Humans help spread the disease when they transport infected plants, plant parts or infested soil.
Some plants absorb excess nitrates or oxalates from the soil and store them in plant tissues. Toxicity problems can occur in animals which feed on these plants.
Excessive summer irrigation of oak and madrone trees may promote fungal diseases such as the oak root fungus (aka armillaria root disease) and crown rot.
OSU research indicates that the less toxic iron phosphate containing slug baits are as effective as those with metaldehyde.
Home remedies have shown some effectiveness against many garden pests and diseases.