Mix 4 ounces of blackstrap molasses with 1 quart of water in a spray bottle and shake well. Spray directly on grasshoppers to clog their pores and suffocate them to death.
Process 3 ounces of garlic to a pulp in a food processor or spice grinder and mix with 1 ounce of mineral oil in a glass jar. Let steep for 24 hours.
Strain the garlic and oil mixture into a clean glass jar and discard the garlic pulp.
Mix 1 teaspoon of fish emulsion and 1 tablespoon of castile soap with 16 ounces of water and slowly pour the mixture into the garlic-infused oil.
Mix 2 tablespoons of the garlic oil and fish emulsion mixture with 1 pint of water in a sprayer and spray grasshoppers directly to kill them. The garlic oil mixture keeps for several months in a glass jar with a well-sealed lid.