Effect of Fungicide Application on the Management of Avocado Branch Canker (Formerly Dothiorella Canker) in California

Twizeyimana, M.; McDonald, V.; Mayorquin, Joey S; Wang, D.; Francis, Nick; Akgül, Davut Soner; Eskalen, Akif

doi:10.1094/pdis-06-12-0518-re

Cited by 18 publications

(6 citation statements)

References 28 publications

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“…While the least (%) success of avocado grafted seedlings on all cultivars in the two seasons were observed on Star copper and Bio Zeid. Twizeyimana et al (2013) found in vitro test that azoxystrobin, fludioxonil, metconazole, and pyraclostrobin inhibited the mycelial growth of Neofusicoccum america, N. luteum, N. parvum, and Phomopsis sp. which are associated with branch cankers of avocado trees (Persea americana) in California.…”

Section: Discussionmentioning

confidence: 97%

Protecting Avocado Seedlings from Grafting Failure During Propagation in Nursery Using Biological and Chemical Control

Monir

Radwan

Hassan

2021

Egyptian Journal of Phytopathology

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During propagation of avocado by grafting in 2019 and 2020, the maximum % grafting failure (GF) of avocado seedlings was recorded on cv. Hass and cv. Fuerte, followed by cv. Benkerton and cv. Reed. While cv. Etinger was the less susceptible one. Lasiodiplodia theobromae was the most frequently isolated from graft failure seedlings in all avocado cultivars, followed by Fusarium moniliforme. While Alternaria alternata recorded the lowest frequency. The highest percentage of grafting failure and death of scions was obtained by the fungus L. theobromae, followed by F. moniliforme and the lowest percentage of grafting failure was observed for A. alternata in all avocado cultivars. The efficacy of biological and chemical control was tested in vitro and in vivo as well as under nursery conditions for controlling GF on avocado seedlings. Amistar Top and Bellis gave the highest reduction in colony growth of the three pathogens, followed by Kocide (2000) and Star copper. While Serenade ASO and Bio Zeid were the lowest ones. Dipping scions in each of the tested suspensions before dipping in spore suspension of each fungus suppressed the spores of the pathogen during grafting and increased the percentage of success of grafted seedlings in the two tested cultivars Hass and Fuerte compared with the control. In this respect, Amistar Top and Bellis were the most effective treatments for controlling the pathogens in the two tested cultivars, followed by Kocide (2000) and Star copper. The lowest efficacy was recorded when scions were dipped on Serenade ASO and Bio Zeid. Also, dipping scions in the suspension of each tested commercial product during grafting increased the percentage of grafting success for all tested cultivars compared with the control. Considering the means of efficacy of the tested treatments on the tested cultivars in the two seasons, Amistar Top, Bellis and Kocide (2000) were the most effective which recorded (91.00 and 94.00%), (85.00 and 87.00%) and (84.00 and 87.00%), respectively (%) success of avocado grafted seedlings on all cultivars in the two years, followed by Serenade ASO (83.00% and 87.00%). While the least (%) success of avocado grafted seedlings on all cultivars in the two seasons was observed on Star copper and Bio Zeid (81.00 and 86.00%) and (81.00 and 84.00%), respectively. Also, the highest effect of all treatments was on cv. Etinger, cv. Reed and cv. Benkerton, while the lowest effect was on cv. Fuerte and cv. Hass in the two seasons. The highest values of production of peroxidase and polyphenoloxidase activities in the two tested avocado cultivars Hass and Fuerte were observed after dipping the scions in Amistar Top and Bellis, followed by Kocide (2000) and Serenade ASO. While the lowest values of peroxidase and polyphenoloxidase activities were recorded after dipping the scions in Star copper and Bio Zeid.

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Section: Discussionmentioning

confidence: 97%

Protecting Avocado Seedlings from Grafting Failure During Propagation in Nursery Using Biological and Chemical Control

Monir

Radwan

Hassan

2021

Egyptian Journal of Phytopathology

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“…In 1996, the manufacturer created metalaxyl-M (mefenoxam), a more active isomer of the fungicide, which is similarly applied (Olson and Benson 2013). Unlike metalaxyl and mefenoxam, which are xylem-mobile fungicides, phosphonate fungicides can move in both the xylem and phloem tissues (Cohen and Coffey 1986;Landschoot and Cook 2005;Twizeyimana et al 2013). The most effective and perhaps well-known phosphonate fungicide is fosetyl-Al, which was also developed in 1977.…”

Section: Fungicides For Oomycete Pathogen Managementmentioning

confidence: 99%

Detection of Oomycide-Insensitive Phytophthora Isolates in Maryland Ornamental Nurseries and Mid-Atlantic Landscapes Provide Data for Reconsidering Management Strategies

Beaulieu

Múnera

Balcì

2021

Plant Health Progress

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Five Phytophthora species comprising a total of 243 isolates (77 P. cinnamomi, 23 P. citrophthora, 18 P. multivora, 18 P. pini, and 107 P. plurivora) were screened for sensitivity to mefenoxam, fosetyl-Al, dimethomorph, dimethomorph + ametoctradin and fluoxastrobin using amended agar assays. Mefenoxam-insensitive isolates were detected within P. cinnamomi (4%), P. multivora (11%), and P. plurivora (12%) even at approximately 2.5x the recommended label rate. These isolates were also insensitive to higher (off-label) concentrations of fluoxastrobin. Concentrations of dimethomorph (400 g/mL) and dimethomorph + ametoctradin (100 g/mL) were mostly effective in mycelial growth inhibition, but two P. plurivora isolates were insensitive, suggesting that resistance management is required. All mefenoxam-insensitive isolates were sensitive to fosetyl-Al at the label rate. Surprisingly, the populations of P. cinnamomi from mid-Atlantic oak forests included insensitive isolates. With almost all species, isolates recovered from asymptomatic hosts (e.g., soil/potting media collected of randomly selected asymptomatic hosts) had a significantly greater relative growth rate when compared to isolates recovered from symptomatic hosts (e.g., isolates recovered from lesions or wilted plants). These findings suggest that mefenoxam should no longer be used to manage oomycetes in Maryland ornamental nurseries and that the use of fluoxastrobin should be limited.

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“…Symptoms of dieback are characterized by necrosis and death of twigs and branch-es in the tree canopy, with symptomatic plants exhibiting dry branches, external necrosis in twigs, and wilting leaves and inflorescences [ 3 , 4 , 5 , 6 , 7 ]. Cankers associated with Botryosphaeriaceae species (formerly Dothiorella canker ) can occur on branches and trunks, where infections are initiated by spores entering through fresh wounds resulting from pruning, mechanical injury, sunburn or frost damage [ 8 ]. Cankers on avocado may exudate reddish-brown sap that turns to a whitish-yellowish powder when dry [ 8 , 9 , 10 , 11 ].…”

Section: Introductionmentioning

confidence: 99%

“…Cankers associated with Botryosphaeriaceae species (formerly Dothiorella canker ) can occur on branches and trunks, where infections are initiated by spores entering through fresh wounds resulting from pruning, mechanical injury, sunburn or frost damage [ 8 ]. Cankers on avocado may exudate reddish-brown sap that turns to a whitish-yellowish powder when dry [ 8 , 9 , 10 , 11 ]. The bark appears darkened and friable and can be easily removed in old cankers.…”

Section: Introductionmentioning

confidence: 99%

“…The bark appears darkened and friable and can be easily removed in old cankers. Underneath the bark, cankers are reddish-brown in colour and variable in shape, sometimes penetrating into the heartwood and affecting the xylem [ 9 , 10 ]; this may lead to dieback and collapse of branches or the entire tree [ 5 , 8 , 10 ]. In addition, fruit rot caused by Botryosphaeriaceae species is a common problem in avocado-producing regions ( Table 1 ), representing an important threat to avocado production throughout the word.…”

Section: Introductionmentioning

confidence: 99%

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Fungal Pathogens Associated with Aerial Symptoms of Avocado (Persea americana Mill.) in Tenerife (Canary Islands, Spain) Focused on Species of the Family Botryosphaeriaceae

et al. 2023

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Fungi of the family Botryosphaeriaceae are considered responsible for various symptoms in avocado such as dieback, external necrosis of branches and inflorescences, cankers on branches and trunks, or stem-end rot of fruits. In recent years, these problems are becoming more frequent in avocado orchards in the Canary Islands (Spain). This work includes the characterization of fungal species involved in these diseases, which were isolated from avocado crops in Tenerife Island between 2018 and 2022. A total of 158 vegetal samples were collected, from which 297 fungal isolates were culture-isolated. Fifty-two of them were selected according to their morphological features as representative isolates of Botryosphaeriaceae, and their molecular characterization was carried out, sequencing the ITS1-2 region as well as the β-tubulin and the elongation factor 1-alpha genes. Five species of Botryosphaeriaceae were isolated, including Neofusicoccum australe, N. cryptoaustrale/stellenboschiana, N. luteum, N. parvum, and Lasiodiplodia brasiliensis. This is the first time that L. brasiliensis has been associated with avocado dieback and that N. cryptoaustrale/stellenboschiana has been cited in avocado causing symptoms of dieback and stem-end rot. However, it was not possible to assign our isolates unequivocally to N. cryptoaustrale or N. stellenboschiana even additionally using the rpb2 marker for their molecular characterization. Botryosphaeriaceae family seem to be involved in avocado dieback, in the premature fall of fruits during their development in the field and in post-harvest damage in Tenerife, but further studies are needed to clarify the fungal pathogens associated with symptoms in relation to phenological plant growth stages or less frequently observed.

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Effect of Fungicide Application on the Management of Avocado Branch Canker (Formerly Dothiorella Canker) in California

Abstract: Twizeyimana, M., McDonald, V., Mayorquin, J. S., Wang, D. H., Na, F., Akgül, D. S., and Eskalen, A. 2013. Effect of fungicide application on the management of avocado branch canker (formerly Dothiorella canker) in California. Plant Dis. 97:897-902.

Cited by 18 publications

References 28 publications

Protecting Avocado Seedlings from Grafting Failure During Propagation in Nursery Using Biological and Chemical Control

Protecting Avocado Seedlings from Grafting Failure During Propagation in Nursery Using Biological and Chemical Control

Detection of Oomycide-Insensitive Phytophthora Isolates in Maryland Ornamental Nurseries and Mid-Atlantic Landscapes Provide Data for Reconsidering Management Strategies

Fungal Pathogens Associated with Aerial Symptoms of Avocado (Persea americana Mill.) in Tenerife (Canary Islands, Spain) Focused on Species of the Family Botryosphaeriaceae

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