Dr. Peter Oudemans

Contact Information

Mailing Address

Rutgers University
Philip E. Marucci Center for Blueberry and Cranberry Research and Extension
125A Lake Oswego Road
Chatsworth, New Jersey 08019
oudemans@aesop.rutgers.edu

Campus Location

Office: Marucci Blueberry and Cranberry Research Center, (609) 726-1590 x 20
Fax: (609) 726-1593

Research Interests

Blueberry Research

Monilinia vaccinii-corymbosi is one of the more serious blueberry pathogens in New Jersey. Our research has targeted understanding the adaptation of this pathogenic fungus to its plant host. The most significant finding from this work demonstrates an innate timing of the over-wintering structures to germinate and produce spores to infect the blueberry plant during a relatively short period of susceptibility during the spring. Although the mechanism for timing spore production is not fully understood, we have determined that timing is an inherited trait very likely related to the fitness of the pathogen. The implications of this work are two-fold. On a practical level, these results provide commercial blueberry growers with the tools to time fungicide sprays accurately and thereby reduce unnecessary sprays. From a more basic point of view, this research is opening doors to the investigation of disease avoidance. This type of resistance is poorly understood but has many advantages from an IPM standpoint.

Cranberry Research

In cranberry, three areas of research are being examined.

1) Cranberry Fruit Rot - Cranberry fruit rot is a complex disease with over 15 fungal species implicated. Left uncontrolled, this disease could eliminate over 80% of cranberry production in New Jersey and Massachusetts within a three-year period. Our research with this disease has focussed on the elucidation of lifecycles, description of the distributions of various fungal species, improved resolution of the taxonomy of these fungi, and development of alternative and low impact control methods. One major finding with this important disease was the identification of the period of susceptibility of the cranberry host. This finding will permit future research such as disease resistance breeding, biocontrol procedures, and disease prediction models to target a shorter period of the cranberry lifecycle. A second finding was the preliminary result that resistance to cranberry fruit rot is not fungal species-specific. In other words, resistance to one pathogenic species will translate to resistance to other species. This has greatly improved the prospects for identification of disease resistant genotypes. A third finding has been the identification of fungal viruses and retrotransposons in the pathogen Colletotrichum gloeosporioides. Besides being useful tools to study the population dynamics of this fungus, these genetic elements may provide a means for development of a biological control.

2) Cranberry Root Rot - Cranberry root rot is caused by various species in the genus Phytophthora. Acute symptoms of the disease result in patches of dead plants ranging in size from a few square meters to several hectares. The disease can also cause chronic effects including a reduction of yield, however, this is not well studied (see next section). Our research has targeted three areas: taxonomy, life history and resistance breeding. The major accomplishments with this disease include identification of inoculum sources, development of a fatty acid profile database for simplified identification of Phytophthora species, identification and characterization of a new Phytophthora species from cranberry, and development of screening methods for root rot resistance in cranberry.

3) Site Specific Management - We are using GPS/GIS/RS techniques to analyze cranberry crop health and yield. Initial studies utilizing color-IR photography and 5-m panchromatic satellite imagery show that accurate estimation of bog acreage and crop health may be derived using remotely sensed techniques. For this study, color-IR photography from the commercial cranberry beds (May 1996) was rectified to earth coordinates using GPS technology. An unsupervised multi-spectral classification was then done to statistically group pixels in the image. Results indicate that using this technique, a number of features within the bogs can be identified, including variations of vegetative cover within and between bogs, irrigation system features, and areas of bogs infected with disease (Phytophthora cinnamomi). Therefore, these techniques can be used to monitor variables such as disease, stress, and vegetation density that affect yield. In addition, remotely-sensed techniques provide complementary information for in-situ studies in providing guidance for smart sampling techniques based on spectral reflectance data.

Extension activities

Published over 30 articles for newsletters, non-refereed extension publications and educational materials for grower use. Presented talks to growers related to disease management (~9/year). Applied for a section 18 emergency exemption for a fungicide on blueberry. Identified new environmentally rational fungicides for both blueberry and cranberry. Reduced use of one fungicide used for root rot control by 100% in blueberry and approximately 30% in cranberry. Provided a free Phytophthora identification service to growers.

Publications

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Rutgers Affiliations

1. New Jersey Agricultural Experiment Station (NJAES)
2. Rutgers Plant Biology Graduate Program
3. Philip E. Marucci Center for Blueberry and Cranberry Research and Extension

Dr. Peter Oudemans is an associate professor in blueberry & cranberry pathology.