Suggestions for weed management in basil include use of the Stale Seedbed Technique and use of plasticulture. Both glyphosate (Roundup) and pelargonic acid (Scythe) are registered for stale seedbed use. Flaming can also be used. Stale seed beds can be used between plastic mulch (be careful with flaming as it melts the plastic). Basil usually grows quickly and shades the planting hole in plasticulture, out-competing weed growth. Apply the plastic at least 2 to 3 weeks prior to planting and kill the weeds between the mulch prior to setting the basil plants on the plastic. On bare ground culture, keep cultivations shallow to protect crop roots. Do not move soil into the crop row as basil plants may be more susceptible to diseases when soil is mounded against the stems of the crop.
Herbicides Used Preemergence to Weeds
napropamide (Devrinol 2-XT): REI 12h, Group 15. Apply 2 to 4 qt/A as a preplant/preemergence application to weed-free soil surface. Apply with ground spray equipment only, in 20-100 gallons of water per acre. Apply to a weed free surface. Shallow incorporate no deeper than seeding depth or sprinkler irrigate within 24-72 hours using sufficient water to wet the soil to a depth of 2 to 4 inches. Use the lower rate on light soil (coarse textured - sandy) and the higher rate on heavy soil (fine textured - clay).
Herbicides Used Postemergence to Weeds
carfentrazone (Aim EC): REI 12h, Group 14. Aim is a burndown herbicide and will injure any foliage it comes into contact with. Apply Aim to row middles of emerged crops with hooded sprayers to control emerged weeds, including crops grown on mulch or plastic. Prevent any spray from contacting the crop, or injury will occur. For best results, make application to actively growing weeds up to 4 inches tall and rosettes less than 3 inches across. Good coverage is essential for good control. Apply up to 2 oz/A per application, and do not exceed a total of 6.1 oz/ per season.
clethodim (Select Max): PHI 14d, REI 24h, Group 1. Has not been tested on all varieties. Crop tolerance should be verified on a small area of the crop at the desired rate. If no crop response is evident seven days after treatment, Select Max Herbicide may be used on the entire field at the rate tested. Will control grass weeds only. Apply to actively growing grasses. See label for rate selection. Multiple applications permitted of 9 to 16 oz/A per application, minimum 14-days between applications, not to exceed 64 oz/A per year. Add 0.25% v:v nonionic surfactant (1 qt per 100 gal of spray). Can also be used as a spot-spray by mixing 1/3-2/3% (0.44 to 0.85 oz per gallon) Select Max and 0.25% v:v nonionic surfactant (0.33 oz per gallon). Spray to wet, but do not allow runoff of spray solution.