____________ fungicides are very prone to development of resistant fungi.

• A. Uni-site
• B. Multi-site
• C. Wettable powder formulations
• D. All

Answer: (A)

Fungicides that affect only a single site in the fungus are most prone to resistance because a single genetic change can make that site unrecognizable or unusable, allowing the fungus to survive the treatment. When these fungi are repeatedly exposed, the few individuals with the resistant mutation have a big survival advantage and are likely to become common in the population. Over time, that resistance spreads.

In contrast, fungicides that hit multiple targets or pathways require several different changes in the organism before it can overcome the treatment, which is much less likely to happen quickly. A wettable powder formulation is just a physical form of the product and doesn’t by itself change how resistance develops, though it can affect application effectiveness. Saying all fungicides have the same resistance risk isn’t correct because multi-site products resist resistance much more effectively.