Spread and distribution

Method of spread	Management issues
Flying - many adult forms of insects have wings.	Difficult to control and difficult to stop them entering an area.
Crawling.	Possible to kill with contact sprays and biological agents.
Wind.	Some weeds, spores and pests can be spread into totally clean areas. Spot treatments are necessary to control quickly.
Water.	Many of these pathogens are organisms assisted to move by moisture.
Seeds.	Sometimes treatment is not possible.
On plant parts.	Sanitation and hygiene are vital to prevent the spread of such problems.
In soil and media.	If your key problem organisms can be spread this way you must ensure they are clean and free of impurities. Quarantine them or limit their movement. Use sanitation and hygiene techniques.
Birds. Spread weed species in particular.	As is the case with wind, surrounding areas may be a source of spot infestations when birds are carriers.
Vectors.	The answer may be to control the vector, not the disease itself.
Wounds.	Prevent damage to your plants with good pruning techniques and avoiding physical damage. Pruning, however, may impact on harvesting techniques and other treatments.