Distribution and activity of spray deposits in an oak canopy following aerial application of diluted and undiluted formulations of Bacillus thuringiensis Berliner against the gypsy moth,Lymantria dispar L. (Lepidoptera: Lymantriidae)

The distribution and biological activity of spray deposits resulting from aerial applications of diluted and undiluted Bacillus thuringiensis, ‘Dipel 64AF’ against the gypsy moth, Lymantria dispar L., were examined in oak stands in south-eastern Ontario, Canada. The sprays were applied by fixed-wing aircraft equipped with four ‘Micronair AU4000’ atomizers. Application of diluted formulation at 30 BIU ha^?1 in 6.0–6.4 litre generally resulted in a higher droplet density (10–28 cm ^?2 leaf) than application of undiluted product at the same dosage rate in 1.8 litre ha^?1 (4–10 cm ^?2). However, spray deposits of undiluted product with a volume median diameter (D_v.5) of 90–130 μm caused as much mortality of gypsy moth larvae in bioassays of sprayed foliage as deposits of diluted product with a D_v.5 of 150–350 μm despite a two- to three-fold reduction in droplet density. Our data suggest that by using fine spray atomization, undiluted application of these formulations can offer the same efficacy against gypsy moth as coarsely atomized sprays of diluted product.     

两种植保无人机对火龙果冠层的作业参数优化

为探究飞行作业参数对植保无人机喷雾雾滴在火龙果冠层沉积分布规律的影响,明确植保无人机作业时雾滴的最佳分布效果,通过采用飞行高度、飞行速度、航线方向3个因素的3个水平正交试验,综合分析T16多旋翼和F5A电动单旋翼2种植保无人机在不同作业参数下在火龙果冠层的雾滴密度和覆盖率。结果表明：在相同喷施量情况下,影响这2种植保无人机雾滴分布的主次因素不一致,影响T16多旋翼植保无人机雾滴分布的主次因素依次为作业高度、作业速度、航线方向;影响F5A电动单旋翼植保无人机雾滴分布的主次因素依次为作业速度、作业高度、航线方向。优化了2种植保无人机在火龙冠层的作业参数,T16多旋翼植保无人机最佳作业参数是平行或垂直于种植行飞行,飞行高度为1.0 m,飞行速度为3.0 m/s;F5A电动单旋翼植保无人机最佳作业参数是垂直或平行于种植行飞行,飞行高度为2.0 m,飞行速度为2.0 m/s。这2种植保无人机飞行速度越小,飞行高度越低,其雾滴在火龙果冠层分布越好,雾滴穿透性也越好。在最优参数下,2种植保无人机喷雾雾滴在火龙果各个冠层都能达到比较好的分布效果,冠层下层雾滴密度高于冠层其他层。     

Distribution and likely effectiveness of spray deposits within a cotton canopy from fine ultralow-volume spray applied by aircraft

In a study to evaluate the deposit distribution from aerial sprays on cotton in the Sudan Gezira, a combination of subjective visual assessment and quantitative chemical analysis was used. Spray deposits on leaf discs, made visible in ultraviolet light by the addition of a fluorescent pigment, were subjectively grouped into classes according to a series of standards. The mean chemical deposit on the discs in each class was measured by the gas-liquid chromatographic determination of the profenofos content. The 810 leaves needed to define the deposit distribution with good confidence could be examined economically within the required period by this combination of quick subjective assessment and subsequent quantitative chemical calibration. Results showed that the vertical profile of the deposit distribution within the canopy followed the classical exponential decay curve. The rate of decrease depended mainly on the foliage density. The foliage effectively dampened the wind turbulence so much that the penetration of visible droplets within the lower two-thirds of the canopy was predominantly by gravity. Suggestions for the use of the deposit distribution probability to predict the likely biological effectiveness in the field are discussed.     

Foliar residues of aminocarb at tree canopy and ground levels in an experimental spray operation in conifer forests

Foliar residues of aminocarb were measured at tree canopy and ground levels in conifer forests in New Brunswick, Canada, following aerial application of three spray mixtures of aminocarb, one water-based, one in a volatile oil of low viscosity, and the third in a non-volatile oil of high viscosity. For a given volume rate of application, all three mixtures provided similar foliar residues at tree canopy level, but the aqueous and the volatile-oil based sprays provided significantly lower residues on cut foliage positioned at ground level, than the non-volatile oil spray mixture.     

Chemical control of isolated invasive conifers using a novel aerial spot application method

Conifer species, which have formed the foundation of commercial forestry industry in many countries, are known to be invasive in natural ecosystems, especially in the Southern Hemisphere. Controlling isolated invasive conifers before they reach reproductive maturity is an essential element of any strategy that aims to reduce spread rate of these species. Using a novel helicopter‐mounted spot‐application gun, which delivers a precise dosage to the crown of each tree, the objective of this research was to test the efficacy of three triclopyr‐based treatments against the four most vigorous wilding conifer species (Pinus contorta, Pinus nigra, Pinus sylvestris and Pseudotsuga menziesii) under New Zealand field conditions. Herbicides tested were triclopyr at two different rates and a combination of triclopyr and picloram. Treated trees covered a wide range of heights (c. 0.5–16 m), and measurements of mortality taken two years post‐herbicide application were used to examine variation in efficacy of the herbicides. Successful treatment was defined by a mortality rate of 85% or higher. A logistic regression model was fitted to the mortality data and used to derive threshold tree heights at which 85% mortality occurred, H₈₅. For all four species, the most effective treatment was application of 1000 ml of herbicide mixture per tree that contained 120 and 20 g, respectively, of the active ingredients triclopyr and picloram. There was a significant decline in efficacy of this treatment with increases in tree size for all four species. Values of H₈₅ for this treatment were 7.4 m for P. nigra, 8.3 m for P. menziesii, 9.7 m for P. contorta and >10 m for P. sylvestris. The methods developed here could be used to effectively manage emerging conifer infestations before they become problematic.     

Influence of formulation properties on droplet size spectra and ground deposits of aerially-applied pesticides

The influence of the physical properties of the spray liquid on droplet size spectra and ground deposits of aerially-applied pesticides was studied using heavy (high-viscosity) oil- and water-based suspensions of wettable powders (w.p.), a clear solution in a light (low-viscosity) oil, and an emulsion-suspension containing a bacterial control agent. The heavy oil provided a highly viscous spray medium, 52 to 64 mPa s (at a shear rate of 480 s^?1), resulting in large droplet sizes and a high deposit on the ground sampling units. When the spray medium was thickened with petroleum jelly to keep the w.p. in suspension during overnight storage, the viscosity became excessively high (102 mPa s at 480 s^?1), and the droplet spectrum was undesirably coarse and resulted in poor coverage of the spray plot and low deposits. The light-oil-based solution (ca 4 mPa s), provided a finer droplet spectrum and lower deposits than the heavy-oil-based formulations. The water-based suspensions of the w.p. (ca 2 mPa s), showed Newtonian behaviour, whereas the emulsion-suspension (ca 240 mPa s at 480 s^?1) showed pseudoplastic behaviour. Consequently, the emulsion-suspension provided a markedly different droplet spectrum from that of the suspensions of the w.p. Nevertheless, all three aqueous media provided deposits comparable to those of the light-oil-based solution, markedly lower than the heavy-oil-based suspensions. The study indicated that highly viscous Newtonian formulations should be avoided in pesticide applications using Micronair AU3000 atomisers at the volume rate (4–7 litre ha^?1) used here if high atomisation efficiency is required.     

胶莱盆地北部风尘堆积物光释光年代序列研究

山东省胶莱盆地的高岗部位存在大量的风尘堆积物,对其年代的研究一直存在较大的分歧.对胶莱盆地的潍坊前埠下风尘堆积剖面进行了系统的光释光年代测试,并与其以北16.9km的昌邑县徐林庄剖面的年代进行了对比,初步建立了胶莱盆地风尘堆积的光释光年代序列,研究表明该区风尘堆积主要是晚第四纪以来形成的堆积物.     

Assessment of production and dispersal of inoculum ofAlternaria Macrospora in various parts of the cotton canopy

Morning and evening counts of spores ofAlternaria macrospora in a cotton (Gossypium barbadense) field were assessed for the number of spores (a) produced on the last night, (b) dispersed during the day, and (c) retained in the spore reserve on leaves. Throughout the season, 1 m² of the field produced (P) and dispersed (D) approximately 163 x 10⁶ and 137 x 10⁶ spores, respectively. The 16% discrepancy between P and D values reflects experimental errors. Most spores were produced on shed leaves on the ground, fewer on leaves in the lower part of the canopy, and least on leaves in the upper canopy. The contribution to total D decreased from leaves in the lower part of the canopy, to shed leaves, and to leaves in the upper canopy. In tests with potted plants with spore-bearing lesions attached to various heights of the canopy under various conditions of weather, dispersal of spores at these heights was conditioned mainly by wind velocity, which decreased from the upper to the lower part of the canopy. In leaves close to the ground, approximately 29% of the released spores were removed by sedimentation to the ground. On any one day, the daily rate of D differed from the daily rate of P. On days in which D was higher than P, the difference was due to a reserve of spores remaining on lesions after dispersal during the previous days. In weather adverse for production of new spores, the reserve was depleted within 4 and 6 days in the top and bottom leaves, respectively, but remained relatively high in the shed leaves on the ground; a similar number of days was needed to restore the depleted reserve in sporulation-favorable weather.     

SUNSCAN冠层分析系统在农田生态系统观测中的应用

在夏玉米实验田对英国Delta公司生产的SUNSCAN冠层分析系统进行了实地验证,观察其对冠层上下PAR、LAI等生态指标的观测状况。结果表明:该系统可同步实现冠层顶部入射PAR、冠层底的TPAR、LAI及入射PAR中散射辐射占的比例等多项生态指标的测量,克服了以往仪器观测的繁琐及时间上的不同步性,其中对LAI的多样本无损伤性观测较传统方法更具有代表性;自动记录观测具有动态监测太阳总辐射的日变化功能,该系统最佳观测时段是上午9∶00～11∶00和下午13∶00～15∶00。SUNSCAN冠层分析系统是一种高效、轻便的测量工具,具有较大的应用潜力。     

Spatiotemporal variation of forest land and its driving factors in the agropastoral ecotone of northern China

As an important natural resource,forest land plays a key role in the maintenance of ecological security.However,variations of forest land in the agropastoral ecotone of northern China(AENC)have attracted little attention.Taking the AENC as an example and based on remote-sensing images from 2000,2010 to 2020,we explored the spatiotemporal variation of forest land and its driving factors using the land-use transfer matrix,spatial autocorrelation analysis and spatial error model.The results showed that from 2000 to 2020,the total area of forest land in the AENC increased from 75,547.52 to 77,359.96 km² and the changes were dominated by the transformations among forest land,grassland and cropland,which occurred mainly in areas with the elevation of 500-2000 m and slope of 15°-25°.There was obvious spatial agglomeration of forest land in the AENC from 2000 to 2020,with hot spots of forest land gathered in the southern marginal areas of the Yanshan Mountains and the low mountainous and hilly areas of the Loess Plateau.The sub-hot spots around hot spots moved southward,the sub-cold spots spread to the surrounding areas and the cold spots disappeared.The spatiotemporal variation of forest land resulted from the interactions of natural environment,socioeconomic and policy factors from 2000 to 2020.The variables of average annual precipitation,slope,terrain relief,ecological conversion program and afforestation policy for barren mountains affected the spatial pattern of forest land positively,while those of annual average temperature,slope and road network density influenced it negatively.     

植保无人机低空低容量喷雾在茶园的雾滴沉积分布及对茶小绿叶蝉的防治效果

为研究植保无人机低空低容量喷雾技术在实现茶园农药减量中的作用,通过在茶园喷施20%吡虫啉可湿性粉剂,比较其与传统大容量喷雾技术对茶小绿叶蝉Empoasca flavescens的防治效果。结果表明,使用3种植保无人机喷雾,安装有TEEJET110015#喷头的植保无人机的雾滴沉积密度为24.1～127.4个/cm~2,平均值为75.8个/cm~2,沉积量为0.002～1.15μg/cm~2,均值0.58μg/cm~2;安装有TEEJET11001#喷头的植保无人机的雾滴沉积密度为15.0～80.4个/cm~2,平均值为47.7个/cm~2,沉积量均值为0.01～1.38μg/cm~2,均值0.70μg/cm~2;安装有TEEJET11003#喷头的植保无人机的雾滴沉积密度为9.2～18.2个/cm~2,平均值为13.7个/cm~2;沉积量为0～1.14μg/cm~2,均值0.57μg/cm~2。农药利用率为49.3%～58.2%。使用3种传统器械喷雾,担架式动力喷雾机喷雾得到的沉积量为0.02～0.30μg/cm~2,均值0.16μg/cm~2,背负式手动喷雾器喷雾得到的沉积量为0.01～0.46μg/cm~2,均值0.23μg/cm~2,背负式电动喷雾器喷雾得到的沉积量为0.01～0.65μg/cm~2,均值0.33μg/cm~2。农药利用率为33.7%～39.6%。结果表明,3种植保无人机喷雾的农药沉积量和利用率均高于3种传统的施药器械,但其喷雾的均匀性还有待提高。施药后4 d,植保无人机低空低容量喷雾对茶小绿叶蝉防治效果为85.8%～90.4%,传统大容量喷雾对茶小绿叶蝉防治效果为91.8%～93.2%,两者差异不显著。药后10 d,前者对茶小绿叶蝉防治效果为72.9%～75.6%,后者防治效果为65.8%～71.6%,说明植保无人机低空低容量喷雾对茶小绿叶蝉的防治效果优于传统大容量喷雾。研究结果表明,植保无人机低空低容量喷雾有着更长的持效期,为茶园的农药减施增效提供了可能性。     

黑龙江省植保无人机应用现状及发展趋势分析

分析2015年以来黑龙江省植保无人机保有量、作业面积、应用作物、作业标准、作业成本、飞手及作业队发展变化,认为黑龙江省植保无人机市场已进入暴发增长阶段,本地中、大型植保无人机作业队已成为作业主导。同时,对2019年市场进行了预测,预计植保无人机市场可能在1～2年内出现快速回落。     

Captan and fenitrothion dissipation in field-treated cauliflowers and effect of household processing

Field trial studies have been performed with captan and fenitrothion on cauliflower to propose maximum residue limits and to study the dissipation of the pesticides. Residue levels have been determined at different times following good laboratory practice using gas chromatography with mass spectrometric detection. The behaviour of residue levels of these compounds after household processing has been analysed using gas chromatography with electron capture detection. Seven days after treatment, residue levels of captan could be detected, but not of fenitrothion. The half-lives of dissipation for captan and fenitrothion were calculated as 0.9 and 1.8 days respectively. Washing did not significantly affect the residual amounts of captan and fenitrothion observed in raw vegetables; however, after cooking, captan had degraded completely, whereas residue levels of fenitrothion were not modified significantly.     

植保无人飞机施用农药应用研究进展及管理现状

植保无人飞机是现代植保施药机械,具有作业效率高、精准、节水省药、灵活机动和对施药人员安全等特点,然而,与传统施药方式不同,其用水量少,喷施农药浓度高,喷雾易飘移,存在潜在的应用风险。目前关于植保无人飞机施药应用研究主要集中在雾滴沉积分布、飘移影响因素和防治效果评价等领域,有关其在膳食风险、环境风险和职业暴露健康风险评估等方面研究较少,且药剂登记和管理标准法规等相对滞后。为全面了解植保无人飞机施药应用以及管理现状,本文综述了植保无人飞机施药应用、风险研究及国际航空植保农药登记管理情况,总结了我国在该领域发展潜力和管理建议,以期为我国植保无人飞机安全施用农药和登记科学管理提供参考。     

Distribution of a chemical following its application at a point source in an irrigation system

The development of large complex irrigation systems presents problems of pest control which are likely to become increasingly difficult to solve by established application methods. By applying a chemical at one point in such a system use can be made of the flow of water through the system to effect the necessary distribution. This technique has been used most effectively with the molluscicide Frescon (N-tritylmorpholine). However, the complexity of many irrigation systems precludes the optimisation of the necessary rate of addition of molluscicide by any simple method. In this paper a mathematical model of an irrigation system is described which enables a detailed study of this type of application to be made with speed and economy. An analogue computer has been used to solve the equations subject to the operating conditions of the irrigation system.     

植保无人机施药沉积飘移监测系统设计与应用

为提升植保无人机施药沉积飘移监测智能化水平,研发植保无人机施药沉积飘移监测系统,该系统机载监测终端实时获取药械状态参数、植保无人机状态参数及位置参数,通过数据处理服务系统将其发送至平台软件,基于作业参数利用沉积飘移预测模型实时监测药液沉积区域及飘移范围。该系统同时具有作业面积计量、飞行轨迹回溯、作业质量空间分析等功能。2015年4月于山东省威海市文登区泽头镇眠虎岭区域对该系统进行性能测试,植保无人机规划靶区作业面积为433 hm²,最终监测作业面积为405 hm²,施药覆盖率为93.5%;施药过程中实时监测沉积区域和飘移范围,受环境侧风影响,药液最大飘移距离可达40 m,系统整体达到预期设计要求。截至目前该系统已在山东、安徽、江苏、云南、河南、浙江、天津等多个省市应用。