Our place has a little orchard that the former owners planted, including 5 apple trees of different varieties. Soon after moving in I learned about coddling moths. In nearly every Apple. I don’t use and kind of pesticide or herbicide. I implemented advice as I found it, and I check apples thoroughly before eating them or preserving them. Here are some things I learned from various sources (previous owner,
books and internet, Clackamas Community college demonstration
project). This year I found only about 1 in 4 had been hosts to the moth larva.
1. Never let windfall apples lie.
2. Sticky traps: about 2 feet above ground, do the sticky traps where you wind a strip of paper around the trunk and coat it with sticky stuff. It’s not poison - it’s a trap. Apply liberally at edges to make a seal.
3: thin the clusters
4: Clackamas Community College did a demonstration project where they placed nylon socks (like the kind that sho store use) over apples when they were still tiny and had amazing results. Unfortunately, while doing a quick search to find a link to the project I couldn’t find it, but instead found that COVID has squelched the Home Or hard Society. Not sure why documents are gone. Maybe my search skills aren’t up to it. I did try this and as long as the socks don’t slide off, it is very effective, though incredibly time consuming and I could only reach where my 8’ orchard ladder took me.
However, I did just now stumble across a newsletter that contains an article that provides even more advice, some of which is easier to do. Below I provide the link to the newsletter. I also copied and pasted the specific article in case that publication also disappears from the internet (or evades identification using ordinary search skills).
https://wcfs.org/wp-content/uploads/2018_02_Spring_BeeLine.pdf
Codling Moth (Cydia Pomonella) and Management Using CYD-X1
Sue Ryburn, Cooperative Workstudy Student, Clackamas Community College, Molalla, Oregon
Codling moth (Cydia pomonella) is the most serious pest of apples in the Pacific Northwest, especially in warmer and drier areas. Larvae
feed directly on the fruit, either by “stinging” it or boring into it and feeding from within. Stings are shallow depressions where feeding occurred and then stopped. Larvae that bore into the fruit leave character- istic bore holes on the exterior, which fill with frass that ex- trudes from the hole.
Biology and Life History
Codling moths overwinter as mature larvae in silken co- coons spun under loose bark, in the soil, or in debris at the base of a tree. Pupation is in the spring around the time the first blossoms show pink Adults emerge around bloom, are active only at dusk and dawn, and lay eggs on leaves and sometimes on fruit.
Larvae emerge, begin feeding on fruit, and may bore to the center of developing fruit to feed on the flesh and seeds. As larvae mature, they push frass out the entry hole. After 3 to 4 weeks, the larvae leave the fruit and seek a sheltered spot on the tree to spin cocoons.
The larvae may overwinter in the cocoon, or they may emerge in 2 to 3 weeks as a new flight of adults. These adults are active in July and August. In warm areas, there may even be a third generation. Larvae of the third genera- tion often penetrate fruit but do not complete development before harvest or winter.
Monitoring
During spring, when blossoms are present, monitor with pheromone traps for the presence of codling moth.
In July and August monitor the fruit weekly for new waves of adults. Evaluate 5% of randomly selected trees for ap- pearance of codling moth present on developing fruit. Cultural Control
Remove fallen fruit and organic debris from around the base of the tree and do not put into
compost.
As a preventative measure, spray with kaolin or place kaolin -soaked socks (on smaller trees) on fruit after thinning. Install bat boxes to attract
bats to prey upon codling moths. According to the PNW Handbook, mating disruption phero- mones can be used but are not effective for orchards less than 10 acres.
Management Using CYD-X
Codling moth granulosis virus CYD-X contains a naturally occurring virus that infects and kills codling moth larvae. This virus is host specific. It does not infect beneficial in- sects, fish, wildlife, livestock or humans.
Granulosis virus is a selective biological insecticide that must be ingested to be effective. Each particle containing the virus is naturally micro-encapsulated within a protein occlusion body (OB) that protects it to some degree from degradation.
Thorough coverage is important. The virus degrades when
2018 3
exposed to UV light. Frequent applications (every 7 to 10 days) are necessary if a grower relies only on granulosis virus for codling moth control especially when codling moth pres- sure is high. The virus controls larvae, but some fruit damage stings may be evident.
How CYD-X Works
The larval digestive tract of the codling moth is at a pH of 10, a high alkaline environment which dissolves the OB and re- leases the virus to penetrate the cells lining the gut. The viral DNA then “hijacks” the nucleus of the cell, directing it to rep- licate many copies of the virus, which rapidly spreads the in- fection to other organs. Within a few days the infected larva stops feeding and its melting organs fill with virus. Upon death the larva “melts,” its fragile outer skin disintegrating to release the liquefied remains of its internal organs, which con- tain billions of new virus OBs, each capable of initiating a new infection if ingested by another codling moth larva feed- ing at that site or wherever OBs have been deposited by raindrops, gravity, or by spraying CYD-X. Laboratory stud- ies have determined that a dose of 1 or 2 OBs is all that is re- quired to cause a lethal infection in half of the codling moth larvae tested. A single ounce of CYD-X biological insecti- cide contains nearly one trillion OBs. The virulent nature of CYD-X toward its host means it is effective at very low usage rates.
Resources
Pacific Northwest Insect Management Handbook, “Apple- Codling Moth.”
https://pnwhandbooks.org/insect/tree-fruit/ apple/apple-codling-moth
Brunner, Jay F. “Codling Moth,” WSU Tree Fruit Research and Extension Center, Orchard Pest Management Online.
http://jenny.tfree,wsu.edu/opm/displaySpecies.php?pn=5
Cyd-X Technical Memo,
http://www.certisusa.com/pdf- technical/cyd-x-technical-2009.pdf