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.
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 leeks near other Alliums (onion family) or alfalfa, clover, cucurbits or brassica crops that can harbor large populations of thrips, which may migrate to leeks 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 a 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.
acetamiprid (Assail 30SG): 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.
Chromobacterium subtsugae strain PRAA4-1 (GrandevoOG): 2 to 3 lb/A; PHI 0d, REI 4h, Bee: M.
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.
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.
malathion (Malathion 57 EC): 1.5 to 2 pt/A; PHI 3d, REI 24h, Bee: H, Group 1B.
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.
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 7d, 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.