Final answer:
Fungicides control fungal pathogens that cause diseases in plants, such as rusts and mildews. They are part of a pest control strategy that includes beneficial microbes like entomopathogenic fungi and parasitic bacteria to reduce chemical pesticide use. Therefore, the correct option is A.
Step-by-step explanation:
Fungicides are chemical agents used to control fungal diseases in plants, which are pathogenic microorganisms that can cause diseases such as rusts, mildews, and blights. The pests controlled by fungicides specifically include fungal pathogens, which can severely affect crops and result in poor yields or total loss of the plants. For example, Botrytis cinerea can cause a destructive disease known as 'grey rot' on grapes, but when controlled, it is used to produce the desirable 'noble rot' in dessert wines. Fungicides also play a role in plant disease control by inhibiting or killing the pathogenic fungi. Entomopathogenic fungi like Beauveria bassiana and Metarhizium spp. are examples of beneficial fungi used in an alternative pest control method. They target and parasitize insect pests, thereby reducing reliance on chemical pesticides, which makes fungal insecticides an attractive alternative for growing food crops. Other beneficial microbes used in pest control include bacterial agents like Bacillus subtilis, which controls plant pathogens, and nematodes that attack insect pests.