We have a very mature peach tree that was here when we moved in. We have since planted 3 more peach varieties. My question is about the mature tree. The peaches are delicious but they almost all have small white worms in them. What do you recommend doing to the tree this Spring to prevent those worms this Summer?
Without finding the host insect most likely a fruit fly here is what I have for SWD
Peach and nectarine —Spotted wing drosophila
(Drosophila suzukii)
For pest description, crop damage, biology, life history, sampling and cultural management see “EMERGING PEST: Spotted wing drosophila (Drosophila suzukii) —a new berry, grape, and stone fruit pest†in this handbook.
Management—chemical control: HOME USE
1. acetamiprid
2. azadirachtin
3. kaolin clay (Surround at Homeâ„¢)
4. pyrethrins
5. spinosad
Management—chemical control: COMMERCIAL USE
1. diazinon (Diazinon 50W) at 1 lb/ 100 gal water. PHI 21 days. There is a maximum of one in-season foliar application regardless of target pest.
2. esfenvalerate (Asana XL) at 2 to 5 fl oz/100 gal water (5 to 12 fl oz/a). PHI 14 days. May disrupt beneficial mite populations. Extremely toxic to fish and aquatic invertebrates; avoid spray drift and runoff to surface waters.
3. fenpropathrin (Danitol 2.4EC) at 10 to 21fl oz/a. PHI 3 days. May disrupt beneficial mite populations. Extremely toxic to fish; avoid spray drift and surface runoff.
4. lambda-cyhalothrin (Warrior II 1CS) at 1.3 to 2.5 fl oz/a. PHI 14 days. May disrupt beneficial mite populations. Extremely toxic to fish; avoid spray drift and surface runoff.
5. malathion (Malathion 8EC) at 5 to 9 pints/a. PHI 7 days.
6. spinetoram (Delegate WG) at 4.5 to 7 oz/a. PHI 14 days for peaches and 1 day for nectarines. Apply at least 1 week apart, with a maximum four applications per season.
7. spinosad—
a. Entrust 80W at 0.4 to 0.8 oz/100 gal water (1.25 to 2.5 oz/a). PHI 14 days.
b. Success 2F at 1.3 to 2.7 fl oz/100 gal water (4 to 8 fl oz/a). PHI 1 day. May act slowly.
Yes, more than likely last year's worms in the peaches were spotted wing drosophila, SWD. This little beast attacks ripening fruit, many different fruits.
You'll find lots of information on the website of the SWD Working Group at http://swd.hort.oregonstate.edu/
One of the primary techniques for gardeners is mass trapping, using as many traps as you can. You'll find that info in the brief videos on the above web page; they show how to make and use very simple traps for SWD. The bait is apple cider vinegar or white wine.
Another part of management is timely harvesting and sanitation of fallen & affected fruits. See the details on the above website.