These include wind-driven rain, flooding, air currents, insects, birds, and human movement within groves over short distances. Overhead irrigation may also play a role in spreading the bacteria. Movement of infected plants, seedlings, propagative material, and fruit is the primary means of spreading the canker pathogen over larger distances. Contaminated clothing, tools, packing boxes, and other items associated with harvesting and postharvest handling of fruit are also potential sources of infection. Canker bacteria survive and multiply primarily in naturally occurring lesions.
Questions concerning whether honey bees spread canker continue to surface.
There is no scientific evidence to my knowledge that this is the case. The insects generally implicated are those that damage the plant in some form such as leaf miners . Although the bees themselves may not contribute to canker spread, the activities of beekeepers in groves are far more suspect. Anyone working in canker areas must take great pains to disinfect people and equipment. Given the seriousness of the situation, one can expect growers to be nervous and conservative about allowing access to Florida groves this spring.