Insect Control

NOTES:  For the insecticides listed below, one product trade name and formulation is provided for each active ingredient (AI) as an example of rates, preharvest interval (PHI), restricted entry interval (REI), and special instructions. In many cases, there are other products available with the same AI. Please see Table 26 and Insecticides Alphabetical Listing by Trade Name for more information on these insecticides.

The designation (Bee: L, M, or H) indicates a bee toxicity rating of low, moderate, or high. See the Protecting Honeybees and Native Pollinators section for more details.

The symbol * indicates a product is a restricted use pesticide. See Pesticide Safety and Use for more details.

The symbol OG   indicates a product is listed by the Organic Materials Review Institute (OMRI) as approved for use in organic production. See Organic Certification section for more details.

Asparagus Aphids (Brachycorynella asparagi)

Asparagus aphids are small (1.6-2 mm), oval, green to gray aphids that may be covered in a waxy secretion. They overwinter as eggs on asparagus residue in the field. Eggs hatch in spring and nymphs and adults feed on spears, then on ferns. During the summer, wingless females produce live young (nymphs) which develop into reproductive females in 8-10 days. Populations can build up rapidly especially in hot, dry weather. Aphids feed on new growth and cause shortening of internodes, rosetting, or ‘witches broom’ appearance of the foliage. High aphid populations reduce root growth and plant vigor and may kill seedlings. Younger plantings are most vulnerable, especially 2 or 3-year-old plantings that are not being harvested.  Cold winters and aphid infestation have a synergistic effect on plant health, greater than either factor alone. Asparagus can also vector viruses, including asparagus virus I and II (AV-I and AV-II) and tobacco streak virus (TSV). During harvest, monitor any plantings that are not being harvested. After harvest, scout ferns for signs of feeding injury and aphid colonies, especially in the basal regions of the plant. Cultural controls include harvesting spears in spring, because only volunteer plants and young plantings that are not harvested will allow aphids to survive and multiply. Remove dead ferns during the fall or winter, and control between-row volunteers through spring tillage or herbicides. Natural biocontrol is provided by insect predators such as lady beetles, lacewings, predatory midges, and flower fly larvae, by the parasitic Braconid wasp, Diaeretiella rapea, and by a fungal pathogen that is more active in humid climates. Treat ferns when populations are low, if 5% of ferns show injury. Conserve beneficials by using a selective product. Scout again in 5-7 days to determine if further treatment is needed.

acetamiprid (Assail 30SG): 2.5 to 5.3 oz/A; PHI 1d, REI 12h, Bee: M, Group 4A.

dimethoate (Dimethoate 4EC): 1 pt/A; PHI 180d, REI 48h, Bee: H, Group 1B. Apply after last harvest. Systemic.

insecticidal soap (M-PedeOG): 1.25 to 2.5 oz/gal water; PHI 0d, REI 12h, Bee: L. Spray to wet all infested plant surfaces. Apply with companion aphicide.

malathion (Malathion 57EC): 1.5 to 2 pt/A; PHI 1d, REI 12h, Bee: H, Group 1B.

petroleum oil (Suffoil XOG): 1 to 2 gal/100 gal water; PHI 0d, REI 4h, Bee: L.

pymetrozine (Fulfill): 2.75 oz/A; PHI 170d, REI 12h, Bee: L, Group 9B. Apply to ferns after harvest, and before populations build to damaging levels. Allow a minimum of 30 days between applications.

pyrethrin (PyGanic EC5.0OG): 4.5 to 17 oz/A; PHI 0d, REI 12h, Bee: M, Group 3A.

Asparagus Miner (Opbiomyia simplex)

This fly was introduced to North America from Europe and is present wherever asparagus is grown. It feeds only on asparagus, and is found primarily on older stalks bearing ferns. The adult fly is shiny black, 3-4 mm long, with clear wings. Larvae are whitish, legless, tapered at both ends, with black mouth hooks at one end. Pupation takes place in the larval mine on the stalk. Overwintering puparia are usually in mines near or below ground level. There are 2 generations per year. Adults emerge in May and lay eggs underneath the epidermis of stems, usually near the base of the plant. Larvae feed in June, pupate inside their larval mines, and a second generation of adults emerges and lays eggs in late-July or early-August. Second generation larvae feed through August and pupate in the fall, overwintering until the following spring. Larvae feed just beneath the surface of the stem, burrowing upwards or downwards and forming mines. While direct feeding damage can girdle stems if there are several mines per stalk, the effect of miners on yield is usually minimal and the injury is largely cosmetic. The most important injury from asparagus miner is due to its association with Fusarium spp. and its ability to vector this pathogen into the plant through feeding wounds. Cultural practices to reduce damage from asparagus miner include removing overwintering stalks and destroying wild asparagus in the vicinity of commercial plantings. Select varieties that are resistant to Fusarium to reduce disease (see Varieties, page 115).

acetamiprid (Assail 30SG): 25.3 oz/A; PHI 1d, REI 12h, Bee: M, Group 4A. Suppression only.

Cutworms

Caterpillars hide under the soil surface adjacent to the plant stem during the day and feed after dark. Crooks (misshaped spears) are often caused by cutworms injuring tips at or just below the soil surface or feeding on the sides of young spears. For best results, make application between midnight and dawn while cutworms are feeding above ground. Synthetic pyrethroids (group 3A) may work best during cool weather in May. See cutworms in the Pepper and Tomato (Outdoor) sections for more information on the black and variegated cutworms.

carbaryl (Sevin XLR PLUS): 1 qt/A prior to fern growth; 2 qt/A on ferns; PHI 1d, REI 12h, Bee: H, Group 1A.

Chromobacterium subtsugae strain PRAA4-1 (GrandevoOG): 2 to 3 lb/A; PHI 0d, REI 4h, Bee: M.

methomyl (Lannate* LV): 1.5 to 3 pt/A; PHI 1d, REI 48h, Bee: H, Group 1A.

permethrin (Pounce* 25WP): 3.2 to 6.4 oz/A; PHI 1h, REI 12h, Bee: H, Group 3A.

spinosad (SeduceOG): 20 to 44 lb/A or 0.5 to1 lb/1000 sq ft.; PHI 60d, REI 4h, Bee: M, Group 5. Scatter bait on soil around plants. For postharvest protection of ferns only.

Asparagus Beetles and Japanese Beetle

The common asparagus beetle (Crioceris duodecimpunctata) and spotted asparagus beetles (Crioceris asparagi) are less than 3/8" long, overwinter as adults in protected areas along fields, feed and lay eggs in the crop, pupate in the soil, and have 2 or sometimes 3 generations per year. The common asparagus beetle (CAB) has a bluish-black body with cream-colored, square or rectangular spots, while the spotted asparagus beetle (SAB) is tan to orange with 12 round, black spots. Eggs of CAB are dark brown, laid standing on end in rows along the spears, with 3-10 in each cluster.  During harvest, adult feeding by CAB on spears or the presence of CAB eggs can render the crop unmarketable. CAB larvae have 4 instars and are wrinkled, plump, hump-backed, and dull gray or brown with black head and legs. CAB larvae may cause severe defoliation of ferns and decline of the planting.  SAB larvae are yellow or orange and feed only on berries. During harvest, scout for adults and eggs on sunny afternoons. Treat spears if >10% of the plants are infested with beetles or 1%-2% have eggs or damage. Scout ferns for all life stages of both pests and treat if 50%-75% are infested. If possible, spot spray along edges of planting where overwintering adults colonize the field and/or band insecticide over the row to help conserve natural enemies. Use selective insecticides on ferns. During harvest, snap or cut spears close to the soil surface daily and eliminate volunteer plants or treat them with an insecticide to use them as a trap crop. Disk old ferns lightly in the fall and clean areas around planting of debris to reduce overwintering populations. Eliminating female plants, and thus berries, can reduce or eliminate SAB populations. Japanese beetles may feed in ferns in mid-summer.

acetamiprid (Assail 30SG): 2.5 to 5.3 oz/A; PHI 1d, REI 12h, Bee: M, Group 4A.

carbaryl (Sevin XLR PLUS): 1 qt/A prior to fern growth; 2 qt/A on ferns; PHI 1d, REI 12h, Bee: H, Group 1A.

dimethoate (Dimethoate 4EC): 1 pt/A; PHI 180d, REI 48h, Bee: H, Group 1B. Asparagus beetle only. Apply after last harvest.

Isaria fumosorosea Apopka Strain 97 (PFR-97 20% WDGOG): 1 to 2 lb/A (foliar or soil drench); PHI 0d, REI 4h, Bee: M, Group M.

kaolin (Surround WPOG): 12.5 to 25 lb/A or 25 to 50 lbs/100 gal water; PHI 0d, REI 4h, Bee: L. Suppression and repellence only. Product residue may need to be washed off if applied to spears during harvest. Generally compatible as a tank mix with other insecticides.

malathion (Malathion 57EC): 1.5 to 2 pt/A; PHI 1d, REI 12h, Bee: H, Group 1B.

methomyl (Lannate* LV): 1.5 to 3 pt/A; PHI 1d, REI 48h, Bee: H, Group 1A. Asparagus beetle only.

permethrin (Pounce* 25WP): 3.2 to 6.4 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A. For Japanese beetle control, use high rate.

petroleum oil (Suffoil XOG): 1 to 2 gal/100 gal water; PHI 0d, REI 4h, Bee: L. For beetle larvae only. Apply as needed.

pyrethrin (PyGanic EC5.0OG): 4.5 to 17 oz/A.; PHI 0d, REI 12h, Bee: M, Group 3A.

spinetoram (Radiant SC): 4 to 8 oz/A; PHI 60h, REI 4h, Bee: M, Group 5. Post-harvest protection of ferns from asparagus beetle only.

spinosad (Entrust SCOG): 4 to 6 oz/A; PHI 60d, REI 4h, Bee: M, Group 5. Post-harvest protection of ferns from asparagus beetle only.