Cutworm larvae feed at night. They come in various colors and patterns but always appear as smooth-skinned caterpillars to the naked eye. They frequently roll into a C-shape when disturbed. The mature variegated cutworm larva is yellow to brown, a little over an inch long (3 cm), with a row of 4 to 6 yellow or pink, diamond-shaped spots down the back. The mature dark-sided cutworm is somewhat larger than the variegated cutworm (1.5–2 inches, 4–5 cm) and gray to greenish gray in color with irregular, longitudinal stripes.
Adult cutworm moths are rather nondescript, with dark gray or brown front wings that have irregular spots or bands and lighter hind wings.
Damage
Larvae feed at night on the tender tips of new asparagus spears, where they eat small holes. One-sided feeding may also cause the spears to curl. The variegated cutworm also feeds underground and at the soil surface. Fern damage is generally rare.
Management
Carry out good weed control in and around the field, and incorporate field trash and previous crop residues thoroughly to reduce egg and worm overwintering. Look for damage symptoms and confirm cutworm presence by digging into the soil an inch or so around a damaged spear.
Organically Acceptable Methods
Good weed management and field cultivation are acceptable to use in an organically certified crop.
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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|
Sevin 5 Bait | Application Timing Varies (See UC IPM Pest Management Guidelines and Label) | 8 |
1A |
Spears: 20 lb Ferns: 40 lb |
12 | 1 | Apply when pests appear in damaging numb... | narrow | low | low | low | short | low | low | intermediate | low | low | 08/2019 | ||
| Lannate LV | Application Timing Varies (See UC IPM Pest Management Guidelines and Label) | 8 |
1A |
1.5–3 pt | 48 | 1 | Use low rate for variegated cutworm. App... | broad | high | high | high | moderate | — | — | — | — | — | 08/2019 | |||
|
|
Pounce 25 WP | Application Timing Varies (See UC IPM Pest Management Guidelines and Label) | 8 |
3A |
3.2–6.4 oz | 12 | 1 | Apply by ground equipment only. Do not a... | broad | low | high | high | long | intermediate | low | extra high | very low | intermediate | 08/2019 |
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.
- 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: Asparagus
UC ANR Publication 3435
E.T. Natwick (emeritus), UC Cooperative Extension Imperial County
B.J. Aegerter, UC Cooperative Extension San Joaquin County (European Asparagus Aphid)
Acknowledgement for Contributions to Invertebrates
R.J. Mullen, UC Cooperative Extension San Joaquin County
W.E. Chaney (emeritus), UC Cooperative Extension Monterey County
C.F. Fouche, UC Cooperative Extension San Joaquin County
