Insect Control

NOTE:  For the insecticides listed below, one product trade name and formulation is provided for each active ingredient (common name) as an example of rates, days to harvest (dh), REI, and special instructions. In many cases there are other products available with the same active ingredient. Please see Table 20 and Alphabetical Listing by Trade Name for more information on products with the same active ingredients.

Onion Thrips

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 dry oz/A (7 dh, REI 12h, Group 4).

Beauveria bassiana (Mycotrol O): 8 to 32 oz/A (0 dh, REI 4h, Group 22). Thoroughly cover foliage. Takes 7 to 10 days after application to see control. OMRI listed.

cypermethrin (Ammo* 2.5 EC): 4 to 5 oz/A (7 dh, REI 12h, Group 3A).

deltamethrin (Decis* 1.5 EC): 1.5 to 2.4 oz/A (1 dh, REI 12h, Group 3A).

kaolin (Surround WP): 25 to 50 lb/A or 0.25 to 0.5 lb/gal (0 dh, REI 4h). Suppression/repellence only. Follow label instructions for mixing. Generally compatible as a tank mix with other insecticides. OMRI listed.

malathion (Malathion 57 EC): 1 1/2 to 2 pt/A (3 dh, REI 12h, Group 1B).

pyrethrin (PyGanic EC 5.0): 4.5 to 18 oz/A (0 dh, REI 12h, Group 3A). OMRI listed.

pyrethrins + piperonyl butoxide (Pyrenone): 1 tsp/gal, or 1 to 12 oz/A (0 dh, REI 12h, Group 3A).

spinetoram (Radiant SC): 6 to 10 oz/A (1 dh, REI 4h,Group 5).

spinosad (SpinTor 2SC): 4 to 8 oz/A (1 dh, REI 4h, Group 5). Suppression only.

zeta-cypermethrin (Mustang*): 3.2 to 4.3 oz/A (7 dh, REI 12h, Group 3A).