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United States Department of Agriculture

Agricultural Research Service

Wojciech J Janisiewicz

Research Plant Pathologist

Dr. Wojciech Janisiewicz
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Research Plant Pathologist


Picture of Dr. Wojciech Janisiewicz




2217 Wiltshire Road

Kearneysville, WV 25430

Voice: (304) 725-3451 x358


CRIS Research Project:

Biological Approaches for Managing Diseases of Temperate Fruit Crops 


Professional Biographical Information:

Ph.D. Plant Pathology               WashingtonStateUniversity                         1983

M.S. Plant Pathology                WashingtonStateUniversity                         1979

B.S. Horticulture                       Academy of Agriculture, Krakow, Poland    1975


Employment History


1984- present,  Research Plant Pathologist, USDA, ARS, Appalachian Fruit Research Station,

1983 - Temporary Appointment Postharvest Pathology, Tree Fruit Research Center, Washington State University,


Research Interests


Isolation of bacterial and yeast naturally occurring on fruit for biological control of postharvest diseases of fruits and vegetables.


Improvement of postharvest biological control system by selecting and developing new strains of antagonists, and by manipulation of chemical and physical environment.


Development of ecological foundation to understand microbial interactions on fruit surfaces and to develop antagonist mixtures with a broader spectrum of activity and superior effectiveness.


Genetic characterization and modification of bacteria and yeasts antagonists to improve biocontrol.


Biological control of foodborne human pathogen with phages, antagonistic yeasts and bacteria.


Control of latent infection on fruits after harvest.


Development of recombinant antibodies to explain mechanism of virulence and develop new approach to control postharvest diseases of fruits.


Developed biological control of blue mold (Penicillium expansum) and gray mold (Botrytis  cinerea) of pome fruits with naturally occurring bacterial and yeast antagonists.

Current Assignment:


Wojciech Janisiewicz is a Research Plant Pathologist for the Biological Approaches for Managing Diseases of Temperate Fruit Crops CRIS Work Unit at the USDA-ARS Appalachian Fruit Research Station


Biological Control of Postharvest Diseases of Pome and Stone Fruits

The overall objectives of the research are to develop non-fungicidal control of postharvest decays on pome and stone fruits by using antagonistic microorganisms and by interference with pathogen virulence factors.

Most of our efforts have been made to control postharvest decays on apples and pears. We are focused on using antagonistic bacteria and yeasts isolated from the fruit surface. One of our antagonists, an innocuous widespread bacterium Pseudomonas syringae (strain L-59-66, non-pathogenic) was developed into commercial product Bio-Save?. Originally the product was developed for control of Penicillium expansum (blue mold), Botrytis cinerea (gray mold), and Mucor piriformis (mucor rot), on apples and pears, but its use has been extended to control blue mold and gray mold on cherries, Fusarium dry rot, and silver scurf on potatoes, mucor rot on sweet potatoes, and blue mold and green mold on citrus fruit. This bacterium can also inhibit growth of human pathogens, such as E. coli O157:H7, on apple. The mechanism of biocontrol of this antagonist has not been fully described but competition for limited nutrients and space appears to play the major role.




Increased use of Bio-Save? for control of postharvest decays has been ongoing since its introduction in the mid 90s. Currently, approximately 4 to 8 million cartons of pear and apple, approximately 8 million lugs of cherry, 1 million cartons of citrus, and 3 million sacks of potato are treated with Bio-Save? annually. Bio-Save ? is listed by the Organic Materials Review Institute (OMRI) for use in organic production and fruits can be shipped internationally as it has no requirement for maximum limits for pesticide residues (MRL). JET Harvest Solutions Co. (LongwoodFL) currently markets Bio-Save?.


Biological and chemical control can be closely related.

In collaboration with Dr. J. Roitman from WRRC we developed the basic knowledge on secondary metabolites produced by one of our antagonists, P. cepacia (now Burkholderia cepacia), which may be involved in mechanisms of inhibition of pathogens on fruit.  We isolated a powerful antifungal compound, pyrrolnitrin, from P. cepacia.  This compound protected apple and pear from gray?mold, blue?mold, and Mucor rot, significantly extended strawberry shelf?life, and controlled B. cinerea on cut roses better than any other available fungicide.  Pyrrolnitrin isolated from this bacterium was also used as a postharvest treatment by other scientists against various diseases of apple, citrus fruit, peaches, nectarines, and strawberry fruit.  In each case, it provided excellent control.




Control of blue mold caused by Penicillium italicum (P.i.) and green mold caused by Penicillum digitatum (P.g.) by Pseudomonas cepacia (P.c.) (on the left) or by various concentrations of pyrrolnitrin (no the right) on lemons.


This and good safety data for mammalian toxicity (obtained by others) indicated the great potential of pyrrolnitrin for postharvest use on fruits and other agricultural products.  A patent has been awarded for this biocontrol agent and on the use of pyrrolnitrin for the control of postharvest diseases. Phenylpyrrole compounds (to which pyrrolnitrin belongs) now constitute a new group of fungicides.  Ciba-Geigy (now Syngenta) developed analogs of pyrrolnitrin, fenpiclonil and fludioxonil, which are now used commercially. Fludioxonil was registered in 2006 for control of postharvest decays on various fruits in the United States under the names ScholarTM and GraduateTM.



Control of blue mold caused by Penicillium expansum on wounded apples (nail wounds) with pyrrolnitrin (PN) isolated from P. cepacia. 







Integrating biological control with other non-fungicidal methods

Normally, biological control of postharvest diseases of pome fruits is very consistent and reliable.  However, under some circumstances, e.g. very mature fruit or on some cultivars, higher concentrations of biocontrol agents must be applied to achieve satisfactory control. To reduce variation in decay control caused by these factors we developed integrated control systems based on a hurdle approach. In cooperation with scientists from a USDA -ARS Laboratory in Beltsville, MD (Dr=s. Conway, Saftner and Leverentz), we developed integrated strategies whereby we combined biological control with various combinations of calcium, heat treatment, sodium bicarbonate (SBC), and controlled atmosphere (CA).  These combined treatments achieved more effective and stable decay control than the individual treatments alone. In years with high field infection rates, biocontrol will be most effective as a part of an integrated control strategy. Good sanitary practices are also very important as the efficacy of these methods decreases with increasing spore loads.




This research demonstrated that biological control of postharvest diseases can be easily integrated with other methods with additive and synergistic effects, which also broadened the spectrum of activity (eradicative effect of heat, reduced decay by Ca) and further advanced the goal of eliminating fungicide treatments on fruits after harvest.


Genetic improvement of biocontrol agents

The continued expansion of biological control of postharvest diseases will largely depend on improving its effectiveness under a broader range of conditions and expanding its activity to new commodities and diseases. Developing new biocontrol agents against postharvest fruit diseases by genetically modifying microbes and using them as a delivery system for various biocontrol traits isolated from other microorganisms or other foreign genes responsible for antifungal activity can be one of the ways to accomplish this goal.

In collaboration with scientists from UFRJ in Brazil (Prof. E. Kurtenbach and J. B. Pereira) we transformed the yeast, Pichia pastoris, that is used in animal feeds and is also very amenable to genetic manipulation, using plasmid pGAPZaC/Psd1, a binary vector encoding the constitutive expression of the gene for pea defensin Psd1. The Psd1 defensin peptide has been shown to have antifungal activity against a variety of fungi.


The severity and incidence of blue mold decay caused by Penicillium expansum were reduced more effectively on apples treated with the transformed yeast expressing the Psd1 gene when compared to apples treated with the nontransformed parental strain, or a recombinant containing the empty binary vector.


Severity of blue mold decay caused by Penicillium expansum (at a concentration of 1x103 and 5x103 conidia mL-1) on 'Golden Delicious' apple inoculated with nontransformed wild-type Pichia pastoris X-33 or transformed with the Psd1 defensin cDNA encoding sequence. The fruit were wound-inoculated with Penicillium expansum conidia alone (CK) or in combination with nontransformed P. pastoris cells (X-33), transformed with the empty pGAPZ?C vector (X-33 + vector) or transformed with the vector containing Psd1 cDNA sequence (colonies Kr 70, Kr 88, Kr 98, and Kr 111), and stored on fruitpack trays in plastic boxes at 24o C for 5 days before evaluating for decay development. Error bars represent standard error from the mean.


Expanding use of biological control 

Most of the earlier biocontrol systems for controlling diseases on field and nursery crops were either never developed into commercial products or had a short commercial life because scientists did not pursue further development and/or expansion of biocontrol. We have been constantly pursuing expansion of our biocontrol system. In collaboration with an engineer, Dr. Peterson, and S. Wolford we developed an efficient drenching system for application of biocontrol agents in small orchard operations.









 For video click on picture








A portable drencher developed for treating entire bins with fruit. It can be used for application of biocontrol agents or any other treatments in small orchard operations or in research to test experimental treatments. The small accumulating reservoir and catching tray reduce the amount of the suspension needed for drenching, which greatly reduces the cost of applying treatments because little of the material is wasted when the suspension is dumped at the end of the day.


We also demonstrated the usefulness of the antagonist Pseudomonas syringae (strain L-59-66 used in Bio-Save?) in controlling decay originating from stempulls on mechanically harvested apples.



The prototype of the mechanical harvester for apples (on the left) and blue mold decay (on the right) originating from wounds made by removal of the stem (stempull), a common injury on some apple cultivars during mechanical harvesting. The antagonist Pseudomonas syringae (L-59-66) can effectively control blue mold decay originating from these stempulls.


We are also actively engaged in expanding the registration of Bio-Save? to control postharvest decays on new commodities.


Current project

Developing effective biological controls of postharvest diseases of stone fruit have been especially difficult because of the role of latent infections and the general lack of strong genetic resistance in commercial cultivars. Therefore,  a completely new biological approach must be developed  and increased knowledge of host-parasite interactions in postharvest diseases is needed if alternative approaches are to be successful with stone fruits.

To address this, in March 2007 we initiated a project which includes the characterization of stone fruit microflora, the search for microbial antagonists that can degrade melanized fungal structures developed during the latent period, and determining the role of fungal polygalacturonases as virulence factors in the pathogenicity of postharvest pathogens such as Monillinia fructicola (causing brown rot of stone fruits) and P. expansum.



Selected references

Janisiewicz, W. J., Pereira, B. I., Almeida, M. S.,  Roberts, D. P.,  Wisniewski, M. and Kurtenbach, E. 2007. Improved biocontrol of fruit decay fungi with Pichia pastoris recombinant strain expressing Psd1 antifungal peptide. Postharvest Biology and Technology. (in press)


Conway, W. S., Janisiewicz, W. J., Leverentz, B.,  Saftner, R. A., and Camp M. J. 2007. Control of blue mold of apple by combining controlled atmosphere, antagonist mixture, and sodium bicarbonate. Postharvest Biology and Technology 45:326-332.


Janisiewicz, W. J. 2006.Biological control of postharvest decays of fruits using strains of Metschnikowia species. United States Patent 6,991,930.


Janisiewicz, W. J., Peterson, D. L., Yoder, K. S., and Miller, S.S. 2005.Experimental bin drenching system for testing biocontrol agents for control of postharvest decay of apples. Plant Disease 89: 487-490. 


Janisiewicz, W. J. and Peterson, D. L. 2004.Susceptibility of the stempull areas of the mechanically harvested apples and its control with biocontrol agent. Plant Disease 88:662-664. 


Leverentz, B., Conway, W. S., Camp, M. J., Janisiewicz, W. J., Abuladze, T., and Sulakvelidze A. 2003.  Biocontrol of Listeria monocytogenes on fresh cut produce by combination of bacteriophages and a bacteriocin. Applied and Environmental Microbiology. 69: 4519-4526.


Janisiewicz, W. J., Leverentz,B., Conway, W. S., Saftner, R. A., Reed, N.A., Camp M. J. 2003.Control of bitter rot and blue mold of apples by integrating heat and antagonist treatments on 1-MCP treated fruit stored under controlled atmosphere conditions.  Postharvest Biology and Technology 29:129-143. 


Janisiewicz, W. J. and Korsten, L. 2002. Biological Control of Postharvest Diseases of Fruits. Annual Review of Phytopathology 40: 411-441.


Janisiewicz, W. J., Tworkoski, T. J. and Kurtzman C. P. 2001. Biocontrol potential of Metchnikowia pulcherrima strains against blue mold of apple. Phytopathology 91: 1098-1108. 


Janisiewicz, W. J., and Yourman, L. 2000. Biological control of postharvest diseases of pome fruits with Pseudomonas syringae pv. lachrymans. United States Patent 6,017,752.  


Janisiewicz, W. J., Conway, W. S., and Leverentz, B. 1999. Biological control of apple decay of apple can prevent growth of Escherichia coli O157:H7 in apple wounds. Journal of  Food Protection 62:1372-1375.


Janisiewicz, W. J. and S. N. Jeffers. 1997. Efficacy of commercial formulations of two biofungicides for control of blue mold and gray mold of apples in cold storage. Crop Protection 16:629-633.


Janisiewicz, W. J. and Roitman, J. 1991. Biological control of postharvest rots in fruits using Pseudomonas cepacia and pyrrolnitrin produced therefrom.  United States Patent, Patent No. 4,975,277.


Janisiewicz, W. J., Yourman, L., Roitman, J. and Mahoney, N. 1991. Postharvest control of blue-mold and gray-mold of apples and pears by dip treatman with pyrrolnitrin, a metabolite of Pseudomonas cepacia. Plant Disease 75:490-494.


Janisiewicz, W. J., Yourman, L., Roitman, J. and Mahoney, N.  1991. Postharvest control of blue?mold and gray?mold of apples and pears by dip treatment with pyrrolnitrin, a metabolite of Pseudomonas cepacia.  Plant Disease 75:490?494.




Last Modified: 8/12/2016
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