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

Table 4

Significance of main effects and interaction for percent visible control of Echinochloa crus-galli, Setaria faberi, and Setaria viridis 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	Echinochloa crus-galli control (%)			Setaria faberi control (%)			Setaria viridis control (%)
	4 WAA	8 WAA	10 WAC	4 WAA	8 WAA	10 WAC	4 WAA	8 WAA	10 WAC
Application timing
5 cm weed height	84^b	81^b	82^b	90^b	51^b	37^c	94^b	96^b	95^b
15 cm weed height	95^a	94^a	96^a	98^a	80^b	77^b	99^a	99^a	99^a
25 cm weed height	96^a	97^a	96^a	100^a	99^a	99^a	100^a	100^a	99^a
Dose		NS		NS	NS	NS			NS
Untreated control	0^c	0^b	0^c	0^b	0^b	0^b	0^c	0^c	0^b
900 g·ae·ha^−1	84^b	87^a	88^b	95^a	77^a	74^a	98^b	98^b	98^a
1350 g·ae·ha^−1	94^a	93^a	93^ab	97^a	80^a	75^a	99^ab	99^ab	98^a
1800 g·ae·ha^−1	96^a	95^a	95^a	98^a	87^a	79^a	100^a	100^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.