Articles
Effect of SO2 treatment on Penicillium spp., the cause of blue mold of table grapes, and increased sensitivity to pyrimethanil when combined with Timorex Gold
Article number
1451_4
Pages
21 – 26
Language
English
Abstract
Blue mold caused by Penicillium spp. is becoming one of the main postharvest rots of table grapes in Chile.
Most of the field and postharvest management have been focused in the control of gray mold (Botrytis cinerea) regardless of the presence of other pathogenic fungi such as Penicillium spp.
The objectives of this research were to evaluate the effect of sulfur dioxide (SO2) on Penicillium spp. and to determine the sensitivity of Penicillium spp. to pyrimethanil alone or mixed with Timorex Gold®. The effect of SO2 was studied in a commercial packinghouse where harvested grapes were treated inside a fumigation chamber by injecting 1,200 mL of SO2, with a recirculation for 6 and 7 min of ventilation.
An alternative process was design injecting 1,800 mL and recirculation for 10 min.
Red globe table grapes were taken from 4 clusters before and after SO2 fumigation, each berry was placed in a tube containing 2 mL of sterile distilled water, vortexed for 1 min and a 100 µL aliquot was plated in acidified water agar, incubated at 20°C for 7 days.
The result was expressed as CFU cm‑2 of berry.
The sensitivity of 18 Penicillium spp. isolates was studied in minimum medium amended with pyrimethanil alone or mixed with Timorex Gold®, at pyrimethanil concentrations of 0, 0.1, 1 and 10 µg mL‑1. After incubating at 20°C for 18 h the conidial germination percentage was determined.
The commercial SO2 treatment did not affect the amount of CFU of Penicillium spp., while the alternative treatment reduced the amount of CFU of Penicillium spp. in two of three trials.
All isolates tested had increased sensitivity to pyrimethanil when mixed with Timorex Gold®.
Most of the field and postharvest management have been focused in the control of gray mold (Botrytis cinerea) regardless of the presence of other pathogenic fungi such as Penicillium spp.
The objectives of this research were to evaluate the effect of sulfur dioxide (SO2) on Penicillium spp. and to determine the sensitivity of Penicillium spp. to pyrimethanil alone or mixed with Timorex Gold®. The effect of SO2 was studied in a commercial packinghouse where harvested grapes were treated inside a fumigation chamber by injecting 1,200 mL of SO2, with a recirculation for 6 and 7 min of ventilation.
An alternative process was design injecting 1,800 mL and recirculation for 10 min.
Red globe table grapes were taken from 4 clusters before and after SO2 fumigation, each berry was placed in a tube containing 2 mL of sterile distilled water, vortexed for 1 min and a 100 µL aliquot was plated in acidified water agar, incubated at 20°C for 7 days.
The result was expressed as CFU cm‑2 of berry.
The sensitivity of 18 Penicillium spp. isolates was studied in minimum medium amended with pyrimethanil alone or mixed with Timorex Gold®, at pyrimethanil concentrations of 0, 0.1, 1 and 10 µg mL‑1. After incubating at 20°C for 18 h the conidial germination percentage was determined.
The commercial SO2 treatment did not affect the amount of CFU of Penicillium spp., while the alternative treatment reduced the amount of CFU of Penicillium spp. in two of three trials.
All isolates tested had increased sensitivity to pyrimethanil when mixed with Timorex Gold®.
Authors
J.L. Henríquez-Sáez, P. Alarcón, C. Salinas, Y. Fernández, C. Arroyo
Keywords
postharvest rots, fungicides, tea tree oil, integrated disease management, sulfur dioxide
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