Fungal diseases

• A. Usually occurs naturally and helps control aphids
• B. Are always harmful to crops
• C. Are only produced in laboratories
• D. Do not affect insect pests

Answer: (A)

Fungal diseases can act as natural pest control. Many fungi are entomopathogens, meaning they infect and kill insects like aphids. In the field, spores from these fungi land on aphids, germinate, and penetrate their bodies, causing disease and reducing pest populations. Because these pathogens occur in nature, they usually arise without human appplication and can help keep aphid numbers in check, which is why this option best describes fungal diseases. It’s also true that not all fungi are harmful to crops, and some fungi used as biopesticides are grown commercially, but they’re not restricted to laboratories, and fungi do affect insect pests, so the other statements aren’t accurate.