Field experiments were conducted in grain sorghum at five locations in Kansas in 2009 and 2010, to evaluate the efficacy and crop safety of early- to mid-POST (EMPOST) and late-POST (LPOST) applications of premixed pyrasulfotole and bromoxynil (PYRA&BROM) in tank mix combinations with atrazine or atrazine plus 2,4-D ester or dicamba compared to bromoxynil plus atrazine. PYRA&BROM at 244 or 300 g ai ha⁻¹ plus atrazine at 560 g ai ha⁻¹ applied EMPOST controlled pigweed species (Palmer amaranth, tumble pigweed, and redroot pigweed), kochia, velvetleaf, common sunflower, ivyleaf morningglory, and common lambsquarters 93% or greater. Puncturevine control among three locations ranged from 85 to 99%. Control of most weed species was not improved by increasing PYRA&BROM rate from 244 to 300 g ha⁻¹ or by tank mixing 2,4-D or dicamba with PYRA&BROM plus atrazine. However, ivyleaf morningglory control was improved at the LPOST timing by adding 2,4-D or dicamba at 140 g ae ha⁻¹. In no instance did any PYRA&BROM treatment provide greater weed control than bromoxynil plus atrazine at 281 560 g ha⁻¹ when applied EMPOST, but in most instances PYRA&BROM treatments were more effective than bromoxynil plus atrazine when applied LPOST. Generally, PYRA&BROM treatments were more effective when applied EMPOST than LPOST, especially when 2,4-D or dicamba was added. PYRA&BROM plus atrazine treatments caused foliar bleaching in sorghum within 7 ± 3 d after treatment, but recovery was complete within 3 to 4 wk and grain yields were not reduced. Tank mixing dicamba with PYRA&BROM and atrazine occasionally reduced visible crop response compared to PYRA&BROM plus atrazine. Our results indicate that PYRA&BROM plus atrazine with or without 2,4-D or dicamba selectively controls several troublesome broadleaf weeds in grain sorghum. Foliar bleaching of sorghum leaves can occur but the symptoms are transient, and grain yields are not likely to be reduced.

Nomenclature: Atrazine; bromoxynil; dicamba; pyrasulfotole; 2,4-D; common lambsquarters; Chenopodium album L.; common sunflower; Helianthus annuus L.; ivyleaf morningglory; Ipomoea hederacea Jacq.; kochia; Kochia scoparia (L.) Schrad.; Palmer amaranth; Amaranthus palmeri S. Wats.; puncturevine; Tribulus terrestris L.; redroot pigweed; Amaranthus retroflexus L.; tumble pigweed; Amaranthus albus L.; velvetleaf; Abutilon theophrasti Medik.; grain sorghum; Sorghum bicolor (L.) Moench.

Se realizaron experimentos de campo con sorgo para grano, en cinco localidades en Kansas en 2009 y 2010, para evaluar la eficacia y la seguridad en el cultivo de aplicaciones tempranas a intermedias POST (EMPOST) y tardías POST (LPOST) de pre-mezclas de pyrasulfotole y bromoxynil (PYRA&BROM) en combinaciones en mezclas en tanque con atrazine o atrazine más 2,4-D ester o dicamba comparadas a bromoxynil más atrazine. PYRA&BROM a 244 ó 300 g ai ha⁻¹ más atrazine a 560 g ai ha⁻¹ aplicado EMPOST controló especies de amaranto (Amaranthus palmeri, Amaranthus albus, y Amaranthus retroflexus), Kochia scoparia, Abutilon theophrasti, Helianthus annuus, Ipomoea hederacea y Chenopodium