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The objective is to investigate whether NH3 and odour emissions can be lowered by implementing three different ventilation control settings (VCS) as low-cost mitigation techniques. In treatment 1 (T1) the set-point temperature (Tset) was set +2 °C higher than the reference strategy (CON). In treatment 2 (T2), the minimum (Vmin) and maximum (Vmax) ventilation settings were set to 75% and 90% of the CON, respectively. For treatment 3 (T3), the Tset was +1 °C higher than the CON, while the Vmin and Vmax settings were initially set at 25% and 80% of the CON but gradually increased during the fattening period. The results implied that T1 was the best VCS, as it significantly lowered odour emissions compared to the CON by 34%. Despite the significant decrease in ventilation rate, the overall hourly average NH3 emissions did not differ between treatments T1, T2, T3 and CON. However, based on the VERA protocol ( https://www.vera-verification.eu/test-protocols/ ), annual NH3 emission factors were calculated and demonstrated the potential of T1 to decrease NH3 emissions by 11% compared to the CON. The lack of significant differences in the overall hourly average NH3 emissions between T1, T2, T3 and the CON was in part due to the seasonal variations in pig housing airflow patterns affecting the air exchange rate in the slurry pit. This indicates that, despite the importance of the ventilation rate on emissions, the effect of the indoor airflow pattern on the gaseous release from the slurry pit into the building is crucial.

This study presents the start-up and 1-year performance study of two full-scale biotrickling filters or biological air scrubbers at a pig fattening facility in terms of ammonia removal and nitrous oxide production. Two newly-built multi-stage biotrickling filters were continuously monitored for these gases and for washing water characteristics. Although pH and electrical conductivity in the washing water are used in practice as a cheap and easy way to monitor the ammonia removal efficiency of biotrickling filters at pig housing facilities, it was shown that the relation between these variables is not always straightforward. Setting up a nitrogen balance over both biotrickling filters suggested denitrification activity. Additionally, the effect of inoculation with activated sludge of a wastewater treatment plant was investigated by inoculation of one of the two biotrickling filters. The inoculated biotrickling filter showed a fast start-up of nitrification and hardly any nitrite accumulation in the washing water. The ammonia removal efficiency was higher and the nitrous oxide production was slightly lower in the inoculated biotrickling filter compared to the non-inoculated.

The aim of this study was to compare the impact of 3 ventilation set-point temperatures (Tset = 21, 23 & 25 °C) on indoor climate and NH3 emission, using 2 pig compartments with underfloor air distribution (UFAD) and equipped with artificial pigs. The artificial pigs consisted of mock-up pigs to simulate heat production and a spraying installation to mimic pig urination by applying urea solution onto the fully slatted pen floors in the test compartments. The study identified ground channel temperature (TGC) as a key factor affecting NH3 emission (P

A naturally ventilated test facility was built.An airflow rate measuring method using 3D ultrasonic anemometers was developed.The method was successfully validated through the law of mass conservation.The effect of the wind incidence angle and speed on the airflow rate was studied.The necessity of measuring the 3D in-/outflow pattern was proven. In order to measure the airflow rate and emission rate of a naturally ventilated livestock building correctly, more reliable measuring techniques need to be developed. A test facility with a cross ventilated room was built at the Institute for Agricultural and Fisheries Research (Belgium) to study a new airflow rate measuring method. This method is based on an automated traverse movement of a 3D ultrasonic anemometer across 2 vents of 0.5mi?1.0m. To cope with the fluctuating wind velocity profile, a velocity measurement of 10s in 16 equally distributed measuring points is needed. Moreover, 10 traverse replicates are needed to obtain a representative average flow rate. Based on the law of mass conservation, the accuracy of the method was determined by calculating the relative deviation between the simultaneously measured airflow rates through both vents. A relative error of -1?11% was found, averaged over all wind incidence angles. However, wind angles parallel to the vent resulted in larger relative errors. A 3D velocity measurement in the in- or outlet opening of the test facility is necessary to obtain a correct flow rate. This was especially true in the outlet where up to 30% of the airflow rate was delivered by velocity components other than normal to the vent. The test facility and the developed ventilation rate measuring method can serve as a reference to study and validate new and existing ventilation rate measuring methods.

BACKGROUND: The potential of the entomopathogenic nematode (EPN) Steinernema feltiae Filipjev as a biocontrol agent againstthecabbagemaggotDeliaradicum(L.),wasassessedinthreefieldtests,focusingonEPNdosage,applicationtechnique and timing. RESULTS: Spraying cabbage plant trays with different doses of infective juveniles (IJs) (50 000, 100 000 and 200 000 per plant) generated a similar reduction of plant mortality. Spraying plant trays with 200 000 IJs of Steinernema feltiae per plant temporarilyreducedthenumberofmaggotsaroundtheplants’roots,whileneithersprayingalowerdose(50000IJs/plant)nor soil drenching with 200000 or 50000 IJs/plant) reduced maggot numbers. When applied as a plant tray spray, IJs of S. feltiae took 1‐2weeks to spread through the soil surrounding the roots. The pathogenicity of the EPNs, as evaluated by a Galleria mellonella bait test, was highest (up to 100% mortality) until up to five weeks after application, and declined to control levels after 4‐7weeks. Follow-up drench applications with EPNs, applied one and/or two weeks after the first EPN application, did not influence control of Deliaradicum. CONCLUSION: Plant tray spraying provides better placement of Steinernema feltiae than soil drench treatments for control of Delia radicum. Plant mortality was not dose-dependent in the presented trials, unlike the reduction of maggot numbers. Further research into timing and application technique of follow-up treatments withS.feltiaeis required to increase efficacy to commercial standards. c � 2013 Society of Chemical Industry

BACKGROUND:SteinernemacarpocapsaeWeiser,anentomopathogenicnematode(EPN),isapotentialbiologicalcontrolagent for the cabbage moth (Mamestra brassicae L.). This research aimed to identify a suitable spray application technique, and to determinewhetheryeast extractaddedtoanEPN sprayhas anattractingand/orafeedingstimulanteffectonM.brassicae.The biological control capabilities of EPN against this pest were examined in the field. RESULTS: Good coverage of the underside of cauliflower leaves, the habitat of young instar larvae (L1‐L4) of M. brassicae was obtainedusingdifferentsprayboomconfigurationswithverticalextensionsthatcarriedunderleafsprayingnozzles.Oneofthe configurations was selected for field testing with an EPN spray. Brewer’s yeast extract stimulated larval feeding on leaves, and increasedthemortalityoftheselarvaewhenexposedtoEPN.ThefieldtrialshowedthatasprayapplicationwithS.carpocapsae, Addit and xanthan gum can effectively lower the numbers of cabbage heads damaged by M. brassicae. Brewer’s yeast extract did not significantly increase this field performance of EPN. CONCLUSION: Steinernema carpocapsae, applied with an appropriate spray technique, can be used within biological control schemes as part of a resistance management programme for Bt. c � 2013 Society of Chemical Industry

This study explores the influence of a selection of adjuvants and of three different nozzle sizes on the foliar application of entomopathogenic nematodes (EPNs). Two EPN species were studied: Steinernema feltiae and Steinernema carpocapsae. A viability test of EPNs suspended in different solutions of adjuvants showed that all selected alcohol ethoxylates and an alkyl polysaccharide have an immobilising effect on the selected nematode species. In a sedimentation test, xanthan gum proved to be the only adjuvant in a broad selection, capable of delaying sedimentation of EPNs in suspension. Without xanthan gum, sedimentation of S. carpocapsae and S. feltiae was noticeable after 20 and 10 minutes, respectively. When xanthan gum (0.3 g/L) was added to the suspension, no signs of sedimentation were noticed after 20 minutes with both EPN species. An ISO 02 flat fan nozzle can clog when spraying S. carpocapsae. A deposition test determined that an ISO 04 standard flat fan nozzle provides a higher relative...

Given the current scarcity of empirical data on ammonia (NH3) emissions from dairy cattle under different management -based mitigation techniques, a modeling approach to assess potential NH3 emission reduction factors is needed. This paper introduces a process-based model that estimates NH3 emission reduction factors for a dairy cattle barn featuring single or multiple management-based NH3 emission mitigation techniques, as compared to another barn, to which no mitigation measure is applied. The model accounts for the following emission mitigation measures: (a) floor scraping, (b) floor type, (c) floor flushing with water and (d) indoor acidification of manure. Model sensitivity analysis indicated that manure acidification was the most efficient NH3 emission reduction technique. A fair agreement was observed between reduction factors from the model and empirical estimates found in the literature. We propose a list of combinations of techniques that achieve the largest reductions. In order of efficiency, they are: (a) floor scraping combined with manure acidification (reduction efficiency 44-49%); (b) solid floor combined with scraping and flushing (reduction efficiency 21-27%); (c) floor scraping combined with flushing and (d) floor scraping alone (reduction efficiency 17-22%). The model is currently being used to advise the Flemish Government (Belgium), on the performance of certain NH3 emission reduction systems for dairy barns in Flanders.

Ammonia, largely emitted by agriculture, involves a great risk for eutrophication and acidification leading to biodiversity loss. Air scrubbers are widely applied to reduce ammonia emission from pig and poultry housing facilities, but it is not always clear whether their performance meets the requirements. Besides, there is a growing international concern for the livestock related greenhouse gases methane and nitrous oxide but hardly any data concerning their fate in air scrubbers are available. This contribution presents the results from measurement campaigns conducted at a chemical, a biological and a two-stage biological air scrubber installed at pig housing facilities in Flanders. Ammonia, nitrous oxide and methane at the inlet and outlet of the air scrubbers were monitored on-line during one week using a photoacoustic gas monitor, which allowed to investigate diurnal fluctuations in the removal performance of air scrubbers. Additionally, the homogeneity of the air scrubbers, normally checked by gas detection tubes, was investigated in more detail using the continuous data. The biological air scrubber with extra nitrification tank performed well in terms of ammonia removal (86 ± 6%), while the two-stage air scrubber suffered from nitrifying bacteria inhibition. In the chemical air scrubber the pH was not kept constant, lowering the ammonia removal efficiency. A lower ammonia removal efficiency was found during the day, when the ventilation rate was the highest. Nitrous oxide was produced inside the biological and two-stage scrubber, resulting in an increased outlet concentration of more than 200%. Methane could not be removed in the different air scrubbers because of its low water solubility.

BACKGROUND: Spray volume can influence the amount of free water on the leaf surface and subsequently the ability of entomopathogenic nematodes (EPNs) to move. In this study, an investigation was made of the effect of spray volume (548, 730 and 1095 L ha −1 ) on the deposition, viability and infectivity of EPNs against Galleria mellonella on savoy cabbage, cauliflower and leek. RESULTS: Increasing spray volume decreased nematode deposition on 7.1 cm 2 leek leaf discs at a 15 ◦ angle with the spray nozzle. Although the number of living nematodes observed on leek after 240 min of exposure was not significantly different between the low-volume application (548 L ha −1 ) and the high-volume application (1095 L ha −1 ), a greater infectivity was obtained in the latter application. The higher number of droplets deposited on the leek discs in the high-volume application may have stimulated nematode movement. No significant effect of spray volume was observed on the relative deposition of Steinernema carpocapsae on the bottom side of cauliflower and savoy cabbage leaf discs. In spite of the low S. carpocapsae deposition on the bottom side of the savoy cabbage discs, high infectivity was obtained againstG.mellonella. Using the lowest spray volume on savoy cabbage, infectivity decreased with increasing exposure time, while infectivity was not affected by exposure time when a spray volume of 730 L ha −1 or more was used. CONCLUSION: Spray volume is an important application parameter, as it affects nematode infectivity. Future research should investigate the effect of spray volume in the field and its influence on the effect of adjuvants. c � 2012 Society of Chemical Industry

BACKGROUND: The present study compared entomopathogenic nematode delivery at the base of savoy cabbage and cauliflower, at the lower side of savoy cabbage and cauliflower leaves and in leek stems and the ground deposition using a five-nozzle spray boom equipped with an ISO 08 flat fan, an air induction flat fan and Twinjet spray nozzles. Additionally, an air support system and a row application system were evaluated. RESULTS: Approximately 40% of the applied nematodes did not reach the foot of the cabbage plants. The use of an air support system or a row application system improved nematode deposition at the savoy cabbage base. Relative nematode deposition on the lower side of savoy cabbage leaves was 27.20%, while only 2.64% of the applied nematodes reached the lower side of cauliflower leaves. After spraying leek with a standard boom, a low relative nematode deposition (26.64%) was measured in the leek stem. Nozzle type affected the distribution of nematodes in droplet spots. CONCLUSION: Nozzle type has a minor effect on the number of entomopathogenic nematodes delivered on difficult-to-reach targets. The use of modified spray application techniques directing the spray to the target site are necessary to increase the chances of contact of entomopathogenic nematodes with their target. Copyright © 2011 Society of Chemical Industry

The application of entomopathogenic nematodes (EPN) is generally done using standard spray application techniques. However, in contrast to chemical pesticides, these biological antagonists must remain viable during and after the application process. For the application of EPN, a good agitation system is indispensable as the nematodes tend to sediment fast in a spray tank without agitation. Three agitation systems, viz. mechanical, pneumatic and hydraulic agitation were tested for their ability to keep Steinernema carpocapsae (Rhabditida: Steinernematidae) suspended in an undamaged way. Hydraulic agitation was tested using a centrifugal and a diaphragm pump. Nematode damage was quantified based on viability and infectivity of the EPN. The ability of the agitation system to keep the nematodes in suspension was examined by comparing the nematode concentration observed in the samples taken at different agitation times. Only the hydraulic agitation using the centrifugal pump damaged the nematodes. Aft...

Damage caused to entomopathogenic nematodes by spray application is generally assessed by observing the viability of the infective juveniles under the microscope. To improve the quality and speed of this observation we developed an image processing technique and tested the efficacy of acetic acid and sodium chloride as chemical stimulants. Because of the lower standard error on the results obtained (0.7 vs 1.7), sodium chloride was eventually selected for all subsequent observations. The viability as observed with the image processing technique rose significantly with the time after the nematodes were suspended in water; however, viability as observed under the microscope was not influenced by the time. These differences can be attributed to the difference in type of stimulant (mechanical vs chemical) used. After nematodes had been in suspension for 3.5 h, the viability as measured using the image processing system was still significantly lower than the viability as measured under the microscope. This difference did not disappear after 24 h at 4, 15 or 24°C. Maintaining nematodes for 24 h at 35°C significantly decreased the viability to 5.9% (microscope) or 11.0% (image processing technique). The decrease in viability as observed with the image processing system corresponded better with the decrease in infectivity (i.e., 13.8%). Our results support further use of the image processing technique, not only to observe the viability of entomopathogenic nematodes but also to count the mobile or total number of nematodes of any species.

The high spatial and temporal variations of airflow patterns in ventilation openings of naturally ventilated animal houses make it difficult to accurately measure the airflow rate:This paper focusses on the development of a fast assessment technique for the airflow rate of a naturally ventilated test facility through the combination of a linear algorithm and local air velocity measurements. This assessment technique was validated against detailed measurement results obtained by the measuring method of Van Overbeke et al. (2015) as a reference.The total air velocity vertical bar(U) over bar vertical bar, the normal vertical bar(Y) over bar vertical bar and tangential velocity component vertical bar(X) over bar vertical bar and the velocity vector vertical bar(U) over bar vertical bar measured at the meteomast were chosen as input variables for the linear algorithms. The airflow rates were split in a group where only uni-directional flows occurred at vent level (no opposite directions of vertical bar(Y) over bar vertical bar present in the airflow pattern of the opening), and a group where bi-directional flows occurred (the air goes simultaneously in and out of the opening). For airflow rates with uni-directional flows the input variables vertical bar(U) over bar vertical bar and vertical bar(Y) over bar vertical bar yielded the most accurate results. For this reason, it was suggested to use the vertical bar(Y) over bar vertical bar instead, of vertical bar(U) over bar vertical bar in ASHRAE's formula of Q = E x A x vertical bar(U) over bar vertical bar.For bi-directional flows a multiple linear model was suggested where input variable vertical bar(U) over bar vertical bar gave the best results to assess the airflow rate.

Currently there exists no generally accepted reference technique to measure the ventilation rate through naturally ventilated (NV) vents. This has an impact on the reliability of airflow rate control techniques and emission rate measurements in NV animal houses. As an attempt to address this issue a NV test facility was built to develop new airflow rate measurement techniques for both side wall and ridge vents. Three set-ups were used that differed in vent configuration, i.e. one cross ventilated set-up and two ridge ventilated set-ups with different vent sizes. The airflow through the side vents was measured with a technique based on an automatic traverse movement of a 3D ultrasonic anemometer. In the ridge, 7 static 2D ultrasonic anemometers were installed. The methods were validated by applying the air mass conservation principle, i.e. the inflow rates must equal the outflow rates. The calculated in - and outflow rates agreed within (5 ± 8)%, (8 ± 5)% and (−9 ± 7)% for the three different set-ups respectively, over a large range of wind incidence angles. It was found that the side vent configuration was of large importance for the distribution of the airflow rates through the vents. The ridge proved to be a constant outlet, whilst side vents could change from outlet to inlet depending on the wind incidence angle. The range of wind incidence angles in which this transition occurred could be clearly visualized.

A risk assessment of pesticide spray drift damage for the major crops in Flanders, Belgium, was set up. The assessment was done according to the principles of Directive 91/414/EC. In the directive, 10 modules reflect the risk for persons arising from occupational, non-dietary exposure and the risk to the environment. For each module the risk is expressed as a risk index, which is the quotient of the estimated human exposure or predicted environmental concentration to a toxicological reference. The Ganzelmeier curves and the IMAG drift calculator were used to predict drift values. Knowing the applied dose of pesticide and the percentage of drift, the predicted environmental concentrations and the human exposures were calculated. The corresponding risks were estimated for the major growths for three of the ten modules: aquatic organisms, human bystanders and earthworms. Coherent with these calculations, the reducing effects of buffer zones were considered. The assessed buffer zone lengths were compared to the buffer zones, legislated by the Belgian government.

Spray retention, i.e. the overall capture of spray droplets by plants on initial or subsequent impact, and after loss due to run-off, is an important stage in the spray application process as droplet losses may result in reduced efficacy, economic loss, and environmental contamination. The aim of this exploratory study is to determine whether a new method based on calculating the volumetric proportions per impact type, i.e. adhesion, rebound and shatter, can be used to predict spray retention. These volumetric proportions are calculated based on logistic regression models, derived from vision-based droplet characteristics and impact assessments, and laser-based spray characteristics. The advantages and limitations of such a method are explored. The volumetric proportions per impact type on a horizontal, synthetic hydrophobic surface were determined for four different nozzles (XR 110 01 VS flat-fan nozzle, XR 110 04 VS flat-fan nozzle, XR 110 08 VS flat-fan nozzle and AI 110 08 VS air-induction nozzle) under controlled realistic conditions, and compared to the results of a retention test. The volumetric proportions of adhesion were much lower than the relative retentions, indicating that a considerable amount of rebound and shatter also contributed to final retention. The method should thus be improved by including the droplets retained after first impact and the retained proportions of partial droplet fragmentation but it is nevertheless considered a promising technique. publisher: Elsevier articletitle: The impact and retention of spray droplets on a horizontal hydrophobic surface journaltitle: Biosystems Engineering articlelink: http://dx.doi.org/10.1016/j.biosystemseng.2014.07.013 content_type: article copyright: Copyright © 2014 IAgrE. Published by Elsevier Ltd. All rights reserved. ispartof: Biosystems Engineering vol:126 pages:82-91 status: published

Steinernema carpocapsae Weiser, an entomopathogenic nematode (EPN), is a potential biological control agent for the cabbage moth (Mamestra brassicae L.). This research aimed to identify a suitable spray application technique, and to determine whether yeast extract added to an EPN spray has an attracting and/or a feeding stimulant effect on M. brassicae. The biological control capabilities of EPN against this pest were examined in the field.Good coverage of the underside of cauliflower leaves, the habitat of young instar larvae (L1-L4) of M. brassicae was obtained using different spray boom configurations with vertical extensions that carried underleaf spraying nozzles. One of the configurations was selected for field testing with an EPN spray. Brewer's yeast extract stimulated larval feeding on leaves, and increased the mortality of these larvae when exposed to EPN. The field trial showed that a spray application with S. carpocapsae, Addit and xanthan gum can effectively lower the numbers of cabbage heads damaged by M. brassicae. Brewer's yeast extract did not significantly increase this field performance of EPN.Steinernema carpocapsae, applied with an appropriate spray technique, can be used within biological control schemes as part of a resistance management programme for Bt.

Spray volume can influence the amount of free water on the leaf surface and subsequently the ability of entomopathogenic nematodes (EPNs) to move. In this study, an investigation was made of the effect of spray volume (548, 730 and 1095 L ha(-1) ) on the deposition, viability and infectivity of EPNs against Galleria mellonella on savoy cabbage, cauliflower and leek.Increasing spray volume decreased nematode deposition on 7.1 cm2 leek leaf discs at a 15° angle with the spray nozzle. Although the number of living nematodes observed on leek after 240 min of exposure was not significantly different between the low-volume application (548 L ha(-1) ) and the high-volume application (1095 L ha(-1) ), a greater infectivity was obtained in the latter application. The higher number of droplets deposited on the leek discs in the high-volume application may have stimulated nematode movement. No significant effect of spray volume was observed on the relative deposition of Steinernema carpocapsae on the bottom side of cauliflower and savoy cabbage leaf discs. In spite of the low S. carpocapsae deposition on the bottom side of the savoy cabbage discs, high infectivity was obtained against G. mellonella. Using the lowest spray volume on savoy cabbage, infectivity decreased with increasing exposure time, while infectivity was not affected by exposure time when a spray volume of 730 L ha(-1) or more was used.Spray volume is an important application parameter, as it affects nematode infectivity. Future research should investigate the effect of spray volume in the field and its influence on the effect of adjuvants.

The present study compared entomopathogenic nematode delivery at the base of savoy cabbage and cauliflower, at the lower side of savoy cabbage and cauliflower leaves and in leek stems and the ground deposition using a five-nozzle spray boom equipped with an ISO 08 flat fan, an air induction flat fan and Twinjet spray nozzles. Additionally, an air support system and a row application system were evaluated.Approximately 40% of the applied nematodes did not reach the foot of the cabbage plants. The use of an air support system or a row application system improved nematode deposition at the savoy cabbage base. Relative nematode deposition on the lower side of savoy cabbage leaves was 27.20%, while only 2.64% of the applied nematodes reached the lower side of cauliflower leaves. After spraying leek with a standard boom, a low relative nematode deposition (26.64%) was measured in the leek stem. Nozzle type affected the distribution of nematodes in droplet spots.Nozzle type has a minor effect on the number of entomopathogenic nematodes delivered on difficult-to-reach targets. The use of modified spray application techniques directing the spray to the target site are necessary to increase the chances of contact of entomopathogenic nematodes with their target.

The withdrawal of approvals for agrochemicals on many food crops within Europe is likely to generate an increasing market for bio-pesticide products, including entomopathogenic nematodes (EPN). However, for the EPN to be a success, a cost-effective and reliable usage should be assured. Therefore, progress in areas like application and formulation technology is needed, next to the development of optimal application strategies. A new research project will focus on optimizing the field application of EPN in vegetables. First, both application and formulation technologies will be optimized. Then, these technologies will be tested under semi-field conditions with special attention for the effect of weather conditions and timing of the application. All the acquired knowledge will be implemented and evaluated in field experiments. In this paper, the first results of the experiments on application technology are discussed.

Application technology for biological insecticides like entomopathogenic nematodes (EPN) has been a relatively neglected area. One of the major considerations involved with the selection and use of an application system should be the application distribution pattern. While completely uniform distribution of the nematodes is not entirely essential to their success in soil applications, because there the nematodes can move short distances on their own, a uniform distribution is more important in foliar EPN applications. The present study examined the volumetric distribution pattern of Steinernema feltiae beneath a single standard flat fan, air induction, deflector and twinjet spray nozzle. A comparison with the distribution of a chemical tracer was made to reveal possible distribution problems. Droplet size spectra of the nozzles were measured and linked with the distribution results. A theoretical calculation of the coefficient of variation of the nematode distribution beneath a spray boom was performed. Finally, the actual spray pattern of the EPN on a horizontal surface beneath a spray boom was studied. We can conclude that the volumetric distribution pattern of EPN is influenced by nozzle type and is different from the volumetric distribution pattern of a chemical compound. By the spray overlap using a spray boom, differences in nematode distribution are however decreased to an acceptable level. Nozzle type significantly influences the number of nematodes deposited on a horizontal Petri dish and their distribution within the droplets. Future experiments are needed to reveal if the measured differences in coverage due to nozzle type will result in significant differences in pest control.

The effect of several passages through a centrifugal pump on the viability and activity of Steinernema corpocapsoe was investigated. A tendency of reduced viability was detected after 10 passages through the centrifugal pump, but the difference was not statistically significant. Activity decreased significantly from 91.9% to 83.6%. The experimental set-up was chosen to eliminate temperature increase. Therefore, the results prove that mechanical pump damage cannot be excluded as the cause of EPN damage during spray application.

Spray drift continues to be a major problem in applying agricultural pesticides. This paper summarizes the results of a 5 year study about drift from field crop sprayers using a unique integrated approach.

The quality of agricultural sprays plays an important role in the application of plant protection products. For 13 nozzle-pressure combinations, droplet size and velocity characteristics were measured 0.50 m below the nozzle using a PDPA laser-based measurement setup. Nozzles were mounted on a transporter to sample the whole of the spray fan. The effects of nozzle type (standard, low-drift, and air-inclusion), nozzle size (ISO 02, 03, 04, and 06) and operating pressure (2.0, 3.0, and 4.0 bar) were tested. Measured droplet sizes and velocities were related, and both were affected by nozzle type, size, and operating pressure. Droplet velocities at 0.50 m were determined by their size and initial ejection velocity. In general, bigger droplet sizes correspond with higher droplet velocities, and smaller droplets with lower droplet velocities. Important differences in velocities were observed depending on the nozzle type and size, both affecting the ejection velocity. For the same droplet size, droplet velocities were highest for the flat-fan nozzles, followed by the low-drift nozzles and the air-inclusion nozzles (because of the lower ejection velocities caused by pre-orifice and Venturi effects). Similarly, the bigger the ISO nozzle size, the faster were the droplets of the same size. Droplet velocities of the larger droplet sizes (>400 µm) varied from about 4.5 to 8.5 m s-1 depending on the nozzle type and size. Below 400 µm, droplet velocities consistently decreased with the decrease in droplet size, and vary from 0.5 to 2 m s-1 depending on the nozzle type and size. All this information is very useful with regard to crop penetration, the risk of spray drift, and the quantity and distribution of the deposit on the target.

Spray drift continues to be a major problem in applying agricultural pesticides. This article summarizes the results of a five-year study of drift from field crop sprayers using a unique integrated approach. Indirect (spray quality and wind tunnel measurements) and direct (field) drift experiments were performed, and drift models were developed to study the effect of spray application technique, droplet characteristics, buffer zones, meteorological conditions, spray liquid properties, border structures, and crop characteristics on drift from field crop sprayers. It was found that indirect drift measurements can be a valuable alternative to field drift experiments. A validated 3-D computational fluid dynamics (CFD) mechanistic drift model was developed, which can be used for a systemic study of different influencing factors. This model was reduced to a fast 2-D diffusion advection model, which is useful as a hands-on drift prediction tool. From the experiments as well as from the models, the fraction of small droplets and the spray boom height were found to be the most influential spray application factors. Moreover, meteorological conditions as well as crop characteristics have an important effect on the amount of spray drift, which can be reduced significantly using intercepting screens or buffer zones. From this study, drift protocols, data, and models are made available, which help to understand and reduce the complex phenomena of spray drift.

Application technology for biological insecticides like entomopathogenic nematodes (EPN) has been relatively neglected. One of the major considerations related to the selection and use of an application system is the application distribution pattern. A completely uniform distribution of the nematodes in soil applications is not essential because the nematodes can move over short distances; however, a uniform distribution is important in foliar EPN applications. The present study examined the volumetric distribution pattern of Steinernema feltiae beneath single standard flat-fan, air-induction, deflector, and TwinJet spray nozzles. A comparison with the distribution of a chemical tracer was made to reveal possible distribution problems. Droplet size spectra of the nozzles were measured and linked with the distribution results. A theoretical calculation of the coefficient of variation of the nematode distribution beneath a spray boom was performed. Finally, the actual spray pattern of the EPN on a horizontal surface beneath a spray boom was studied. We can conclude that the volumetric distribution pattern of EPN is influenced by nozzle type and is different from the volumetric distribution pattern of a chemical compound beneath a TT 110 08 deflector nozzle. The spray overlap from a spray boom decreases differences in nematode distribution to an acceptable level. Nozzle type significantly influences the number of nematodes deposited on a horizontal Petri dish and their distribution within the droplets. Future experiments are needed to reveal if the measured differences in deposition and coverage due to nozzle type will result in significant differences in pest control.