Pest Extermination is a quest unlocked as soon as the player has completed Harvest a Friend's Farm.
The player has to exterminate bugs from his own Farm twice in order to complete the quest.
Click on the [Farm] -> Click on a crop with pests on it -> Exterminate pests from two crops. Click the icon above a crop to exterminate pests. Exterminating pets (sic!) can bring Farm experience.
The player is rewarded 2.000 Gold.