Description of the Pest
The pepper weevil is a common pest in southern California where it can migrate in from areas with warm winters or survive year-round in years when winters are mild. The adult pepper weevil is a small beetle, about 1/8 inch (3 mm) long, with a dark body that has a brassy luster to it. Larvae are off-white grubs with a brown head and are about 1/4 inch (6 mm) when mature.
Adult females lay eggs in holes they create in pepper buds or in the base of young pepper pods. Larvae develop and feed inside on the seed core or tissue of the pod wall. The pepper weevil has three larval instars and larval development requires 2 to 3 weeks. Pupation occurs within the pepper pod and requires 3-6 days. There are multiple generations a year. Peppers are the primary host, but feeding also occurs on nightshades, especially silverleaf nightshade, Solanum elaeagnifolium.
Damage
Adult weevils feed on fruit and leaf buds. Larvae feed inside the pods and cause young fruit to drop prematurely, reducing yields. Larger fruit often do not drop when infested, resulting in crop contamination.
Management
Pepper weevils can be managed with field sanitation and crop rotation, which is critical in managing this pest. Monitor with pheromone-baited sticky traps to determine the need to treat.
Biological Control
Parasitic wasps have been observed on the weevil larvae, but their impact in controlling this pest appears to be minimal.
Cultural Control
- Inspect pepper transplants to make sure they aren't infested, and remove nightshade plants from the pepper field and its margins.
- During fruit development and at harvest, remove culled or dropped fruit from the field.
- Immediately following harvest, remove and destroy fruit from the field and the surrounding areas. Shred and disc pepper plant residue.
- If pepper weevil is a problem, rotate to another crop next season. Pepper weevils only develop on solanaceous plants, so avoid rotating to crops like tomato and eggplant, and control solanaceaous weeds.
Organically Acceptable Methods
Cultural controls and sprays of pyrethrin are acceptable for use on organically certified produce.
Monitoring and Treatment Decisions
As recommended by University of Florida research, estimate adult pepper weevil numbers with pheromone-baited yellow sticky traps and by visual examination. Pheromone-baited yellow sticky traps may also be useful in early detection.
Prior to bloom, place traps in the field to detect first adult emergence, and on the perimeter of the field to detect migration into the field. Mount traps on poles that can be adjusted during crop growth to ensure that the bottom of the traps are just at or slightly below the tops of the plants. Check traps twice a week in the morning or more frequently if adults are known to be present. Apply treatments when the first adult is captured.
Alternatively, the terminal buds can also be used to determine the treatment threshold. Check two terminal vegetative buds per plant for adults and treat when one or more adults are found per 400 buds.
| Common name | Amount per acre** | REI‡ | PHI‡ | |
|---|---|---|---|---|
| (Example trade name) | (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. | ||||
| A. | ESFENVALERATE | |||
| (Asana XL)* | 5.8–9.6 fl oz | 12 | 7 | |
| MODE-OF-ACTION GROUP NUMBER1: 3A | ||||
| COMMENTS: Do not exceed 0.35 lb a.i./acre per season. Can cause leafminer outbreaks to occur by reducing natural enemies such as parasitic wasps. If leafminers are present in the pepper crop, use of this product should be limited to late in the season to minimize negative impacts on biological control. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | ||||
| B. | CARBARYL* | |||
| (Sevin 4F or XLR Plus) | 0.5–1 qt | 12 | 3 | |
| MODE-OF-ACTION GROUP NUMBER1: 1A | ||||
| COMMENTS: Thorough coverage is important. Do not use when psyllids are present. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | ||||
| C. | BIFENTHRIN | |||
| (Brigade 2EC) | 2.1–6.4 fl oz | 12 | 7 | |
| MODE-OF-ACTION GROUP NUMBER1: 3A | ||||
| COMMENTS: Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | ||||
| D. | PERMETHRIN | |||
| (Pounce 25WP)* | 6.4–12.8 oz | 12 | 3 | |
| MODE-OF-ACTION GROUP NUMBER1: 3A | ||||
| COMMENTS: For use on bell peppers only. Do not apply more than 0.8 lb a.i./acre per season. Only use this product late in season if leafminers are present; it is destructive of their parasites. | ||||
| E. | PYRETHRIN# | |||
| (PyGanic EC 1.4) | 16 oz | 12 | 0 | |
| MODE-OF-ACTION GROUP NUMBER1: 3A | ||||
| COMMENTS: Begin applications when insects first appear; do not wait until the plants are heavily infested. Apply in sufficient water for thorough coverage of the plants. Apply at intervals of 7 days or less. Repeat as necessary to maintain control. Highly toxic to bees; do not spray directly or allow to drift onto blooming crops or weeds where bees are foraging. | ||||
| ** | See label for dilution rates. |
| ‡ | 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. |
| # | Acceptable for use on organically grown produce. |
| 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). |