Description of the Pest
Adults are dark brown compact weevils up to about 0.5 inch long with longitudinal striations. They are flightless and nocturnal, hiding at the base of fruit or under dirt clods during the day and crawling up the tree at night to feed. Larvae are white, legless grubs that feed on tree roots. Adult emergence often begins in May, and adults are present all summer. There is one generation per year.
Adults feed on foliage, notching out the edge of the leaves, giving them a ragged appearance. Under high population pressure, only the midvein of the leaf will remain. Adult feeding on the bark of young twigs may cause dieback. Mature trees can withstand attack without significant damage; however, feeding before harvest may damage fruit stems. Replanted trees may be severely defoliated and die. No damage has been associated with larval feeding.
To reduce damage on young trees that are infested, apply a 3- to 4-inch band of sticky material on the trunk of young trees to trap crawling adults in May when the first adult feeding is observed. Apply Tanglefoot over a special tape or painted areas of the trunk of young trees to prevent bark damage. Reapply the sticky material when it becomes dirty or loses its effectiveness. Alternatively, some growers have had success with an insecticide treatment applied at night when the insects are exposed, but research has not been done to verify this.
|Common name||Amount to use||REI‡||PHI‡|
|(Example trade name)||(conc.)||(dilute)||(hours)||(days)|
|Not all registered pesticides are listed. The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Always read the label of the product being used.|
|(Sevin 4F)||3–4 qt/acre||12||1|
|MODE-OF-ACTION GROUP NUMBER1: 1A|
|COMMENTS: Apply at night when insects are active and exposed may provide control; research data is lacking. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.|
|‡||Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.|
|*||Permit required from county agricultural commissioner for purchase or use.|
|1||Rotate chemicals with a different mode-of-action Group number, and do not use products with the same mode-of-action Group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a Group number of 1B; chemicals with a 1B Group number should be alternated with chemicals that have a Group number other than 1B. Mode-of-action Group numbers are assigned by IRAC (Insecticide Resistance Action Committee).|