Pest Management Options:  Codling Moth Virus

Apple and pear growers looking for an organic option to codling moth control should consider the codling moth granulosis virus (CpGV).  The virus is naturally occurring, specific to codling moth, and is noninfectious toward beneficial insects and other invertebrates, amphibians, reptiles, birds, and mammals.  A single ounce of a CpGV suspension can contain up to 3 trillion microencapsulated viral particles.  To be effective, the virus must be ingested by codling moth larvae.  Once inside the larval gut, the virus multiplies, and after a few days, feeding stops and the larva dies.  New viral particles ooze out of dead larvae, and spread to the surface of the fruit, able to cause new infections in other larvae.

Used alone, this biocontrol option gives only moderate control (from 60% to 80% control).  In organic orchards, the CpGV virus should be used alternatively with oil or Entrust (spinosad) and/or with mating disruption, or it can be used in conventional orchards to reduce chemical inputs.Cyd-X is available for Utah, Idaho, Colorado, and Montana growers: 4 oz/acre, $350-$400 for 1 quart; Cropworx in Eckert, CO, 970-835-3335, or online at www.cropworx.net.

Some points to remember when using codling moth virus:

• Thorough coverage is very important because codling moth larvae are on the surface of the fruit for a very short amount of time.
• Use the highest rate on the first application; afterward, use a lower rate at shorter intervals (every 7 days).
• Apply in late afternoon or on a cloudy day to prevent initial breakdown of the product by the sun.
• Some surface feeding damage (stings) may occur because the larvae are not killed immediately; if this type of injury is unacceptable, use granulosis virus for the first generation only.
• Store the product in a refrigerator to reduce degradation of the virus.
• Can be mixed with most other pesticides, except for Bt or antibiotics.
• Can be used up to the day of harvest; 4-hour re-entry interval.
• Resistance to the virus has been reported in other countries, so growers should not overuse this product.