Arizona Crop Information Site logo
University of Arizona
Vegetable IPM Updates Archive
Cooperative Extension
Plant Disease Resistance (Aug. 3, 2011)

Plants can be resistant to many potential pathogens, but just how is this resistance accomplished? One method is the use of physical defense. Just as our skin provides a physical barrier preventing movement of microbes into our bodies, the cuticle or surface covering on plants serves the same function. Many plant pathogens must adhere to the plant surface for a given time in order to penetrate into the plant and cause infection. This ability to colonize plants may be disrupted by the amount of wax present and the quality of the cuticle that covers plants. Waxes prevent the formation of a film of water on plants, which is essential for deposition and growth of bacterial and fungal pathogens on plants. Abundant plant hairs can perform a similar water repellency function. Cuticle thickness and toughness of epidermal cell walls play an important role in the resistance of plants to several pathogens. However, this form of disease resistance can be circumvented by wounds. Many pathogenic bacteria and fungi enter plants only through stomata or other natural openings. The structure and size of these openings can greatly affect the ability of some pathogens to invade plants. These physical plant attributes that are present before exposure to potential plant pathogens play an important role in a plant’s ability to resist many diseases. Without the presence of these physical barriers, plants in general would be susceptible to infection by many more plant pathogens than they are now.

To contact Mike Matheron go to:


For questions or comments on any of the topics please contact Marco Pena at the Yuma Agricultural Center.
College of Agriculture, The University of Arizona, Tucson, AZ.

Home | Cotton | Veggies | Forages | Grains | Citrus | Crop x Crop
Insects | Diseases| Weeds | Pesticides | Economics | News | Weather | Research | Photos | Contacts | General Info.

Copyright © 2001 University of Arizona,
College of Agriculture and Life Sciences
Webmaster: Al Fournier (