Endosulfan

• The insect that causes the most damage to peach trees is the peach tree borer and lesser peach tree borer. Borers weaken or kill peach trees. For commercial peach growers, products with the active ingredient endosulfan is a treatment for peach tree borers that will last about six weeks. You can apply it twice a year and it can contact the fruit. If you have a small orchard you can also use products containing endosulfan, but instead of spraying, you brush these products on the bark.
  
  

Malathion

• In some regions peach trees are susceptible to brown scale, a small sap-feeding insect. These insects feed on the bark of the peach tree and cause considerable damage. Malathion insecticide is a member of the organophosphate chemical family. It has been used since 1950 and is one option for controlling brown scale in peach trees. Before using this product be sure to read manufacturer's instructions for applying it.
  
  

Cottonseed Oil

• Cottonseed oil is an option for people who prefer using natural insecticides. Of all vegetable oils, cottonseed oil is the most effective, according to the Colorado State University Extension Service. Cottonseed oil does not contain petroleum products or chemical solvents. Unlike dormant oil insecticides, you can spray it on your peach trees all season and it will not damage foliage in warmer temperatures. Beneficial insects, such as lady beetles, are not harmed when they come to the tree after it has been sprayed. Most insecticides kill by poisoning the insects, but cottonseed oil spray suffocates them, which is why insects have not developed resistance to it. Use this insecticide for scales, mites and aphids.
  
  

Diflubenzuron

• Growers following an integrated pest management approach can use diflubenzuron for twig borer control. You spray this at the bloom period to avoid harming beneficials. You can also use this as a dormant-season spray to kill the overwintering population of the pest.
  
  

Bacillus thuringiensis (BT)

• BT is effective for a variety of chomping insects, including caterpillars in the leafroller family. These culprits include the obliquebanded leafroller, the omnivorous leafroller and the fruittree leafroller.