Citrus Region Research Articles

Impacts of trade policy on the welfare of citrus producers and consumers in Indonesia

PurposeThis study aims to investigate the factors influencing the citrus trade in Indonesia, the effects of tariff and non-tariff policies on the industry and the welfare of producers and consumers.Design/methodology/approachThe research used annual series data from 1991 to 2021 and employed inferential, simulation, and descriptive analyses. The two-stage least squares (2SLS) of 19 simultaneous equations were used to estimate parameters.FindingsThe results indicate that free trade policies and restrictions have influenced the citrus industry, leading to a reduction in Indonesian citrus imports, and increased consumer and producer prices. However, eliminating import tariff policies on citrus from China and import restrictions increased producer surplus while decreasing consumer surplus, government revenue, and total welfare. Therefore, trade policies should be combined with non-trade policies such as citrus region development policies and advancing cultivation technology.Originality/valueThis study provides empirical evidence for the Indonesian government to formulate effective citrus trade and development policies. It emphasizes the importance of carefully considering the impact of trade policy on the citrus industry and the need to implement non-trade policies such as citrus zone development policies and advancing cultivation technology to benefit both producers and consumers.Peer reviewThe peer review history for this article is available at: https://publons.com/publon/10.1108/IJSE-02-2023-0148

First report of Neodidymelliopsis ranunculi causing foliar black spot on citrus leaves in orchards of Algeria

During pest and disease surveys in summer 2017, severe leaf drops were observed in four citrus orchards, two sweet orange (cvs Thompson Navel and Washington Navel) and two mandarin (cvs Nova and Oro Grande) orchards, located in Chlef, one of the most important citrus region in Algeria. Visual inspection of green dropped leaves and leaves on tree canopy revealed unusual symptoms consisting of greasy black protuberant spots on the abaxial side and yellowing on the adaxial surface. A quick survey was conducted to determine the incidence of the disease. The proportions of trees affected by the disease were 50 and 35% for the sweet orange and mandarin orchards, respectively. The incidence of the diseased leaves ranged from 30 to 60% for sweet orange, while 50–70% of leaves were symptomatic in the mandarin orchards. Morphological identification and a multi-locus sequencing approach associated this disease to the fungus Neodidymelliopsis ranunculi. Koch's postulates also confirmed N. ranunculi to be the causal agent. This is the first report of black spot symptoms caused by N. ranunculi on citrus in Algeria. The rapid spread of the disease since its first detection, poses a serious threat to the sustainability of citrus production in Algeria and calls for the implementation of urgent management actions.

Genetic diversity of Candidatus Liberibacter asiaticus strains from the Central Pacific citrus region in Mexico

Huanglongbing (HLB) is associated with Candidatus Liberibacter asiaticus (CLas). It is a destructive disease of citrus. The objective of this study was to determine the genetic diversity of 90 strains of CLas infecting eight citrus species trees from the Central Pacific in Mexico. Genetic diversity among CLas was estimated by fourteen variable numbers of tandem repeat (VNTRs) loci. Three loci were polymorphic, SSR00 and SSR077 amplified four alleles each, while the locus SSR-A amplified two alleles, and the other loci only one allele per locus, resulting in a total of 21 alleles. Dendrogram analysis showed two clusters. No clear genetic structure was found in relation to geographical origin or host. The cluster I was mostly constituted by the majority of CLas strains (82%), but the cluster II comprised twelve strains of CLas collected in Tecoman location, State of Colima, and were obtained from different citrus hosts species. The frequency of 17 haplotypes among strains of CLas from the states of Nayarit, Jalisco, Colima and Michoacán was analyzed; in Colima 14 haplotypes were determinated, while in Michoacan all strains were identified in one haplotype. These results indicate a large genetic diversity among the strains of CLas present in the Central Pacific region in Mexico.

The Surface Defects Detection of Citrus on Trees Based on a Support Vector Machine

Machine learning and image processing have been combined to identify and detect defects in mature citrus fruit at night, which has great research and development significance. First, a multi-light vision system was used to collect citrus UV images, and from these, 1500 samples were obtained, 80% of which were training and 20% were experimental sets. For a support vector machine (SVM) model with “2*Cb-Cr”, “4*a-b-l”, and “H” as the training features, the accuracy of the final training model in the experimental set is 99.67%. Then, the SVM model was used to identify mature citrus regions, detect defects, and output the defective citrus regions label. The average running time of the detection algorithm was 0.84097 s, the accuracy of citrus region detection was 95.32%, the accuracy of citrus defect detection was 96.32%, the precision was 95.24%, and the recall rate was 87.91%. The results show that the algorithm had suitable accuracy and real-time performance in recognition and defect detection in citrus in a natural environment at night.

CITRUS RECOGNITION IN REAL SCENARIOS BASED ON MACHINE VISION

At present, citrus is mainly harvested manually with low efficiency and high cost, thereby resulting in an imminent demand for fruit-harvesting robot. Hence, recognizing and locating citrus from complex backgrounds using machine vision technology is the premise and a key technology for robots to harvest them. To accurately and immediately recognize mature citrus, this study proposes a novel method based on the Otsu adaptive threshold method and on the improved random ring method. First, a citrus region was segmented using the Otsu adaptive threshold method overthe V component of the Luminance Chrominance (YUV) color space, extracting then the real citrus region after undergoing a de-noising processing. Second, the citrus edge was extracted using a Canny detection operator with the curvature catastrophe point removed. The short citrus edge was placed in the background to obtain the citrus edge of each segment. Lastly, the citrus feature circle was fitted for continuous citrus edge in each segment using the improved random ring method based on the greedy algorithm. Experiments were conducted using the citrus images in various real scenarios. Results demonstrate that the proposed method increases the overall recognition rate of citrus to 95% with time consumption of approximately 80 ms. The proposed method improves the recognition efficiency, enhances the accuracy of citrus recognition, and provides technical support for fruit-harvesting robots. Lastly, the proposed method can be generalized to the location and recognizition of other similar fruits, thereby providing significant research value. Keywords: Citrus recognition, Otsu adaptive threshold method, Greedy algorithm, Random ring method

Overlapping citrus segmentation and reconstruction based on Mask R-CNN model and concave region simplification and distance analysis

Accurate segmentation and reconstruction of overlapping citrus target contours is the primary problem for picking robots. In view of the poor effect of existing research methods on the segmentation and reconstruction of overlapping citrus fruit target contours under complex background, a segmentation and reconstruction method based on region simplification and distance analysis is proposed. Firstly, the overlapping citrus region (Mask region) is obtained by using the previously trained Mask R-CNN model. Then, the convex hull curve of the region is obtained by the roll-wrapped convex shell algorithm, and the region enclosed by the convex curve and the Mask region are pixel-operated. The concave region is polygon-simplified; then the vertices of the polygon are extracted by the Shi-Tomasi corner detection algorithm, and the contour segmentation points are determined by analysing the distance from each vertex to the contour convex-hub curve. Finally, the segmentation contour is reconstructed by the least squares fitting method. The experimental results show that the average error of the proposed method for the reconstruction of overlapping citrus contours is 3.21%, the non-coincidence degree and time are 4.13% and 0.273s respectively, which superior to RANSAC algorithm and Hough transform algorithm. It can satisfy the recognition requirements of overlapping citrus in natural environment for citrus picking robots.

BIODIVERSITY AND DIET OF COCCINELLIDAE ON CITRUS IN METIDJA (ALGERIA)

Biological control is a viable alternative to the use of chemical pesticides that are harmful to the environment. From this perspective, this work aims to make an inventory of Coccinellidae and to classify them according to their diet. Sampling by yellow sticky plates is carried out each week from 23 April to 24 July 2014 at the Eastern Metidja very important citrus region in Algeria. A total of 16 ladybug species are sampled in four citrus species, orange, lemon, clementine and pomelo. It is the Coccidiphagous that are the richest with a total of 7 species, followed by the aphidophagous with 5 species and mycophagous with the two species. Finally found the aleurodiphagous and acariphagous, with a single species for each group. With regard to relative abundance, a total of 467 individuals coccinellidae were captured, of which the species Clitostethus arcuatus (ladybug aleurodiphagous) alone counted 285 individuals, that is 61.29%.

Deep Sequencing Analysis of RNAs from Citrus Plants Grown in a Citrus Sudden Death-Affected Area Reveals Diverse Known and Putative Novel Viruses.

Citrus sudden death (CSD) has caused the death of approximately four million orange trees in a very important citrus region in Brazil. Although its etiology is still not completely clear, symptoms and distribution of affected plants indicate a viral disease. In a search for viruses associated with CSD, we have performed a comparative high-throughput sequencing analysis of the transcriptome and small RNAs from CSD-symptomatic and -asymptomatic plants using the Illumina platform. The data revealed mixed infections that included Citrus tristeza virus (CTV) as the most predominant virus, followed by the Citrus sudden death-associated virus (CSDaV), Citrus endogenous pararetrovirus (CitPRV) and two putative novel viruses tentatively named Citrus jingmen-like virus (CJLV), and Citrus virga-like virus (CVLV). The deep sequencing analyses were sensitive enough to differentiate two genotypes of both viruses previously associated with CSD-affected plants: CTV and CSDaV. Our data also showed a putative association of the CSD-symptomatic plants with a specific CSDaV genotype and a likely association with CitPRV as well, whereas the two putative novel viruses showed to be more associated with CSD-asymptomatic plants. This is the first high-throughput sequencing-based study of the viral sequences present in CSD-affected citrus plants, and generated valuable information for further CSD studies.

Spatial heterogeneity of Anastrepha ludens populations over a large citrus region including a sterile insect release area in northeastern Mexico

We analyzed Anastrepha ludens (Loew) (Diptera: Tephritidae) populations for 2 years (2008–2009) over the most important area of citrus-growing in Tamaulipas, Mexico. This study aimed to characterize the spatial heterogeneity of A. ludens populations between areas with and without the release of sterile flies. The analyses include high populations of the pest during two periods per year: Valencia orange and grapefruit production. Populations were spatially characterized by using the geostatistical method indicator kriging integrated to a geographic information system. Through indicators as the upper quartile, the spatial-variation of the populations was ranked into four categories of probability to exceed the settled threshold: 0–25, 25–50, 50–75, 75–100%. Models indicated that spatial heterogeneity of A. ludens between 2008 and 2009 showed changes according to the citrus production period. In 2008, spatial distribution was more homogeneous across the region, but in 2009 in spite of higher populations than in 2008, a spatial heterogeneity was observed for the two periods of citrus production. Probability tendencies of high densities (>50%) of the pest were observed towards the west, while eastwards, where the release area was located, lower probability (<50%) was indicated. A more homogeneous density level of the pest was plotted on the release area in 2009, in contrast with the area without sterile fly release. This contribution supports an impact of the sterile insect technique and promotes use of spatial analysis tools for analyzing pest populations at regional scale in northeastern Mexico.

English

Diaphorina citri is the insect vector of the disease, Huanglongbing (HLB) which is the most devastating citrus disease worldwide. It is necessary to identify potential risks; this can be done based on favorable thermo-pluviometrical conditions for the vector. The present study aims to identify potential risks in the Nuevo Leon citrus region in areas, which have not yet been devastated by the citrus disease. The presence of HLB and the population growth of the D. citri will be influenced by four factors involved in the epidemiological system: the disease-prone host - citrus fruits; the pathogen agent; the biology of the vector; and the climate conditions that foster the vector establishment and reproduction. With information from 65 weather stations, some indices were estimated: potential generations of the vector per year, days with favorable temperature and suitable rainy days for the vector, area planted with citrus fruits, and finally, the potential risk index. This shows that the Nuevo Leon citrus region is a HLB free region. The method can be applied to citrus producing areas which have not been devastated by the citrus disease worldwide. Key words: Citrus greening disease, climate conditions, Huanglongbing, potential risks.

Population Dynamics of Anastrepha ludens (Loew) (Diptera: Tephritidae) on Citrus Areas in Southern Tamaulipas, Mexico.

An analysis of adult population fluctuation of Anastrepha ludens (Loew) was performed in southern Tamaulipas, Mexico from 2008 to 2011. The aim was to analyze population dynamics of A. ludens and its relationships with climatic factors in the citrus region of Llera, Tamaulipas, Mexico. Population densities were weekly examined to identify variation through the year and study period. Four periods were identified according to population size, amplitude, host availability and season of the year. The correlation between population density vs. rainfall and temperature (average, minimum and maximum) was determined by linear and multiple regression analyses. Simple linear regression analysis showed that population density with minimum temperature and rainfall was the most consistent correlation, whereas in multiple regression analysis, rainfall and maximum temperature showed more consistency. A seasonal association between the availability of commercial host, climatic variation, and population peaks of A. ludens was determined. This study may have practical implications for the design of specific control strategies, monitoring, and infestation prevention based on different phases of the pest through the year. This strategy, along with the area-wide approach implemented by the Plant Protection Service may lead to an optimization of material, financial and human resources.

Infestation dynamics of Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) in citrus orchards as affected by edaphic and climatic variables.

Brevipalpus phoenicis (Geijskes) is a cosmopolitan and polyphagous mite that transmits important phytoviruses, such as coffee ringspot virus, passion fruit green spot virus and Citrus leprosis virus C. To characterise the dynamics of the probability and the rate of B. phoenicis infestation in response to edaphic and climatic factors, monthly inspections were performed in nine orchards in a citrus region of the State of Bahia, Brazil, for 35 months. Three fruits per plant were examined using a magnifying glass (10×) on 21 plants distributed along a "W"-shaped path in each orchard. Meteorological data were collected from a conventional station. To determine the correlations among the climatic variables, the data were analysed using Spearman correlations. Variables were selected by principal component analysis, and those that contributed the most to differentiate the groups were evaluated via a Mann-Whitney test. Using the quantile-quantile method, the limit values for the following climatic variables were determined: temperature (24.5 °C), photoperiod (12 h), relative humidity (83%), evapotranspiration (71 mm) and rainy days (14 days). The combination of longer days, higher temperatures, lower relative humidity levels and lower evapotranspiration increased the probability of B. phoenicis infestation, whereas successive rain events decreased that risk. Infestation rates were negatively affected by relative humidity levels above 83% and were positively affected by a decreasing available soil-water fraction and increasing insolation and photoperiod.

HLB in Argentina: a New Disease Outbreak

Huanglongbing (HLB) caused by Candidatus Liberibacter asiaticus was reported in 2004 in São Paulo, Brazil and three years later in the southern state of Paraná, 300 km away from Argentina’s Northeastern border. In 2009 the Argentine citrus industry (AFINOA and CECNEA) and the institutions MAGyP, SENASA, INTA, INASE, and Obispo Colombres set up a task force to develop quarantine guidelines for prevention of introduction of HLB into Argentine citrus areas. This program is based on measures including 1) border inspections, 2) citrus nursery certification, 3) control on the production, transit and trade of citrus fruit, 4) field survey and diagnosis for the early detection of the disease in trees or the vector Diaphorina citri in citrus groves, 5) development of research and technology capacity, and 6) communication about the quarantine program and the disease. Diagnostic laboratories were set up in each citrus region and more than 100 inspectors were deployed in different citrus areas for 1) survey of Diaphorina citri by yellow sticky traps, 2) visual inspection of Murraya paniculata, 3) inspection of all citrus nursery production under aphid mesh screen according to Resolution 930/09, and 4) survey of 100 % of the citrus area (150,000 ha)&nbsp; with at least 10 surveys of the highest risk area; There are 52,000 inspection locations for 13,160 tree or Diaphorina samples.&nbsp; In June 2012, a positive detection of HLB was confirmed in a backyard tree in the Northern Misiones Province across the border from Brazil. Since then, 5 surveys were carried out in the area surrounding the focus with the detection of 15 positive trees, all in backyards.&nbsp; The HLB positive trees include 12 tangerines, and 3 Rangpur limes from 7 to more than 10 years old.&nbsp; In all cases, the trees were eradicated by the owner.&nbsp; The psyllid population in this area is very low and all PCR samples of the vector are negative.&nbsp; At present, HLB has not been detected in commercial groves.

Estimating the Economic Impact of an Eventual Introduction of Huanglongbing (HLB) in the State of Bahia, Brazil

Bahia is the second most important citrus region in Brazil, accounting for 5.5% of Brazilian production. 80% of this production comes from family based farms, which depend on this crop for economic support. Huanglongbing (HLB) was never recorded in Bahia, but is already spreading in three other citrus-producing states of the country, one of which borders the state of Bahia. Thus, this study aimed to estimate the potential economic impact resulting from an eventual introduction of HLB in Bahia. The mathematical model of Gompertz and a logistic model were used to determine the epidemiological pattern of the disease, considering three scenarios. In scenario A, the efforts of the Bahia State Agency of Agricultural Defense were positive preventing the establishment of HLB (baseline scenario). In scenario B, there was the introduction of the bacteria into Bahia citrus orchards, and the absence of control measures contributed to the expansion of HLB in the following years. In scenario C, after detection of the disease, the producers would adopt control measures: eradication of symptomatic hosts and the insect vector population suppression. The costs of disease control were measured by the need for sprays, carrying out periodic inspections and eradication of plants with symptoms. The net present value (NPV) was used for comparing different scenarios. The results showed that, if HLB is introduced in Bahia, the losses would be very significant in the following 20 years. Should control and eradication procedures not be followed, losses of up to US $ 890,7 million&nbsp; could occur.

Estimativa dos impactos econômicos decorrentes de eventual introdução do huanglongbing (HLB) no estado da Bahia

A Bahia é o segundo mais importante Estado produtor de citros do Brasil, responsável por 5,5% da produção do País. 80% da produção vem de propriedades de base familiar, as quais dependem desse cultivo para seu sustento econômico. O Huanglongbing (HLB) nunca foi registrado na Bahia, mas está disseminando-se em outros três Estados do Brasil (São Paulo, Paraná e Minas Gerais), um dos quais faz fronteira com a Bahia. Assim, este estudo teve como objetivo estimar o impacto econômico potencial de uma eventual introdução do HLB na Bahia. Foram utilizados os modelos de Gompertz e logístico associados a diferentes estratos de idade das plantas para estimar, respectivamente, a evolução da incidência e da severidade da doença no parque citrícola baiano, num horizonte de 20 anos. O progresso da doença foi usado para estimar os danos à produção em três cenários. No cenário-base (A), os esforços da agência estadual de defesa agropecuária previniria a entrada do HLB. No cenário B, a doença seria introduzida e não haveria esforços para seu controle, levando a uma disseminação nos anos seguintes. No cenário C, após a detecção da doença, os produtores adotariam medidas de controle: eliminação de plantas sintomáticas e supressão das populações do inseto vetor. Os custos do controle foram calculados considerando-se a necessidade de pulverizações, inspeções periódicas e eliminação das plantas doentes. O valor presente líquido (VPL) foi usado para comparar os três cenários. Os resultados indicam que as perdas seriam muito significativas caso o HLB fosse introduzido na Bahia. Assim sendo, se as medidas de controle não fossem aplicadas, os prejuízos poderiam superar R$1,8 bilhão.

Prevalence, incidence and distribution of citrus variegated chlorosis in Bahia, Brazil

Citrus variegated chlorosis (CVC) is one of the most important diseases for Brazilian citricultureIt is caused by Xylella fastidiosa subsp. pauca, a xylem limited, cycadelid and budwood transmitted bacterium. In Bahia, the second most important citrus region in Brazil, has been present since 1997. Our objectives were to characterize the regional spatial pattern of and to establish a relationship between epidemiological variables and horticultural practices, as well as to evaluate whether control measures used so far have been effective and, based on that, to conceive suitable control measures. A series of surveys were performed in two regions of Bahia State (Reconcavo Baiano and Litoral Norte), along with a survey of horticultural and control practices associated with sampled groves. was restricted to Litoral Norte region, especially to three municipalities along the border between Bahia and Sergipe StatesThe mean incidence in these municipalities followed a gradient, higher in the countryside and decreasing along the coast. Presence and dissemination of was related to poor nursery practices, a massive use of a susceptible orange variety, and an extreme concentration of orange groves in high incidence municipalities, as well as to the absence of specific control. Considering that was not found in Reconcavo Baiano, this region could be considered a CVC free zone by the local government.

Detection of Citrus psorosis virus in the northwestern citrus production area of Argentina by using an improved TAS-ELISA

Citrus Psorosis in Argentina is a serious disease. Citrus is produced in two regions located in the northeast (NE) and northwest (NW) area of the country. These two areas have different climates and soil types, and therefore different citrus species and varieties are cultivated. In the NE region, Psorosis is epidemic, and in the NW region, the disease was described on several occasions since 1938, but it is not observed commonly in the orchards. Recently, trees with symptoms of Psorosis were observed in the Tucumán and Salta Provinces located in the NW region. Epidemiological studies in Argentina and Texas suggested that the disease is spread naturally by an unknown vector. The causal agent of the disease is the Citrus psorosis virus (CPsV), which can be detected by TAS-ELISA, RT-PCR and indicator plants. A new more rapid TAS-ELISA-HRP (horseradish peroxidase) is described which is more reliable, faster and more sensitive than the currently used for this virus, the TAS-ELISA-AP (alkaline phosphatase). Psorosis was detected by this improved method in few trees in the orchards of the Tucumán Province, in the NW citrus region, although natural spread does not seem to occur.

Preliminary spatial pattern analysis of Huanglongbing in São Paulo, Brazil

3 USDA, ARS, USHRL, 2001 S. Rock Road, Fort Pierce, FL, 34945 USA ABSTRACT. Huanglongbing (HLB) was reported in 2004 in Sao Paulo, Brazil. Assessments of diseased trees by visual symptoms were made in 36 plots from 8 farms in the central citrus region of Sao Paulo State. A total of 155 HLB spatial maps (varying from 0.14 to 25.99% disease inci- dence) were analyzed, considering quadrat sizes of 2 × 2, 4 × 4, 6 × 6 and 8 × 8 trees, by ordinary runs analysis, binomial index of dispersion and binary form of Taylor's power law. Aggregation among HLB-symptomatic trees was detected by ordinary runs analysis, with clustering in both within- and across-rows directions. However the percentage of aggregation within- and across- rows was low. The binomial index of dispersion for various quadrat sizes suggested aggregation of HLB-symptomatic trees for about 40% of the plots. The relationship between log (observed vari- ance) and log (binomial variance) was highly significant for all four quadrat sizes. Estimated parameters of the binary form of Taylor's power law provided an overall measure of aggregation of HLB-symptomatic trees for all quadrat sizes tested. All power law estimates of b and A, were sta- tistically different from 1, which indicated a general and significant pattern of aggregation of symptomatic plants for all quadrat sizes tested. The degree of aggregation was also positively related to disease incidence. Data from 20 plots ranging in disease incidence were also analyzed by spatial autocorrelation to examine the association among groups of infected trees using the 2 × 2 quadrat size. In 14 of 20 cases, clusters of HLB-infected trees were found to be associated with secondary clusters whose centers were at distances ranging from 4.2 to 22.1 tree spaces distant, indicating psyllid vector movement resulting in transmission to nearby trees causing clusters and to trees at considerable distance initiating new foci of infection. Index words . Binomial analysis, disease incidence, infection foci, Taylor's power law.

Performance of `Oroblanco' and `Melogold' Pummelo × Grapefruit Hybrids on Nine Rootstocks on a Calcareous, Poorly Drained Soil

Adjacent but separate trials of `Oroblanco' and `Melogold', both triploid pummelo [Citrus grandis (L.) Osbeck] × grapefruit (Citrus paradisi Macf.) hybrids, were established on nine rootstocks in the Indian River citrus region of Florida in 1993. The trees on the citrandarin rootstock ×639 [Cleopatra mandarin (C. reticulata Blanco) × trifoliate orange (Poncirus trifoliata L.)] were significantly more productive than trees on any other rootstock tested for `Oroblanco' and all rootstocks except Swingle citrumelo (C. paradisi × P. trifoliata) and Cleopatra mandarin for `Melogold'. Cumulative production of `Oroblanco' on ×639, through year 9, was 50% higher than for Swingle or Volkamer lemon [C. limon (L.)], which were the next highest in yield. `Melogold' displayed extremely low yield, with 45% of trees producing fewer than 50 fruit total in the 9 years of this study. Carrizo citrange (C. sinensis Osbeck × P. trifoliata) produced the smallest trees with both scion varieties, reflecting poor adaptation of this rootstock to the calcareous soil at the trial site. As expected, acidity of `Oroblanco' and `Melogold' was much lower than would be observed for grapefruit when fall harvested, with similar total soluble solids (TSS), and much higher TSS: titratable acidity ratio. Some rootstock effects on internal quality were observed.

Pesticide Spraying in Indian River Grapefruit: II. Overview of Factors Influencing Spray Efficacy and Off-target Deposition

Foliar application of spray materials is an integral component of commercial citrus production. An intensive assessment of spray application practices has been stimulated by low fruit value and increased concern about potential surface water contamination in the Indian River citrus region of Florida. Many publications report research results regarding distribution of spray materials within orchards and off-target deposition, but interpretation is challenging because so many factors influence spray results, and integrating this information into practical recommendations is difficult. Canopy geometry and density are prominent factors contributing to variable deposition and spray drift. Environmental factors such as temperature, relative humidity, wind speed, and wind direction also greatly influence spray deposition and drift, and substantial changes can occur within seconds. In addition the physical and/or mechanical set up of the sprayer interact significantly with the other factors. A better understanding of these interactions should help growers optimize spray effectiveness and efficiency while reducing potential off-target effects.