The trapping of spray droplets by insects

The paper describes a methodology for specifying the deposition of spray droplets on flying insects and insects at rest on a quantitative basis. Processes of deposition by sedimentation and inertial impaction are viewed in terms of a deposition velocity defined by v_g = v_sa_x + E_iua_z, in which v_s is the droplet settling velocity, u the air speed relative to the insect, E_i a collection efficiency associated with inertial impaction and a_x, a_z signify horizontal and vertical projections of a representative trapping area. Published data on the deposition of small droplets (diameter < 20μm) on mosquitoes show that the trapping efficiency is dominated by inertial impaction and it is assumed that the collection efficiency is specified by E_i = St²/(St + 0.2)² in which St is the Stokes number. Analysis of a second data set regarding the deposition of larger drops on flying locusts shows that the dependence of the observed collection efficiency on droplet size can be explained satisfactorily by this simplified approach. Further, it is demonstrated that a characteristic length which forms an essential component of the Stokes number is matched to the general size of the insect. The paper concludes with an analysis of a further data set concerning the deposition of small drops onto resting tsetse flies; this provides insight into the effective air speed controlling the deposition process.     

The persistence of spray droplets above two vegetation canopies

Droplets were released from an ‘instantaneous line source’ perpendicular to the wind at heights of 4 and 7 m above the ground. Droplets were collected by rotating samplers at three heights; sets of samplers were positioned in a line parallel to the wind, downwind of the line source. Trials were carried out in moderately unstable conditions during the day, and under stable conditions shortly after dark, both over short rough stubble and over mature cotton. A substantial proportion of the small droplets were found to travel as far as 500 m over cotton; over grass, few of even the smallest droplets were collected 250 and 500 m downwind of the line source. Collection at the distant samplers was on average slightly, but not significantly, more when the spray was released at the greater height.     

喷洒部件及喷雾助剂对担架式喷雾机在桃园喷雾中的雾滴沉积分布的影响

采用诱惑红为指示剂研究测定了喷洒部件以及喷雾助剂Silwet408对电动担架式喷雾机在桃园喷雾中的雾滴沉积分布的影响,试验结果表明：采用喷枪大容量喷雾,当施药液量为250 L/667 m2时,有35.2%的药液流失到地面,喷雾雾滴在桃树冠层内膛和外膛的上/下层沉积比分别为0.59和0.62;当在喷雾液添加0.1%的Silwet408并把施药液量降低到125 L/667 m2时,药液在地面的流失率减少到21.2%,喷雾雾滴在桃树冠层内膛和外膛的上/下层沉积比分别为1.28和1.19,沉积分布均匀性明显提高。采用装配小喷片的组合喷头喷雾,当施药液量为250 L/667 m2时,有28.4%的药液流失到地面,当在喷雾液添加0.1% 的Silwet408并把施药液量降低到185 L/667m2时,喷雾压力分别为0.25 Mpa和0.35 Mpa时,药液在地面的流失率分别减少到18.5%和8.6%。研究测定结果表明,通过更换喷洒部件、增加喷雾压力、减少施药液量、添加喷雾助剂等措施可以显著减少果园喷雾中的药液流失率、提高喷雾雾滴在桃树冠层的沉积分布均匀性。     

植保施药机械喷雾雾滴飘移研究进展

中国农药产品80％以上通过喷雾方式施用,药液从喷头到靶标作物过程中产生的随风飘移和蒸发飘移是农药造成人畜健康风险、生态环境破坏的重要因素之一.随着航空施药技术的发展,解决或减少喷雾雾滴飘移的问题成为施药技术研究的重点和热点.基于此,本文分别从喷雾雾滴(尺寸分布、黏度、表面张力、蒸气压、挥发性、密度等)、喷雾模式(喷头类...     

Tracing insecticide spray droplets by sizes on natural surfaces. The state of the art and its value

Recent trends in integrated chemical and biological pest control call for further refinement of the effectiveness of existing chemical pesticides by more efficient spray application. One aspect of improving spray efficiency is by the use of the correct range of droplet sizes. In this way the volume of spray, and the amount of active ingredient used, particularly in ultra-low volume techniques, can be further optimised, and when combined with correct application time, gives maximum biological efficiency with minimum disturbance of the environment. This necessitates a study of the size spectrum of droplets deposited on rigorously defined biological targets which in turn calls for an investigation of suitable tracer methodology. Additional details of the previously published fluorescent particle method are discussed, and its reappraisal shows that it is a unique method capable of estimating droplet sizes on all biological surfaces, especially insect larvae. The reversibly soluble fluorescent pigment method based on the relative balance between soluble and insoluble state of the pigment proves highly successful in imprinting fluorescent droplets on broad leaves, particularly on cotton.     

喷雾助剂和静电喷雾对喷施炔草酯的减量增效作用

为了明确喷雾助剂和静电喷雾器对炔草酯的减量增效作用,采用田间小区试验测定了63％激健水剂、3％安融乐悬乳剂和75％超加必乳油3个喷雾助剂以及采用静电喷雾器施药对炔草酯除草效果的影响.结果表明:喷雾助剂激健、安融乐和超加必对常规背负式喷雾器喷施炔草酯增效作用明显,在有效成分剂量(下同)34 g/hm2的15％炔草酯可湿性...     

喷头和施药液量对水稻植株上农药沉积和药剂防治效果的影响

为明确喷头及施药液量对水稻植株上农药沉积及药剂防治效果的影响,采用丽春红-G示踪法测定了4种喷头ST11001、ST11002、TR8001、TR8002在不同施药液量条件下喷雾农药在水稻植株上的沉积分布特性,并比较了4种喷头施用相同剂量的40%氯虫苯甲酰胺·噻虫嗪WDG对水稻纵卷叶螟Cnaphalocrocis medinalis和褐飞虱Nilaparvata lugens的防治效果。结果表明,选择ST11002和TR8001喷头,在施药液量300 L/hm~2条件下喷雾,单株水稻上的丽春红-G沉积量分别达到27.55μg和28.16μg;选择ST11001和TR8002喷头,在施药液量900 L/hm~2条件下喷雾,单株水稻上的丽春红-G沉积量仅分别为12.27μg和14.86μg。喷头和施药液量的改变不影响水稻植株上农药沉积分布特性,均为上层沉积量中层沉积量下层沉积量。当施药液量从300 L/hm~2增加到900 L/hm~2,4种喷头ST11001、ST11002、TR8001、TR8002喷雾在水稻基部的雾滴密度分别增加了8.21、8.54、7.79和9.69倍;但在相同施药液量下,4种喷头在水稻基部的雾滴密度没有显著差异。同一剂量下,喷头和施药液量不同组合的防治效果间差异显著。表明针对稻田不同防治对象,选择合适的喷头及施药液量将有助于提高农药沉积及防治效果。     

Using a videographic system to assess spray droplet impaction and reflection from leaf and artificial surfaces

A video motion analysis system was used with two different monodisperse droplet generators to quantify droplet impaction and any consequent reflection. By using different magnification/droplet generator combinations, droplet impaction was detailed at various stages. Low (7×) magnification, together with a generator that produced a spray cloud, allowed determination of the height and numbers of droplets reflected from plant surfaces. Higher (15×) magnification and a single-drop generator enabled the trajectory, and changes in velocity, of a rebounding droplet to be followed. By using high (90×) magnification and the single-drop generator, detailed measurements of a droplet deforming on impact could be made. Examples of how these techniques could be used are given. © 1998 SCI     

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。     

The effect of drop speed,size and surfactant on the deposition of spray on barley and radish or mustard

Sprays composed of uniformly-sized drops were applied at different drop speeds to barley and either radish or mustard. Retention by the two broad-leafed species showed no major response to changes in drop speed, nor to the presence or absence of a surfactant. In contrast, the barley retained less spray when there was no surfactant and when the drops possessed higher momenta. The application of spray dropsat higher speeds would therefore appear to provide a basis for the development of selective retention techniques.     

The influence of molasses on the physical properties and sprayability of two pesticide formulations

The effects of molasses on some of the physicochemical properties and on the sprayability of a carbaryl wettable powder (w.p.) and triazophos emulsifiable concentrate (e.c.) were studied in the laboratory and the field. When sprayed in the laboratory on bean leaves, the deposit obtained from either formulation decreased as the percentage of molasses was increased. In an aerial application field trial on cotton, 10% molasses gave a smaller deposit of active ingredient than obtained in the absence of additive, while 20% molasses gave a greater deposit, with either formulation. Molasses had an adverse effect on some properties of the spray mixtures, which resulted in lower deposits when spraying was done at high humidity in the laboratory. This effect was offset when spraying was done at lower humidity in the field, because molasses improved the impaction of droplets by increasing their density and by preventing the complete evaporation of small droplets.     

喷头类型对植保无人机低容量喷雾雾滴在稻田冠层沉积分布及防治效果的影响

为减少植保无人机施药过程中的雾滴飘移,提高农药有效沉积率,选用多旋翼植保无人机探讨喷头类型和添加迈飞助剂对10%溴氰虫酰胺可分散油悬浮剂喷雾雾滴的沉积分布及其防治水稻二化螟Chilo suppressalis效果的影响。结果表明：IDK120-01型喷头+1.0%迈飞助剂处理在水稻冠层、中层、底层的雾滴体积中径D_V50均显著高于其他处理,在冠层的单位面积沉积量和农药有效沉积率分别为1.57 μg/cm²和63.89%,也均显著高于其他处理,且单位面积沉积量以冠层最高,中层次之,底层最低;喷头与助剂互作对防飘移率的影响显著,IDK120-01型喷头+1.0%迈飞助剂处理的防飘移率为76.08%,显著高于其他处理,该条件下喷施10%溴氰虫酰胺可分散油悬浮剂对二化螟的防治效果可达74.58%,水稻理论产量为8 905.80 kg/hm²,均显著高于其他处理。表明在溴氰虫酰胺药液中添加1.0%迈飞助剂,采用IDK120-01型喷头进行植保无人机喷洒作业防治水稻二化螟时,能有效减少雾滴飘移,增加单位面积沉积量及农药有效沉积率,提升对二化螟的防治效果。     

Factors affecting the foliar absorption and redistribution of pesticides. 1. Properties of leaf surfaces and their interactions with spray droplets

Foliar uptake into eleven plant species, grown under controlled environment, has been determined for spray deposits of glyphosate, 2, 4-D and prochloraz applied as solutions in aqueous solvents in the presence and absence of an ethoxylated nonylphenol surfactant. Over 24 h, uptake of glyphosate did not exceed 6% of applied chemical into any species whereas uptake of 2, 4-D and prochloraz differed between species and was modified significantly by the addition of surfactant. Uptake of prochloraz was increased consistently by adding surfactant, but the response of 2, 4-D was variable. Increased uptake was attributed mainly to surfactant-enhanced wetting of the leaf surfaces. Uptake of prochloraz per unit wetted area increased in the presence of surfactant but that of 2, 4-D decreased. Uptake of either chemical did not correlate with the presence of specialised leaf surface structures, cuticular morphology or distribution of the chemicals within the dried deposits. The dried chemicals were distributed either uniformly or as annuli as a result of complex interactions between the active ingredient, surfactant and the leaf surfaces. Regression analysis indicated that the epicuticular wax and cuticular membrane were the major sinks for both 2, 4-D and prochloraz during the 24-h period.     

The effect of different spray liquids on the foliar retention of agricultural sprays by wheat plants in a canopy

The aim of this work was to examine the effect of liquid properties on spray retention in a range of situations representative of practical pesticide application. Liquids with different physical properties were sprayed with conventional flat-fan and air-induction nozzles onto outdoor-grown wheat plants (Triticum aestivum L cv Axona) at growth stages between GS 22 and GS 35. Since total retention is affected by leaf surface as well as plant growth stage and canopy density, the experiments included spraying both single leaves and groups of plants with different canopy densities. Retention on whole plants was strongly influenced by plant growth and canopy properties. Individual leaf surfaces were not as water-repellent as was found previously for younger indoor-grown plants, reducing the effect of dynamic surface tension on retention. This, combined with the increased probability of droplets hitting foliage in a denser canopy, gave reduced differences in retention between liquids when compared with similar measurements made previously on younger plants. With a leaf area index greater than 7, retention on whole plants was almost independent of liquid. Air-induction nozzles gave lower levels of retention than flat-fan nozzles, with this difference greatest when spraying high dynamic surface tension liquids and at low crop densities.     

喷雾助剂对苯唑草酮防除玉米田杂草的减量增效作用

为了评价不同喷雾助剂对苯唑草酮减量施用下的增效作用,采用仪器分析和田间试验的方法研究了7种助剂对30%苯唑草酮悬浮剂的药液特性和杂草防效的影响。结果表明,7种助剂均能显著降低药液的表面张力、接触角和干燥时间,增加药液铺展直径。其中,杰效利对表面张力和接触角的影响最大,迈丝和渗透者对干燥时间的影响最小。田间试验结果表明,添加迈丝和渗透者对苯唑草酮的增效作用好于其他助剂,苯唑草酮的田间用量可以减少30%以上。     

A gas-liquid chromatographic method to determine size spectra of droplets of an aerially applied non-volatile spray mix deposited on kromekote® cards

A non-volatile oil-based spray mix of a low-vapour-pressure insecticide, aminocarb, containing an oil-soluble red dye was applied at a dosage rate of 70 g AI in 1-5 litre ha^?1, using a fixed wing aircraft equipped with four ?Micronair’?® AU3000 atomizers, over a 1000 × 500 m spray block selected in Bathurst, New Brunswick, Canada. Spray was applied twice, at an interval of five days, to provide a total dosage rate of 140 g AI in 3.0 litre ha^?1. Spray mass recovery was assessed on glass plates and droplets were collected on ?Kromekote’?® cards, both at ground level. The stain sizes were grouped into different categories. The area containing the stains was excised, and the aminocarb present was quantified by gas-liquid chromatography (GLC). The mass of aminocarb per droplet in each stain size category was evaluated. From the mass, the spherical droplet diameter (d), number and volume median diameters (D_N.5 and D_v.5 respectively), a new parameter [mass (of aminocarb) median diameter] (D_M.5), and the droplet size spectra were calculated. The D_M.5 for the first application was 56 μm, which was identical to the D_v.5. whereas the D_N.5 was smaller at 45 μm. The corresponding values for the second application were: D_M.5 = D_v.5 = 63 μm, but the D_N.5 was 53 μm. Because the spray mix was non-volatile, all the droplet size spectra parameters were identical both at spray release height and at ground level. The present study has provided, for the first time in the literature, a novel method to determine directly the spherical diameters of the droplets deposited on artificial samplers, without having to go through the tedious procedures of spread factor measurements under laboratory conditions. In fact, the present study has made it possible to calculate spread factors under field conditions, by using the stain diameters measured and the spherical diameters calculated from the aminocarb concentration levels.     

背负式静电喷雾器静电喷施对2种玉米田除草剂的减量效应

为了明确背负式静电喷雾器静电喷施对玉米田除草剂的减量效应,以土壤处理除草剂40%乙·莠SE和茎叶处理除草剂30%苯唑草酮SC+90%莠去津WG+专用助剂作为参试除草剂,测定了背负式静电喷雾器在不同施药剂量下的静电喷施效果。结果表明:背负式静电喷雾器静电喷施对40%乙·莠SE和30%苯唑草酮SC+90%莠去津WG+专用助剂均有明显的减量效应。当40%乙·莠SE和30%苯唑草酮SC+90%莠去津WG+专用助剂中90%莠去津WG的施用量分别降至2 850 mL/hm 2和825 g/hm 2时,较各自推荐施用量分别减少用药量36.67%和21.43%,对玉米田主要杂草仍有理想的控制效果,株防效超过64%,鲜重防效超过95%;并可最大限度地改善玉米茎、穗部性状,减轻对玉米产量的影响,较人工除草分别减产1.96%和0.29%。可见,背负式静电喷雾器在玉米田土壤处理除草剂和茎叶处理除草剂喷施中具有较大的应用价值。     

塔里木沙漠公路防护林土壤盐结皮化学特征及其对土壤蒸发的影响

盐结皮是广泛分布于塔里木沙漠公路防护林土壤表层的一个特殊层次,目前对其化学特征及其对土壤蒸发的影响尚无系统研究。文中对塔克拉玛干沙漠腹地不同定植年限防护林土壤盐结皮有机质含量、全盐量、八大离子含量和pH值进行了分析,并进行了盐结皮抑制土壤蒸发试验,结果表明:土壤盐结皮有机质含量随着防护林定植年限的增加而增加;全盐量、各离子含量、pH值均随着防护林定植年限的增加而逐渐降低。其中,全盐量均远高于流沙地;各离子含量与流沙地相比有不同程度的增加,Cl-、Na+和SO24-增加量最为明显,Mg2+、K+、Ca2+和HCO-3次之,CO23-含量极微且基本没有变化,pH值均呈碱性,定植11年防护林盐结皮pH值甚至低于流沙地;盐结皮可以有效的抑制土壤水分的蒸发。     

四种喷雾助剂对嘧菌酯在玉米叶片上耐雨水冲刷能力及其对玉米安全性的影响

在室内模拟雨水冲刷条件下,分别通过荧光显微镜法和高效液相色谱法探究了添加4种自制喷雾助剂AY904-1 (含有40%乙酸乙烯酯-丙烯酸共聚物和10%异构醇聚氧乙烯醚)、AY904-2 (含有30%乙酸乙烯酯-丙烯酸甲酯共聚物和10%异构醇聚氧乙烯醚)、AY904-3 (含有20%乙酸乙烯酯-丙烯酸乙酯共聚物和10%异构醇聚氧乙烯醚) 和AY904-4 (含有10%乙酸乙烯酯-丙烯酸丁酯共聚物和10%异构醇聚氧乙烯醚) 对提高嘧菌酯在玉米叶片表面耐雨水冲刷效果的影响,并测定了喷雾助剂对嘧菌酯药液物理性状及其玉米安全性的影响。结果表明:在室内模拟冲刷试验中,两种检测方法所测结果具有良好的相关性;在嘧菌酯中添加质量分数为0.1%~1.0%的AY904-1和AY904-2以及添加质量分数为0.5%~1.0%的AY904-3和AY904-4均可显著提高嘧菌酯在玉米叶片上的持留量,且助剂的添加量越大,耐冲刷效果越好,其中以AY904-1的效果最好。在嘧菌酯药液中添加4种喷雾助剂,均能降低药液在玉米叶片表面的接触角,但与嘧菌酯药剂对照相比无显著差异。AY904-1和AY904-2的干燥薄膜在水中溶胀度较低,成膜性能较好。将4种喷雾助剂与氯虫苯甲酰胺药液桶混后喷雾,发现其对3个品种玉米均有很高的安全性。