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 27 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.

Bulb Mites

Two genera of mites are known to infect species of Allium. The dry bulb mite (Aceria tulipae) is an eriophyid mite that survives on cultivated Allium species. Bulb mite species in the genus Rhizoglyphus can also be troublesome on Alliums. Infected seed may fail to germinate. Plants grown from infected seed may lack vigor and produce stunted, deformed leaves. Plants may outgrow the damage if the infestation is not heavy, but mites may increase in number over the growing season and will remain in the harvested garlic. They are particularly troublesome in storage, causing dessication and creating wounds that allow for entry of pathogens.

Bulb mites are favored by mechanical injury, disease, cool soil temperatures, and soils with high organic matter content. Avoid adding manure and use fallow periods to eliminate crop residue. In smaller plantings, removing culls from the field immediately after harvest will reduce overwintering populations. Dark plastic mulch will increase soil temperatures and control mites. Plant clean seed and rotate out of Alliums for at least four years after an infestation. Avoid planting Alliums directly after Brassicas, corn, grain, or grass cover crops.

Onion Maggot (Delia antiqua)

For more information on this pest and for cultural and biological controls, see onion maggot in the Onion section.

diazinon (Diazinon* AG500): 2 to 4 qt/A; REI 3d, Bee: H, Group 1B. Broadcast and incorporate just before planting. Will not control organophosphate-resistant onion maggots. DO NOT make more than one application per year.

Onion Thrips (Thrips tabaci)

Thrips are favored by hot, dry weather. Heavy rain or overhead irrigation can lower populations quickly. Lacewing larvae, pirate bugs and predatory thrips are important natural enemies. Reduce populations by cleaning up crop residue after harvest to limit overwintering sites. Do not plant garlic near other Alliums (onion family) or alfalfa, clover, cucurbits or Brassica crops that can harbor large populations of thrips, which may migrate to garlic when these crops are cut or harvested. Begin applications when damage is first noticed. Repeat applications at 7 to 10-day intervals. Use a shorter interval in hot, dry weather. Use spreader-sticker for better coverage. Apply in early evening, using high pressure and 100 gal water/A for best results. See onion thrips in the Onion section for more information.

The most common controls for leek and garlic diseases include the use of disease resistant cultivars and pathogen-free seed and bulbs, and cultural practices such as crop rotation and crop residue management that restrict the pathogens. 

acetamiprid (Assail 30 SG): 5 to 8 oz/A; PHI 7d, REI 12h, Bee: M, Group 4A.

Beauveria bassiana (Mycotrol ESO): 0.25 qt to 1 qt/A; PHI 0d, REI 4h, Bee: L, Group 22. Treat when populations are low and thoroughly cover foliage. Takes 7 to 10 days after the first spray to see control. Repeat applications may be needed.

Burkholderia spp. strain A396 cells and spent fermentation media (Venerate XCOG): 1 to 8 qt/A; PHI 0d, REI 4h, Bee: M. Suppression only.

Chenopodium extract (Requiem EC): 1.5 to 3 qts/A; PHI 0d, REI 4h, Bee: L. Begin application as soon as thrips are seen. Thoroughly cover foliage.

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

cyantraniliprole (Exirel): 13.5 to 20.5 oz/A; PHI 1d, REI 12h, Bee: H, Group 28. Suppression only.

deltamethrin (Delta Gold*): 1.5 to 2.4 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.

dinotefuran (Venom): 3 to 4 fl oz/A foliar, 5 to 6 fl oz/A soil; PHI 1d foliar, 21d soil, REI 4h, Bee: H, Group 4A.

gamma-cyhalothrin (Declare*): 1.02 to 1.54 oz/A; PHI 14d, REI 24h, Bee: H, Group 3A.

imidacloprid (Admire Pro): 14 oz/A; PHI 21d, REI 12h, Bee: H, Group 4A. Soil applications only.

kaolin (Surround WPOG): 25 to 50 lb/A or 0.25 to 0.5 lb/gal; PHI 0d, REI 4h, Bee: L. Suppression/repellence only. Good coverage into plant crown is essential. Generally compatible as a tank mix with other insecticides.

lambda-cyhalothrin (Warrior* II): 1.28 to 1.92 oz/A; PHI 14d, REI 24h, Bee: H, Group 3A.

malathion (Malathion 57 EC): 1.5 to 2 pt/A; PHI 3d, REI 24h, Bee: H, Group 1B.

permethrin (Pounce* 25WP): 9.6 to 12.8 oz/A; PHI 1d, REI 12h, Bee: H, Group 3A.

pyrethrin (PyGanic EC5.0OG): 4.5 to 17 oz/A; 0.25 to 0.50 oz/gal, 3 gal/1000 sq ft in greenhouse for backpack sprayers; PHI 0d, REI 12h, Bee: M, Group 3A.

sodium tetraborohydrate decahydrate (Prev-AM): 100 oz/100 gal; REI 12h, Bee: L, Group 25. Do not apply in midday sun or mix with copper, sulfur or oils.

spinosad (Entrust SCOG): 4 to 8 oz/A; PHI 1d, REI 4h, Bee: M, Group 5. Suppression only. Use adjuvant for better control.

spinetoram (Radiant SC): 6 to 10 oz/A; PHI 1d, REI 4h, Bee: M, Group 5. Thorough coverage is essential. Efficacy improves with the addition of an adjuvant.

spirotetramat (Movento): 5 oz/A; PHI 3d, REI 24h, Bee: M, Group 23. Must be tank-mixed with a spray adjuvant with spreading and penetrating properties to maximize leaf uptake and sytemicity; don't use sticker adjuvants. Controls immature stages; may also reduce adult fertility.

zeta-cypermethrin (Mustang*): 3.2 to 4.3 oz/A; PHI 7d, REI 12h, Bee: H, Group 3A.