Water-sensitive Cards Research Articles

Deep learning guided variable rate robotic sprayer prototype

This paper presents the development of a robotic sprayer that combines artificial intelligence with robotics for optimal spray application on citrus nursery plants grown in an indoor environment. The robotic platform is integrated with an embedded firmware of MobileNetV2 model to identify and classify the plant samples with a classification accuracy of 100 % which is used to dispense variable rate spraying of pesticide based on the health status of the plant foliage. The disease detection model was developed through the edge impulse platform and deployed on Raspberry Pi 4. The robot navigates through an array of plants, stops beside each plant, and captures an image of the citrus plants. It feeds the image into the deployed embedded model to generate a disease inference that informs the variable rate application of spray during real-time actuation. To test the spraying performance of the prototype within the growing environment, water sensitive cards were placed in each plant's canopy. After spraying, the samples of water sensitive cards were collected and quantified using a smart spray app to determine the classification accuracy as well as the extent of spray coverage on the citrus samples. The robot spray coverage results show an average spray coverage of 87 % on lemon foliage when compared with 67 % for navel orange, during the spray performance test of the robot.

Efecto del uso de boquillas de aire inducido y adyuvante sobre la calidad de aplicación de fitosanitarios

Spraying of phytosanitary products must ensure efficient pest control while avoiding losses that could damage human health and environment. The objective of the study was to evaluate the effect of conventional hollow cone and air-induced hydraulic nozzles, and the addition of an adjuvant (Methylated Seed Oil [MSO]) upon the application quality of a fungicide (penetration, distribution, and uniformity) and losses due to endodrift on wheat and soybean canopies. In each crop, the experimental design was completely randomized,with four replications and a factorial arrangement of nozzles x adjuvant. Droplet spectrum was evaluated by using water-sensitive cards, and brilliant blue as a tracer in the application mixture. According to the results, the MSO did not homogenize the distribution of droplets generated by air-induced nozzles in the wheat canopy, as it depended on the crop height evaluated. In addition, the MSO reduced endodrift independently of the type of nozzle used. Thedistribution of droplets on the soybean canopy depended on the height and not on the type of nozzle nor the addition of MSO. The MSO and its combination with the nozzle type did not reduce endodrift in this crop.

Evaluation of row width and nozzle selection on spray coverage and weed control in flooded rice

Abstract Barnyardgrass and other troublesome weeds have become a major problem for producers in a flooded rice system. Cultural control options and more efficient herbicide applications have become a priority to increase efficiency and weed control in rice. This study aimed to determine the effects of row width and nozzle selection on spray coverage and weed control in a flooded rice system. A field experiment was conducted at 7 site-years (Lonoke, AR, in 2021 and 2022; Pine Tree, AR, in 2021 and 2022; Rohwer, AR, in 2022; and Stoneville, MS, in 2021 and 2022) as a randomized complete block split-plot design. Five nozzles (XR, AIXR, TTI, TTI60, and AITTJ60) (subplot factor) were used for herbicide applications, and plots were drill-seeded in four row widths (whole plot factor) (13, 19, 25, and 38 cm). A droplet size experiment was conducted to evaluate the droplet size and velocity of each nozzle type used in the field experiment. Overall, as row width increased, barnyardgrass density increased. The rice grown in a wider width took longer to generate canopy closure, allowing weed escapes in the crop. For example, the 13-cm width had a 12 percentage point canopy coverage increase compared to the 38-cm row width at the preflood timing resulting in a reduction of six barnyardgrass plants per square meter. The smallest droplet size-producing nozzle (XR) provided greater weed control throughout the study but is more prone to drift. The dual-fan nozzles (AITTJ60 and TTI60) had variable weed control impacts, and it was difficult to predict when this might occur; however, they did have increased deposits on water-sensitive cards compared to single-fan counterparts (AIXR and TTI). In conclusion, a narrower row width (e.g., 19-cm or less) and a smaller droplet size producing nozzle (XR) are optimal for barnyardgrass control in a flooded rice system.

Reducing herbicide input and optimizing spray method can minimize nontarget impacts on native grassland plant species.

Invasive plants threaten biodiversity worldwide and effective management must control the target invader while conserving biodiversity. Herbicide is often used to control invasive plants, but potential negative impacts on biodiversity have led to spot spraying being recommended over boom spraying to minimize the exposure of nontarget species to chemicals. We examined the influence of herbicide application methods on off-target plant communities in threatened temperate grasslands of southeastern Australia, where spraying with the broadleaf herbicide fluroxypr is commonly used to control St. John's wort, Hypericum perforatum L. It is well established that fluroxypr effectively controls H. perforatum but few studies have examined its impact on native forbs. A spray drift experiment using water-sensitive cards indicated that ground surface coverage was higher for spot spraying (91%-99%) than for boom spraying (5%-31%). We established a replicated, 3-year, before-after-control-impact experiment across 48 1-m2 quadrats to determine how three herbicide application methods (spot spray, fine boom and coarse boom) affected nontarget native forbs, the group most likely to be affected by broadleaf herbicides. This experiment was conducted in grasslands where H. perforatum was almost absent, so responses would reflect the direct impacts of the chemical, rather than structural changes resulting from removal of the target invader. Spot spraying decreased the probability of occurrence of native leguminous forbs, while increasing the occurrence of exotic leguminous forbs and the richness of all exotic species and exotic annual forbs. Spot spraying reduced the occurrence of the native Desmodium varians and the abundance of the native Chrysocephalum apiculatum. During this 3-year study, native species appeared to be impacted either directly by fluroxypr or indirectly by increased competition with exotic species. Where herbicide application is deemed crucial in these grasslands, we recommend boom spraying when H. perforatum density is moderate to high. Spot spraying should only be used when the density of H. perforatum is very low. Given the regional variation in H. perforatum density, the spatial scale of invasion, soil depth, and conservation values, we present a decision tree to assist managers in evaluating the costs and benefits of chemical control, indicating situations where alternative or modified methods could be used.

Opportunities to Mitigate Particle Drift from Ground-Based Preemergent Herbicide Applications

Highlights Drift data collected from herbicide applications for corn, soybean, and cotton, including three commercial producers. Drift volumes and drift distances were estimated and correlated to wind speed, boom length, spray height, tractor speed, and droplet size (DV50). Boom length and spray height appear to be the dominant parameters affecting drift volume and drift distance, respectively. The results show a three- to fourfold reduction in drift using a hooded sprayer or spraying in calm weather. Abstract. Although several best practices are available, there are still opportunities to mitigate off-target pesticide drift, protect nearby sensitive crops, and address health concerns for humans/animals. The purpose of the study is to identify opportunities to mitigate drift from ground-based preemergent herbicide applications. Seven herbicide applications were tested for corn, soybean and cotton, including three regional commercial producers. Drift data were collected using water sensitive cards. ImageJ was used to analyze the droplet spectrum. Drift volumes and drift distances were estimated for each experiment. Data collected on wind speed, boom length, spray height, tractor speed, droplet size (DV50), and chemical application rate were used as explanatory variables of drift volume and drift distance. Individual and multiple linear regressions (MLRs) were carried out between drift volume, drift distance, and the explanatory variables. Our results show a three- to fourfold reduction in drift using a hooded sprayer or spraying in calm weather. Boom length and spray height appear to be the dominant parameters affecting drift volume and drift distance, respectively. The MLR results suggest that we can estimate drift (a) volume reasonably using a combination of boom length, DV50, and tractor speed and (b) distance reliably using a combination of spray height, boom length, and DV50. Keywords: Drift distance, Droplet spectrum, Fence board, Herbicide drift, Hooded sprayer, Preemergent herbicide, Water sensitive card.

Reducing the Nursery Pesticide Footprint with Laser-guided, Variable-rate Spray Application Technology

Nursery producers are challenged with growing a wide range of species with little to no detectable damage from insects or diseases. Growing plants that meet consumer demand for aesthetics has traditionally meant routine pesticide application using the most time-efficient method possible, an air-blast sprayer, despite its known poor pesticide application efficiency. New variable-rate spray technology allows growers to make more targeted applications and reduce off-target pesticide loss. In this study, a prototype laser-guided variable-rate sprayer was compared with a traditional air-blast sprayer. Pesticide volume, spray application characteristics, and the control of powdery mildew were evaluated over the course of two growing seasons. Spray application characteristics were assessed using water-sensitive cards (WSCs) and DepositScan software. This prototype sprayer reduced pesticide volume by an average of 54% across both years despite being tested against a low rate (<250 L⋅ha−1). In 2016, the conventional sprayer had more than double the deposit density on target WSCs among distal trees than the variable-rate sprayer; however, within proximal trees, there was no difference between the two sprayer types. In 2017, when the trees were larger, within both the distal and proximal trees, the conventional sprayer had greater deposit density on target WSCs than the variable-rate sprayer. In 2016, coverage on target WSCs was nearly 7-fold greater with the conventional treatment than with the variable-rate treatment. In 2017, when trees were larger, there was greater coverage on target WSCs in proximal trees (3.8%) compared with those in distal trees (1.0%) regardless of the sprayer type. This variable-rate spray technology provided acceptable control of powdery mildew severity on individual branches and whole trees and maintained the incidence of powdery mildew to levels comparable to that occurring among trees sprayed with a traditional air-blast sprayer. Therefore, the variable-rate spray technology has the potential to effectively control disease, dramatically reduce the pesticide footprint, and preserve natural resources such as ground and surface water, soil, and beneficial insects found within and around nurseries.

Variable-rate Spray Technology Optimizes Pesticide Application by Adjusting for Seasonal Shifts in Deciduous Perennial Crops

To optimize pesticide applications to the canopies of deciduous perennial crops, spray volume should be adjusted throughout the year to match the changes in canopy volume and density. Machine-vision, computer-controlled, variable-rate sprayers are now commercially available and claim to provide adequate coverage with decreased spray volumes compared with constant-rate sprayers. However, there is little research comparing variable- and constant-rate spray applications as crop characteristics change throughout a growing season. This study evaluated spray volume, spray quality (e.g., coverage and deposit density), and off-target spray losses of variable- and constant-rate sprayers across multiple phenophases in an apple (Malus domestica) orchard and a grape (Vitis vinifera) vineyard. The variable-rate sprayer mode applied 67% to 74% less volume in the orchard and 61% to 80% less volume in the vineyard. Spray coverage (percent), measured by water-sensitive cards (WSC), was consistently greater in the constant-rate mode compared with the variable-rate mode, but in many cases, excessive coverage (i.e., over-spray) was recorded. The variable-rate sprayer reduced off-target losses, measured by WSC coverage, up to 40% in the orchard and up to 33% in the vineyard. Spray application deposit densities (droplets per square centimeter) on target canopies were typically greater in variable-rate mode. However, the deposit densities were confounded in over-spray conditions because droplets coalesced on the WSC resulting in artificially low values (i.e., few, very large droplets). Spray efficiencies were most improved early in the growing season, when canopy density was lowest, demonstrating the importance of tailoring spray volume to plant canopy characteristics.

Comparison of UAV and fixed-wing aerial application for alfalfa insect pest control: evaluating efficacy, residues, and spray quality.

Integrating unmanned aerial vehicles (UAV) as a new method of pesticide application into existing commercial crop protection systems requires extensive research and comparison to conventional, proven application technology. Pest control expressed as efficacy against target pests, and spray quality expressed as coverage and chemical residue are three key criteria. We investigated and compared these quantitative parameters between a multi-rotor UAV and conventional piloted airplanes in two commercial alfalfa production systems. Effective and equivalent control of leaf-feeding insect pests was achieved by both methods of aerial application when delivering chlorantraniliprole at the same labeled use rate in different spray volumes (46.8 and 93.5L ha-1 ) on commercially grown alfalfa in California. Residue levels and spray coverage were also comparable and consistent between the UAV and airplane applications across three sampling techniques, specifically residue levels on alfalfa, insecticide recovery from filter paper, and spray coverage on water sensitive cards. Differences in droplet size and deposit characteristics were more variable for the UAV than airplanes based on analysis of deposition images. The results of this study provide confidence supporting the use of small-scale multi-rotor UAVs for pesticide application on agricultural crops. According to the parameters tested, UAV application quality and crop protection performance were comparable to that of the conventional fixed wing airplane application. However, the droplet spectrum and the short-term fate of droplets from unmanned aerial spray system require further optimization for effective and efficient crop protection with minimal risk to the environment.

COMPARATIVE HYGIENIC ASSESSMENT OF WORKING CONDITIONS AND OCCUPATIONAL RISK IN THE APPLICATION OF PESTICIDES (ON THE EXAMPLE OF FUNGICIDE AMISTAR EXTRA 280, SC) USING DIFFERENT TYPES OF SPRAYERS

The aim: Was a comparative hygienic assessment of working conditions and occupational risk in the application of fungicide Amistar Extra 280, SC using slotted and injector sprayers. Materials and methods: Sprayers Super Poly 110-04 (variant №1) and Guardian Air GA110-04 (variant № 2), and certified equipment were used. The occupational risk was assessed in accordance with the methodological recommendations proposed by the L.I. Medvedia Scientific Center for Preventive Toxicology, Food and Chemical Safety specialists. Results: When using the slotted sprayer Super Poly 110-04 in the air of the working zone of the tractor driver the content of azoxystrobin was 0.0015 ± 0.0001 mg/m3, cyproconazole - 0.085 ± 0.002 mg/m3, at a distance of 10 m from the edge of the field on the leeward side - 0.003 ± 0.001 and 0.11 ± 0.02 mg/m3, respectively. Visual analysis of water-sensitive cards after using slotted sprayers showed the presence of single drops of pesticide working solution in the wear zone. When applying the pesticide using a Guardian Air GA110-04 injector sprayer in the air of the working zone of the tractor driver, areas of possible wear (10 and 100 m), theconcentration of the active substances of Amistar Extra 280, SC formulation was below the limit of quantification of the method. When assessing the complex risk for tractor drivers, a statistically significant difference was found for azoxystrobin (p = 0.002) and cyproconazole (p = 0.001) when using a slotted sprayer Super Poly 110-04 and injector Guardian Air GA110-04. Conclusions: Values of the combined complex risk of application of the Amistar Extra 280, SC formulation for tractor drivers of variant №2 application were significantly lower than those for tractor drivers of variant №1.

Advancing Sustainability in Tree Crop Pest Management: Refining Spray Application Rate with a Laser-guided Variable-rate Sprayer in Apple Orchards

Advanced variable-rate spray technology, which applies pesticides based on real-time scanning laser rangefinder measurements of plant presence, size, and density, was developed and retrofitted to existing sprayers. Experiments were conducted to characterize the application of four programmed spray rates (0.03, 0.05, 0.07, or 0.09 L·m−3 of crop geometric volume) when applied to Malus domestica Borkh. ‘Golden Delicious’ apple trees using this crop sensing technology. Water-sensitive cards (WSCs) were used as samplers to quantify spray coverage, deposits, and deposit density in the target and nontarget areas, and an overspray index based on a threshold of greater than 30% coverage was calculated. The application rate ranged from 262 L·ha−1 at the programmed spray rate of 0.03 L·m−3 to 638 L·ha−1 at the rate of 0.09 L·m−3. For a given WSC position, spray coverage and deposits increased as the spray rate increased. WSC positions 1 and 2 were oversprayed at all rates. The effect of spray rate on deposit density varied with WSC positions, with high densities achieved by low spray rates for WSCs closest to the sprayer but by high spray rates for WSCs positioned either deeper within or under the canopy. When coalescing deposits were accounted for, deposit densities met or exceeded the recommended pesticide application thresholds (insecticides 20–30 droplets/cm2; fungicides 50–70 droplets/cm2) at all WSC positions for each spray rate tested. The lowest spray rate reduced off-target loss to the orchard floor by 81% compared with the highest rate, dramatically reducing potential exposure to nontarget organisms, such as foraging pollinators, to come into contact with pesticide residues. Applying the lowest rate of 0.03 L·m−3 met deposit density efficacy levels while reducing spray volume by 83% compared with the orchard standard application of 1540 L·ha−1 and by 87% compared with the 1950 L·ha−1 application rate recommended when using the tree row volume method. Thus, there is potential for growers to refine pesticide application rates to further achieve significant pesticide cost savings. Producers of other woody crops, such as nursery, citrus, and grapes, who use air-assisted sprayers, may be able to achieve similar savings by refining pesticide applications through the use of laser rangefinder-based spray application technology.

Spray nozzle performance on wheat

Fungal diseases in wheat crops (Triticum aestivum) cause significant yield and quality grain losses worldwide. The increase in the crop production area under no-tillage and environmental changes has favored residue-borne fungal survival and, therefore, disease development. Field trials were carried out at the beginning of anthesis on wheat crops (state z61), in order to evaluate different spray nozzle performance. The test was arranged in a 4x2 factorial design with ten repetitions. Factors consisted in four nozzles: flat-fan (XR11002), air induction asymmetrical dual flat-fan (AI3070-02), air induction symmetrical dual flat-fan (GAT11002), hollow cone (TXA8002), and two artificial targets, one vertical and another horizontal related to head and flag leaf location, respectively. Water-sensitive cards and CIR 1.5® software were used to determine droplet density (DD), coverage, and deposition. The latter was contrasted using Brilliant Blue tracer. Data were subjected to anova and means were compared by Tukey test (p≤0,05). The use of fine droplets and multiple directions such as TXA8002 increases coverage and deposition in the vertical and horizontal target, under optimum environmental conditions. The methodologies used to evaluate spraying performance are complementary to completely characterize the application parameters.

An Evaluation of Spray Rig Designs for California Strawberries Using Water-Sensitive Paper

ABSTRACT The aim of this work was to fill the gap in California pest management by evaluating coverage and spatial uniformity of spray rig designs used in California strawberry production. Coverage can be improved up to 30% if the important design parameters are identified, which would reduce pests. Field evaluations were conducted in beds with 4 canopy lines in Santa Maria, CA on 162 cm beds and in Oxnard, CA on 172 cm beds as well as in beds with 2 canopy lines in Watsonville, CA on 122 cm beds and 132 cm beds. Water-sensitive paper cards placed adaxial and abaxial, both horizontally and vertically on plant canopies located near the middle and edge of the bed were used as the evaluation criteria. Data were analyzed by regression. Results from spray evaluations (n = 21) included recording the nozzle used, manifold height, number of nozzles per bed, volume sprayed, nozzle pressure, and tractor speed, as well as determining the percent coverage from 1,568 water-sensitive spray cards. Increasing nozzle pressure can potentially increase coverage by 9.18%. Positioning the nozzle closer to the canopy level can also significantly increase coverage.

A Comparison of Ground-Based Air-Blast Sprayer and Aircraft Application of Fungicides to Manage Scab in Tall Pecan Trees.

Pecan scab (caused by Venturia effusa) is a destructive disease of pecan in the southeastern United States. Susceptible cultivars must be sprayed with fungicide every 10 to 21 days to ensure yield and kernel quality. Fungicide is most often applied using large orchard air-blast sprayers. Pecan trees grow tall, and air-blast sprays result in a gradient in spray deposition and consequently of scab. Aerial fungicide application is also practiced. Disease distribution and spray deposition of the two methods have not been compared but will provide information aiding decisions on spray application methods. We compared air-blast, aerial, and air-blast + aerial applications for efficacy controlling scab at five heights in the canopy of 25-m cultivar Schley pecan trees. There was a negative relationship between scab severity and height in control trees, a positive linear relationship with height in air-blast treated trees, and a generally negative linear relationship between scab severity and height in aerially treated trees. Air-blast + aerial treatments resulted in low severity of scab at all heights. Spray deposition on water-sensitive cards indicated a declining gradient with height using an air-blast sprayer, whereas aerial applications resulted in a low deposition at all sample heights. Air-blast sprays tended to result in less good control at heights >12.5 m, and aerially treated trees at ≤7.5 m. The results provide insight into the efficacy and advantages of these methods for applying fungicide to control scab in tall pecan trees; further research is needed to better understand the impact of frequency and timing of these two methods.

Efecto de variables operativas sobre la calidad de aplicación y la deriva en la pulverización de agroquímicos

La pulverización con plaguicidas es la forma más difundida de control de plagas pero su uso es complejo, desde el punto de vista agronómico. Se realizó un ensayo a campo con el objeto de evaluar la incidencia de tres técnicas de aplicación de agroquímicos; en todas ellas se utilizó una pastilla abanico plano aire inducido, empleando distintas tasas de aplicación, velocidades de avance y distanciamientos entre pastillas quedando definidas tres técnicas: T1 (57 l ha-1, 18 km h-1 y 0,35 m), T2 (28,7 l ha-1, 18 km h-1 y 0,70 m) y T3 (57 l ha-1, 9 km h-1 y 0,70 m). Para evaluar las técnicas se colocaron tarjetas hidrosensibles sobre el suelo y en columnas verticales, determinando la calidad de aplicación, la deriva de sedimentación y la exoderiva acumulada. Las tres técnicas fueron similares en calidad de aplicación alcanzando T1 una mayor cobertura. Para el factor exoderiva, T2 alcanzó diferencias significativas con respecto a las otras dos técnicas, por lo que altas velocidades de avance y distanciamientos entre picos y bajas tasas de aplicación aumentan la exoderiva. No hubo diferencias en deriva de sedimentación. Las variables operativas inciden sobre los riesgos ambientales independientemente del tamaño de gota producido.

50 MANAGEMENT OF COFFEE LEAF MINER: SPRAY VOLUME, EFFICACY OF CARTAP HYDROCHLORIDE AND IMPACT ON PARASITISM

The leaf miner is a key pest of coffee and the use of insecticides for its control results in high water consumption. The objective in this study was to evaluate the quali-quantitative aspects of reduced spray volumes with and without the addition of adjuvant, the efficacy of the insecticide cartap hydrochloride in the control of the pest and its effects on the parasitism. Two experiments were carried out in coffee plantations in São Desiderio, BA. Initially, solution of Brilliant Blue tracer (0.15% p v-1) of the 43, 112, 146 and 309 L ha-1 volumes was sprayed with and without the soybean oil methyl ester adjuvant (0.25 % v v-1). Before spraying, water-sensitive cards were fixed to the plants and subsequently used for analyze the droplet spectrum in Gotas 1.0 software. The tracer deposit was determined by spectrophotometry. Posteriorly, the insecticide cartap hydrochloride (0.5 kg a.i. ha-1) was applied in the same volumes and types of spray used in the first test. Infestation rates of pest and parasitism were evaluated before and after application of the insecticide. The quali-quantitative aspects of the sprays were affected by the volume of spray applied, by the adjuvant and by the interaction of the factors. The intermediate volumes yielded better spraying quality without the presence of the adjuvante, with higher number and desity of drops. The spraying volume affected the depoisto the Brilliant Blue tracer in a linear and positive form. The efficacy of the insecticide was prolonged with the lowest volume spray and with adjuvant and its impact on parasitism varied with the volume applied and time after application.

Prestación de pastillas en el control de enfermedades de trigo

Las enfermedades fúngicas en el cultivo de trigo (Triticum aestivum) ocasionan pérdidas importantes en rendimiento y calidad de los granos. Se realizaron ensayos sobre un cultivo de trigo en antesis temprana (estado Z61), para evaluar la prestación de diferentes pastillas. El ensayo fue conducido en un esquema factorial de 4x2 con 10 repeticiones. Los factores fueron cuatro pastillas: abanico plano (XR11002), doble abanico asimétrico con aire inducido (AI3070- 02), doble abanico simétrico con aire inducido (GAT11002), cono hueco (TXA8002), y dos objetivos artificiales, uno vertical representando la espiga y otro horizontal para la hoja bandera. Se utilizaron tarjetas hidrosensibles y el programa CIR 1.5® para la determinación de densidad de impactos (DI, imp cm-2), cobertura (COB, %) y deposición (%), siendo ésta contrastada con el uso de trazador Azul Brillante. Se realizó análisis de la varianza y las medias fueron comparadas por el test de Tukey (p≤0,05). La pastilla TXA8002 alcanzó la mejor prestación, en DI, COB y deposición. AI3070 logró similar depósito que TXA8002 en la espiga, 51% y 45% respectivamente, pese a tener la menor DI, (44 imp cm-2), mientras que en hoja bandera TXA8002 tuvo el mayor porcentaje de depósito (40%). Las pastillas con aire inducido tuvieron la menor DI pero una mayor uniformidad entre las distintas caras de la espiga. Las metodologías de evaluación utilizadas resultaron complementarias para realizar un análisis completo de caracterización de la aplicación.

Design and Evaluation of Solid Set Canopy Delivery System for Spray Application in High-density Apple Orchards

Abstract. Permanent or solid set canopy delivery (SSCD) system with certain types of emitters placed along the tree rows have shown promise in the past for foliar application in tree fruit orchards. However, limited knowledge exists in terms of designing a SSCD system for uniform canopy spray coverage in tree fruit orchards. This study examined the spray coverage in high-density, super spindle apple orchards created by different nozzles and their configuration within a canopy on a SSCD system. Three different types of emitters (sprinkler, full cone, and hollow cone) and two different design configurations were evaluated in the orchard using three consecutive tree fruit rows that were 9 m long. Application pressures were 241, 379, and 517 kPa. Coverage analysis on the upper- and under-side of leaves was determined using water sensitive cards (WSC) on three randomly selected trees (23= cards/tree). The results indicated that the design configuration with two 80° hollow-cone nozzles, installed at three different canopy heights, and spray application pressure of 379 kPa provided greater coverage on upper-side (87%) and on the under-side (50%) of tree leaves. Additional studies would have to be conducted for other fruit crops and training systems to optimize system design for intended spray coverage. Keywords: Application pressure, Emitter, Solid set canopy delivery, Spray nozzle, Spray coverage.

Evaluating insecticide coverage in almond and pistachio for control of navel orangeworm (Amyelois transitella) (Lepidoptera: Pyralidae).

Insecticide application is essential to control navel orangeworm (Amyelois transitella) in California almond and pistachios. Coverage is difficult because of tree height and applicator practices. Studies were conducted to characterize insecticide deposition by both ground and air, and to develop alternatives to the use of water-sensitive cards to assess spray coverage. We used almond challenge bioassays to demonstrate that insecticide application failed first in the upper canopy (5.2-6.1 m) when application speed exceeded 2.9 kph. In pistachios, we used filter paper and insecticide extraction from hulls to demonstrate that deposition increased with application volume. Typically, in ground applications, coverage decreased with height, whereas for application by air, coverage was greatest at the top of the canopy (6 m) and decreased as the spray penetrated the canopy. In the best ground applications there was no loss over height. We were able to demonstrate a dose-response relationship for methoxyfenozide using contact toxicity bioassays. Coverage was best at or below the recommended speed of 3.2 kph and improved when water volume increased. There was a 50% loss in insecticide efficacy at the height of 4-4.8 m; we suggest that future monitoring concentrate on this portion of the canopy. The best ground application provided uniform deposition throughout the canopy, whereas the applications by air were most effective in the upper canopy. The use of filter paper can provide information for chemical deposition and enable contact toxicity bioassays, whereas water-sensitive paper cannot do this. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

Water sensitive sample for determination of drops spectrum in spraying in coffee canephora

The objective of this study was to determine the minimum number of water sensitive paper cards to be sampled in an experiment involving different spray nozzles and parts of conilon coffee. The experimental design was completely randomized in a factorial 2 x 2 x 2 (2 spray nozzles, 2 side spray, one in the direction of traversal of the spray and the other in the opposite direction; 2 Application heights in the plant, the lower half and the upper half), with 4 replicates. Each of the 24 experimental units consisted of 48 water sensitive paper cards. Four reproductive branches were selected, two branches belonging side of the sprayer to the pathway and the other two branches facing the opposite side of the spray traversal. They were established 24 water sensitive paper labels at the bottom and 24 on top of the plant, totaling 48 water sensitive paper. The average DMV, DMN, <100 and AR were significantly higher in the upper half of the plant on the same side of the spraying operation, regardless of the tip used. Using the tip JA-2 the lower side of the plant showed a mean VMD values, DMN, <100 AR and smaller than the upper half. The variances between DMV, DMN and RA were homogeneous. The number of labels per nine plant is indicated, since the greater the half-value widths (4.6 and 8%), the more homogeneous the number of labels per plant, independent of the variable, state and position of labels.

Lambda-cyhalothrin efficiency on fruit borer control and quali-quantitative spraying aspects in a pinecone crop

ABSTRACT In Brazil, the state of Bahia is one of the largest pinecone (Annona squamosa L.) growers; nevertheless, fruit borer (Cerconota anonella L.) presence limits production. This research aimed to test the efficiency of lambda-cyhalothrin in controlling fruit borer using different spray volumes; additionally, this research tested qualitative and quantitative operational aspects. Trials were carried out in pinecone orchards in Caraíbas-BA, Brazil. Pesticide efficiency was tested by a randomized block experiment with six treatments and five replications. Treatments consisted of lambda-cyhalothrin application (1.5 g a.i. 100 L-1 water) with a surfactant (0.03% v v-1) at spray volumes of 100, 200, 268, 382 and 488 L ha-1 and one control (without spray). Pest infestation was assessed by counting symptomatic fruits for further percentage calculation. Five treatments with five replications were developed to evaluate spraying performance. These treatments consisted of an aqueous solution with a Brilliant Blue tracer at 0.15% (p v-1) and a surfactant at 0.03% (v v-1), using the same spray volumes as the first experiment. Qualitative assessments were performed on water-sensitive paper cards and were quantified through tracer deposit levels on leaves. Spray volumes between 100 and 382 L ha-1 with lambda-cyhalothrin were efficient to control Cerconota anonella in the pinecone crop, providing good quality application.