Peanut Weed Control Update 2004 Eric P. Prostko Extension Weed Specialist

Things to Talk About Valor Arrow Prowl H 2 0 newer metolachlor formulations postemergence Strongarm reduced rates glyphosate problems

Peanuts Valor Formulations 2001: 51 WDG : 51 WP 2004: Valor SX 51WDG * smaller particles * dispersing agents * easier to get into suspension * 10% price reduction in 04

Valor Formulation Test May 23 (11 DAP) Untreated Valor SX 3 ozs/A applied 1 DAP

Valor Formulation Test June 11 (30 DAP) Untreated Valor SX 3 ozs/A applied 1 DAP

Valor Formulation Test July 29 (78 DAP) Untreated Valor SX 3 ozs/A applied 1 DAP

Peanut yield response to Valor SX (3 ozs/A) applied 1 DAP (2003). PE Attapulgus P = 0.80 CV = 12

Possible Interactions With Valor and Soil Insecticides No problems if applied at the right time. If applied late, maybe some problems with Thimet variable

Peanut Injury in Response to Valor /Insecticide Interactions when applied 5 DAP - Tifton, 2003 DP-1 Planted May 20, Ratings June 24 b c a b

Peanut Injury in Response to Valor /Insecticide Interactions when applied 5 DAP - Plains, 2003 GA Green Planted May 8, Ratings June 11 b bc a

Peanuts Arrow 2EC clethodim POST grass control in broadleaf crops generic Select Makhteshim-Agan ozs/A price/service

Texas Panicum Control with POST Grass Herbicides (44 DAT) PE Ponder Farm Applied to 2-4 tall grass

Peanuts Prowl H CS lbs/gal 2.0 pts/A water-based micro-encapsulated less staining better for strip-tillage? increased price

Prowl H 2 0 pendimethalin EC Prowl H 2 O

Peanut Yield Response to PRE Applications of DNA Herbicides PE Ponder Farm P = pts/A3 pts/A1.8 pts/A2.4 pts/A1.6 pts/A2.1 pts/A

Peanuts New Metolachlor Formulations Cinch – Dupont –same as Dual II Magnum – cannot use POST Stalwart C – Sipcam Agro USA Inc. – old Dual EC formulation (7.8 lbs/gal) – not labeled for peanut Me-Too-Lachlor –Drexel –old Dual EC formulation (8 lbs/gal) – rates are too low

Peanuts Strongarm Postemergence labeled in March 2000 PPI, PRE, AC broadleaf weeds 0.45 ozs/A $15-18/A 6% of GA acres in month cotton rotation restriction ALS inhibitor

Untreated Strongarm applied 17 DAP Strongarm applied 31 DAP PE DAP Tropical spiderwort control with POST applied Strongarm, 2003

Bristly Starbur Control with POST Applied Strongarm, 2003 PE DAT Untreated 0.45 ozs/A ozs/A

Untreated Strongarm 0.45 ozs/A % v/v (Applied 5 WAP) 11 WAP Annual MG Control with POST Applied Strongarm, 2003

PE DAT Wild poinsettia control with POST herbicides, 2003 Untreated 1.44 ozs/A 0.45 ozs/A

Wild Radish Control with POST Applied Strongarm (1, 3-4 leaf) Untreated Strongarm 0.45 ozs/A Strongarm ozs/A 40 DAT

Peanuts Strongarm Postemergence Summary good to excellent POST control of several species reduced rates on sensitive species such as bristly starbur, annual morningglory, wild radish timing and rate are critical on some species such as beggarweed no POST control of sicklepod not labeled at this time but working on this issue rotation restrictions?????

Bristly Starbur in Peanut 6th most troublesome weed in GA a.k.a. goat-head, Texas sandspur weed-free - 6 weeks interference - 2 weeks 1 plant per meter of row = 14% yield loss Strongarm, Basagran SWSS Weed ID Guide

Bristly starbur control with POST applications of Strongarm, tall bristly starbur Included 0.25% v/v

Reduced Rates of Strongarm and Valor - I PE-01A DAP Untreated Strongarm 0.45 ozs/A Valor 3 ozs/A Strongarm ozs/A + Valor 0.75 ozs/A

Reduced Rates of Strongarm and Valor - II PE-01B DAP Untreated Strongarm 0.45 ozs/A Valor 3 ozs/A Strongarm ozs/A + Valor 0.75 ozs/A

Economic Returns from Reduced Rates of Strongarm (S), Valor (V), and Cadre - I PE-01A-03 Tifton

Economic Returns from Reduced Rates of Strongarm (S), Valor (V), and Cadre - II PE-01B-03 Attapulgus

Summary Reduced Rates less injurious than Valor at full rate similar weed control except for tropical spiderwort and annual mg when used in total program (pre + post), equivalent yields and net returns when compared to full rate programs same program in one field may not be the best in another field digging efficiency/weed seed bank concerns in field with a few escapes?

Glyphosate Mishaps in Peanut!

Roundup WeatherMax vs. Crop Oil

Yield Losses Caused By Roundup Weather Max Applied to Virginia 30 DAP. Source: Adapted from B. Robinson, NCSU (3 years of data)