|MadSci Network: Microbiology|
You picked a really interesting bacterium to study for your project. Agrobacterium tumefaciens plays an important role in science; it causes Crown Gall disease affecting a number of broad leafed plants (dicots) especially woody plants (roses, some fruit trees) worldwide, causing a great financial loss in commercial nurseries where up to 80% of stock have been reported diseased in some cases. A. tumefaciens plays a more positive role as a tool in the genetic engineering of plants, and the infectious process is very interesting from biological prespective. The Microbe World has a great site for discussing crown gall disease and A. tumefaciens.
For your science project I would suggest using tomato plants- they are susceptible to the infection and are pretty cheap and easy to grow. To ensure infection you may want to pin prick the stem of the tomato plants (wound them) and subsequently spot a suspension of A. tumefaciens to the wound site. This will promote and speed up the infection process. Keeping the plants in a relatively warm environment (20-25 C) will also help speed the infection process.
Regarding control of the disease, I was unable to find much information about chemicals to control crown gall disease. I did find a vague reference to the use of copper, perhaps you could ask someone who works at a greenhouse for information as they likely must guard against crown gall disease. One interesting method of control is through using a biocontrol agent. A. radiobacter can kill off A. tumefaciens and thereby prevent the infection from occurring. The website above does a good job of describing this phenomenon but check out this website for a company that has commercialized the technology.
Good luck with your project and just remember to carefully plan your experiment to make sure you have good positive and negative controls. Have fun!
Try the links in the MadSci Library for more information on Microbiology.