Before a proper cure can be selected, a diagnosis must be made. All personnel should receive instruction in the art of plant problem diagnosis. If nothing else, this instruction will encourage them to sound the alarm if plants appear to be damaged.
Damage may be caused by:
Timely diagnosis is critical, but it can be difficult. Many damage symptoms such as yellowing or necrosis have many different potential causes. Also, damage agents may have many different symptoms, and different crops will respond differently to each damage agent.
Proper diagnosis will depend on scouting records that allow evaluation of a problem over time. Some diagnoses will require the assistance of offsite laboratory facilities.
Thorough examination of the damaged plants and the adjacent cropping area should always be the first step in diagnosis. Frequently, survey and scouting records from previous cropping cycles will allow for rapid recognition of the problem. If the problem cannot be solved by in house experts, then additional experts such as extension agents or research scientists should be consulted.