Project Title: No Effect Level of Thifensulfuron, Bensulfuron, and Glyphosate on Peaches Based on Crop Yield

Principal Investigator: David F. Ritchie (NCSU)

1996 Report for Project SUR-96-003 Test#Ol
David F. Ritchie
North Carolina State University
Raleigh, NC 27695

This experiment was initiated in late winter 1995. Treatment perimeter protocols are described in 1995 report.

The objective of 1996 was to measure peach fruit yield from trees that were treated in 1995. In March and April 1996, several periods of sub-freezing temperatures occurred during early and late bloom, respectively. These freezes resulted in total crop loss. Thus no fruit yield data were obtained in 1996.

A measure of treatment effects on vegetative (terminal shoot) growth was done in July 1996. As described on the data sheets, 10 terminals of current year's (1996) growth were arbitrarily selected around the outside circumference of the tree at 4-6 ft height. The terminals were measured for length and the number of leaf nodes within this length was counted. Thus, the data reported are mean terminal length, mean number nodes per terminal, and the mean internodal distance.

No significant (a=0.05, L.S.D.) differences were detected among any treatments in length of terminal growth. Although a few significant differences were detected among treatments for number of leaf nodes and internodal distances, there was no trend for any treatment. These difference are likely not real because the probably of greater F of the analysis of variance was high and thus it is not valid to perform a means separation test such as L.S.D.

In conclusion, no detectable effect on vegetative growth of the 1995 treatments was observed in early spring 1996 or measured in July 1996 (see terminal growth measurement data).

DFR, NC State Univ., August 1996

Tree Growth in 1996 as Measured by Length of Current Year's Terminal Growth, Number Leaf Nodes/Terminal, and Internodal Space.

		Terminal Growth Parameters
Chemical	Rate(g ai)/Ha	Mean Terminal Length (inches)		Mean Number Leaf Nodes/Terminal	Mean Internodal Space (inches)
Thifensulfuron	1.75	19.0a		24.8 cd	0.77ab
Thifensulfuron	4.05	20.2a		26.8abc	0.75ab
Thifensulfuron	9.25	19.9a		27.4ab	0.72 b
Thifensulfuron	21.30	19.7a		26.0abcd	0.77ab
Thifensulfuron	48.95	18.8a		25.8abcd	0.73 b
Thifensulfuron	112.00	20.1a		26.4abcd	0.77ab
Bensulfuron	1.75	19.5a		25.4 bcd	0.77ab
Bensulfuron	4.05	18.9a		25.6abcd	0.74ab
Bensulfuron	9.25	19.8a		25.8abcd	0.76ab
Bensulfuron	21.30	19.5a		25.6abcd	0.77ab
Bensulfuron	48.95	20.8a		27.8a	0.75ab
Bensulfuron	112.00	20.2a		26.abc	0.76ab
Glyphosate	78.00	19.2a		25.8abcd	0.75ab
Glyphosate	156.25	20.0a		26.8abc	0.75ab
Glyphosate	312.50	20.5a		26.5abcd	0.78ab
Glyphosate	625.00	19.3a		26.6abcd	0.73 b
Glyphosate	2500.00	18.6a		24.4 d	0.77ab
Glyphosate	5000.00	20.1a		25.0 cd	0.81a
Check (water + adjuvant)		20.2a		26.6abcd	0.76ab
Check (water + adjuvant)		19.0a		25.6abcd	0.75ab
Check (water + adjuvant)		19.5a		25.4 bcd	0.76ab
L.S.D. (~=0.05)		2.36 (N.S.)	2.40		0.08_

Means within a column followed by the same letter do not differ significantly, (~ = 0.05).