1. Corn Response to Foliar Fungicide and Preharvest Desiccant
Gregory J. Endres1* and Joel K. Ransom2
North Dakota State University
1Extension Area Agronomist, Research Extension Center, 663 Hwy. 281 N., PO Box 219, Carrington, ND 58421-0219
2Extension Agronomist – Cereal Crops, Dept 7670, PO Box 6050, Fargo, ND 58108-6050
Abstract
Farmers are interested in potential increase in corn yield with fungicides in the absence of foliar disease. Also, interest exists with use of a preharvest desiccant to hasten corn drying and harvest. A field study is being conducted by North
Dakota State University to examine corn response to a foliar fungicide and pre-harvest desiccant. Experimental design was a randomized complete block with four replications. Trials were conducted at Carrington and Prosper, ND in 2008 and
2009 with early- and late-maturing hybrids at each location. Best management practices were used for corn production. Headline (pyraclostrobin) fungicide was applied at 6 fluid ounces (fl oz)/acre during tassel to early-silk stages of growth.
Gramoxone Inteon (paraquat) herbicide was applied at 32 fl oz/acre at physiological maturity (PM). Fungicide use resulted in a yield increase of 10 bushels/acre (8 percent) compared to the untreated check (UTC) in one of four site-years
(Carrington, 2008). Average yield with Headline was 3 bushels/acre (2 percent) greater than the untreated check across site-years. Seed moisture was reduced 1.3 percentage points with the desiccant compared to the untreated check during
one of four site-years (Prosper, 2008), while yield was similar among all trials. Fungicide, desiccant, and hybrid interactions were statistically non-significant among grain yield, moisture and test weight. The current results of this study indicate a
site years non significant
consistent and positive corn response is not likely with use of these input strategies.
Introduction Table 2. Impact of preharvest desiccant on corn grain
Results and Discussion
Foliar fungicides are being marketed to improve crop yield in the absence of moisture, Carrington and Prosper, 2008-091.
Leaf disease severity was very low (1 to 5 percent) at all sites. Fungicide
plant disease. University data is lacking in North Dakota to support this corn improved corn seed yield compared to the untreated check in one of four
input strategy. Gramoxone Inteon UTC
site-years (Table 1). Averaged across site-years, fungicide tended to
improve yield by 3 bushels/acre compared to the untreated check. Seed 35
Rapid field dry-down is a critical process in North Dakota due to the short
p y p moisture and test weight were similar to the UTC (data not shown)
shown). 31.8
30.5 30.3
growing season and generally unfavorable environmental conditions during 29.9
30
late fall. A preharvest desiccant may be feasible to use to hasten corn *
harvest and avoid grain yield or quality loss. Grain yield was statistically similar among site-years with desiccant and
25
%
untreated check (data not shown), while grain moisture was slightly reduced
at one site with desiccant (Table 2). During both years of the study, 22.2
21.0 21.0
accumulated growing degree units at both locations were less than the long- 20.1
Objectives 20
term average. Timing of desiccant application after corn PM and before a
•To determine if Headline applied at early reproductive stage of corn will killing frost was challenging, and partially explains the minimal crop
increase grain yield. response. 15
•To determine if Gramoxone Inteon applied at PM can increase the rate of
To Carrington 08 Carrington 09 Prosper 08 Prosper 09
grain moisture loss to reduce time required to start and complete harvest. 1Statistical differences with treatments (LSD 0.05): Prosper, 2008
Fungicide, desiccant and hybrid interactions were statistically non-significant
among grain yield, moisture and test weight. Across site-years, grain
moisture tended to have a similar decrease with desiccant between early-
Materials and Methods and late-maturing hybrids (Table 3). Note that the early-maturing hybrids Table 3. Impact of hybrid RM by preharvest desiccant on
Locations and years: Carrington and Prosper, ND; 2008-09. were at a more favorable moisture level for harvest. corn grain moisture, Carrington and Prosper, 2008-09.
Treatments: Gramoxone Inteon UTC
•Corn hybrid relative maturity (RM): 79 and 88 day (Carrington); 82 and 99
day (Prosper).
34
•Fungicide: Headline at 6 fl oz/A applied at tassel to early-silk stages and 32 30.8
UTC.
29.7
•Preharvest desiccant: Gramoxone Inteon at 32 fl oz/A applied at PM and Table 1. Impact of fungicide on corn grain yield, 30
UTC. Carrington and Prosper, 2008-091.
28
Headline UTC
%
Experimental Design: Randomized complete block with four replications.
180
26
168
170 164 24
Yield (bu/acre)
160 21.8
150 22 21.0
139
140 20
129 129 130
130 * 121 119 Early Late
120
110
100 Summary
Carrington Carrington Prosper 08 Prosper 09 •Foliar fungicide significantly improved grain yield at 25 percent of the sites.
08 09 •Preharvest desiccant tended to slightly reduce grain moisture but the
1Statistical differences with treatments (LSD 0.05): Carrington, 2008
0 05): Carrington environments posed challenges for crop maturity and application timing of
desiccant.
The study continues in 2010 with potential of more favorable environments
Figure 1. Preparing for preharvest application of and corn response to the inputs.
desiccant, Carrington, 2008.