Many garden enthusiasts select certain plants to attract butterflies in order to enjoy the colorful butterflies flitting around their gardens. However, butterfly larvae, or caterpillars, can actually cause quite a bit of damage to peach trees. Before metamorphosing into butterflies, caterpillars eat nonstop, gobbling up the leaves, flowers and fruits of peach trees, causing sometimes severe defoliation. You can control caterpillar invasions of your peach trees using several methods.
Prune away all badly damaged and infested branches of the peach tree. Destroy the infested wood.
Thin out the fruiting buds on the peach tree in the spring. Remove any double or triple fruiting buds on a single stem so that you have a single bud on each stem.
Treat the tree with Bacillus thuringiensis or "BTK," a bacterial spray that kills only caterpillars. Mix the BTK solution and apply it to the peach tree according to the instructions on the label.
Spray all the leaves on the infested peach tree thoroughly, including the undersides of the leaves, as well as any flowers that the caterpillars are feeding on. Repeat the BTK application as needed if caterpillars infest the peach tree again.
Water your peach trees deeply once a week during the summer and fall to keep the tree strong. Water the trees more frequently during dry spells or droughts.