The pastor claimed that some people were healed of various illnesses after he had sprayed them.
Lethebo Rabalago was found guilty on five charges of grievous assault and contravening chemicals laws for using 'Doom', a well-known household insecticide, as a weapon.
"This was a dangerous act. The fact that these people were sprayed on their faces with Doom makes this offence the worst of its kind," magistrate Frans Mahodi said, according to public broadcaster SABC.
"Spraying people with Doom injured victims seriously," he added.
Some suffered coughing for more than seven months.
Photographs of Rabalago — dunned "the Prophet of Doom" — spraying volunteers at his church in Limpopo, in the northwest of South Africa, spread on social media in 2016.
The pastor claimed that some people were healed of various medical complaints after he had sprayed them.
Rabalago said at the time he was "glorifying God" by spraying his congregation at the Mount Zion General Assembly (MZGA) church.
"Everything here on Earth belongs to God. Petrol belongs to God. Doom belongs to God," he said.
Brand Tigers, which manufactures the well-known household spray, issued a statement calling on Rabalago to halt his ritual healing.
He is yet to be sentenced.