Lexington, KY 40546
Online at: www.uky.edu/KPN
Number 1366
January 28, 2014
ANNOUNCEMENT -IPM Training for Field Crops
CORN -2013 Regional Corn Fungicide Summary
ANNOUNCEMENT IPM Training for Field Crops 2014 IPM Training focusing on corn and soybeans will be held on March 5 at the UK Research and Education Center in Princeton, KY. Topics for the day will include updates on resistant weeds, Bt corn varieties, and invasive insects. Additional talks include Buffering Your Soil Nitrogen for Corn against Changing Weather and a presentation on IPM-related apps. The meeting will start at 9 am and end at 3 pm. Application has been made for 5.0 CEU’s for CCA (2 Pest Management, 1 Nutrient Management, 1 Soil & Water and 1 Professional Development) and pesticide education hours have been requested in categories (1A) AG Plant Pest, (4) Seed Treatment, (10) Demonstration and Research, (12) Pesticide Sales Agent, and (14) Pest Control Consultant. A complete copy of the program is available on the IPM website at http://www.uky.edu/Ag/IPM/ipm.htm.
CORN 2013 Regional Corn Fungicide Summary Paul Vincelli, Extension Plant Pathologist For a number of years, the Corn Disease Working Group has shared fungicide results from university trials across many U.S. states as well as Ontario. These results have been compiled each year by Dr. Kiersten Wise of Purdue University. Here are two highlights from the results of 442 test comparisons conducted in 2013.
1. As in years past, early applications (V3-V7) seem to have little yield benefit (Table 1). In contrast, the average yield response to a VT/R1 application was close to a breakeven point. There may be individual cases where meaningful yield increases occur in response to an application at V3-V7, but I am aware of no guideline that allows for prediction of those cases which will exhibit an economic yield response from an early application. Table 1. Mean yield response to fungicide application at various growth stages in corn
Timing of application V3-V7
# of fungicides tested 17
# of observations 97
Mean yield response compared to non-treated control * (bu/A) 0.1
VT/R1
14
286
4.5
V5 + VT/R1
11
42
3.7
*
Mean calculated over all fungicides compared in individual state trials
2. As in past years, a greater yield response is seen from a fungicide application in fields with higher disease pressure (Table 2), although the difference wasn’t as dramatic in 2013 as in some years. Results such as these reinforce the value of allocating fungicide applications to fields with the most risk from key foliar diseases (Figure 1).
Table 2. Mean yield response to fungicide application in corn with differing disease levels Level of leaf blight at dent
Mean yield response compared to * non-treated control (bu/A)
Less than 5%
4.3
More than 5%
6.2
*
Mean calculated over all fungicides compared in individual state trials. Only applications made at VT/R1 were included in this dataset.
Figure 1. Figure 1. Risk factors for gray leaf spot of corn. For the most part, the same risk factors apply to northern leaf blight as well.
Acknowledgement: Thanks to Kiersten Wise (Purdue University) for reviewing a previous draft of this article.
Note: Trade names are used to simplify the information presented in this newsletter. No endorsement by the Cooperative Extension Service is intended, nor is criticism implied of similar products that are not named.