OFFICE OF 

PREVENTION, PESTICIDES, AND 

TOXIC SUBSTANCES 

MEMORANDUM September 22, 2008 

 

SUBJECT: Review of Pioneer’s Benefits Document in Support of a Sec(3) Product 

Registration for Optimum® AcreMaxTM 1 Insect Protection, also known 

as Stack Herculex XTRA (Cry34/35Ab1 +Cry1F) with Herculex I (Cry1F, 

refuge seed for CRW) [MRID 473567-10 and supplemental data] 

TO: Mike Mendelsohn, Regulatory Action Leader 

 Microbial Pesticide Branch 

 Biopesticides and Pollution Prevention Division (7511P) 

FROM: Jeannette Martinez, Biologist 

 Microbial Pesticide Branch 

 Biopesticides and Pollution Prevention Division (7511P) 

SECONDARY Alan Reynolds, Entomologist 

REVIEW: Microbial Pesticide Branch 

 Biopesticides and Pollution Prevention Division (7511P) 

ACTION REQUESTED: 

BPPD1

 has been asked to review the Benefits Document submitted by Pioneer Hi-Bred, 

International, Inc. in support of the Optimum® AcreMaxTM 1 Insect Protection registration. The 

product, for which Pioneer Hi-Bred, International, Inc. seeks a registration, is a corn seed blend 

containing seeds that express Cry34Ab1, Cry35Ab1, and Cry1F in a Bt stack for corn rootworm 

and lepidopteran protection and seeds that express the event Cry1F for lepidopteran protection 

and constitute an incorporated refuge for corn rootworm. In addition, Pioneer seeks to 1) reduce 

the non-Bt CRW refuge requirement from 20% to at least 2% seed mix, and 2) replace the 20% 

CRW refuge requirement for the common refuge with the 100% HXRW (Cry34/35Ab1) option 

of up to 25% refuge. 

 

1

 The use of BPPD in this review refers to BPPD IRM team. 

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

WASHINGTON, D.C. 20460 
- 2 -

I. CONCLUSIONS AND RECOMMENDATIONS 

1. BPPD notes that many of the uncertainties noted below are also germane to Insect Resistance 

Management (IRM). BPPD will be conducting a separate assessment of IRM for Optimum® 

AcreMaxTM1 (OAM1) and will also include a discussion of these issues in that document. 

Pioneer may address these uncertainties (and any deficiencies) as a part of the IRM plan 

development for OAM1. 

2. Provided that Pioneer addresses the uncertainties described below, BPPD concludes that 

OAM1 should have the following benefits: 1) reduced pesticide use (in refuge), 2) increased 

grower compliance with IRM requirements, and 3) grower benefits (including ease of 

planting). 

3. Restricted use pesticides are still used today in combination with Bt products to combat 

CRW infestations. Pioneer states that Optimum AcreMax1 would contribute to a reduction of 

such conventional pesticides because of increased rootworm protection (reduced refuge) and 

thus result in benefits to field workers, by-standers, and environment. BPPD notes that while 

this assumption is probable, Pioneer did not provide field efficacy studies comparing 

rootworm control between blocked refuge (current IRM option) and seed blend refuge 

(proposed option) but rather between different percentages of seed blends. Therefore, the 

above claimed ‘direct’ benefits, while possible, are not based on hard data but assumptions. 

4. BPPD agrees that a seed blend product containing the refuge already in the bag would lead to 

100% grower compliance for planting a refuge. However, whether refuge plants will be 

randomly distributed and the correct % of refuge is planted depends on the distribution of 

refuge seed in the bag at time of planting and non-biased ‘dropping’ of seeds, i.e. properly 

functioning planting equipment should refuge seed and Bt seed not have same phenotype. 

Furthermore, BPPD does not have data to assess the accuracy of Pioneer’s new seed mixing 

technology (see discussion under 6). 

5. Pioneer states that Optimum AcreMax 1 would reduce economic damage to corn growers by 

providing maximized CRW protection on all acres with a reduced in-field seed blend refuge 

of ≥2% and eliminating the non-Bt corn for CRW protection in common refuge for 

lepidopterans and CRW. Pioneer did not provide field efficacy studies comparing rootworm 

control between blocked refuge and seed blend refuge, and so there is no data to support this 

claim. In addition, whether Optimum AcreMax 1 would reduce economic damage through 

reducing the in-field refuge to ≥2 % rather than any other percentage tested is also not as 

obvious as the registrant reports (see discussion under 9). 

6. Pioneer states that HXX and HX1 refuge seeds were uniformly mixed by hand 10 times 

before being packed into bags. After having reviewed the ‘Trait Durability Plan’, BPPD 

learned that Pioneer plans on blending seeds with modern technology (no further description 

provided) to accurately control the blend ratio in a uniform process. Pioneer states that the 

resulting blended products will be tested to ensure acceptable plantability for growers. BPPD 

notes that the accuracy of this new technology should have been field tested prior to the 

submission of the registration request for Optimum AcreMax 1. In addition, the registrant 
- 3 -

does not provide any description of this new technology. BPPD requests that Pioneer provide 

a description of their new mixing technology and data to demonstrate accuracy (repeat of the 

dropper experiment, including reporting of standard error). 

7. Pioneer assessed the distribution of refuge in bags after having been shipped long-distance 

and states that approximately 33% of total refuge seed were distributed into each third of a 

bag and that the counts of refuge seed were consistent across different blended seed even 

when the refuge seed had a different shape (i.e. flat vs. round). BPPD would like to have 

more information on how many replicates/bags there were for each seed phenotype 

combination tested. 

8. Pioneer assessed the uniform release of seeds from planters by collecting twelve samples 

during the simulated dispensing of a bag. The registrant states that when refuge seed content 

was 20% in the bag, the percentage of refuge seeds in the samples collected from the planter 

ranged from 15% to 20% and that there was no trend towards greater or less refuge seeds 

being planted at any time. Pioneer proposes to use ≥2% refuge seed content in Optimum 

AcreMax1. Since Pioneer proposes to use ≥2% refuge seed blend for Optimum AcreMax1, 

Pioneer should provide BPPD with estimated error for the 20% seed blend experiment. The 

standard error becomes very important when considering the implementation of a small seed 

blend refuge as proposed by the registrant. In addition, BPPD would also like to know how 

large the sample sizes were each time a sample was taken from the planter (sample consists 

of how many kernels). BPPD recommends that Pioneer provide this information to resolve 

some of the uncertainties.

9. Pioneer also assessed the distribution of refuge plants in a five acre field using a simulated 

approach with glyphosate tolerant and non-glyphosate tolerant hybrid seed and concluded 

that in the ten plots surveyed, an average of 21.8% (±2.5) plants were injured. BPPD agrees 

that this matches the expected 20% “refuge” seed planted. The registrant ran a linear 

regression analysis to show that the distribution of refuge plants in the ten plots did not differ 

(R2

=0.02). However, nothing was said in Pioneer’s report about testing for random 

distribution of plants in the field. Since Pioneer relies on the random distribution of refuge 

plants, the random distribution needs to be statistically assessed. Furthermore, BPPD would 

like to know how many plants were assessed in the sub-plots surveyed. It is not apparent to 

the reviewers how many plants are represented in a 4 row x 50 feet plot. 

10. BPPD is unclear how Pioneer could conclude that only ≤10% refuge seed provided similar 

protection as 100% HXX with no statistically significant reduction in yield. BPPD looked at 

the 2007 efficacy results and did not see supporting evidence that would lead to such a 

conclusion. Rather, when three effects where measured at four treatment levels in eight 

different locations, there was no statistically significant difference between treatments (0%, 

5%, 10%, 20% refuge) with the exception of one effect measured in two treatments at one 

location). 
- 4 -

II. BACKGROUND 

The registration for Cry1F Event TC1507 (Event DAS-01507-1), also known as Herculex I, was 

first granted by the Agency on May 18, 2001 for commercial plantings beginning with the 2002 

growing season. The registration was extended from September 30, 2001 to October 15, 2008 

(US EPA 2004). Herculex I expresses the Cry1F insecticidal crystal protein as well as a pat gene 

expressing the PAT (phosphinothrin acetyl transferase) protein which confers tolerance to the 

herbicidal active ingredient glufosinate-ammonium. Its primary target pest is the European corn 

borer (ECB, Ostrinia nubilalis), but other target pests are corn earworm (CEW, Helicoverpa 

zea), southwestern cornborer (SWCB, Diatrea grandiosella), fall armyworm (FAW, Spodoptera 

frugiperda), western bean cutworm (WBCW, Richia albicosta), and black cutworm (BCW, 

Agrotis ipsilon). The main target pests for which IRM requirements apply are ECB, CEW, and 

SWCB. 

The registration for Event DAS-59122-7, also known as Herculex Rootworm, was granted by the 

Agency in August, 2005 for commercial plantings beginning with the 2006 growing season. 

Herculex Rootworm expresses Bt toxins Cry34Ab1 and Cry35Ab1, which are efficacious against 

the main target pests western corn rootworm and northern corn rootworm (CRW, Diabrotica

species). Maize containing Event 59122-7 has been modified to express the PAT protein which 

confers tolerance to gluphosinate-aluminum herbicide. 

In June, 2005 Pioneer and Mycogen Seeds submitted an application to register Herculex XTRA 

(Event TC1507 x DAS59122-7); the product was conditionally registered in October 2005 (EPA 

Reg. No. 68467-6, 299964-5) and released to growers in 2006. Herculex XTRA is the result of a 

conventional breeding cross between Herculex I and Herculex Rootworm and is considered a 

stacked PIP because it targets two different kinds of pests (lepidoptera and coleoptera) and 

contains two separate PIP active ingredients. 

In February, 2008, Pioneer Hi-Bred International, Inc. submitted an application to register 

Optimum® AcreMaxTM 1 Insect Protection, a new blended seed product that contains two 

different kinds of seeds of the already registered products Herculex XTRA and Herculex I. The 

new product incorporates the CRW refuge into the seed bag. In this review, BPPD evaluates and 

comments on the registrant’s benefits claims associated with this new seed blend. 

III. REVIEW OF PIONEER’S PUBLIC INTEREST DOCUMENT 

General benefits as they apply to Herculex XTRA (HXX) and Herculex I (HX1) have already 

been addressed in BPPD’s past reviews, and benefits summaries are available in the respective 

BRADs (US EPA, 2005, US EPA 2004). The benefits and uncertainties discussed in this review 

are those that arise from joining the two products, HXX and HX1, in a corn seed blend as 

Optimum AcreMax 1 and from a proposed reduction in refuge. 
- 5 -

a. Environmental benefits

Reduced pesticide use

Pioneer provides data showing that since the introduction of Bt-CRW products in 2003, corn 

acres treated with chemical pesticides (pyrethroids, carbamates, and organophosphates), some of 

which are restricted use insecticides, have been reduced by 43% from 2004 to 2006. Then 

Pioneer states that such pesticide use can be further reduced with Optimum AcreMax 1 because 

there is more CRW protection packed into the seed blend (proposed reduction from 20% block 

refuge to ≥2% seed mix refuge) eliminating the need to spray corn with conventional pesticides 

and resulting in direct benefits to field workers, by-standers, and the environment. BPPD notes 

that while this assumption is probable, Pioneer did not provide field efficacy studies comparing 

rootworm control between blocked refuge (currently required options) and seed blend refuge. 

Rather different percentages of seed blends were tested. Therefore, these direct benefits, while 

possible, are not based on hard data, and BPPD cannot further comment on them. 

BPPD notes that the following may be indirect benefits of introducing Optimum AcreMax 1 into 

the market as stated by Pioneer: reduced energy consumption for manufacture, transport, and 

application of chemical insecticides; reduced waste streams arising from pesticide manufacture; 

reduced disposal of pesticide waste containers and residues from pesticide applications. 

b. Growers benefits

Pioneer states that Optimum AcreMax 1 would reduce economic damage to corn growers by 

providing maximized CRW protection on all acres with 1) a reduced in-field seed blend refuge 

of ≥2% and 2) eliminating non-Bt corn for CRW protection in common refuge for lepidopterans 

and CRW. As mentioned above, part of this claim may be probable; however, Pioneer did not 

provide field efficacy studies comparing rootworm control between blocked refuge and seed 

blend refuge but rather between different percentages of seed blends. In addition, there is no 

overwhelming evidence, as discussed in the efficacy section of this review, that Optimum 

AcreMax 1 would reduce economic damage by reducing the refuge to ≥2% rather than 5% or 

10% (see Tables 2 and 3). 

With Optimum AcreMax 1, Pioneer has incorporated the CRW refuge (seed containing nonCRW Bt trait) in the seed bag, which would translate into 100% grower compliance with respect 

to fulfilling refuge requirements. In addition, it would make the already complex CRW corn 

refuge requirements and corn management less complex for corn growers. ABSTC’s compliance 

assurance statistics (phone survey, on-farm visits) show that compliance with refuge 

requirements for individual trait Bt corn (in 2007, 80 % compliance with refuge distance and 

size) is higher than for the stacked Bt corn products (in 2007, compliance is 66% for refuge 

distance and 70% for refuge size). Pioneer attributes this to the more complicated refuge 

deployment requirements. To summarize, Pioneer states that Optimum AcreMax1 would 1) 

eliminate the challenges with respect to IRM requirements for ECB/CRW stacked Bt corn since 

the refuge is already contained in the bag and 2) protect the durability of the product. BPPD 

agrees that compliance with refuge planting would be 100%. However, whether refuge plants 
- 6 -

will be randomly distributed and the correct percent of refuge will be planted depends on the 

distribution of refuge seed in the bag at time of planting and non-biased ‘dropping’ of seeds, i.e. 

properly functioning planting equipment of growers should the phenotype of refuge seed and Bt 

seed differ. 

It appears that Optimum AcreMax 1 may have additional benefits to growers with respect to 

weed management (i.e. planting of similar maturity and herbicide tolerant corn to control weed, 

handling multiple seed sources in same field challenging) as Pioneer states because the product 

contains an herbicide tolerant (HT) trait. However, BPPD notes that the widespread introduction 

of all HT traits into the environment may also increase the speed of evolution of resistance in 

weedy plants and brings into question the durability of any HT trait. In addition, herbicide 

tolerant traits in PIPs are not pesticidal and, thus, are not directly regulated by EPA/BPPD. The 

reviewers will not comment further on the proposed benefits of herbicide tolerance. 

c. Uniformity, Plantability, and Efficacy of Product

BPPD would like to discuss the mixing of the various seed types (different size and shape) as 

reported in ‘uniformity during seed shipping’ section of the benefits chapter. Pioneer states that 

“seed [refuge seed and non-refuge seed] was uniformly blended by hand mixing the seed ten 

times before packaging 80,000 kernels per bag.” BPPD notes that this type of mixing lacks a 

methodology that ensures consistent mixing of 1) large quantities of seed per se and 2) when 

different people are employed as handlers. The mixing of the refuge seed with the non-refuge 

seed is the first crucial step in a sequence of steps upon which a random distribution of refuge 

plants in the field hinges. After having reviewed the ‘Trait Durability Plan’ (MRID473567-09), 

BPPD learned that Pioneer plans on blending seeds with modern technology (no further 

description provided) to accurately control the blend ratio in a uniform process. Pioneer states 

that the resulting blended products will be tested to ensure acceptable plantability for growers. 

BPPD notes that the accuracy of this new technology should have been field tested prior to the 

submission of the registration request for Optimum AcreMax 1. In addition, the registrant does 

not provide any description of this new technology. BPPD would like to get additional 

information from Pioneer regarding their large-scale mixing technology and data to demonstrate 

accuracy (repeat of the dropper experiment, including reporting of standard error). Most of the 

IRM benefits are contingent upon a viable seed mixing process. 

Uniformity of seed in seed bags during shipping

Pioneer assessed the impact of seed sizes and seed shapes on uniformity within in a bag after it 

had been shipped. The phenotypes chosen for this experiment were 1) mid-sized flat, 2) midsized round, 3) large flat 4) large round, and 5) small flat. Each package or bag contained 80% 

HXRW seed treated with Poncho 250 (insecticide treatment henceforth referred to as P250) and 

20% non-Bt hybrid treated with Poncho 1250 (insecticidal treatment henceforth referred to as 

P1250). The registrant packed five different seed phenotypes in six pair-wise (80% Bt and 20% 

refuge seed) combinations, shipped them via UPS from Iowa to Michigan, then to Indiana and on 

to Illinois, and finally back to Iowa. Upon return of the shipment, uniformity within each 
- 7 -

shipping box was determined by examining the distribution within each third of a box. Pioneer 

states that approximately 33% of total refuge seed was distributed into each third of a bag and 

that the counts of refuge seed were consistent across different blended seed even when the refuge 

seed had a different shape (i.e. flat vs. round). BPPD would like to know how many bags were 

tested per seed phenotype combination; replication would instill more confidence into the results. 

Uniform release of seed from planter

To test whether refuge seed would be differentially segregated by a planter machine, Pioneer 

tested an entire bag of 80% simulated Bt seed with P250 and 20% simulated refuge seed with 

P1250 (same phenotype as simulated Bt seed), which contained enough kernels to plant 2.5 

acres. Twelve times during the dropping of seed, samples were collected to determine the 

percentage of refuge and non-refuge seed. Pioneer states that % refuge seed ranged from 15% to 

20% of the seed dropped through the planter and that there was no trend towards greater or less 

refuge seeds being planted at any time. Since Pioneer proposes to use ≥2% refuge seed blend for 

Optimum AcreMax1, Pioneer should provide BPPD with estimated error for the 20% seed blend 

experiment. The standard error becomes very important when considering the implementation of 

a small seed blend refuge as proposed by the registrant. In addition, BPPD would also like to 

know how large the sample sizes were each time a sample was taken from the planter (sample 

consists of how many kernels). Since such information is important for IRM, BPPD recommends 

that Pioneer provide this information to resolve some of the uncertainties.

Uniformity in the field

Pioneer planted 80% glyphosate tolerant hybrids (medium-sized flat seed) and 20% nonglyphosate tolerant hybrids (medium-sized flat seed) to simulate the Bt treatment refuge plants, 

respectively. At the V4-V6 stage, the five acre plot was sprayed with glyphosate; fourteen days 

later, ten sub-plots (4 rows x 50 ft each) were assessed within the sprayed area to determine the 

number and distribution of injured ‘refuge’ plants. Pioneer reports that an average of 21.8% 

plants per plot (±2.5%) were injured thus matching the 20% simulated refuge seeds in the bag. 

No difference in distribution of glyphosate injured plants was detected in the ten plots surveyed 

when a linear regression analysis was conducted (R2

=0.02); no significant relationship was 

detected from the first to the last seed planted in these subplots. BPPD notes that the number of 

plants injured in the subplots matches the 20% “refuge” seed in the bag closely. However, the 

linear regression did not test the distribution of refuge plants per se but whether there was a 

difference in the relative percentage of refuge plants between subplots. Since Pioneer appears to 

rely on the random distribution of refuge plants, the distribution of refuge plants needs to be 

determined. BPPD would also like to know how many plants were assessed in the sub-plots 

surveyed. It is not apparent how many plants are represented in a 4 row x 50 feet plot. 

In the benefits chapter submitted, Pioneer appears to use the terms “uniform” and “random” 

(referring to position of refuge plants in the field) synonymously: “Structured refuges as blends 

require that the blended seed be uniformly distributed across the field so that susceptible insects 

are nearby any resistant insects that are emerging” and “.. seed bags show uniform distribution of 
- 8 -

CRW refuge seed [in container] during handling and shipping...the random distribution of 

refuge plants throughout the field maximizes proximity of susceptible corn rootworm insects to 

any potential resistant insects, thereby preserving the long-term trait durability”. It is not clear to 

BPPD how “uniformity of seeds in the bag” and “uniform planting” translates into “random 

distribution of refuge plants in the field”. The two terms are not synonymous, and “random 

distribution” cannot be achieved with “uniform planting”. At this point BPPD assumes that this 

is purely a matter of semantics. However, BPPD awaits an analysis to test the data from the 

glyphosate experiment for random distribution of refuge plants. 

Efficacy and yield benefits

Pioneer conducted a two year study (2006-2007) to assess efficacy and yield benefits of a 

blended seed refuge. The purpose of the study was to determine the effects of a blended refuge 

approach on field standability, root ratings, and yield (three effects measured at each treatment 

level). The 2006 experiment was replicated at eight different locations in a randomized block 

design with four replicates for all five treatments. The treatments were 1) untreated control, 2) 

conventional seed treated with P1250, 3) 100% HXRW seed treated with P250, 4) 10% seed mix 

of conventional seed treated with P250 and 90% HXRW seed treated with P250, and 5) 20% 

seed mix of conventional seed treated with P1250 and 80% HXRW seed treated with P250. 

During July 2006, five roots per plot were randomly selected, root damaged scored using the 

Iowa State 0-3 node injury scoring, and yield determined at end of the growing season. Under 

low insect pressure, Pioneer reports little difference in node injury or yields between treatments 

(no data provided). Under high insect pressure, all HXRW treatments had approximately equal 

grain yield and node injury (see Table 1 below) and the 10% and 20% seed blends were 

equivalent to the control of 100% HXRW (59122 maize). 

 

Table 1 Pooled Plant Damage and Yield Results Under High Insect Pressure by Treatments for 2006 Season 

(derived from Table 3 in MRID 473567-10) 

Treatment HXRW 

Hybrid 

Refuge 

Hybrid 

IST on Refuge 

Hybrid 

Node 

Injury 

Score 

Grain Yield 

(Bu/a) 

% Root 

Lodging 

Control 9 P250 1.56 155 27 

Poncho 1250 9 P1250 0.65 179 5 

HXRW 9 None P250 0.10 192 4 

10% seed blend 9 9 P250 0.32 188 6 

20% seed blend 9 9 P1250 0.17 193 5 

LSD (p=0.5) 0.22 9 10 

In 2007, the study was repeated with the addition of HX1 as refuge seed (treated with P250 and 

P1250). Otherwise testing conditions and locations were the same as in 2006. Pioneer reports 

that insect pressure was moderate in six out of eight locations; insect pressure was high in the 

remaining two locations. According to Pioneer’s report, the 5% and 10% seed mix treatments 

had similar root lodging and node injury as the 100% HXX treatment, and both root damage 

ratings and lodgings were higher for the 20% refuge treatments than the 100% HXX treatment. 

Pioneer concludes that HXX/HX1 seed blends with ≤10% refuge seed provided similar 
- 9 -

protection with no statistically significant reduction in yield as compared to 100% HXX. Based 

on the results provided in Table 2, BPPD does not see statistically significant differences 

between node injury, % root lodging, and grain yields between any of the HXX treatments 

except with respect to node for the 20% refuge with P250. So BPPD is unclear how Pioneer 

could conclude that only ≤10% refuge seed provided similar CRW protection compared to 100% 

HXX. Furthermore, the data indicate that the 20% refuge seed produced the same grain yield as 

the 100% HXX (no refuge). 

Table 2 Pooled Plant Damage and Yield Results by Treatments for the 2007 Season 

Treatments Node Injury 

Score 

Grain Yield 

(Bu/a) 

% Root Lodging 

% HXX % HX1 (Poncho rate) 

0 100 (P1250) 0.60 c 182 b 19 b 

0 100 (P250) 0.89 d 178 b 16 b 

100 0 0.10 a 192 a 4 a 

95 5 (P1250) 0.10 a 190 a 5 a 

95 5 (P250) 0.19 ab 194 a 6 a 

90 10 (P1250) 0.14 ab 194 a 5 a 

90 10 (P250) 0.15 ab 194 a 6 a 

80 20 (P1250) 0.17 ab 192 a 4 a 

80 20 (P250) 0.25 b 192 a 9 a 

LSD (p=0.05) 0.12 7 6 

HXX contains Cry34/35 and Cry1F; HX1 contains Cry1F 

Upon request, Pioneer supplied BPPD with supplemental data (no MRID assigned) for all eight 

locations which is presented in Table 3 and discussed below by the Agency. There was no 

statistically significant difference between mean node injuries and grain yields of HXX 

treatments at seven out of eight locations (exception at Readlyn, Iowa). In Readlyn, mean node 

injury of the 10% and 20% refuge treatments with P250 differed from the other HXX treatments 

at that location. No yield data could be collected at Readlyn due to storm damage. There was no 

statistically significant difference between the mean root lodgings of any of the HXX treatments 

at all eight locations tested. BPPD recalls from Pioneer’s report that six of the eight locations had 

moderate insect pressure, while at two locations, insect pressure was considered high. In order 

for Pioneer’s conclusion to hold “that only the ≤10% refuge seed provides similar protection and 

yield”, there would have had to be more substantial and supporting evidence especially from the 

high infestation locations. Based on the results provided by Pioneer, BPPD does not see a strong 

case for concluding that only the ≤10% refuge seed provides similar protection and yield as 

compared to 100% HXX. 
- 10 -

Table 3 Plant Damage and Yield Results by Location and by Treatments for the 2007 Season 

Treatments Node Injury 

Score 

Grain Yield 

(Bu/a) 

% Root Lodging 

% HXX % HX1 (Poncho rate) 

Orange City, IA 

0 100 (P1250) 0.54 b 115 b 0 a 

0 100 (P250) 0.81 c 89 c 3a 

100 0 0.18 a 125 ab 0 a 

95 5 (P1250) 0.16 a 130 ab 1 a 

95 5 (P250) 0.19 a 140 a 1 a 

90 10 (P1250) 0.21 a 122 ab 0 a 

90 10 (P250) 0.18 a 141 a 0 a 

80 20 (P1250) 0.31 a 120 ab 0 a 

80 20 (P250) 0.34 a 130 ab 0 a 

LSD (p=0.05) 0.20 25 NS 

Mankato, MN 

0 100 (P1250) 0.60 b 134 b 53 c 

0 100 (P250) 0.60 b 140 b 42 bc 

100 0 0.06 a 152 a 20 a 

95 5 (P1250) 0.11 a 152 a 22 ab 

95 5 (P250) 0.15a 154 a 25 ab 

90 10 (P1250) 0.17 a 156 a 22 ab 

90 10 (P250) 0.15 a 154 a 34 abc 

80 20 (P1250) 0.20 a 161 a 15 a 

80 20 (P250) 0.22 a 156 a 31 ab 

LSD (p=0.05) 0.19 12 21 

Readlyn, IA 

0 100 (P1250) 2.47 d --- 11 b 

0 100 (P250) 2.90 d --- 37 c 

100 0 0.53 a --- 0 a 

95 5 (P1250) 0.81 ab --- 0 a

95 5 (P250) 0.79 ab --- 0 a

90 10 (P1250) 0.80 ab --- 0 a

90 10 (P250) 1.15 bc --- 0 a

80 20 (P1250) 1.01 ab --- 0 a

80 20 (P250) 1.56 c --- 1 a

LSD (p=0.05) 0.52 --- 7 

Henderson, NE 

0 100 (P1250) 0.44 b 223 a 3 a 

0 100 (P250) 0.66 b 221 a 2 a 

100 0 0.07 a 223 a 2 a 

95 5 (P1250) 0.07 a 211 a 0 a 

95 5 (P250) 0.10 a 219 a 3 a 

90 10 (P1250) 0.06 a 222 a 0 a 

90 10 (P250) 0.07 a 212 a 3 a 

80 20 (P1250) 0.14 a 222 a 0 a 

80 20 (P250) 0.16 a 214 a 2 a 

LSD (p=0.05) 0.26 NS NS 

Johnston, IA 

0 100 (P1250) 0.54 b 197 a 4 a 

0 100 (P250) 0.99 c 206 a 5 a 

100 0 0.22 a 207 a 3 a 

95 5 (P1250) 0.18 a 202 a 4 a 
- 11 -

Treatments Node Injury 

Score 

Grain Yield 

(Bu/a) 

% Root Lodging 

% HXX % HX1 (Poncho rate) 

95 5 (P250) 0.15 a 203 a 2 a 

90 10 (P1250) 0.22 a 213 a 4 a 

90 10 (P250) 0.25 ab 213 a 2 a 

80 20 (P1250) 0.27 ab 208 a 5 a 

80 20 (P250) 0.43 ab 211 a 5 a 

LSD (p=0.05) 0.31 NS NS 

Rochelle, IL 

0 100 (P1250) 0.89 b 197 a 48 b 

0 100 (P250) 0.71 b 185 a 45 b 

100 0 0.07 a 209 a 2 a 

95 5 (P1250) 0.09 a 204 a 6 a 

95 5 (P250) 0.07 a 210 a 4 a 

90 10 (P1250) 0.08 a 211 a 2 a 

90 10 (P250) 0.06 a 201 a 0 a 

80 20 (P1250) 0.11 a 214 a 2 a 

80 20 (P250) 0.19 a 206 a 15 a 

LSD (p=0.05) 0.29 NS 21 

Princeton, IL 

0 100 (P1250) 0.33 b 214 a 0 a 

0 100 (P250) 0.34 b 222 a 0 a 

100 0 0.05 a 220 a 0 a 

95 5 (P1250) 0.07 a 212 a 0 a 

95 5 (P250) 0.06 a 214 a 0 a 

90 10 (P1250) 0.07 a 223 a 0 a 

90 10 (P250) 0.08 a 226 a 0 a 

80 20 (P1250) 0.07 a 214 a 0 a 

80 20 (P250) 0.10 a 221a 0 a 

LSD (p=0.05) 0.19 NS NS 

Windfall, IN 

0 100 (P1250) 0.76 b 193 b 0 a 

0 100 (P250) 2.02 c 186 b 0 a 

100 0 0.12 a 210 a 0 a 

95 5 (P1250) 0.12 a 215 a 0 a 

95 5 (P250) 0.16 a 215 a 0 a 

90 10 (P1250) 0.24 a 211 a 0 a 

90 10 (P250) 0.26 a 210 a 0 a 

80 20 (P1250) 0.22 a 206 a 0 a 

80 20 (P250) 0.43 a 207 a 0 a 

LSD (p=0.05) 0.32 10 NS 

NS = no significant differences 
- 12 -

IV. REFERENCES 

Bailey, L., R. Binning, L. Higgins, D. Langer, R. Layton, S. Lefko, T. Nowatzki, E. Owens, and 

T. Rood. 2008. Trait Durability Plan for Optimum® AcreMaxTM1 Insect Protection Following 

Commercialization. Unpublished report submitted to the US EPA (MRID 473567-09). 

Davis, P. and S. MacIntosh. 2008. Benefits Document of Optimum® AcreMaxTM 1 Insect 

Protection. Unpublished report submitted by Pioneer Hi-Breed International, Inc. to the US EPA 

(MID 473567-10). 

Others: 

US EPA. 2005. Bacillus thuringiensis Cry34Ab1 and Cry35Ab1 Proteins and the Genetic 

Material Necessary for Their Production (Plasmid Insert PHP 17662) in Event DAS-59122-7 

Corn. Biopesticide Registration Action Document 

US EPA. 2004. Biopesticide Registration Action Document Bacillus thuringiensis Cry1F Corn. 

Updated in 2005