Fruit trees have a number of pests, but few are as widespread and damaging as codling moth.
Best known as an apple pest – their preferred diet – codling moths can also damage pears and quince, larger stone fruits such as plums and peaches, and walnuts. Most home garden control is focused on apple and pear.
There are two generations of codlng moth per year in western Oregon. The first matures in April and May, adult moths flying to mate and find suitable egg laying locations. Eggs hatch into larvae – the worms – and burrow into the developing fruit. They feed through the fruit for 3-4 weeks, then emerge and crawl down the tree to cocoon and finish developing, usually on the ground.
A second generation follows the same basic pattern, adults flying July into early August; this generation will overwinter in their cocoons for the following spring.
Control can be managed as a timed spray – 3 sprays, 7-10 days apart, starting very early May and repeated 3 more times in very early August.
Control with Timed Sprays
Effective controls include:
- Baccilus thuringensis or B.T. (Fertilome BT Caterpillar Killer)
- Spinosad (Captain Jack’s Deadbug)
- Pyrethrin/pyrethroid insecticides (Bonide Eight, Bonide Orchard Spray, Fertilome Triple Action).
Timed spray applications are extensive, because dates are approximate and you want to make sure you are getting effective control over the entire potential pest season.
Codling moth traps can limit how many sprays are needed, if used correctly. Place traps out in March or April. Check traps weekly as the apples bloom; if and when you start seeing codling moths (these will be males) in your traps, mark your calendar and spray in 10 days, with only one follow-up spray instead of two. Repeat trapping in July – use new traps, the lures only last a few weeks.
Non-Spray Controls
If codling moth infestations are heavy, spraying may be the only real practical control; but if problems are light or intermittent, you may be able to mostly avoid spraying.
Here are some cultural controls to reduce codling moth problems:
- Use codling moth traps. They will interfere with mating, lowering codling moth populations, and they are useful to monitor if maybe you really should spray this year, or if you can probably go without. Use 1-2 traps per mature tree if you want this to be your primary control measure, and don’t forget to check the traps to see populations are large enough to require spraying.
- Practice good sanitation. Clean up any and all fruit that falls, as larvae can continue to develop in fallen fruit. Dispose of fruit well away from the orchard, or bury at least a foot deep.
- Cocoon interference. Wrap corrugated cardboard around apple tree trunks in early May. Many of the larvae try to cocoon in the grooves; remove and destroy/burn by no later than mid June, and repeat from early August through any time in September.