Natural Spray Insecticides for an Apple Tree

Soap Spray

• Detergent or soap may be sprayed onto apple trees as a natural insecticide, a method that has been used for two centuries. Some major pests to fruit trees in general are soft-bodied arthropods, which are the most vulnerable to detergent sprays. Water down the detergent to a 2 percent dilution to spray on the apple trees to rid them of aphids, spider mites, psyllids and mealybugs. Don't use regular dish detergent instead of commercial soap insecticide sprays as a greater risk of injury to the plant exists. Apple trees, fortunately, are not particularly susceptible to phytotoxicity damage from soap insecticides like plum or cherry trees.

Kaolin Clay

• Kaolin clay is a nontoxic barrier, not a true pesticide, to pests like apple maggots. Diluting the kaolin at 3 to 16 parts water makes it sprayable for topical application to the apple trees. The film it clearly leaves on the tree, especially the apples themselves, irritates insects and deters them from landing on the trees. The clay needs to be applied weekly or biweekly and more often when there is rain. Since it is a natural and nontoxic barrier and not a true insecticide, it can be applied up until the day the apples are harvested and washed off with either a power washer or brush under a faucet.

Sprayable Sulfur

• A sulfur mix of 3.4 oz. to 1 gallon makes for a sprayable insecticide that aids in controlling a variety of apple tree pests. A regular application of sprayable sulfur should be used in conjunction with other treatments like kaolin clay and lime sulfur on a rotating schedule, applying three to four days before it rains. Use on the apple trees from early spring through four weeks after the apple blossoms petals fall. It can also be used through the summer biweekly up through the harvest or the end of August, whatever comes first, according to Michigan State University.