Description of the Pest
Larvae are pale green, often with whitish stripes down each side of the body and a narrow stripe down the middle of the back. The adult of one common species is a grayish moth with a 1-inch wingspan. Most species overwinter as pupae (except Amphipyra, which overwinters in the egg state). All species have one generation each year, but because egg hatch occurs over an extended period in spring, all sizes of larvae may be present at the same time.
Larvae eat large holes in young leaves and fruit. Fruit damage usually begins after petal fall.
Regular monitoring each spring during bloom and after is important so that prompt action can be taken if damaging populations develop. For more information, see MONITORING PESTS AT BLOOM.
Certain parasitic wasps (Apanteles, Eulophus, Meteorus, and Ophion spp.) help keep green fruitworm populations under control.
Organically Acceptable Methods
Sprays of Bacillus thuringiensis and the Entrust formulation of spinosad are acceptable for use on an organically certified crop.
Monitoring and Treatment Decisions
Check the orchard in early spring for presence of larvae and feeding damage. When larval damage is evident in the orchard, apply an insecticide shortly after petal fall.
|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.|
|PETAL FALL TO PREHARVEST|
|(Intrepid 2F)||10–16 fl oz/acre||4||7|
|MODE-OF-ACTION GROUP NUMBER1: 18|
|COMMENTS: Most effective when applied at petal fall. Do not apply more than 16 fl oz/acre per application or 64 fl oz/acre per season. Coverage is extremely important; sprayer speed should not exceed 2 mph.|
|B.||BACILLUS THURINGIENSIS ssp. KURSTAKI#|
|(various products)||Label rates||4||0|
|MODE-OF-ACTION GROUP NUMBER1: 11A|
|COMMENTS: Least harmful to beneficials. Bacillus thuringiensis is a stomach poison and must be consumed by the leafroller; therefore it is most effective when applied during warm, dry weather when larvae are actively feeding. Most effective against young larvae. Requires more than 1 treatment; apply second application 7–10 days after first.|
|(Entrust)#||1.25–2.5 oz||0.42–0.83 oz||4||7|
|MODE-OF-ACTION GROUP NUMBER1: 5|
|COMMENTS: Most effective when applied at petal fall. This product is toxic to bees for 3 hours following treatment; apply in late evening after bees have stopped foraging. Do not apply more than 9 oz/acre per year. Toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.|
|(Delegate WG)||4.5–7 oz/acre||4||7|
|MODE-OF-ACTION GROUP NUMBER1: 5|
|COMMENTS: Toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging.|
|MODE-OF-ACTION GROUP NUMBER1: 28|
|COMMENTS: Do not use with an adjuvant. A newer material; impact on beneficials not yet determined. May cause mite flare ups.|
|(Sevin XLR PLUS)||3–4 qt/acre||12||1|
|MODE-OF-ACTION GROUP NUMBER1: 1A|
|COMMENTS: May cause increased spider mite problems. Do not apply more than 14 qt XLR PLUS/acre per season. The XLR PLUS formulation is less hazardous to honey bees than other formulations if applied from late evening to early morning when bees are not foraging.|
|**||For concentrate applications, use the amount given in 80–100 gal water/acre, or lower if the label allows; for dilute applications, amount is per 100 gal water to be applied in 300–400 gal water/acre, according to label.|
|‡||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).|
|#||Acceptable for organically grown produce.|