Ivyleaf Morningglory (Ipomoea hederacea) Control with Herbicides in Soybeans (Glycine max)

Abstract

When trifluralin [α,α,α - trifluoro - 2,6 - dinitro -N,N-dipropyl-p-toluidine] was manually incorporated in small field plots to a depth of 10 cm, ivyleaf morningglory [Ipomoea hederacea(L.) Jacq.] was controlled more effectively than when incorporation was only 5 cm deep. No significant differences in ivyleaf morningglory control were observed between different incorporation depths when trifluralin was mechanically incorporated in large field plots. Ivyleaf morningglory emerging from 10 cm deep was controlled to a greater degree than that emerging from 5 cm deep. Preplant incorporated (PPI) trifluralin plus alachlor [2 - chloro – 2′, 6’ - diethyl -N- (methoxymethyl)acetanilide ] applied preemergence (PE) controlled up to 92% of the ivyleaf morningglory compared to 33 and 15% respectively, when these herbicides were applied alone at equal rates. This indicates a synergistic interaction between these two compounds. Trifluralin PPI plus RH 8817 [5-(2-chloro-4-trifluoromethyl phenoxy) - 2 - nitrobenzoic acid ethyl ester] and alachlor applied PE controlled ivyleaf morningglory more effectively (88 to 94%) than all other treatments. Soybean [Glycine max(L.) Merr.] injury and stand reduction were less than 5% in all studies.

Trifluralin‐Substituted Amide Herbicide Interactions

“…lacunosa L.) morningglory. Prosch and Kapusta (1983) have reported similar results. There have been reports, however, of an interaction between dinitroanilines and substituted amides in controlling morningglory.…”

“…Metzer et al (1974) reported that a preplant incorporated application of trifluralin followed by a preemergence application of alachlor gave greater than 90% control ofivyleafmorningglory in cotton (Gossypium hirsutum L.). Prosch and Kapusta (1983) reported similar findings in soybean and identified this as a synergistic effect. High levels of jimsonweed and velvetleaf control were also noted.…”

“…These results, along with those !PUblished previously (Prosch and Kapusta, 1983;Prosch and Weber, 1982), suggest that the relative toleranc{: of soybean to combinations oftrifluralin plus alachlor is somewhat more dependent on the rate of alac:hlor than on the rate of trifluralin. A possible mechanism for the interaction of the two herbicides in ivyleaf morningglory is an alachlor-induced increase in the uptake of trifluralin.…”

“…The interaction of trifluralin with alachlor in controlling broadleaf weed species in soybean was first reported for a sequential application, trifluralin preplant incorporated followed by alachlor preemergence (Prosch and Kapusta, 1983). A single tank-mix application surface blended would enhance the chemicals' usefulness, since the chemicals would only need to be handled one time.…”