Can i use dawn dish detergent on white flies that are on my tomato plants?
Either detergents or soaps work to kill insects that have soft bodies such as aphids, whiteflies, mealybugs, and spider mites. Detergent is just more likely to injure the plants. This is known as “phytotoxicity.” It is most likely to occur when it is hot so spray early or very late when it is cooler. Soap can be less likely to injure the plants but must be used with soft water or distilled water. With detergent the water hardness does not matter. Some varieties of tomatoes are known to be sensitive to detergent on their leaves so do not mix it stronger than 2%. http://www.ext.colostate.edu/pubs/insect… The spray only works while wet so spraying while it is cool out means the detergent takes longer to dry and is more effective. Another reason to use a solution no stronger than 2% is “Fruit crops may be damaged if sprayed heavily enough that soap accumulates at the base of the fruit.
