Field studies conducted over two growing seasons evaluated the effect of 2,4-D applied at 1.6 kg ai/ha to LCP 85-384 sugarcane (Saccharum interspecific hybrid) 7, 5, 3, and 1 wk before planting (WBP). Sugarcane was planted in mid-September using both whole stalk and billet (45 cm) seed pieces. When 2,4-D was applied 5 wk or closer to planting, sugarcane shoot emergence and population averaged across planting methods was reduced 5, 7, and 28 wk after planting (WAP) when compared to the nontreated control. Sugarcane height in one of two years was reduced when 2,4-D was applied 5 wk or closer to harvest of sugarcane for seed and sugarcane and sugar yield were reduced around 11% when compared with the nontreated control. For LCP 85-384 a 7 wk period should be allowed between 2,4-D application and harvest for seed when planted using whole stalks or billets.
In field studies complete control of red morningglory (Ipomoea coccinea L.) 30 and 60 cm in height was obtained 14 or 21 days after treatment (DAT) over two years with 2,4-D at 0.53 kg/ha, 2,4-D at 0.4 kg/ha or more plus dicamba, atrazine at 2.23 kg ai/ha, flumioxazin at 0.10 kg ai/ha, sulfentrazone at 0.35 kg ai/ha, and V10064 at 1.75 kg ai/ha. Red morningglory 1.8 m tall was controlled 100% 28 DAT the first year with 2,4-D at 1.06 kg/ha and 78% the second year. In the second year when herbicides were applied three weeks earlier than the previous year and when weed growth was more vigorous, the 2,4-D plus the 2,4-D and dicamba premix at 0.79 + 0.1 / 0.04 kg/ha provided control greater than that of 2,4-D alone at 1.06 kg/ha, but was the only treatment that included dicamba to control red morningglory equal to that of 2,4-D at 1.59 kg/ha (87%). Directed applications to the lower 45 cm of 1.8 m red morningglory plants with atrazine at 4.47 kg/ha, sulfentrazone at 0.35 kg/ha, and V10064 at 1.75 kg/ha the first year controlled weeds at least 96%, but control was 23 to 30 percentage points less the second year.