Articles
NEW POSTHARVEST DECAY CONTROL TREATMENTS THAT ARE EXEMPT FROM RESIDUE TOLERANCES IN THE UNITED STATES
Article number
1079_36
Pages
299 – 306
Language
English
Abstract
Biopesticide and exempt-from-tolerance compounds have been recently registered (e.g., potassium phosphite, K-PO3), are currently in the registration process (e.g., polyoxin-D), or are being evaluated (e.g., EXP-13) for their potential in postharvest decay control of fruit.
Citrus brown rot originates from field infections by Phytophthora species and can cause significant losses.
Phosphonates are registered preharvest treatments.
Because no effective postharvest treatments were available for its management, potassium phosphite was evaluated.
At 1000-4000 mg/L, K-PO3 was similarly effective as azoxystrobin, mandipropamid, or fluopicolide in protecting fruit from brown rot when applied before inoculation.
Only potassium phosphite, however, had post-infection activity, reducing decay to low levels in treatments done 20-24 h after inoculation.
Potassium phosphite is now registered for postharvest use with exempt status in the US. International tolerances are being pursued for major export markets.
Polyoxin-D, a fermentation product of Streptomyces cacaoi var. asoensis, has a US biopesticide registration for field use on various crops.
We found it most effective against gray mold (Botrytis cinerea). At 50-200 mg/L, it was similarly effective to conventional postharvest fungicides on stone fruits.
On pome fruits and pomegranate, its efficacy was more variable and depended on fruit cultivar and treatment time after inoculation.
Polyoxin-D is scheduled for postharvest registration in 2015. Currently, we are evaluating EXP-13 for control of Penicillium decays of citrus and pome fruits.
Although moderately effective by itself, high control was achieved when mixed with low concentrations of registered fungicides.
Our investigations indicate that exempt-from-residue and biopesticide compounds can be valuable postharvest treatments and potentially, may be approved for organic production.
They can also be mixture partners with other fungicides in an effort to minimize resistance development.
Citrus brown rot originates from field infections by Phytophthora species and can cause significant losses.
Phosphonates are registered preharvest treatments.
Because no effective postharvest treatments were available for its management, potassium phosphite was evaluated.
At 1000-4000 mg/L, K-PO3 was similarly effective as azoxystrobin, mandipropamid, or fluopicolide in protecting fruit from brown rot when applied before inoculation.
Only potassium phosphite, however, had post-infection activity, reducing decay to low levels in treatments done 20-24 h after inoculation.
Potassium phosphite is now registered for postharvest use with exempt status in the US. International tolerances are being pursued for major export markets.
Polyoxin-D, a fermentation product of Streptomyces cacaoi var. asoensis, has a US biopesticide registration for field use on various crops.
We found it most effective against gray mold (Botrytis cinerea). At 50-200 mg/L, it was similarly effective to conventional postharvest fungicides on stone fruits.
On pome fruits and pomegranate, its efficacy was more variable and depended on fruit cultivar and treatment time after inoculation.
Polyoxin-D is scheduled for postharvest registration in 2015. Currently, we are evaluating EXP-13 for control of Penicillium decays of citrus and pome fruits.
Although moderately effective by itself, high control was achieved when mixed with low concentrations of registered fungicides.
Our investigations indicate that exempt-from-residue and biopesticide compounds can be valuable postharvest treatments and potentially, may be approved for organic production.
They can also be mixture partners with other fungicides in an effort to minimize resistance development.
Publication
Authors
J.E. Adaskaveg, H. Förster
Keywords
biopesticides, biofungicides, chemical fungicides, disease management
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