Articles
Overview of management practices with the use of biocontrols, natural products, and conventional fungicides to combat pre- and postharvest diseases of peach and nectarine fruit
Article number
1352_2
Pages
17 – 26
Language
English
Abstract
Bacterial or yeast biocontrol agents as well as natural products can be used to manage brown rot blossom blight of peach and nectarine with similar efficacy as conventional fungicides when used under moderate to low disease pressure.
In general, however, they are less effective when used as treatments against pre- and postharvest fruit diseases.
They are mostly ineffective as postharvest treatments when mature fruit are inoculated 12 to 14 h before treatment to simulate standard practices where fruit injuries are created during bulk harvesting and transportation to packinghouses with a time delay in applying packingline treatments to prevent decay.
Historically, conventional fungicides such as benomyl, thiophanate methyl, dichloran, triforine, and iprodione were used as postharvest treatments with high efficacy against major decays.
In the United States, the shift to safer fungicides began with the Food Quality Protection Act of 1995 that resulted in the identification of reduced risk fungicides like fludioxonil and fenhexamid that were introduced as safer postharvest treatments.
More recently, the United States Environmental Protection Agency has classified natural products produced by fermentation such as natamycin and polyoxin-D as agricultural biopesticides that are exempt from tolerance and were recently organically approved.
Our research demonstrates that these fermentation products can provide high levels of efficacy against major decays (i.e., brown rot, gray mold, Rhizopus rot) as post-harvest treatments of peach and nectarine.
Some decays such as sour rot, however, are difficult to manage because most conventional fungicides are not effective in inhibiting growth of the pathogen Geotrichum candidum. Propiconazole, however, has been identified to be effective, has been registered, and is used commercially.
Although natamycin is effective against sour rot of citrus caused by G. citri-aurantii, it is ineffective against sour rot of peach and nectarine.
Curiously, the effective concentrations to inhibit 50% growth of both Geotrichum species are similar.
Our studies with phytosterol binders as pre-treatments prior to natamycin application demonstrate that the efficacy of natamycin against sour rot of peach and nectarine can be dramatically improved.
Apparently, phytosterols in these fruits competitively bind to natamycin and limit binding of natamycin with the fungal ergosterol to inhibit mycelial growth.
Fungal organisms are known to have different amounts of ergosterol, and this can explain the differential performance of natamycin in managing different decays of peach and nectarine.
In general, however, they are less effective when used as treatments against pre- and postharvest fruit diseases.
They are mostly ineffective as postharvest treatments when mature fruit are inoculated 12 to 14 h before treatment to simulate standard practices where fruit injuries are created during bulk harvesting and transportation to packinghouses with a time delay in applying packingline treatments to prevent decay.
Historically, conventional fungicides such as benomyl, thiophanate methyl, dichloran, triforine, and iprodione were used as postharvest treatments with high efficacy against major decays.
In the United States, the shift to safer fungicides began with the Food Quality Protection Act of 1995 that resulted in the identification of reduced risk fungicides like fludioxonil and fenhexamid that were introduced as safer postharvest treatments.
More recently, the United States Environmental Protection Agency has classified natural products produced by fermentation such as natamycin and polyoxin-D as agricultural biopesticides that are exempt from tolerance and were recently organically approved.
Our research demonstrates that these fermentation products can provide high levels of efficacy against major decays (i.e., brown rot, gray mold, Rhizopus rot) as post-harvest treatments of peach and nectarine.
Some decays such as sour rot, however, are difficult to manage because most conventional fungicides are not effective in inhibiting growth of the pathogen Geotrichum candidum. Propiconazole, however, has been identified to be effective, has been registered, and is used commercially.
Although natamycin is effective against sour rot of citrus caused by G. citri-aurantii, it is ineffective against sour rot of peach and nectarine.
Curiously, the effective concentrations to inhibit 50% growth of both Geotrichum species are similar.
Our studies with phytosterol binders as pre-treatments prior to natamycin application demonstrate that the efficacy of natamycin against sour rot of peach and nectarine can be dramatically improved.
Apparently, phytosterols in these fruits competitively bind to natamycin and limit binding of natamycin with the fungal ergosterol to inhibit mycelial growth.
Fungal organisms are known to have different amounts of ergosterol, and this can explain the differential performance of natamycin in managing different decays of peach and nectarine.
Publication
Authors
J.E. Adaskaveg, D. Chen, D. Cary, H. Förster
Keywords
integrated disease management, fungicides, food preservatives
Groups involved
Online Articles (87)