatus

BACKGROUND: Nanoemulsion composed of neem oil and non‐ionic surfactant Tween 20, with a mean droplet size ranging from 31.03 to 251.43 nm, was formulated for various concentrations of the oil and surfactant. The larvicidal effect of the formulated neem oil nanoemulsion was checked against Culex quinquefasciatus. RESULTS: O/W emulsion was prepared using neem oil, Tween 20 and water. Nanoemulsion of 31.03 nm size was obtained at a 1:3 ratio of oil and surfactant, and it was found to be stable. The larger droplet size (251.43 nm) shifted to a smaller size of 31.03 nm with increase in the concentration of Tween 20. The viscosity of the nanoemulsion increased with increasing concentration of Tween 20. The lethal concentration (LC₅₀) of the nanoemulsion against Cx. quinquefasciatus was checked for 1:0.30, 1:1.5 and 1:3 ratios of oil and surfactant respectively. The LC₅₀ decreased with droplet size. The LC₅₀ for the ratio 1:3 nanoemulsions was 11.75 mg L^?1. CONCLUSION: The formulated nanoemulsion of 31.03 nm size was found to be an effective larvicidal agent. This is the first time that a neem oil nanoemulsion of this droplet size has been reported. It may be a good choice as a potent and selective larvicide for Cx. quinquefasciatus. Copyright © 2011 Society of Chemical Industry     

微囊化溶剂对吡唑醚菌酯微囊悬浮剂应用性能的影响

利用安全溶剂替代农药制剂中的有毒溶剂符合农业可持续发展的要求，乳油中有害溶剂替代已经颇具成效，而微囊剂型中的溶剂替代也应该引起重视。本文先通过比较油酸甲酯和150# 溶剂油对油相稳定性的影响以确定溶剂的种类和用量，采用界面聚合法分别以油酸甲酯和150#溶剂油为溶剂制备了9%吡唑醚菌酯微囊悬浮剂，之后考察了两种制剂的释放性能、抗光解性能和田间应用效果。结果表明；以油酸甲酯为溶剂，当原药与溶剂质量比为1 : 2时，所得的吡唑醚菌酯微囊为球形，平均粒径为2.92 μm，与以150# 溶剂油为溶剂制备的微囊相比，在快速释放液中，20 min时前者中吡唑醚菌酯的累积释放率为92%，后者仅为50%。在模拟紫外光强度下，在100 min时，以油酸甲酯作溶剂的微囊中吡唑醚菌酯含量比以150#作溶剂的微囊中吡唑醚菌酯的含量高30.59%。田间药效试验结果表明，在施药后32 d，用以油酸甲酯为溶剂制备的9%吡唑醚菌酯微囊悬浮剂处理比以150# 溶剂油为溶剂的微囊悬浮剂处理和250 g/L吡唑醚菌酯乳油处理对花生叶斑病的防效分别高16.59%和29.34%。表明溶剂对农药微囊制剂的稳定性和应用性能均存在影响，应该优化筛选。本研究可为农药微囊制剂的精细化加工提供理论依据。     

多旋翼植保无人飞机水稻飞防中的农药飘移和施药人员暴露

为研究多旋翼植保无人飞机施药时农药雾滴飘移规律以及施药作业人员职业暴露情况，依据喷雾飘移田间测试国际标准ISO22866和人体暴露贴片测试法，对多旋翼植保无人飞机和电动背负式喷雾器在水稻田喷施氯虫苯甲酰胺和苯醚甲环唑时的农药雾滴飘移量及施药作业人员人体农药沉积量进行了对比测试和分析评价。结果表明:在本试验环境条件下，多旋翼植保无人飞机在作业速率4 m/s和作业高度1.8 m参数下施药时，在距施药区下风向边界0~30 m范围内地面均有农药飘移性沉积，30 m处氯虫苯甲酰胺飘移率为0.9%，而背负式喷雾器施药的飘移量则主要集中在距施药区0~3 m区域内，3 m以外区域飘移率均≤0.6%；背负式喷雾器在距施药区5 m以及10 m远处空中不同高度的飘移量均小于0.001 μg/cm2，多旋翼植保无人飞机在距施药区5 m远处空中的飘移量大于10 m处，并且在垂直分布上，距冠层2 m左右 (无人飞机的飞行高度) 处飘移量最多。结合两种施药机具的雾滴粒径(背负式喷雾器DV₅₀ 值为149.4 μm，多旋翼植保无人飞机DV₅₀ 值为115.3 μm) 分析，无人飞机的雾滴具有更高的飘移潜力。由于实现了人机分离，多旋翼植保无人飞机进行作业时人体暴露量很低，而背负式喷雾器施药时对作业人员身体各部位均会造成一定的暴露，其中以手前臂和腿部正面暴露最为严重，在施用苯醚甲环唑时，右前臂背面暴露量最高，达到15.19 μg/cm2。本文中针对多旋翼植保无人飞机喷雾作业时在下风向的飘移沉积研究方法和试验结果，以及对多旋翼植保无人飞机施药过程中职业暴露的研究，可为农药喷雾作业缓冲区距离确定和人员作业安全评估提供参考。     

植保无人飞机低容量喷洒15%苯甲·吡唑酯微乳剂对3种苹果叶部病害的防效评价

为明确纳米杀菌剂的减量增效作用,本研究采用2种喷施方法,以水敏纸为雾滴沉积指示剂, 分析植保无人飞机和背负式电动喷雾器喷施15%苯甲·吡唑酯微乳剂(ME)和25%苯甲·吡唑酯悬浮剂(SC)两种不同剂型杀菌剂的雾滴密度及雾滴覆盖率,调查并计算苹果病叶率、病情指数、防治效果和综合效益。结果表明,植保无人飞机飞行高度影响雾滴密度和覆盖率,纳米农药15%苯甲·吡唑酯ME的雾滴密度和覆盖率与25%苯甲·吡唑酯悬浮剂(SC)的雾滴密度和覆盖率有差异。各杀菌剂处理对苹果锈病的防效最好,防治效果均在97%以上,对苹果黑星病的防治效果次之,末次药后15 d的防治效果均在90%以上,对苹果斑点落叶病有效,末次药后15 d的防治效果均在50%以上。植保无人飞机喷施纳米杀菌剂15%苯甲·吡唑酯ME在防治成本、时效性和节能上均明显优于背负式电动喷雾器。因此,采用植保无人飞机喷施纳米杀菌剂15%苯甲·吡唑酯ME可有效防治苹果黑星病和苹果锈病,同时实现杀菌剂减量,综合效益较高。     

Evaluation of field resistance in field-collected mosquito Culex quinquefasciatus Say through quantification of ULV permethrin/PBO formulation in field bioassays

BACKGROUND

Pyrethroids are among the most applied adulticides worldwide to control mosquito vectors for prevention of arboviral diseases transmission. However, pesticide resistance development in a mosquito population could lead to decreased control efficacy. While most studies investigate the resistant genotype (i.e. kdr, CYP450, etc.) as explanatory variables, few field efficacy studies have measured pesticide quantities deposited at different distances from the sprayer in association with observed mosquito mortality. The current study determined field delivered amounts of an applied ULV permethrin/PBO formulation (31% permethrin + 66% piperonyl butoxide) by GC/MS and estimated practical resistance ratios using caged mosquito females.

RESULTS

For field samples, the extraction method recovered 78 ± 3.92–108 ± 8.97% of the permethrin/PBO formulation when utilizing the peaks of PBO from GC/MS to estimate the concentrations of adulticide deposited near the mosquito cages. The field bioassay showed that the spatial distribution of permethrin/PBO formulation was heterogeneous among three pseudo-replicates within the same distance. Within the quantifiable permethrin/PBO range of 15.7–51.4 ng/cm², field-collected mosquito mortalities started at 64% and linearly increased reaching 100% only in two areas, while all Sebring susceptible mosquitoes died. The field LC₉₅ resistance ratio (RR) of F₀ Cx. quinquefasciatus ranged from 2.65–3.51, falling within the 95% CI of RR₉₅ estimated by laboratory vial assays. Tests with and without PBO indicated P450's enzymes contributed to field resistance.

CONCLUSION

Results showed the suitability of the collection and quantification method to estimate the field resistance ratio at the applied pesticide rate. Pesticide quantification would also allow the association of the known frequencies of resistance mechanisms (e.g. kdr, CYP450) with field mortalities to estimate the resistance level conferred by such mechanisms. © 2023 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Effect of spray application technique on spray deposition in greenhouse strawberries and tomatoes

BACKGROUND: Increasingly, Flemish greenhouse growers are using spray booms instead of spray guns to apply plant protection products. Although the advantages of spray booms are well known, growers still have many questions concerning nozzle choice and settings. Spray deposition using a vertical spray boom in tomatoes and strawberries was compared with reference spray equipment. Five different settings of nozzle type, size and pressure were tested with the spray boom. RESULTS: In general, the standard vertical spray boom performed better than the reference spray equipment in strawberries (spray gun) and in tomatoes (air‐assisted sprayer). Nozzle type and settings significantly affected spray deposition and crop penetration. Highest overall deposits in strawberries were achieved using air‐inclusion or extended‐range nozzles. In tomatoes, the extended‐range nozzles and the twin air‐inclusion nozzles performed best. Using smaller‐size extended‐range nozzles above the recommended pressure range resulted in lower deposits, especially inside the crop canopy. CONCLUSIONS: The use of a vertical spray boom is a promising technique for applying plant protection products in a safe and efficient way in tomatoes and strawberries, and nozzle choice and setting should be carefully considered. Copyright © 2009 Society of Chemical Industry     

Air-assisted sprayers for application in vine,orchard and similar crops1

Spraying in so-called space cultures (orchards, vineyards) is determined by two main aims which require contrary technical measures for their realization: (1) optimal even distribution of droplet deposition on the target. This generally requires sufficient air assistance of droplet transportation and penetration in order to bridge the distance between the nozzle outlet and the target; (2) the surplus energy which normally exists should be minimized in order to avoid any droplet flow outside the target. Several possibilities exist to approach these requirements: (1) optimal blower design and correct adjustment for each specific purpose; (2) catching and recycling of misdirected droplets by recycling units; (3) sensoring of gaps in the canopy and activation of a nozzle shut-off. The legal requirements of the BBA are given, together with the results of experiments on drift and ground deposition of chemicals from air-assisted sprayers, with special attention to recycling units and sensored sprayers.     

Notes on Ultra-low Volume Aerial Application Equipment and Techniques

The influence of the droplet size on efficiency and drift is considered as well as the suitability of ULV equipment. It is recommended that where ULV work is contemplated, trials be initially carried out to determine the optimum within various parameters. Measures aiming at minimizing drift during application are stressed, referring mainly to methods of using boom and nozzle equipment, the nozzle position relative to airflow, nozzle spacing, and flight height.     

喷雾量及助剂对棉花苗期植保无人飞机作业效果的影响

采用大疆MG-1P型植保无人飞机在棉花苗期进行喷雾,探讨喷雾量及助剂对农药在棉花上的沉积分布及对棉蚜防治效果的影响。以5%啶虫脒乳油为试验药剂,在3个喷雾量(15.0、22.5和30.0 L/hm²)及添加2种飞防助剂(YS09和倍达通)条件下进行喷雾,以诱惑红为雾滴沉积和农药利用率测定的指示剂,采用Deposit-Scan软件分析雾滴密度和雾滴覆盖率。结果表明：采用植保无人飞机施药,棉花叶片上的雾滴密度和覆盖率随着喷雾量的增加而提高,其中,喷雾量为30.0 L/hm²时叶片正面和背面的雾滴密度最高,分别为43.42和58.04个/cm²,雾滴覆盖率分别为6.44%和6.34%。3个喷雾量下农药沉积率分别为3.53%、3.70%和4.00%,低于背负式电动喷雾器喷雾处理,药后1～3 d对棉蚜的防效也低于背负式电动喷雾器喷雾处理。喷雾量为22.5 L/hm²时,添加助剂YS09和倍达通对叶片上雾滴密度、雾滴覆盖率及农药利用率无显著影响,但可提高对棉蚜的防效,药后1 d防效为86.24%和84.40%,...     

The influence of the extensional viscosity of very low concentrations of high molecular mass water-soluble polymers on atomisation and droplet impact

BACKGROUND: Water-soluble polymers are increasingly added to herbicide and pesticide formulations at very low concentrations (100-1000 mg L(-1)) in order to control the spray characteristics, notably to reduce spray drift and influence droplet bounce. The incorporation of polymeric adjuvants improves the efficacy of the spray solutions, thus enabling crop growers to maximise the performance of agrochemical sprays at lower dose rates of active ingredient. It is important to establish a fundamental understanding of how polymers influence the processes involved in droplet deposition.RESULTS: The shear and extensional viscosities of a series of high molecular mass (M(w)) poly(acrylamides) (M(w) approximately 10(6)-10(7)) have been determined at very low concentrations (100-1000 mg L(-1)). The polymer solutions demonstrated typical shear thinning characteristics under shear, and strain hardening behaviour under extension above a critical strain rate. The presence of the polymers was shown to increase the size of droplets produced in atomisation using an agricultural spray nozzle, as measured by laser diffraction. This was attributed to the increase in the extensional viscosity at the strain rates generated under pressure in the spray nozzle and was a function of both polymer concentration and M(w). In addition, the presence of polymer was found to have a significant influence on droplet bounce.CONCLUSIONS: The presence of very low concentrations of high molecular mass poly(acrylamides) significantly influences the size of droplets formed on atomisation and subsequent bounce characteristics. Large extensional viscosities generated above a critical strain rate are responsible for both processes.     

喷雾参数对自走式喷杆喷雾机稻田喷雾农药利用率及雾滴沉积分布的影响

比较在不同喷雾压力和施药液量条件下,采用自走式喷杆喷雾机在水稻分蘖期、孕穗期、扬花期进行喷雾处理的农药利用率、沉积分布均匀性及水稻茎基部雾滴密度的差异,为建立自走式喷杆喷雾机在稻田的高效施药技术提供理论依据。以生物染料丽春红-G作为农药示踪剂,估测不同喷雾参数的农药利用率,并用变异系数、绝对份额比例值比较农药分布的均匀性。同时通过水敏纸收集水稻基部雾滴密度,分析不同喷雾参数下农药雾滴穿透水稻冠层的能力。结果表明:在水稻分蘖期,采用自走式喷杆喷雾机在喷雾压力为1.2 MPa、施药液量为375 L/hm^2条件下喷雾,每个采样点的丽春红-G的平均沉积量仅为0.11 mg,与喷雾压力为0.4 MPa、施药液量为300 L/hm^2条件下喷雾的沉积量相比减少了56.00%。在水稻孕穗期,当喷雾压力为1.2 MPa、施药液量为375 L/hm^2时进行喷雾处理,每个采样点的丽春红-G的平均沉积量达0.26 mg,显著高于其他4个处理。在水稻扬花期,不同喷雾参数间的沉积量差距减小。在合适的喷雾压力和施药液量时,自走式喷杆喷雾机在水稻分蘖期、孕穗期和扬花期进行喷雾处理,农药利用率分别达到40.57%、54.97%和55.50%。综合变异系数和绝对份额比例两个指标,采用自走式喷杆喷雾机在喷雾压力为0.8 MPa、施药液量为300 L/hm^2条件下喷雾,农药分布更均匀。喷雾压力对水稻基部雾滴密度有显著影响,在水稻生长中后期,当喷雾压力低于0.8 MPa、施药液量为225~375 L/hm^2时,水稻茎秆基部雾滴密度均小于30个/cm^2。研究结果表明,喷雾压力和施药液量对自走式喷杆喷雾机稻田喷雾的农药利用率、分布均匀性及水稻茎秆基部雾滴密度有显著影响。在水稻生长前期,不宜采用高压力大水量喷雾作业;在水稻生长中后期,为增加对水稻基部病虫害的防治效果,需提高喷雾压力。     

六种杀虫剂在保护地黄瓜冠层的沉积分布及其对蚜虫防治效果的影响

为明确不同药剂在保护地黄瓜上的沉积分布及其对蚜虫防治效果的影响,利用农药雾滴采集装置收集农药雾滴,以诱惑红为示踪剂测定农药沉积量,通过DepositScan软件测定雾滴覆盖率,分析药剂在黄瓜冠层的沉积分布与其对蚜虫防效的关系。结果表明:阿维菌素、螺虫乙酯、吡虫啉、吡丙醚、噻虫嗪和啶虫脒6种药剂的沉积量与雾滴覆盖率之间均无显著差异,分布趋势均表现为顶部>中部>底部;药后1 d和3 d,不同药剂对同一冠层部位以及同一药剂对不同冠层部位黄瓜蚜虫的校正防效之间均无显著差异,且防效均达65%以上。背负式手动喷雾器按田间推荐剂量喷雾防治黄瓜蚜虫时,喷雾雾滴主要沉积在黄瓜冠层顶部,沉积量占到总沉积量的1/3以上,在冠层中部和底部的沉积量相对较少,但沉积到冠层中部和底部的农药剂量仍能发挥良好的防治效果。该研究结果可为合理使用农药防治黄瓜蚜虫提供科学依据。     

雾滴密度与喷雾方式对毒死蜱防治褐飞虱效果的影响

分别选用实心圆锥雾和扇形雾TP6501E两种喷头,以3WP-2000型行走式喷雾塔模拟对水稻植株压顶喷雾和侧向喷雾,探究雾滴密度、喷雾方式对48%毒死蜱乳油防治褐飞虱效果的影响。结果表明：压顶喷雾当底层雾滴密度分别达到99.4个/cm^2和94.9个/cm^2,且48%毒死蜱乳油有效剂量分别高于68.00 mg/m^2和55.64 mg/m^2时,对褐飞虱的防治效果达80%;侧向喷雾当底层雾滴密度分别在10.4～49.0个/cm^2和12.3～55.4个/cm^2范围内,且48%毒死蜱乳油有效剂量分别在41.21～82.42 mg/m^2和72.12～82.42 mg/m^2区间内对褐飞虱的防治效果均高于80%。相同有效剂量条件下,侧向喷雾的防效高于压顶喷雾。采用侧向喷雾方式时,水稻基部较易获得高密度雾滴,药剂在低有效剂量条件下即可取得预期防治效果。     

Adjuvants and herbicidal efficacy – present status and future prospects

The influence of adjuvants on spray liquid behaviour and herbicide performance is reviewed. Total formulation efficacy can be expressed as a function of [deposition:retention:uptake: translocation:a.i. toxicity]. Adjuvants influence the physico-chemical and plant interactions involved for each factor. Deposition efficiency of spray droplets on to a target is dependent largely on the droplet spectrum, whereas retention performance is dependent on plant leaf surface character, orientation and canopy architecture, as well as droplet volume, velocity and dynamic surface tension effects. Uptake into plant foliage is affected by the leaf surface wax, cuticle age and composition and species variability. Uptake can be improved through appropriate formulation to provide either stomatal infiltration or much greater and faster cuticular absorption of the active ingredient. The inherent translocation capability of the a.i. is not affected directly by adjuvants, which are relatively immobile, but they can increase the mass of absorbed a.i. translocated, as a consequence of improved uptake or may reduce it as a result of localized contact phytotoxicity. Considerable progress has been made in developing models of spray droplet deposition, adhesion and retention, as well as uptake. In future, individual models may be combined to provide an integrated formulation efficacy decision support system.     

丙环唑和醚菌酯药液浓度、雾滴密度与其对小麦白粉病防效的关系

采用室内生物测定和田间试验相结合的方法,研究了丙环唑和醚菌酯的药液浓度及雾滴密度与其对小麦白粉病防效的关系,首次提出了杀菌剂雾滴抑制中密度 (即达到50%抑制率时所对应的雾滴密度,EN₅₀) 这一概念。结果表明:1)室内喷施丙环唑及醚菌酯药液,当丙环唑质量浓度从0.01 g/L提高到1.0 g/L时,对应的EN₅₀值从18.7 cm–2下降至5.1 cm–2,EN₉₀值从755.8 cm–2下降至92.8 cm–2,雾滴杀伤半径 (r₅₀) 从0.92 mm增大到1.77 mm;当醚菌酯质量浓度从0.01 g/L提高到1.0 g/L时,对应的EN₅₀值从227.1 cm–2下降至1.0 cm–2,EN₉₀值从596.1 cm–2下降至26.9 cm–2,雾滴杀伤半径从0.27 mm增大到4.00 mm。2)田间使用MG-1S植保无人机和背负式电动喷雾器喷施丙环唑和醚菌酯防治小麦白粉病,无人机施药液量为15.0 L/hm2,药液质量浓度为5.0 g/L时,在小麦旗叶及倒二叶的雾滴密度分别为29.7和9.5 cm–2,喷施丙环唑和醚菌酯3、5、7 d后,对小麦白粉病的防效分别为41.9%、80.7%、90.2%和30.8%、67.9%、84.5%;电动喷雾器施药液量为450.0 L/hm2,药液质量浓度为0.17 g/L时,在小麦旗叶及倒二叶的雾滴密度分别为287.9和204.2 cm–2,喷施丙环唑和醚菌酯3、5、7 d后的防效分别为42.1%、85.3%、94.3%和28.5%、80.1%、90.5%。研究表明,田间施用丙环唑和醚菌酯时,无需把叶片全部喷湿,只需达到一定雾滴密度即可;运用植保无人机进行高浓度、低容量喷雾时,10~30 cm–2雾滴量即可达到理想的防治效果。