Codling moths are serious insect pests of apples. If your apples have “worms,” you probably have codling moths.
Life Cycle of the Codling Moth
The codling moth’s life cycle has an important stage in the soil or organic debris around the base of your apple tree. The full-grown larvae of the moth, in silken cocoons, overwinter in this environment, and develop into adult moths around mid-March to early April.
The moths fly into the tree to mate and deposit their eggs on the leaves, spurs or immature fruit. They are one-half to three quarters inch long, with a dark band at their wingtips. They can be difficult to spot because their colors blend with the tree’s bark, and they are active for only a few hours before and after sunset.
The eggs hatch in early to mid-May, and the young larvae tunnel into the core of the fruit and eat their fill, leaving behind reddish-brown frass (insect waste).
After they develop fully, the larvae drop from the fruit and tree to continue their life cycle in the soil or debris at the base of the tree.
A second generation often occurs in cooler coastal environments such as the Monterey Bay area, with the new group of young larvae attacking the fruit in mid-July.
Management of the Codling Moth
Organic pesticides for home gardeners are CYD–X Insecticidal Virus, which infects and kills the larvae of codling moths, and Spinosad, which is a nerve and stomach poison derived via fermentation from naturally occurring bacterium. These products might be found in a garden center; or can be ordered from GrowOrganic.com or other online sources.
Apply insecticide sprays as the eggs hatch and the larvae begin to attack the fruit and make the first “sting” (a tiny mound of frass on the fruit, marking a larva’s entry). Timing can be tricky, because temperature and other factors affect the moths’ schedule. For example, mating occurs only when sunset temperatures exceed 62 degrees Fahrenheit.
A Good Reference
The primary source of information for today’s column is the University of California publication, “Codling Moth: Integrated Pest Management for Home Gardeners and Landscape Professionals.” For additional approaches to management of these pests, download this free publication at www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7412.html.
Managing an established population of codling moths will require both insecticide sprays and additional methods. For example, sanitation, always a good practice, involves promptly removing infested and dropped fruit.
Eating a fresh apple from your own tree can be delightful, but you might have to compete with the wildlife.
Here is one of several Spinosad products that have been formulated and packaged for home gardening. This products is available in gardens centers and online from Peaceful Valley ,
Monterey Garden Spray Concentrate – Spinosad (Pint)
$19.99 + $9.99 shipping
Spinosad for home gardeners Use on vegetable and fruit crops, ornamentals, and turf to control caterpillars as well as beetles, leafminers, thrips, Colorado potato beetles, fire ants and more! Use 4 Tbs/gal water. Spinosad insecticides are nerve and stomach poison derived via fermentation from naturally occurring bacterium Saccharopolyspora spinosa. New chemistry represents an alternative to Bt for worm control and offers excellent control of targeted pests and low toxicity to non-target organisms, including most beneficial insects. Low mammalian toxicity, helps conserve beneficials.