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ARS Home » Pacific West Area » Parlier, California » San Joaquin Valley Agricultural Sciences Center » Commodity Protection and Quality Research » Research » Publications at this Location » Publication #283500
Title: Biological Control of Phacidiopycnis Rot in ‘d’Anjou’ Pears

Author
item Xiao, Chang-Lin
item BOAL, R - Washington State University

Submitted to: Acta Horticulturae
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/10/2013
Publication Date: 8/27/2013
Citation: Xiao, C., Boal, R.J. 2013. Biological Control of Phacidiopycnis Rot in ‘d’Anjou’ Pears. Acta Horticulturae. 1001:255-258.

Interpretive Summary: Postharvest fruit rot diseases result in significant economic losses to the pear industry in the Pacific Northwest. Phacidiopycnis rot, caused by the fungus Phacidiopycnis piri, is a recently reported postharvest fruit rot disease of pears in the U.S. Fungicides applied after harvest are commonly used to control postharvest rots in pears, but limited options are available for control of postharvest diseases in organic fruit. In this study, we evaluated two biocontrol agents, BioSave (a Pseudomonas syringae strain) and Cryptococcus laurentii strain 87-108, for control of Phacidiopycnis rot in comparison with the conventional fungicide thiabendazole (TBZ). BioSave and C. laurentii significantly reduced incidence of Phacidiopycnis rot by 96-98% and 38-45% compared to the nontreated control, respectively. BioSave was more effective than the C. laurentii. No decay was observed on TBZ treated fruit, but there was no statistical difference in decay incidence between BioSave and TBZ treatments. The results suggest that BioSave is effective for controlling Phacidiopycnis rot and can provide a level of control of Phacidiopycnis rot comparable to that of TBZ.

Technical Abstract: Phacidiopycnis rot, caused by Phacidiopycnis piri, is a recently reported postharvest fruit rot disease of pears (Pyrus) in the U.S. and a major disease of ‘d’Anjou’ pears grown in Washington State. Phacidiopycnis rot can originate from infection of wounds on the fruit. In this study, two biocontrol agents, BioSave (a Pseudomonas syringae strain) or Cryptococcus laurentii strain 87-108, compared to the conventional fungicide thiabendazole (TBZ) were evaluated for control of Phacidiopycnis rot. ‘D’Anjou’ pear fruit were surface disinfested, wounded with a finishing nail head, treated with one of the biocontrol agents or TBZ, and inoculated with conidial suspension of P. piri. A non-treated control was included with pathogen alone. The experiment was conducted twice using fruit from different orchards where no fungicides were used. Each treatment contained four 20-fruit replicates. Inoculated fruit were placed on fiber fruit trays wrapped with perforated bags and stored in cardboard boxes at 0°C for three months, at which time decay was assessed. Over 92% of the fruit in the non-treated control developed Phacidiopycnis rot. BioSave and C. laurentii significantly reduced incidence of Phacidiopycnis rot by 96-98% and 38-45% compared to the control, respectively. BioSave was more effective than the C. laurentii. No decay was observed on TBZ treated fruit, but there was no statistical difference in decay incidence between BioSave and TBZ treatments. The results suggest that BioSave is effective in controlling Phacidiopycnis rot originating from wound infections by P. piri and can provide a level of control of Phacidiopycnis rot comparable to that of TBZ.