Early season weed management is critical

Specialists Speaking

Emi Kimura

TEXAS

Early season weed management is critical; effective early control typically reduces the difficulty of management later in the season. In peanut production, there are five primary herbicide application timings: pre-plant burndown (PP), pre-plant incorporated (PPI), pre-emergence (PRE), early post-emergence (EPOST; 10–20 DAP), and post-emergence (POST; 30–45 DAP).

Research indicates that the critical period for weed control in peanuts ranges from 4.3 to nine weeks after planting (WAP) for grass species and from 2.6 to eight WAP for broadleaf weeds (Everman et al., 2018). As weed interference intervals increase, peanut yields significantly decrease. Therefore, the utilization of PP, PPI, and PRE herbicides is essential for minimizing early season competition.

April is an ideal window for planning and applying PP and PPI treatments, while PRE applications should occur at planting. Early emerging weeds, such as Russian thistle and kochia, can be managed via tillage or burndown herbicides. Paraquat is particularly effective against Russian thistle, while glyphosate provides broad-spectrum control of annual and perennial grasses and broadleaf weeds. PPI herbicides labeled for use in peanuts include ethalfluralin, pendimethalin, and trifluralin. These dinitroaniline (DNA) herbicides — often referred to as ‘yellow herbicides’ — are effective against annual grasses and small-seeded broadleaves, including Palmer amaranth (pigweed), Russian thistle (tumbleweed), and kochia. However, they are generally ineffective against large-seeded broadleaves, such as cocklebur and sunflower, or sedges (yellow and purple). Integrating a PRE herbicide will enhance the control of these challenging species.

Always consult the product label for specific incorporation methods; if incorporation is too deep and the peanuts are planted shallowly, the roots must emerge through treated soil, which may result in crop stunting.   ∆

Emi Kimura

Texas