Disease Control

Most plant diseases are the result of fungal infections, but bacteria and viruses are also responsible for many crop diseases. Other plant diseases are abiotic, caused by nutritional disorders or environmental conditions.

Consider the signs (physical evidence of the pathogen like fungal fruiting bodies) and the symptoms (the visible effect of the disease such as leaf wilting).  Many plant diseases have symptoms that are common to fungal, bacterial and viral infections so close inspection is necessary.  

Bacterial diseases in plants have symptoms very similar to fungal diseases, but a few things set them apart. They often have a rotten or fishy odor, are water soaked with a bacterial ooze, are initially confined between the leaf veins, and may have a chlorotic halo surrounding the infected area.


Always review product labels prior to purchase to confirm your purchase is labeled for the specific pest, disease and/or crop you are treating. Accurate identification of pest and/or disease is essential to successful treatment, as are proper cultural and sanitation practices. Local extension offices can help identify pests and diseases. Additionally, feel free to send us images and we will do our best to assist you.


PNW Plant Disease Management Handbook (accessed November 2023)

RHS Diseases and Disorders

Greenhouse Grower, A closer look at 10 of the worst greenhouse plant disease problems., Janeen Wright 2021

New England Greenhouse Floriculture Guide, Disease Management, 2021


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