Weed Control in Dicamba-Resistant Soybean with Glyphosate/Dicamba Applied at Various Doses and Timings

Table 3

Significance of main effects and interaction for percent visible control of Amaranthus spp., Ambrosia artemisiifolia, and Chenopodium album in soybean treated with glyphosate/dicamba at various POST timings at four Ridgetown, ON, sites (2016–2018) and two Exeter, ON, sites (2017-2018).

Main effects	Amaranthus spp. control (%)			Ambrosia artemisiifoliacontrol (%)			Chenopodium album control (%)
	4 WAA	8 WAA	10 WAC	4 WAA	8 WAA	10 WAC	4 WAA	8 WAA	10 WAC
Application timing				NS
5 cm weed height	96^b	92^b	87^b	99^a	95^b	93^b	99^b	94^b	89^b
15 cm weed height	99^a	96^b	94^b	99^a	98^ab	97^ab	100^a	96^b	95^ab
25 cm weed height	99^a	99^a	99^a	99^a	100^a	99^a	100^a	99^a	99^a
Dose					NS	NS		NS	NS
Untreated control	0^c	0^c	0^c	0^c	0^b	0^b	0 c	0^b	0^b
900 g·ae·ha^−1	97^b	94^b	90^b	98^b	96^a	95^a	99^b	94^a	92^a
1350 g·ae·ha^−1	98^ab	97^ab	95^ab	99^ab	98^a	97^a	100^a	97^a	95^a
1800 g·ae·ha^−1	99^a	99^a	97^a	100^a	99^a	99^a	100^a	99^a	98^a
Interaction
R × T	NS	NS	NS	NS	NS	NS	NS	NS	NS

Note. NS: not significant at level; POST: postemergence; R: herbicide rate; T: application timing; WAC: weeks after final herbicide application; WAA: weeks after herbicide application. Means followed by the same letter within a column are not significantly different according to a Tukey–Kramer multiple range test at . Differences among simple effects are not presented due to negligible R × T interactions. Significance at and levels denoted by and , respectively.