Monterey B.t. Insecticide - DoMyOwn.com Monterey B.t. Insecticide is mixed at 1.5 oz. per 3 gallons of water per 1,000 sq. ft. for Fruits and Vegetables and 2 oz. per 3 gallons of water per 1,000 sq. ft. for Ornamentals. Was this answer helpful to you? Yes No 3 of 5 people found this answer helpful Q Will Sevin Insecticide Granules kill gypsy moth caterpillars?