Application Of Copper Fungicides Research Articles

Synthesis and Characterization of Slow-Release Chitosan Oligosaccharide Pyridine Schiff Base Copper Complexes with Antifungal Activity.

Herein, a series of chitosan oligosaccharide copper complexes modified with pyridine groups (CPSx-Cu complexes) were successfully prepared via the Schiff base reaction and ion complexation reaction for slow-release fungicide. The structures of the synthesized derivatives were characterized via Fourier transform infrared spectroscopy and 1H and 13C nuclear magnetic resonance spectroscopy, and the unit configuration of the complexes was calculated using Gaussian software. The slow-release performance experiment demonstrated that the cumulative copper ion release rate of CPSx-Cu complexes was dependent on the type of substituents on the pyridine ring. Furthermore, the in vitro and in vivo antifungal activities of the CPSx-Cu complexes were investigated. At a concentration of 0.4 mg/mL, CPSx-Cu complexes completely inhibited the growth of Pythium vexans and Phytophthora capsici. Results indicated that CPSx-Cu complexes with slow-release ability exhibited better antifungal activity than thiodiazole-copper and copper sulfate basic. This study confirmed that combining chitosan oligosaccharide with bioactive pyridine groups and copper ions is an effective approach to further developing slow-release copper fungicides, providing new possibilities for the application of copper fungicides in green agriculture. This study lays the foundation for further studies on biogreen copper fungicides.

Effect of direct tea plant covering on the incidence of anthracnose

Considering the growing global demand for matcha, the Shizuoka prefectural government is promoting the export of matcha prepared from cover-cultured tea. To improve matcha production, it is important to investigate the characteristics of pest incidence under covering culture and develop suitable pest management strategies. In this study, we investigated the effects of direct tea plant covering and copper fungicide application to curb the incidence of tea anthracnose (Discula theae-sinensis (I. Miyake) Moriwaki & Toy. Sato), the most serious tea disease that occurs primarily during or after the second tea season. Our results indicated that the incidence of tea anthracnose decreased when cover culture treatment was used compared to that with no-cover treatment during the second tea season. In addition, the tea plants grown under cover and pre-treated with a copper fungicide showed less anthracnose symptoms during the sprouting period than those not treated with the fungicide. These findings suggest that tea anthracnose can be effectively controlled using covering culture after the application of copper fungicide.

Efficacy and optimal timing of low-volume aerial applications of copper fungicides for the control of red needle cast of pine

Background: Red needle cast (RNC) is a foliar disease of radiata pine (Pinus radiata D.Don), caused by Phytophthora pluvialis Reeser, Sutton & E.Hansen and occasionally Phytophthora kernoviae Brasier, Beales & S.A.Kirk. The disease has impacted plantations in New Zealand since at least 2008. To develop management recommendations for red needle cast, research has focused on identifying chemical control options and understanding pathogen epidemiology to guide optimal timing of spray application. The objectives of this study were to: (1) assess the efficacy of aerial copper fungicide application for the control of red needle cast in mature radiata pine plantations; and (2) investigate optimal spray timing. Methods: To address these objectives, three operational-scale field trials were undertaken in successive years between 2017 and 2019 at a forest in the Central North Island of New Zealand. RNC severity was assessed in canopies of forest blocks exposed to cuprous oxide applied at 0.855 kg ha-1 active ingredient in low-volume aerial spray at different times of the year (November, February and April (or May)). Needle cast from plantation trees and infection levels on trap plants were also assessed in some years. Results: Application of cuprous oxide significantly reduced RNC severity in all three trials. As well as reducing disease severity, application of cuprous oxide also tended to reduce needle cast from plantation trees and infection on trap plants in years when these were also assessed. No consistent effect of spray timing was observed. Generally, all three spray timings reduced disease severity compared to the unsprayed control, but differences were not always significant, and few differences were detected between different spray timings. Conclusions: The results reported here are the first to show that low-volume aerial applications of cuprous oxide applied at 0.855 kg ha-1 active ingredient can reduce the severity of RNC in commercial radiata pine plantations. No consistent effect of spray timing was detected. These findings support the development of management recommendations for RNC.

Colletotrichum gloeosporioides s.l. causes an outbreak of anthracnose of cacao in Ghana

Outbreak of anthracnose of cacao (Theobroma cacao L.), covering an estimated total growing area of 248.47 hectares, occurred in parts of Ghana from July to October 2019. Disease samples were collected from the outbreak areas to isolate and identify the pathogen and establish its pathogenicity. Disease symptoms appeared on leaves as dark brown patches with yellow halo margins. Colletotrichum gloeosporioides s.l. was isolated from infected plant tissues and pathogenicity tests confirmed it as the causative agent. The disease was widespread in the Prestea-Huni Valley district of the Western Region, particularly in the Yareyeya community, where a 14.8-hectare farm was seriously affected. Anthracnose has long been known as a sporadic but minor disease of cacao in Ghana. The current shift in status and rapid spread of the disease from infected farms to new farms, though it may or may not be contiguous, cannot be readily explained. Application of copper fungicides, namely Nordox 75 WG (86% cuprous oxide), Champion (77% cupric hydroxide) and Royal Cop 50 WP (77% copper hydroxide) at 75 g, 100 g and 100 g, respectively, each in 15 litres of water, at 2-week intervals for four months, effectively managed the disease.

Antifungal Effect of Ambrosia artemisiifolia L. Extract and Chemical Fungicide Against Spilocaea oleagina Causing Olive Leaf Spot

Olive leaf spot or peacock eye disease caused by Spilocaea oleagina is one of the most common diseases attacking olive trees all over the world. Control of the disease by application of copper fungicides is not always feasible and requires proper management practices. The use of plant extract is considered a safe alternative to the harmful effect of chemical fungicides. In this work, different concentrations (0.5, 1.0, 1.5, 2.0, 2.5, 5.0 and 10% w/v) of Ambrosia artimisiifolia aqueous leaf extract were tested for their efficacy against OLS spore germination. All concentrations proved to have an inhibitory effect on conidial germination under in vitro conditions. The concentrations 2.5 and 5% were the most effective with germination rates of 8.3 and 2.8%, respectively. The results of this work provided new possibilities to control the disease using A. artimisiifolia leaf extract.

Evaluation of a Small-Molecule Compound, N-Acetylcysteine, for the Management of Bacterial Spot of Tomato Caused by Copper-Resistant Xanthomonas perforans.

Bacterial spot caused by Xanthomonas spp. is one of the major diseases in tomato. Xanthomonas perforans is the main pathogen of bacterial spot on tomato in Florida. Currently, application of copper fungicides is the primary measure used to manage this disease. However, the development of copper resistance in X. perforans and accumulation of copper in the environment are major concerns for excessive use of copper-based products in agriculture. Due to its antibacterial properties and low environmental impact, N-acetylcysteine (NAC), a small molecule commonly used in medicine for human bacterial diseases, has been studied in agriculture for the control of plant bacterial pathogens, including X. citri and Xylella fastidiosa. This study evaluated the effect of NAC alone and in combination with copper on a copper-resistant X. perforans strain in vitro and its ability to control bacterial spot of tomato under greenhouse and field conditions. In vitro, the minimum inhibitory concentration of NAC against the X. perforans strain was 2,048 mg liter-1. NAC increased sensitivity of the copper-resistant X. perforans to copper in vitro when application of NAC was followed by copper application after 6 h. In greenhouse assays, NAC applied alone or in combination with copper significantly (P < 0.05) reduced the disease severity of bacterial spot on tomato compared with the untreated control. NAC at 100 mg liter-1 + copper at 300 mg liter-1 consistently exhibited synergistic effects against bacterial spot. In the field trials, NAC at 1,000 mg liter-1 + copper at 150 mg liter-1 significantly reduced disease severity compared with the untreated control. Results from this study demonstrated that NAC significantly reduced the disease severity of bacterial spot of tomato and enhanced the efficacy of copper against copper-resistant X. perforans, indicating that NAC could be applied for the effective management of bacterial spot of tomato.

Physiological responses of soybean (Glycine max (L.) Merrill) cultivars to copper excess.

Successive applications of copper fungicides on vines have resulted in increased copper content in vineyard soils over the years. This high copper content has affected the growth of young vines in eradicated vineyards. Thus, the cultivation of annual species for a few years is an alternative to copper phytostabilization, because it would be a good way to decrease copper availability to plants. The aim of this study was to evaluate the physiological responses of different soybean cultivars to copper concentration increase. Four different soybean cultivars were grown under three copper concentrations: 0.5, 20 and 40 μM in nutrient solution. The main outcomes of this study were: i) Cultivar M 6410 IPRO recorded the highest photosynthetic rate when plants were exposed to 40 μM of copper in the nutrient solution; ii) plants in cultivar M 6410 IPRO accumulated large copper concentrations in their roots although did not decrease the root dry mass, possibly due to the higher superoxide dismutase activity; iii) cultivar DM 5958 RSF IPRO recorded drastically reduced photosynthetic rate and dry mass production due to copper excess. We conclude that each cultivar responded differently to the excess of copper, but none of them showed tolerance to it.

Aerial application of copper for dothistroma control in New Zealand\u2019s planted forests\u2014effect on stream environments

Limited information is available on the risk to aquatic environments from the aerial application of copper fungicides to treat dothistroma needle blight in managed forests. Cuprous oxide was aerially applied to three catchments of Pinus radiata of varying age classes in the central North Island of New Zealand. Copper was monitored in stream water and sediments prior to and for 1 month after application. Copper deposits collected from tracer plates deployed above the water surface along the stream channels within the treated areas at each site ranged from 13 to 406 ppm. Lowest concentrations occurred above small stream channels with dense overhead riparian vegetation. Peak copper concentrations in stream water across the three sites ranged from 28 to 60 μg L−1 and were below the analytical detection limit within hours. Copper concentrations were higher and persisted for longer in stream sediment (range 1.7–6.1 mg kg−1, sampled at two sites only). Copper concentrations in sediments were below environmental guidelines. Copper concentrations in water and sediment indicated a low risk to aquatic organisms based on the exposure times to the concentrations measured in this study.

English

Citrus black spot (CBS) caused by Phyllosticta citricarpa (McAlpine) Van der Aa (asexual state) synonym Guignardia citricarpa Kiely (sexual state) is one of the most devastating diseases of citrus which occurs in various citrus producing areas around the globe. Management is mainly based on monthly applications of copper fungicides and strobilurins under field conditions. In this study, bio-control agents were evaluated as alternative post-harvest treatments against citrus black spot disease. Two bio-control agents namely, Bacillus subtilis Cohn and Trichoderma harzianum Rifai were evaluated for their efficacy against P. citricarpa. Their efficacy was further compared with commercial fungicides Dithane 750 (Mancozeb, 750 g/kg). Results obtained showed that T. harzianum treatments were highly suppressive towards pathogen growth in vitro (85%) as compared to B. subtillis (4%) and Dithane 750 (12%). Treatment of artificially inoculated fruits with combined formulations of both biocontrol agents resulted in reduced CBS severity as compared to their single applications. These findings suggest that T. harzianum had highest suppression of pathogen growth as compared to B. subtilis. The results also suggest that their combined application can provide an effective disease management when compared to sole application of Dithane 750. Further studies are however, needed to determine their effectiveness under field conditions and also their efficacy can be sustained when applied with commercial fungicides. &nbsp; Key words: Bacillus subtilis, biocontrol, dithane 750, Trichoderma harzianum.

Application of Copper Fungicide and Row Covers to Control Phytophthora Seedling Blight Disease on Cocoa

Phytophthora seedling blight disease is one of the important diseases in cocoa. The disease is caused by the fungus of Phytophthora palmivora belongs to class Oomycetes. The aim of this research was to determine the effectiveness of the use of row covers and copper oxide fungicide applications to control seedling blight Phytophthora. Covering treatment was to place cocoa seedlings inside bamboo frame covered by transparent plastic in order to avoid from rainfall effect. The research was conducted in the Kaliwining Experimental Station at Indonesian Coffee and Cocoa Research Institute (ICCRI). Experiments were carried out four treatments and repeated 6 times. Each treatment consists of 100 seedlings planted in polybags and placed in the nursery area with a protective paranet. The treatment consisted of (1) row covers, (2) spraying of copper oxide 0.2%, (3) a combination of row covers and copper oxide 0.2% and (4) control (no covers and spray). Observations made 7 days after treatment with an interval of 7 days for 10 weeks. The results showed that row covers able to prolong the incubation period of the disease for 14 days, while the application of row covers + copper oxide 0.2% was able to save cocoa seedlings by 96.2%.

Innovative ‘Artificial Mussels’ technology for assessing spatial and temporal distribution of metals in Goulburn–Murray catchments waterways, Victoria, Australia: Effects of climate variability (dry vs. wet years)

The “Artificial mussel” (AM), a novel passive sampling technology, was used for the first time in Australia in freshwater to monitor and assess the risk of trace metals (Cd, Cu, Hg, Pb, and Zn). AMs were deployed at 10 sites within the Goulburn–Murray Water catchments, Victoria, Australia during a dry year (2009–2010) and a wet year (2010–2011). Our results showed that the AMs accumulated all the five metals. Cd, Pb, Hg were detected during the wet year but below detection limits during the dry year. At some sites close to orchards, vine yards and farming areas, elevated levels of Cu were clearly evident during the dry year, while elevated levels of Zn were found during the wet year; the Cu indicates localized inputs from the agricultural application of copper fungicide. The impacts from old mines were significantly less compared ‘hot spots’. Our study demonstrated that climate variability (dry, wet years) can influence the metal inputs to waterways via different transport pathways. Using the AMs, we were able to identify various ‘hot spots’ of heavy metals, which may pose a potential risk to aquatic ecosystems (sub-lethal effects to fish) and public (via food chain metal bioaccumulation and biomagnification) in the Goulburn–Murray Water catchments. The State Protection Policy exempted artificial channels and drains from protection of beneficial use (including protection of aquatic ecosystems) and majority of sites (‘hot spots’) were located within artificial irrigation channels.

The effect of application of copper fungicides on photosynthesis parameters and level of elementary copper in hops

Photosynthesis and transpiration rates in the interval of 30 min before and 30 min after copper fungicide application show an increase from the level of 5.0 to 7.0 &amp;micro;mol CO&lt;sub&gt;2&lt;/sub&gt;/m&lt;sup&gt;2&lt;/sup&gt;/s and 0.75 to 1.00 mmol H&lt;sub&gt;2&lt;/sub&gt;0/m&lt;sup&gt;2&lt;/sup&gt;/s. Long-term measurements show that the increase of photosynthesis rate after copper application is temporal and fades away after 10&amp;minus;14 days. No stress response was induced after the application of copper fungicides. Contents of copper in hop cones are up to 500 mg/kg if total amount of applied copper does not exceed 15 kg/ha. Contents of copper on leaves are 2&amp;ndash;5 times higher at the same application dose. Application of 5 kg copper per one hectare of vigorous growth of Agnus variety increases content of copper on hop leaves by 1000 mg/kg at least. The same amount of copper increases its content in hop cones by 300 mg/kg at the ripening period. Tight correlation between the amount of copper applied and its content in hops does not exist. Elementary copper from leaves is brought into harvested hops in the form of biological admixtures. Copper content in hop cones shows a decreasing trend, which is given by gradual increase of cones size at the ripening period. Similar trend on hop leaves shows that washing off and dissolving of copper compounds by atmospheric water can participate in this process as well. Common content of copper in untreated hop cones and leaves is up to 20&amp;minus;25 mg/kg. &amp;nbsp; &amp;nbsp;

The effect of copper fungicides on the rate of photosynthesis and the transpiration of hop plants

The paper evaluates the effect of copper fungicide spraying on the rate of photosynthesis and transpiration of hops, the influence of spraying on the elemental copper content in the leaves and cones hop variety Agnus. Photosynthetic rate was measured by LC pro+ (infrared analyzer) in the Hop Research Institute Saaz in the field in some periods of 2008, 2009 and 2010. Dry cones and leaf samples (taken before and after application of copper fungicides) were analyzed in an accredited laboratory for elemental copper.

Obsah elementární mědi ve chmelu po opakovaných aplikacích měďnatých fungicidů.

Obsah elementární mědi ve chmelu po opakovaných aplikacích měďnatých fungicidů.

Plasmopara viticola: a review of knowledge on downy mildew of grapevine and effective disease management

Normal 0 14 false false false IT ZH-TW X-NONE MicrosoftInternetExplorer4 The oomycete Plasmopara viticola is native to North America and was accidentally introduced into Europe at the end of the 19th century, where it caused widespread damage to the grape industry. Since that time, the damage caused by this plant pathogen has generally been controlled with multiple fungicide applications. Modern fungicides applied as prescribed by weather-based warning systems can effectively prevent any damage that might be caused. Alternatives to chemical treatments, such as the use of biocontrol agents or resistant cultivars, currently play a marginal role in controlling this disease. Until the middle of last century, research efforts were mainly concentrated on optimizing the application of copper fungicides and developing new molecules and formulations for controlling the disease. During the second half of the last century, highly efficient products for control were available, so research efforts moved toward optimizing and minimizing chemical control, mostly through the use of weather-based warning systems based on complex biological models. In the last 20 years, parallel to the development of technologies for genomic and transcriptomic analyses, host-pathogen interactions and population genetics have captured the interest of researchers in this field. Breeding for resistance against downy mildew has always coexisted with chemical control. However, the results of these breeding programmes have traditionally been cultivated only in marginal areas and organic production systems. This review traces the history of European knowledge of P. viticola .

Free Cu 2+ Ions, Cu Fractionation and Microbial Parameters in Soils from Apple Orchards Following Long-Term Application of Copper Fungicides

Soil samples were collected from apple orchards 5, 15, 20, 30, and 45 years old, and one adjacent forest soil was used as reference to investigate the free Cu 2+ ion activity in soil solution and the soil Cu fractionation in the solid phase following long-term application of copper fungicide, Bordeaux mixture, in apple orchards and to investigate the relationships among soil free Cu 2+ ions, Cu fractionation and soil microbial parameters. The total Cu concentration in the orchard soils varied from 21.8 to 141 mg kg −1, increasing with the orchard age, and the value for the reference soil was 12.5 mg kg −1. The free Cu 2+ ion concentrations in the soil solutions extracted by 0.01 mol L −1 KNO 3 ranged from 3.13 × 10 −8 (reference) to 4.08 × 10 −6 mol L −1 (45 years-old orchard). The concentration of Cu complexed in the fulvic fraction increased with orchard age from 5.16 to 52.5 mg kg −1. This was also the case for other soil Cu fractions except the residual one. The residual soil Cu remained practically constant, ranging from 4.28 to 5.66 mg kg −1, suggesting that anthropogenic soil Cu mainly existed in the more labile active fractions. Regression analyses revealed that both the free Cu 2+ ions in the soil solution and the humic acid-complexed Cu fraction in the solid phase were strongly related with soil microbial parameters.

Rain-induced removal of copper from apple leaves: Influence of rain properties and tank-mix adjuvants on deposit characteristics at the micro scale

Application of copper fungicides is an integrative component in the control of apple scab. As shown in the past, tank-mix adjuvants might reduce the rain-induced removal of active ingredients. The aims of this study were a) to characterize the impact of defined rain amount on the removal of Cu-oxychloride (Cu-Ox) and Cu-hydroxide (Cu-Hyd) from apple seedling leaves, b) to examine the influence of ethoxylated seed oil adjuvants on deposit properties at the micro scale and their possible influence in reducing the fungicide erosion from the leaves, and finally c) to evaluate the influence of previous adjuvant application on the rainfastness of copper ions. Losses of Cu-Hyd and Cu-Ox from seedling leaves exposed to 5 mm heavy rain reached almost 80% of the original Cu load. Wash-off extent of Cu-Ox could be reduced by using the rapeseed oil ethoxylate RSO 5 (47%), the linseed oil ethoxylate LSO 10 (47%), or the soybean oil ethoxylate SBO 10 (40%). However, in case of Cu-Hyd, none of the adjuvants was able to increase the tenacity of the copper on the leaves. Rainfall removed the bulky deposits and induced changes in the typical shape of the crystals. Furthermore, a reorganization of the spatial distribution of the remaining active ingredient (a.i.) was induced, which was very often embedded in a thin layer of adjuvants. In general, the adjuvants had a significant impact on droplet spread, whereas the area effectively covered with the a.i. was affected to a lesser extent. For both Cu-Hyd and Cu-Ox rewetting of the original deposit under controlled conditions resulted in an increased spread area but reduced the area effectively covered with Cu. Our results showed no clear relationship between the area covered by Cu ions and their adhesion to the surface, i.e. rainfastness. Finally, our studies indicated that previous spray treatments might influence the rain-induced removal of copper.

Microbial and enzyme properties of apple orchard soil as affected by long-term application of copper fungicide

Copper-based fungicides have been applied in apple orchards for a long time, which has resulted in increasing soil Cu concentration. However, the microbial and enzyme properties of the orchard soils remain poorly understood. This study aimed to evaluate the effect of long-term application of Cu-based fungicides on soil microbial (microbial biomass carbon (C mic), C mineralization, and specific respiration rate) and enzyme (urease, acid phosphatase, and invertase activities) properties in apple orchards. Soil samples studied were collected from apple orchards 5, 15, 20, 30, and 45 years old, and one adjacent forest soil as for reference. The mean Cu concentrations of orchard soils significantly increased with increasing orchard ages ranging from 21.8 to 141 mg kg −1, and the CaCl 2-extractable soil Cu concentrations varied from 0.00 to 4.26 mg kg −1. The soil mean C mic values varied from 43.6 to 116 mg kg −1 in the orchard soils, and were lower than the value of the reference soil (144 mg kg −1). The ratio of soil C mic to total organic C (C org) increased from 8.10 to 18.3 mg C mic g −1 C org with decreasing orchard ages, and was 26.1 mg C mic g −1 C org for the reference soil. A significant correlation was observed between total- or CaCl 2-extractable soil Cu and soil C mic or C mic/C org, suggesting that the soil Cu was responsible for the significant reductions in C mic and C mic/C org. The three enzyme activity assays also showed the similar phenomena, and declined with the increasing orchard ages. The mean soil C mineralization rates were elevated from 110 to 150 mg CO 2–C kg −1 soil d −1 compared with the reference soil (80 mg CO 2–C kg −1 soil d −1), and the mean specific respiration rate of the reference soil (0.63 mg CO 2–C mg −1 biomass C d −1) was significantly smaller than the orchard soils from 1.19 to 3.55 mg CO 2–C mg −1 biomass C d −1. The soil C mineralization rate and the specific respiration rate can be well explained by the CaCl 2-extractable soil Cu. Thus, the long-term application of copper-based fungicides has shown adverse effects on soil microbial and enzyme properties.

Seletividade de fungicidas cúpricos e sistêmicos sobre o fungo Cladosporium cladosporioides em cafeeiro

A ocorrência do fungo Cladosporium sp. em frutos do cafeeiro é freqüente e coincide com o período de controle de doenças desta cultura. O fungo Cladosporium sp. tem sido relatado associado a cafés de boa qualidade portanto, é importante que os fungicidas sejam seletivos aos agentes antagonistas de fungos deletérios à qualidade do café sendo o Cladosporium sp incluído neste grupo. Deste modo, o objetivo do presente trabalho foi testar a seletividade de alguns produtos utilizados visando o controle de doenças do cafeeiro sobre o fungo Cladosporium cladosporioides (Fres.) de Vries. O trabalho foi desenvolvido em uma lavoura da cultivar Acaiá Cerrado MG 1474, com 6 anos de idade no espaçamento adensado de 2,0 x 0,6 m, onde foram testados produtos preventivos, a base de cobre, e sistêmico, aplicados isoladamente e associados. Foram empregados como produtos cúpricos o oxicloreto de cobre (50% de cobre metálico) e Calda Viçosa comercial e como sistêmico o epoxiconazole. A avaliação da incidência de C. cladosporioides foi realizada através de notas subjetivas, em quatro épocas, registrando em porcentagem a área com crescimento fúngico sobre os frutos do cafeeiro. Verificou-se que enquanto nos tratamentos com fungicida epoxiconazole aplicado isoladamente ou associado ao fungicida cúprico o fungo apresentava-se inicialmente com baixa incidência, aumentando progressivamente a partir do mês de maio, nos tratamentos com apenas fungicidas cúpricos a incidência do fungo mostrou-se elevada desde maio, indicando não ter sido afetada e/ou mesmo favorecida por pulverizações anteriores do produto.

Airblast Application of Copper Fungicide to Grapefruit Does Not Affect Windscar

Wind-induced blemishing known as windscar and lesions from the disease melanose (caused by Diaporthe citri) are two of the most important causes of fresh grapefruit (Citrus paradisi) cullage in Florida. Copper hydroxide fungicides are the primary means of controlling melanose, but high air velocities from passing sprayers have been suspected of increasing windscar. In 1998 and 1999, airblast applications of Cu(OH)2 (1.7 kg·ha-1 Cu) were made at a range of early fruit development stages to a fresh grapefruit orchard in the Indian River region of Florida. These applications supplemented aerial sprays of Cu(OH)2 that were made uniformly across the entire experimental site at biweekly intervals beginning near full bloom. During the commercial harvest period fruit were sampled from three regions (interior, upper exterior, and lower exterior) of each treatment tree and were evaluated for percentage of fruit surface covered by windscar and severity of melanose. Airblast applications did not affect windscar in either year, but windscar was significantly greater from the upper exterior of the canopy, which is likely to experience the highest natural wind velocities. From these data, it appears unlikely that airblast applications significantly contribute to windscar of Indian River grapefruit. In 1998, no trees receiving airblast applications had significantly lower melanose incidence than the trees sprayed only via aircraft; however, trees receiving four airblast applications were scored as having higher apparent melanose on exterior samples than trees receiving most other treatments. This is consistent with high levels of Cu injury on these fruit which can superficially resemble melanose. Following treatment in 1999, trees receiving four airblast applications of Cu(OH)2 had significantly lower melanose scores than trees receiving either no or only early airblast applications, but were not significantly different from trees receiving a single spray 5.5 weeks postbloom. A computer model, which estimates Cu levels on fruit based on fruit growth, rainfall, and application parameters, indicated exterior fruit receiving four airblast sprays had &gt;3 μg·cm-2 [Cu] for 40 days in 1998 but only 10 days in 1999, which reflects increased probability of Cu damage in 1998. It appears that aerial application supplemented by airblast merits further study as an economical means of melanose control.