Midwest Vegetable Guide - 2022 - 288

Sweet Potato - Weeds
Thrips
Pesticide
Admire Pro (4.6SC) (imidacloprid) | In-furrow spray or
side dress 4.4-10.5 fl. oz. per acre or 0.31-0.74 fl. oz. per
1,000 ft. of row. Do not exceed 10.5 fl. oz. or 1 application
per acre per season. REI: 12-hour. PHI: 125-day. IRAC 04A.
Entrust SC (2) (spinosad) | Use 2SC formulations at 4.510.0
fl. oz. per acre and do not exceed 21 fl. oz. per acre per
season. Use 80WP formulations at 1.5-3.0 oz. per acre and do
not exceed 9 oz. per acre per season. REI: 4-hour. PHI: 7day.
IRAC 05. OMRI-listed.
Radiant 1SC (spinetoram) | 6.0-8.0 fl. oz. per acre. Do not
exceed 32 fl. oz. per acre per season. REI: 4-hour. PHI: 7day.
IRAC 05.
Warrior II (2.08CS) (lambda-cyhalothrin) | 1.28-1.92 fl.
oz. per acre. Do not exceed 7.68 fl. oz. per acre per season.
REI: 24-hour. PHI: 7-day. IRAC 03A. RUP.
Wireworms
Pesticide
Brigade 2EC (bifenthrin) | 9.6-19.2 fl. oz. per acre. Use
2EC formulations at 9.6-19.2 fl. oz. per acre and do not
exceed 6.4 fl. oz. per acre per season as a preplantincorporated
broadcast, directed bed spray, or T-band spray
into the planting furrow and do not exceed 32 fl. oz. per acre
per season.. Do not use 10DF, 10WP, or 10WSB
formulations as they are not labeled for sweet potatoes. Allow
21 days between applications. REI: 12-hour. PHI: 21-day.
IRAC 03A. RUP.
Capture LFR (1.5) (bifenthrin) | Apply at planting at 12.7525.5
fl. oz. per acre, or apply as a foliar spray at 2.8-8.5 fl. oz.
per acre. Do not exceed 2 applications per season. REI: 12hour.
PHI: 21-day, IRAC 03A. RUP.
Platinum 2SC (thiamethoxam) | Use 2SC formulations at 58
fl. oz. per acre and do not exceed 8 fl. oz. per acre per
season. Use 75SG formulations at 1.66-2.67 oz. per acre and
do not exceed 2.67 oz. per acre per season. Apply as infurrow
spray during planting only. REI: 12-hour. IRAC 04A.
Sweet Potato - Weeds
Reviewed by Stephen Meyers, Ben Phillips - Sept 2021
Recommended Controls
All Weeds
The critical period for weed control in sweet potato is
between 2-6 weeks after transplanting. Maintaining the crop
weed-free during this period of time allows the vines to close
canopy and compete better with weeds later in the season.
Herbicide choices are limited, especially for postemergence
control of broadleaf weeds. For this reason, it is important to
include pre-emergence herbicides and mechanical control in
the weed management plan.
For specific weeds controlled by each herbicide, check the
Relative Effectiveness of Herbicides for Vegetable Crops
table.
Rates provided in the recommendations below are given for
overall coverage. For a banded treatment, reduce amounts
according to the portion of acre treated.
Non-Pesticide
A stale seedbed can be prepared prior to transplanting with
flame weeding or very shallow cultivation to control emerged
weeds, instead of herbicides. The more quickly vines cover
the soil surface, the better they will suppress late-emerging
weeds. In-row plant spacing can be decreased to close canopy
more quickly. However, this practice can delay storage root
bulking later in the growing season. Sweet potatoes can
benefit from the soil warming properties of plastic mulch in
addition to the in-row weed control it provides. Materials
include landscape cloth/fabric, plastic, and biodegradeable
plastic. Straw mulch can delay growth by suppressing soil
temperatures. Weeds between rows and along the edges of
beds can be controlled with a combination of cultivation,
mowing, or hand-hoeing/pulling. Weeds along the edge of the
mulches can be a particular challenge to avoid ripping the
mulch. Some fresh market plantings are often small enough
to accommodate some hand hoeing or pulling. For larger
plantings it may make more sense to mechanically cultivate
with tow-able tools between plastic rows or between bare-soil
rows. In bare-soil production, rolling cultivators on wide toolbars
offer effective high-speed cultivation between rows and
can also hill before row closure from vines.
Pesticide
288
Midwest Veg Guide 2022
Midwest Vegetable Guide - 2022

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