Vol. 51—1997 - NorthEastern Weed Science Society

23
COMMON LAMBSQUARTERS CONTROL IN CORN
M.J. VanGessel, Q. Johnson, and M. Isaacs 1
ABSTRACT
Two fiel~ experiments were conducted in 1996 to evaluate the effectiveness of
various herbicides for common lambsquarters control (Chenopodium album L.) in corn
(Zea mays L.).! The PRE study was designed to evaluate weed control without
triazines. The POST study was designed to evaluate effectiveness of non-volatile
herbicides. Common ragweed (Ambrosia artemisiifolia L.) density was high in
experimental areas and was also rated. The studies were conducted at the University
of Delaware's lResearch and Education Center on sandy loam soils. Both studies were
planted on Mat 15, 1996 with corn hybrid 'Pioneer 3394'. The plots were four rows
wide (30 inch rows) and 25 feet long. All treatments were applied broadcast with a
backpack sprayer at 29 psi, delivering 25 gpa. The treatments were arranged as a
randomized complete block design with three replications.
Preemergenc' study. All soil-applied herbicides were applied on May 20 and POST
treatments on ~une 12. The treatments are listed in Table 1. None of the treatments
resulted in crop injury. Broadstrike+Dual and Prowl were the only soil-applied
herbicides tha~ provided effective common lambsquarters control at 7 weeks after
planting. All treatments with a POST application provided excellent common
lambsquartersjccntrol. Common ragweed control was not commercially acceptable with
any soil-apptied herbicide except Prowl plus Topnotch. All treatments with a POST
application prqvided excellent common ragweed control. Yield was reduced with all
soil-applied herbtcides applied alone. Yield with either Frontier or Micro Tech plus
Permit plus B11nvelwas reduced due to poor weed control prior to the POST herbicide
application.
Postemergen~e study. The second study examined POST herbicides, all applied on
June 7, when the crop was at the fourth collar stage (7 leaves) and 11 inches tall.
Treatments ar~ listed in Table 2. Treatments containing Tough showed more injury
than other treatments, Common lambsquarters control was highest for Buctril alone
and in combination with Permit or Exceed; Tough alone or in combination with Exceed;
or Pinnacle. Banvel and 2,4-0 also provided excellent common lambsquarters control.
Most treatments provided excellent common ragweed control. Pinnacle, Tough alone,
and 2,4-0 did /not provide the same level of common ragweed control as the other
treatments. !
There ~re alternatives to volatile and triazine herbicides for use alone or in
combination to provide effective common lambsquarters or common ragweed control.
However, exc~pt for Prowl, these treatments are not as cost-effective as Banvel, 2,4-0,
or triazines. :
I
'Assistl Prof., Ext. Assoc., and Dir. Res. and Educ. Ctr., Dept. Plant and Soil
Sci., University of Delaware, Res. and Educ. Ctr., Georgetown, DE 19947.