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.
Pesticides and Natural Enemy Releases
Not all registered pesticides are listed. The following are ranked by their IPM value, with the most effective and least harmful to natural enemies, honey bees, and the environment listed at the top of the table. When choosing a pesticide, consider information related to water and air quality, resistance management, and the pesticide's properties and application timing. Use PestManage to compare summarized management options for different pests in the same crop. Always carefully read the label of the product being used and take all necessary precautions when handling pesticides.
| Rank | Active ingredient | Example trade name | Group | Group Order | MoA 1 | Amount per acre | REI (hours) ‡ | PHI (days) ‡ | Comments | Selectivity 2 | Bees 3 | Predatory mites 4 | Predators 5 | Parasitoids 5 | Residue duration 6 | Leaching(fish) 7 | Adsorbed runoff(fish) 8 | Solution runoff(human) 9 | Leaching(human) 10 | Solution runoff(human) 11 | Last updated 12 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|
Brigade 2EC | Application Timing Varies (See UC IPM Pest Management Guidelines and Label) | 8 |
3A |
2.1–6.4 fl oz | 12 | 7 | Highly toxic to bees; do not spray direc... | broad | high | high | high | long | intermediate | low | extra high | very low | intermediate | 06/2016 | ||
| Sevin XLR Plus | Application Timing Varies (See UC IPM Pest Management Guidelines and Label) | 8 |
1A |
0.5–1 qt | 12 | 3 | Thorough coverage is important. Do not u... | — | — | — | — | — | low | low | intermediate | low | low | 06/2016 | |||
|
|
Asana XL | Application Timing Varies (See UC IPM Pest Management Guidelines and Label) | 8 |
3A |
5.8–9.6 fl oz | 12 | 7 | Do not exceed 0.35 lb a.i./acre per seas... | broad | high | moderate | high | moderate | high | intermediate | extra high | low | intermediate | 06/2016 | ||
|
|
Pounce 25 WP | Application Timing Varies (See UC IPM Pest Management Guidelines and Label) | 8 |
3A |
6.4–12.8 oz | 12 | 3 | For use on bell peppers only. Do not app... | broad | low | high | high | long | intermediate | low | extra high | very low | intermediate | 06/2016 | ||
|
|
PyGanic EC 1.4 II # | Application Timing Varies (See UC IPM Pest Management Guidelines and Label) | 8 |
3A |
16 oz | 12 | 0 | Begin applications when insects first ap... | broad | — | moderate | moderate | short | low | low | high | very low | intermediate | 06/2016 |
Legend
- ‡ a b Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without personal protective equipment. Preharvest interval (PHI) is the number of days from treatment to harvest. In some cases, the REI exceeds the PHI. The longer of the two intervals is the minimum time that must elapse before harvest.
- * a Permit required from county agricultural commissioner for purchase or use.
- # ↩ Acceptable for use on certified organic crops. Check with your certifier to confirm before application.
- 1 ↩ Group numbers for insecticides and miticides are assigned by the Insecticide Resistance Action Committee (IRAC). Insecticides with unknown modes of action are assigned mode-of-action group numbers (MoAs) that begin with UN. Rotate pesticides 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; insecticides with a 1B group number should be alternated with insecticides that have a group number other than 1B.
- 2 ↩ Range of insect and mite groups affected by a pesticide. Broad means the pesticide affects most groups of insects and mites; narrow means the pesticide affects only a few specific groups.
- 3 ↩ Risk of harm to honey bees. For more information, see Bee Precaution Pesticide Ratings.
- 4 ↩ Risk of harm to predatory mites. Toxicities are generally to western predatory mite, Galendromus occidentalis. Where differences have been measured in toxicity of the pesticide-resistant strain versus the native strain, these are listed as pesticide-resistant strain or native strain.
- 5 a b Risk of harm to parasitoids and general predators. Toxicities are averages of reported effects and should be used only as a general guide. Actual toxicity of a specific insecticide depends on factors including the application rate, environmental conditions, and the life stage and species of a parasitoid or predator.
- 6 ↩ Length of time residue affects natural enemies. Short means hours to days; moderate means days to 2 weeks; and long means many weeks or months.
- 7 ↩ Risk of harm to fish from leaching, based on USDA Natural Resources Conservation Service Windows Pesticide Screening Tool (WIN-PST).
- 8 ↩ Risk of harm to fish from adsorbed runoff, based on USDA Natural Resources Conservation Service Windows Pesticide Screening Tool (WIN-PST).
- 9 ↩ Risk of harm to fish from solution runoff, based on USDA Natural Resources Conservation Service Windows Pesticide Screening Tool (WIN-PST).
- 10 ↩ Risk of harm to humans from leaching, based on USDA Natural Resources Conservation Service Windows Pesticide Screening Tool (WIN-PST).
- 11 ↩ Risk of harm to humans from solution runoff, based on USDA Natural Resources Conservation Service Windows Pesticide Screening Tool (WIN-PST).
- 12 ↩ Date information was last updated in the UC IPM Pest Management Guidelines.
UC IPM Pest Management Guidelines: Peppers
UC ANR Publication 3460
E.T. Natwick (emeritus), UC Cooperative Extension Imperial County
J.T. Trumble, Entomology, UC Riverside
J.L. Aguiar, UC Cooperative Extension Riverside County
Acknowledgement for Contributions to Invertebrates
W.J. Bentley (emeritus), UC IPM and Kearney Agricultural Research and Extension Center, Parlier
W.E. Chaney (emeritus), UC Cooperative Extension Monterey County
R.L. Coviello, UC Cooperative Extension Fresno County
C.F. Fouche, UC Cooperative Extension San Joaquin County
C.G. Summers (emeritus), Entomology, UC Davis and Kearney Agricultural Research and Extension Center, Parlier
