Synergism, hard to define.

[Shinhan Shiu]

I am a first-year grad. And I am going to study the mechanism of synergism 
between Verticillium dahliae (the potato-early-dying pathogen) and 
Pratylenchus penetrans (root lesion nematode). According the field data, 
yeild loss and symptoms tend to be severe when both pathogens are present in 
the same plot. What we and the other group observe is that the effect is 
simply additive but synergistic.

Before I look into the mechanism of such synergistic effect, I would 
like to know if there is any well-defined system of synergistic 
interaction. Please indicate the information source if possible.

And, I am tring to send some messages to Prof Carl H. Beckman, Univeristy 
of Rhode Island, who studies wilt disease of various plants. If anybody 
know his e-mail add, please inform me about that.

Thank you.

Shinhan Shiu
han at plantpath.wisc.edu                            
Department of Plant Pathology
University of Wisconsin-Madison