Georgia Peanuts: Considerations on Using Strongarm

Had a few questions about Strongarm (diclosulam) use in peanuts yesterday that I thought might be interesting to all:



1. In general, what application method is more effective for weed control in peanut (PPI or PRE)?

When averaged over 7 weed species, there was little difference in weed control between PPI and PRE applications of Strongarm (Table 1).  However, in dryland production fields with minimal future rain predictions, PPI applications would be preferred.

Table 1. Application Method Effects on Residual Weed Control with Strongarm 84WG @ 0.45 oz/A in Peanut.1

Weed

Control (%)

Application Method

PPI2

PRE3

sicklepod

54

44

Florida beggarweed

78

87

bristly starbur

94

97

purple nutsedge

59

73

yellow nutsedge

78

78

morningglory sp. (Ipomoea sp.)

89

99

smallflower morningglory

94

96

All (average)

78

82

1Source: Grey et al.  2003.  Peanut Science 30:27-34.
2PPI = preplant incorporated.
3PRE = preemergence.

Also very important to remember that Strongarm provides a much broader spectrum of weed control when applied PPI or PRE when compared to POST applications. However, the following 7 weeds are sensitive to Strongarm when applied POST: tropical spiderwort/Benghal dayflower; common cocklebur; common ragweed; bristly starbur; horseweed/marestail; morningglory sp.; and eclipta.



2. What application method is more effective for the control of tropical spiderwort/Benghal dayflower?

Data collected a few years ago in Grady Co. indicated that POST applications were more effective than PRE applications for the control of tropical spiderwort/Benghal dayflower (Table 2).

Table 2. Application Method Effects of Strongarm 84WG @ 0.45 oz/A on Benghal Dayflower/Tropical Spiderwort Control in Peanut.1

Application

Method

Control (%)2

46 DAP3

69 DAP

114 DAP

PRE4

75 cd

68 b

11 e

EPOST5

97 a

90 a

75 abc

LPOST6

88 ab

78 ab

60 c

1Source: E.P. Prostko and J.T. Flanders, 2003, PE-24-03, Unpublished data.
2Means in the same column with the same letter are not significantly different according to DMRT (P=0.05).
3DAP = days after planting.
4PRE = preemergence.
5EPOST = early-postemergence, 17 days after planting (2’’ tall, 3 leaf stage).
6LPOST = late-postemergence, 31 days after planting (6” tall).

Source URL: http://ugaweedscience.blogspot.com/2019/04/strongarmpeanut-questions-prostko.html