UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 

MAY 0 6 2015 

MEMORANDUM 

OFFICE OF CHEMICAL SAFETY 

AND POLLUTION PREVENTION 

SUBJECT: BEAD Chemical Profile (SCP) for Registration Review: Tetraconazole (120603) 

FROM: Leonard Yourman, Plant Pathologist A 

Biological Analysis Branch t/ ;,;-

THRU: 

TO: 

R

Sc

afae

ience 

l A. 

ln

Prieto

fo(lllation 

, Environmenta

and Analysis 

l Protect

Branch 

ion Spec alI . f ,A 1'-0 . / /_ . 11' ~ 

Michelle Ranville, Economist 

Economic Ana lysis Branch 

Biological and Economic Anal 

Arnet Jones, Chief 

Biological Ana lysis Branc 

Diann Sims, Chief 

Science Information and Analysis Branch .._ 

Timothy Kiely. Chief ~ ~ (~, Economic Analysis Branch J ~ Biological and Economic Analy · Division (75 3P 

Veronica Dutch, Chemical Review Manager 

Risk Management and Implementation Branch 5 

Pesticide Re-evaluation Division (7508P) 

Peer Review Panel date: March 18, 20 15 
SUMMARY 

Tetraconazole is a demethylation inhibiting (DMI) fungicide first used in 1999 under a Section 

18 Emergency Exemption for managing Cercospora leaf spot on sugar beet. It is registered for 

use on soybeans, sugar beets, corn, peanuts, pecans, and some berries. In terms of percent crop 

treated, tetraconazole was used on 30 percent of the sugar beet crop. The predominant uses in 

terms of pounds a.i. applied.are on sugar beets with 40,000 lbs and soybeans with 30,000 lbs 

applied annually (average use 2004-2012). For the years 2008-2012, overall tetraconazole 

annual agricultural usage averaged 77,000 lbs of a.i. treating an average of 1.1 million acres with 

an overall average application rate of 0.07 pounds a.i. per acre. 

INTRODUCTION 

The Biological and Economic Analysis Division (BEAD) Chemical Profile (BCP) provides an 

overview of the pest management roles and quantitative usage information for tetraconazole. 

The BCP includes summaries of previous BEAD products and available public and/or private 

use and usage data for tetraconazole to describe the role of this chemical in pest management. 

Additional information on use is available in the Tetraconazole Label Data Report. Infom1ation 

provided in this BEAD Chemical Profile (BCP) may be used by stakeholders (e.g., users and 

registrants), OPP risk assessors and OPP risk managers, and the general public during the 

Registration Review process of this pesticide. 

Tetraconazole is a demcthylation inhibiting (DMI) fungicide listed by the Fungicide Resistance 

Action Committee as a Group 3 fungicide (FRAC, 2014). Tetraconazole was given a Section 3 

registration in 2005. However, in 1999, it was the first DMI fungicide available (with a Section 

18 label) for use on sugar beet to manage Cercospora leaf spot initially in Minnesota and North 

Dakota (Federal Register. 1999). The predominant use of tetraconazole in terms of percent crop 

treated is on sugar beets with 30 percent of the crop treated. The predominant uses in terms of 

pounds a.i. applied are on sugar beets with 40,000 lbs and soybeans with 30,000 lbs applied 

annually, on average, from 2004-2012 (Screening-Level Usage Analysis. November 20 14). 

USE SITES 

Agricultural uses 

Tetraconazole is registered for use on corn (field, pop). peanuts. pecans. soybeans, and sugar 

beets. It is also registered for some crops of the IR-4 crop subgroups including l 3-07F (small 

fmit vine climbing subgroup, except fuzzy kiwifruit) and 13-070 (low growing berry subgroup, 

excluding cranberry). 

Non-agricultural uses 

There are no non-agricultural registered uses for tetraconazole. 

2 
FORMULATIONS AND APPLICATION METHODS 

Tetraconazole is formulated as an emulsifiable concentrate. Depending on the crop, it may be 

applied broadcast by ground or air, by chemigation or sprinkler irrigation, or with a high volume 

or low volume sprayer. 

HISTORY OF TETRACONAZOLE AND BEAD PRODUCTS 

BEAD reviewed Section l 8·Emergency Exemption requests for sugar beets grown in Montana, 

North Dakota, Minnesota, and Colorado prior to the Section 3 registration. The Section 18 

requests were to control Cercospora leaf spot disease (caused by Cercospora beticola) and were 

based on disease resistance to other fungicides. BEAD has not conducted any other assessments 

for tetraconazole. 

In 2005, tetraconazole received a Section 18 label for managing Asian soybean rust. Asian 

soybean rust has had limited impact on soybean production, but tetraconazole is used to manage 

Cercospora blight. frogeye leaf spot, powdery mildew, brown spot, and anthracnose. 

USAGE 

Usage Trends 

Figure 1 presents tetraconazole usage in pounds a.i. applied and Figure 2 shows tota l area treated 

in acres over the 1999-20 12 timeframe (Proprietary Data, 1999-201 2). Figures 1 and 2 show that 

over this time period there was a decrease until 2006, a spike in 2008, and then a decrease in use 

in terms of both pounds applied and acres treated. The increased use may be due to the concern 

of Asian soybean rust (Phakopsora spp.) having been identified in the U.S. for the first time 

around this period. Preventative fungicide sprays of various fungicides (primarily Group 3 or 

Group 11 fungicides) were applied. The decline in tetraconazole use may be at least partially 

explained by additional registrations of DMI fungicides for managing Cercospora leaf spot in 

sugar beet (e.g., Carlson et al., 2013) 

3 
ct 

"O "' 

c 

:J 

0 

a. 

120,000 

~°> R><:) R>"" R>"' R>,,, R>t>. R>" R><o ~ R>'b R>°> ~<:) ~"" ~"' ~ '\..(:) '\..(:) -f5 '\..(:) '\..(:) '\..(:) '\..(:) '\..(:) '\..\:) '\..(:) '\..<:) '\..<:) '\..<:) 

Year 

Figure 1. Total Pounds of Tetraconazole Applied (1999-2012). 

Sou rec: Proprietary Data, 1999-20 12 

Vi' 

QI 

... 

u 

<t 

~ 

"O 

QI 

-ni 

QI 

... 

tni 

QI 

... 

<t 

1,600,000 

Year 

Figure 2. Total Area Treated (TAT) of Tetraconazole in Acres ( 1999-2012). 

Source: Proprietary Data, 1999-2012 

For the years 2000-2004, tetraconazole annual agricultural usage averaged 88,000 lbs of active 

ingredient (a.i.) treating an average of 900,000 acres, with an overall average application rate of 

0.10 pounds a.i. per acre. (Proprietary data, 2000-2004). 

For the years 2008-20 12, tetraconazole annual agricultural usage averaged 77,000 lbs of a. i. 

treating an average of 1.1 million acres, with an overall average application rate of 0.07 pounds 

a.i. per acre. (Proprietary data. 2008-2012). 

4 
For the 2000-2004 time period, essentially all tetraconazole use was on sugar beet (Table I). For 

the 2000-2004 time period, the states with the highest use of tetraconazole were Minnesota and 

North Dakota. For the 2008-2012 time period, the crops receiving the most tetraconazole were 

soybean and sugar beets (Tables I and 2). For the 2008-2012 time period, the states with the 

highest use oftetraconazole were Minnesota and Illinois (Table 3). The percent of total use of 

tetraconazole on sugar beets may have decreased relative to soybean due to registrations of other 

DMI fungicides for managing Cercospora leaf spot on sugar beet and an increased use of OMI 

fungicides in response to the concern for Asian soybean rust that first was observed in the U.S. in 

2004 (Rupe and Sconyers, 2008). 

Soybeans is the top crop during the 2008-2012 time span, replacing sugar beets, which was the 

main crop in terms of tetraconazole use during the 2003-2007 time span (figure 3). Use of 

tetraconazole on other crops such as grapes, is negligible for the 2010-2012 time span and zero 

for the earlier years. 

80,000 

VI 

a. 

0 

u 

a. 

0 .._ 

..... 

0 

.... 

ct 

VI 

-0 

c 

:::l 

0 

0.. 

~ ~ ~ ~ ~ ~ ~ ~ Y N 

'I-" '\.G '\.cs "'cs "'cs '\.G "'" "'<:) "'<:) '\." 

Year 

Figure 3. Pounds of Tetraconazole for Top Crops, 2003-20 12. 

-+-Sugar Beets 

-+-Soybeans 

- • Grapes (Wine & 

Raisin) 

Table 1. Comparison of Crops with Highest Use ofTetraconazole in Terms of Pounds Applied 

for Years 2000-2004 and 2008-2012. 

2000-2004 2008-2012 

Croo % Lbs Crop % Lbs 

Sugar beets >99 Soybeans 63 

Aooles < I Sugar beets 35 

Other• 2 

• Other includes: Wine grapes. raisin grapes. peanuts. 

com. drv beans/peas. and table "grapes. 

Source: Proprietary Data. 2000-2004, 2008-20 12. 

5 
T a bl e 2 . T etraconazo I e U se on T C op rops an d Average A. IR . ate, 2008 -2012 

Crop Tota l Pounds Applied Total Ar ca T reated* Al Rate (lbs Al/acres)** 

Soybeans 250.000 4,000.000 0.062 

Sugar beets 140,000 1,400.000 0.093 

Source: Proprietary Data, 2008-201 2 

* Total Area Treated sums all acres treated for a crop, including those acres that receive multiple treatments. 

** Average Al rates fo r fruits and vegetables are lower than those reported for soybeans and sugar beets. For 

example. the average Al rate for grapes is 0.033 lbs Al/acre. 

Geographic Distribution of Tetraconazole Use 

According to the following map, North Carolina is the state with the highest usage (0.8 lbs) in 

terms of pounds per 1,000 crop acres grown. 

Pounds Active Ingredient 

per 1,000 C~op Acres Grown 

i=J NoOete 

<O 05 

005 - 0 4 

. 0.5·08 

- >08 

Figure 4. Annual averagc ·agricultural use intensity of tetraconazole (2009-2013). 

The map included herein is primarily for the use of the risk assessors in the Environmental Fate 

and Effects Division. The map provides a very broad geographical view of the average annual 

amount (in pounds) of the active ingredient applied per 1,000 acres of crop acres grown. These 

data are included in the maps because risk assessors are interested in the amount of a pesticide 

used across agricultural land. The calculated values presented in the map are not equivalent to 

an application rate (lb ail A). 

6 
The data used to make these maps have several limitations. Any interpretation of the maps 

should consider the underlying data and the associated limitations carefully. 

The nwnerator (annual average pounds applied) is based on private market surveys of pesticide 

use in agriculture averaged over the last five years (Proprietary Data, 2008-2012). These surveys 

cover about 60 crops and are targeted in states that produce the majority of the crop. Although 

the surveys capture most of the use of a particular active ingredient in agriculture, there are 

several limitations to these surveys. 

• States with minor production of a surveyed crop are not sampled 

• Not all types of pesticides are surveyed in every crop in every year 

• Many specialty crops with very small acreages are not included in the survey 

The result of these limitations is that states that show no usage may actually have a small amount 

of the active ingredient being used. In some cases the displayed use intensity may be distorted 

because the surveyed crops and the reported pesticide usage may not accurately represent the 

actual pesticide usage on the crops produced in the state. 

The denominator ( 1,000 crop acres grown) was also obtained from the same private market 

survey database. The "Crop Acres Grown" variable represents the total acres grown in a given 

state of al I of the surveyed crops. This value is independent of pesticide usage and pesticide 

registration. It is important to note that the surveyed crops (about 60) are sampled from states 

that are major producers of each crop. Therefore, there are cases where the actual crop acreage in 

a state is higher than that reported by crop acres grown in the survey because either that state 

and/or crop was not included in the survey. 

The reader should pay particular attention to the figure legends and realize that a map prepared 

for a particular chemical is not directly comparable to a map prepared for a different chemical as 

the legend bins will likely be different. 

Table 3. Comparison of States with Highest Use of Tetraconazole in Terms of Pounds Al for 

Years 2000-2004 and 2008-2012 

2000-2004 2008-2012 

State % Lbs State % Lbs 

Minnesota 61 Minnesota 2 1 

North Dakota 30 lllinois 15 

Michigan 7 North Carolina 10 

Other• 2 Other• 54 

* Other includes: Colorado. Montana, Nebraska, and • Other includes: North Dakota, Iowa, Mississippi. 

North Carolina. Tennessee, Michigan. Arkansas, South Dakota. Ohio. 

California. Indiana. Montana. Alabama. South Carolina, 

Kentucky, Louisiana, Kansas, Colorado. Nebraska, 

Virginia, Wisconsin, Missouri, Florida, Georgia, and Idaho. 

Source: Proprietary Data. 2000-2004. 2008-20 12. 

7 
CHEMICAL AND USE CHARACTERISTICS FOR TETRACONAZOLE 

Tetraconazole is a demethylation inhibiting (DMI) fungicide listed by the Fungicide Resistance 

Action Committee as a Group 3 fungicide (FRAC, 2014). Other Group 3 fungicides include 

tebuconazole, myclobutanil, metconazole, difenoconazole, and several others. DMI fungicides 

provide protectant and some curative activity due to systemic xylem mobility. As is the case 

with a ll disease management strategies, pre-infection protective applications allow for the most 

effective disease management. Group 3 fungicides are considered cross-resistant for purposes of 

resistance management although the specific mode of action may vary among individual active 

ingredients within the Group 3 fungicides. Therefore, while an individual Group 3 active 

ingredient may be more effective against a particular pathogen/host system than another Group 3 

fungicide Group 3, fungicides should not be used as alternating partners in a fungicide spray 

program (FRAC, 2014). 

Typically, an individual fungicide would not be relied on exclusively to manage a disease and 

tetraconazole would be one among other fungicides included in a spray program. A fungicide 

used in a tank-mix or alternated with other fungicides would include those of different modes of 

action (i.e., different fungicide Groups). Resistance to at least two important fungicide groups, 

Group 3 and Group 11 (Qol-quinone outside inhibitors such as pyraclostrobin), has been 

observed for powdery mildew pathogens on grape in the mid-Atlantic region where dual 

resistance is known (e.g., DeMarsay, 2012). For grapes in eastern Washington, resistance by 

powdery mildew pathogens to Group 3 and Group 11 fungicides had not become a problem (as 

of 20 I 1 ), but "this could change rapidly given the nature of powdery mildew and the resistance 

history (in grapes) of Group 11 and Group 3 fungicides,. (Grove and Nelson, 2011 ). 

ROLE OF TETRACONAZOLE IN PEST MANAGEMENT 

Tetraconazole is used for managing several diseases on labeled crop (some applications manage 

more than one disease). Tetraconazole was first used in 1999, as an emergency treatment for 

Cercospora leaf spot on sugar beets. Under high disease pressure, there was up to 30% loss of 

recoverable sugar with revenue losses reported up to 43% (Khan and Smith, 2005). In 1998, the 

fungicides used to treat Cercospora leaf spot were fentin hydroxide, mancozeb, and thiophanatemethyl. These provided inconsistent control, especially thiophanate-methyl due to high 

populations of thiophanate-methyl-resistant pathogens. Tetraconazole has provided effective 

control of Cercospora leaf spot since 1999. According to Carlson et al. (2013), from an 

historical perspective, tetraconazole and pyraclostrobin have had a large impact on controlling 

Cercospora leaf spot. ln 1998, their survey indicated that 36% of respondents found Cercospora 

leaf spot to be their worst production problem. After the introduction oftetraconazole and 

pyraclostrobin, by 2000, 3% of respondents felt that Cercospora leaf spot was a problem. This 

percent has remained below I% since that time. Additional registrations has likely caused the 

use of tetraconazole to decline (Table 1 ). Since that time several other DMI fungicides have 

been registered including prothioconazole (Proline), propiconazole (Ti lt). Cenbuconazole 

(Enable), difenoconazole + propiconazole (Inspire XT), and flutriafol (Topguard) (Khan and 

Hakk, 2013). In addition, Group 11 fungicides (pyraclostrobin, azoxystrobin, and 

trifloxystrobin) are registered and used with other registered fungicides as rotating partners for 

8 
resistance managment. However, when tested (Secor et al., 2013) C. be1icola resistance to 

tetraconazole and difenoconazole + propiconazole (Inspire) has increased significantly since 

20 11. 

Tetraconazole and other DMI and Qol fungicides were among those that were considered 

effective in managing Asian soybean rust if the disease became a problem after being first 

introduced into the U.S. in 2004. In 2005, tetraconazole received a Section 18 label for 

managing Asian soybean rust. Asian soybean rust has had limited impact on soybean 

production, but tetraconazole is used to manage Cercospora bl ight, frogeye leaf spot, powde ry 

mildew, brovm spot, and anthracnose. These diseases may occur in high density plantings where 

humidity initiates pathogen activity. The extent of the recent increased use of tetraconazole on 

soybean is likely a result of several factors including price incentives for higher quality beans 

and perceived value of additional input for crop production. Extension specialists debate the 

value of fungicide applications on soybean. but many growers attribute an increase in yield to 

fungicides (e.g., Roberson, 20 I 0). 

Lesser uses of tetraconazole include grapes and small berries where tetraconazole (as well as 

several other fungicides) is very effective against powdery mildew (e.g .. UC, 2013). On peanuts, 

tetraconazole is used to manage early leaf spot (Cercospora arachidicola) and late leaf spot 

(Cercosporidium persona/um) as well as web blotch (Phoma arachidicola) and peanut rust 

(Puccinia arachidis). Several pecan diseases may be managed with tetraconazole, including 

powdery mildew, scab, brown leaf spot, downy mildew, and leaf blotch. Com diseases managed 

with tetraconazole include gray leaf spot, rusts, anthracnose, eye spot, northern corn leaf blight, 

no11hern corn leaf spot, and southern corn leaf blight. 

DATA NEEDS 

Obtaining additional usage information on small vine fruits and pecans (including lbs applied, 

total area treated, states, application rates, target pests) may improve future BEAD assessments 

of the importance of tetraconazole and may be required as part of the registration review of this 

pesticide. 

REFERENCES 

Carlson, A. L., Khan, M. F. R., and Boetel, M.A. 2013. Survey of fungicide use in sugarbeet in 

Minnesota and eastern North Dakota in 2013. North Dakota State University Extension. 

http://www.sbreb.org/research/plant/plant 13/CarlsonSurveyOIFungicidc.pdf. Accessed February 

2015. 

DeMarsay, A. 2012. Guidelines for Developing an Effective Fungicide Spray Program for Wine 

Grapes in Maryland. 20 12. 

http://marylandgrapcs.org/growinu/FungicideSprayProgramGuidc2012.pdf. Accessed February 

20 15. 

9 
Federal Register. 1999. Tetraconazole- Pesticidc tolerances for emergency exemptions 11 /99. 

Federal Register: Dec. 6. 1999 (Vol 64. Number 233). http://pmcp.cce.cornell.edu/proliles/funQnemat/tcmtb-ziram/tetraconazole/tetracon exm 1199.html. Accessed February 2015. 

FRAC. 2014. f ungicidc Resistance Action Committee Code List: Fungicides Sorted by Mode of 

Action. http://\\'' w. frac. info/pub! ication/anhang/2014 %20 FRA C%20Codc%20 List. pdf. 

Accessed February 2015. 

Grove, G. G. and Nelson, M. E. 20 11. New Fungicides for Grapevine Powdery Mildew 

Management, 20 11. Washington State University Extension. 

http://wvnv.wmvgu.orn/files/documents/2011 Jul\' 26 Powderv Mildcw.pdf. Accessed 

February 2015. 

Khan. M. F. R. and Hakk, P. 20 13. Efficacy of fungicides for controlling Cercospora leaf spot on 

sugarbeet. North Dakota State University Extension. 

http://wv..rvv.sbrcb.oru/rcscarch/plant/plant 13/KhanEfficacyOtFungicidcsCLS.pdf. Accessed 

February 2015. 

Khan, M. F. R. and Smith, L. J. 2005. Evaluating fungicides for controlling Cercospora leaf spot 

on sugar beet. Crop Protection 24:79-86. 

http://wwv.-.scicncedircct.com/scicnce/a11icle/pii/S0261219.f0-WO 167X. Accessed February 

2015. 

Proprietary Data. 1999-2012; 2000-2004; 2008-2012. 

Roberson, R. 20 10. Do soybean fungicides pay? Farm Industry News. July 16. 20 I 0. 

http://farmindustrvnews.com/fungicides/do-soybcan-fungicidcs-pav. Accessed February 20 15. 

Rupe. J. and Sconyers. L. 2008. Soybean Rust. The Plant Health Instructor. American 

Phytopathology Society. 

http://'vvww.apsnct.org/cdcenter/intropp/lessons/l'unui/Basicliomvcctes/Pagcs/SovbcanRust.aspx. 

Accessed February 20 15. 

Secor, G., Rivera, V., Bolton, M., and Khan, M . 2013 . Sensitivity of Cercospora beticola to 

foliar fungicides in 2013. North Dakota State University Extension. 

http://www.sbrcb.org/rcscarch/plant/plant 13/SecorSensitivityOfCcrcosporaBeticola.pdf. 

Accessed February 2015. 

UC. 2013. 20 13 Fungicide Efficacy and Treatment Timing for Grapevines. UC Pest 

Management Guidelines, University of California Extension. 

http://wv.w.ipm.ucdavis.edu/PMG/r3029021 l l .html. Accessed February 2015. 

10