Plant Biotechnology: Current and Potential Impact For Improving Pest Management In U.S. Agriculture An Analysis of 40 Case Studies June 2002

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1 Plant Biotechnology: Current and Potential Impact For Improving Pest Management In U.S. Agriculture An Analysis of 40 Case Studies June 2002 Insect Resistant Field Corn (2) Leonard P. Gianessi Cressida S. Silvers Sujatha Sankula Janet E. Carpenter National Center for Food and Agricultural Policy 1616 P Street, NW Washington, DC Phone: (202) Fax: (202) ncfap@ncfap.org Website: Financial support for this study was provided by the Rockefeller Foundation, Monsanto, The Biotechnology Industry Organization, The Council for Biotechnology Information, Grocery Manufacturers of America, and CropLife America.

2 29. Field Corn Insect Resistant (2) Production All 48 coterminous states have corn acreage and, in many states, corn is the single most important crop in terms of acreage and production value. Corn production is centered in the Midwest, where ten states account for 85% of the US acreage and production. Individually the states of Illinois and Iowa account for more than 10 million acres of corn each. Table 29.1 contains estimates of field corn production and acreage for 10 major corn-producing states for Black Cutworm Cutworms are among the major soil insects of field corn, along with rootworms, white grubs and wireworms [5]. Many species of cutworms injure corn throughout the US, but the black cutworm (BCW) is the most widespread and causes the most damage. Black cutworms do not overwinter in most of the Midwest [6]. Black cutworms overwinter in southern Gulf states and migrate northward primarily in April and May as adults. Although black cutworm occurs throughout the contiguous US, the damage caused by the black cutworm has most often been reported in the region east of the Mississippi River and in the contiguous states west of this boundary. Table 29.2 shows estimates of BCW infestation by state. In several states, damage is more likely to occur in particular areas, such as Southern Illinois, Southeastern Iowa, Southern Indiana, Kentucky and Southeastern Ohio [24, 31, 32, 33, 34]. Cutworms have a wide host range, including several field crops. Black cutworm moths deposit their eggs on vegetation or debris, usually before the crop is planted. Fields most susceptible to cutworm damage include fields with heavy early season weed growth, reduced or no till fields or fields adjacent to permanent vegetation [6,7,8]. Moths tend to be attracted to fields where green weeds are present, particularly grasses or winter annuals such as common chickweed. 2

3 Black cutworm larvae are pests of seedling corn. They kill plants and reduce yields by reducing plant stands [28]. Several generations may occur each season, but because young corn plants are most at risk, only the first cutworm generation is of economic importance [8]. Newly hatched larvae feed on weeds until new corn seedlings emerge. When larvae are small, their feeding may go unnoticed. Young larvae feed on corn leaves, but the larger larvae cause the most damage by feeding on stems. On younger, small-stemmed corn plants, larvae cut the plant off at or near soil level. The feeding larva then often attempts to pull the plant into the soil for further feeding, leaving part of the dismembered plant sticking out of the soil. One larva can cut several seedlings, moving quickly down a planted row. A single cutworm is capable of cutting four to six plants during its lifetime. Corn plants that are too large for larvae to cut through may have a hole bored into the stem. If cutworm damage occurs above the growing point of the corn plant, and no further feeding damage occurs, the plant may recover [28]. Although cutworms do not completely sever large plants, they may chew a large hole in the stalk below the surface causing the plants to wilt and die. Black cutworm larvae frequently cause damage severe enough to necessitate replanting. Large populations can decimate an entire field of corn seedlings. In a study of simulated damage by BCW, yield losses varied from 0 to 24% and 0 to 81% when plants were damaged at the 3 and 5 leaf stages, respectively [25]. A survey of Extension Specialists indicated that yield losses to uncontrolled BCW could be as high as 25% [5]. Fall Armyworm Fall armyworm (FAW) is native to the tropics [11]. Unlike most insects in temperate regions, the FAW does not have a diapause mechanism, and it is unable to survive winters in northern climates. In the United States, FAW overwinters only in Florida and southern Texas. Southeastern states experience annual FAW infestations although the economic impact of those infestations varies from year to year [10]. Fall armyworm infestation levels in middle and northern states depend on weather and wind currents in the south that bring migrating adults north. FAW is found throughout most of the US 3

4 east of the Rocky Mountains, from Texas to Montana in the west and from Florida to Maine in the east. Ordinarily it is confined to the Gulf states, but under conditions favorable to its development, this pest spreads northward as the summer advances. The number of generations of FAW a region has depends on how far north FAW migrate in a given year and on regional climates. Where FAW overwinters, continual generations are possible, with moth flights from April to December, if not longer. Southern states such as Louisiana or the Carolinas may see three or four generations. Further north, states such as Minnesota and New York generally have one FAW generation, if any. Although FAW larvae feed on a variety of plants, corn, peanuts, sorghum and Bermudagrass are favored hosts [11]. By the time FAW moths arrive in northern corn growing states, early planted corn is often far enough in development that it is no longer attractive to the egg laying moths. Late planted corn is therefore most susceptible to FAW damage [12]. Economically damaging FAW infestations occur sporadically in northern regions. Fall armyworm adults are nocturnal, with most feeding, mating and egg laying activity beginning at dusk [11]. A few hours of feeding is generally followed by mating activity. Female moths perched atop crop canopies initiate mating by releasing sex pheromones into the air. Airborne male moths detect plumes of pheromone in the air and follow them to a source. Female FAW mate only once per night, but their pheromones generally attract more than one male at a time, so males must directly compete with each other to access the female and mate. Defeated males return to the air until they encounter another pheromone plume to follow. Mating activity usually peaks by midnight, but may continue all night depending on the time of season and the temperature. Mated females are selective about oviposition sites when populations are low, choosing to lay eggs on the underside of leaves. If population densities are high, eggs may be found on any plant part [11]. Female FAW moths lay eggs in clusters of about 100 to 4

5 150 eggs, covered with a layer of gray, fuzzy protective scales. One moth may lay over 1,500 eggs during the course of her lifetime. Egg clusters are usually deposited on corn in the whorl stage. Upon hatching, FAW larvae first consume their egg cases, then move on to foliage. Larvae feed on above ground parts of corn plants, causing damage in four possible ways: foliage, tassels, ears or stalks [10]. The most frequent FAW damage is to whorls in the earlier stages of crop development. Larval feeding throughout the tightly coiled blades results in the unfurled blades being riddled with holes, possibly leading to reduced production by the plant. Older larvae are capable of eating all the leaf tissue, leaving only the center vein. In high infestations, FAW larvae may eat all available food and crawl en masse in armies to adjoining fields [10]. Larvae may also feed on undeveloped tassels and older larvae may even bore into stalks. Feeding damage to developing ears may occur as FAW larvae enter ears from the silk end, as do corn earworm larvae. FAW larvae may also bore directly through husks to enter ears. FAW damage estimates are available for field corn in Georgia. From 1991 to 1997, annual control cost and damages attributed to FAW in Georgia ranged from $184,000 to $325,000 [42]. The average yield loss to FAW on untreated acreage was estimated at 10% [42]. Table 29.3 shows infestation and costs related to FAW from 1991 to Corn Earworm The corn earworm (CEW) is present throughout the US. Although most of the moths migrate from the southern states in the spring to deposit their eggs for the first generation earworms, there is some evidence that a small percentage of the moths emerge from overwintering pupae in the soil in the southern part of some of the North Central States. First generation earworms often feed in corn whorls, producing shotholes and damaging developing tassels. The second flight of moths emerges about the time of silking of midseason corn, searching out green corn silks on which to deposit their eggs. The eggs are laid singly, although several may be laid on the same silk mass. The larvae feed on the 5

6 silks, then bore through the silk channel to the developing ear. The tip kernels are usually devoured first and as the larva increases in size, it extends its feeding area along the kernel rows. This area is filled with fecal pellets or with watery fecal material depending on the developmental stage of the ear [7]. The larger larvae are cannibalistic, so usually only one reaches maturity in an ear of corn. The mature larva eats through the shuck, crawls down the stalk and enters the soil for pupation. In the southern tier of states in the North Central States area, there are three moth flights, the last in September and October. In that region, CEW usually destroys from 1 to 4 % of the crop each year. This amount is not enough to warrant control with the short residual insecticides available, yet is enough to seriously affect the income of the corn producer. Not only does this pest cause direct loss by feeding on the kernels but also provides opening in the husks for entry of disease organisms and birds. On developing corn the larvae may feed in the whorl, causing a shredded appearance to the damaged leaves. Sometimes they feed deep enough to destroy the growing tip, thus stopping the development of the plant [7]. First generation CEW caterpillars attack the whorl stage while the second generation is largely found in corn ears. Whorl stage infestation is common but seldom reduced grain or silage yield. Infestations are highest in early planted corn, but populations seldom reach economic thresholds. Economic damage does not occur when less than 50% of the plants are infested. Yield losses are typically low, ranging from 3 to 5% [43]. CEW damage estimates are available for field corn in Georgia. From 1991 to 1997, annual control cost and damages attributed to CEW in Georgia ranged from $192,000 to $872,000 [42]. Average yield losses to CEW on untreated acreage was estimated at 6% [42]. Table 29.4 shows infestation and costs related to CEW from 1991 to

7 Black Cutworm, Fall Armyworm and Corn Earworm Control Growers may employ both cultural and chemical methods for the control of BCW, FAW and CEW in corn. Experts in states routinely faced with cutworm problems frequently recommend delaying planting seven days or longer after seedbed preparation to lessen the number of cutworms surviving at crop emergence [13]. In Texas, where black cutworm overwinters, it is common for growers to control weeds six weeks before planting, in order to eliminate possible weedy hosts from fields to be planted to corn [29]. Although some growers apply soil insecticides to prevent an infestation of cutworms, this practice is usually not justified economically throughout most of the Corn Belt. Densities of cutworms are sporadic and difficult to predict. Consequently, many growers scout their cornfields, looking for the presence of cutworms and their injury, and apply a foliar insecticide if the numbers of cutworms found exceed established economic thresholds [6]. Areas treated for cutworm control are shown in Table Several soil insecticides applied at planting to control other soilborne pests such as corn rootworm may also control cutworm. In the south, early planting of corn is the most effective cultural practice for lowering FAW damage risk [10]. Insecticide treatments are not always economically justified. In late planted fields and in fields with a history of FAW problems, early monitoring for egg masses and larvae can indicate whether an insecticide application is needed. Fall armyworm management with conventional insecticides can be difficult. In high densities, female moths do not target a particular plant part or stage for egg deposition, so targeting female moths as a management strategy is not effective for FAW. Eggs of FAW are protected from insecticidal applications by a special coating. And larvae of FAW are protected by feeding in whorls and ears. In addition, older FAW larvae are not as susceptible to pesticides as younger larvae, so the treatment window is narrowed to only younger larvae [14]. Treatments must be carefully timed to target young larvae before they burrow into whorls and ears [15]. In addition, FAW populations in the 7

8 Southeast US are resistant to carbaryl, methyl parathion, and diazinon, whereas FAW in the mid-south and west of the Mississippi River do not appear to have a high level of resistance to these insecticides [16] Corn earworm populations can be suppressed by cultivating after harvest to destroy pupae. Tillage is not an option with no-till production that is common in the southern corn belt on more highly erodible soils. Corn earworm control with insecticides is difficult, requiring multiple insecticide applications which is generally not economically justified in field corn [43]. Foliar insecticides registered and recommended for FAW, BCW and CEW management include carbaryl, chlorpyrifos, esfenvalerate, lambdacyhalothrin, methomyl, methyl parathion, bifenthrin, zetacypermethrin and permethrin [17,18,19,20]. Bt Corn A type of Bt field corn was developed using genetic material from Bacillus thuringiensis var. aizawai. The insecticidal protein in this type of Bt corn is referred to as Cry1F. Dow AgroSciences, in cooperation with Pioneer Hi-Bred International, Inc., developed the corn, which will be marketed under the trade name Herculex. Bt field corn with the Cry1F gene was approved by US regulatory agencies in USDA approval was granted in June 2001[37]. A preliminary approval was granted by EPA in May 2001, and reregistration was granted in 2001 [39]. FDA consultation was finalized in May 2001 [38]. Dow AgroSciences has committed to not commercialize Cry1F until food, feed and import approval is granted by Japan [21]. Field corn genetically engineered to express the Cry1F Bt protein protects against the European Corn Borer (ECB), southwestern Corn Borer (SWCB), and provides intermediate suppression of corn earworm (CEW) similar to the Cry1A(b) Bt field corn varieties currently marketed. In addition Cry1F provides protection against black cutworm (BCW) and fall armyworm (FAW) [1]. 8

9 Field testing has been conducted to assess the efficacy of Cry1F field corn against ECB, SWCB, BCW, FAW, CEW and other insect pests. Efficacy of Cry1F for control of ECB and SWCB is expected to be at least as good as the control provided by currently marketed Yieldgard (Cry1A(b)) Bt corn varieties. Improved control of BCW and FAW is expected to be the major advantage of Cry1F corn. The results of several efficacy trials of Cry1F corn are reported below. Tests conducted in Pennsylvania comparing ECB control with Cry1F to a non-bt isoline, showed less feeding damage in terms of leaf feeding, tunneling, shank feeding and larval survival (Table 29.5). Efficacy of Cry1F corn for control of SWCB was evaluated in trials conducted in Kansas. Early and late season observations were made (Tables 29.6 and 29.7). High levels of plant protection were measured and were judged to be equal to that of Cry1A(b) corn [36]. In trials conducted in Iowa comparing Cry1F to a non-bt hybrid, black cutworm control was assessed. Two separate trials were conducted with four replications. The number of cut plants was lower in the Bt corn plots (Table 29.8). Cry1F was compared to conventional insecticides in trials conducted in Illinois. The percentage of cut plants 17 days after infestation were compared (Table 29.9). In this test, 20% of the untreated plants were cut, the Bt corn plants incurred 3% damage from cutting, which was equivalent to control with insecticides. In experiments conducted in Georgia, FAW leaf feeding was significantly reduced in Cry1F corn compared to Cry1Ac corn and an untreated conventional variety. However, there was no difference in ear damage between Cry1F and the conventional isoline (Table 29.10) [35]. Corn earworm control of Cry1F corn was compared to an isoline, in trials conducted in Nebraska. The average number of CEW larva per ear tip was not significantly different 9

10 (Table 29.11) [9]. In trials conducted in Kansas, comparing Cry1F, a non-bt isoline and Cry1A(b) corn, both types of Bt corn were shown to suppress kernel damage at the ear tip by corn earworm (Table 29.12) [36]. Dow AgroSciences and Pioneer Hi-Bred International, Inc. submitted pooled results from trials conducted in several locations against ECB, SWCB, FAW, CEW and BCW to EPA as part of their pesticide registration application. Those results are shown in Tables and Estimated Impacts Cry1F field corn cultivation is most appropriate in corn growing areas where black cutworm, fall armyworm, European corn borer and southwestern corn borer are consistently problematic. Cry1F corn hybrids offer additional benefits beyond those delivered by Cry1A(b) hybrids, specifically protection from BCW and FAW damage. These additional benefits are estimated separately, as BCW and FAW are problematic in different geographic areas. The impacts of Cry1F field corn are estimated as incremental to those provided by Cry1A(b) field corn. For example, in areas where growers find currently marketed varieties of Bt field corn to be beneficial for control of ECB and/or SWCB, only the additional benefits of controlling black cutworm and fall armyworm are estimated. Estimates of additional benefits associated with CEW control are calculated when FAW benefits are estimated. In order to assess the incremental value of Cry1F field corn above the benefit of currently available Bt corn varieties, several assumptions are made. First, it is assumed that Cry1F is as effective as the currently available foliar insecticides for black cutworm. Next, it is assumed that in areas where growers face both cutworm and rootworm infestations, that the technology will not be appropriate, as growers will chose to continue to use soil insecticides for rootworm that also control cutworm. This assumption led to the 10

11 exclusion of Iowa and Pennsylvania in the impact analysis, as experts indicated that the pests overlapped in those states [22, 23]. Finally, the benefits of the technology for ECB or SWCB control are not considered. In areas where currently available Bt field corn varieties have already been planted, only the value of gaining control of cutworm or fall armyworm is considered. In areas where growers may have ECB or SWCB pressure that is not severe enough to warrant adoption of currently available Bt field corn varieties, but who may receive additional benefits from the control of these pests if they adopt Cry1F field corn, those benefits are also not considered. It is likely that Cry1F corn would be adopted by growers who have already adopted Cry1A(b) Bt corn, in order to capture the additional insect control benefits. In that case, the estimates of the benefits of the technology are conservative, as it is assumed that growers will incur the entire technology fee solely for the benefits of controlling BCW, FAW and CEW. Clearly, if a grower switches from Cry1A(b) corn to Cry1F corn, the additional cost will be the difference in the technology fees between the two products, which would be much less than the cost of the technology assumed in the calculations presented here. Based on a 1992 survey of Extension Service specialists, area infested with cutworm and the area treated for cutworm is estimated [5]. For some states, experts provided revised estimates from the results of the 1992 survey. Table 29.2 shows estimates of acreage infested and treated for cutworm by state. On infested acreage that is not currently treated with insecticides, it is assumed that growers will achieve increased yields. A yield loss of 12% is assumed on untreated acreage infested with black cutworm, based on the average yield loss on 3 rd leaf stage corn on a study of simulated black cutworm damage [25]. It is assumed that insecticide treatments or Cry1F would reduce this yield loss to 2%. On acreage that is currently treated, it is assumed that the impact would be a reduction in insecticide use and related costs. The cost of an insecticide treatment for black cutworm varies between $4.64 and $17.90 per acre, depending on the product and rate used [26]. A $10 per acre treatment cost is assumed. The insecticide use reduction 11

12 is calculated assuming current application rates are 0.15 lbs/acre, the average of application rates for recommended foliar insecticides used for cutworm control [27]. It is assumed that growers would adopt the technology on all cutworm infested acreage, based on the value of the technology in terms of increased yields (+10%) being higher than the technology fee ($8.50/acre), which is assumed to be lower than insecticide cost ($10/acre). The impact estimated from adoption of Bt corn for black cutworm control are presented in Table The benefits of Cry1F for FAW and CEW control are estimated for Georgia. About 5% of Georgia corn acreage is regularly infested with FAW and another 9% is regularly infested with CEW. It is assumed that 5% of Georgia corn acreage (15,000 acres) would be planted to Cry1F corn. Approximately 70% of the acreage infested with FAW and CEW is assumed to be treated with an insecticide. On these 10,050 acres, growers will avoid making an $8/acre insecticide treatment of 0.5 lbs AI/acre. Average application rates were calculated based on insecticide treatment recommendations [17]. A yield increase of 6% is assumed on 30% of the adoption acreage which is currently untreated. Table summarizes the impact estimates for Georgia. It is estimated that the value of increased production, from planting Cry1F on acreage currently untreated for black cutworm would be worth approximately $26 million/year. On acreage that is currently treated, growers would save $15 million on insecticides. If the technology fee is $8.50 per acre, total technology costs would be $22 million which would result in a net increase gain of $19 million /yr. For Georgia growers, the benefit of adopting Cry1F corn on 5% of the corn acreage is estimated at $14,000/y. Technology fees for Georgia would total $128,000 with an associated reduction of insecticide costs of $84,000 and an increase in production value of $58,000 (Table 29.16). 12

13 Estimated impacts by state are shown in Table

14 Table Corn for Grain 2000 State Harvested (000 acres) Yield (bushels/ acre) Production (million bushels) Price ($/bushel) Value of Production ($million) GA IL IN KS KY LA MS MO OH TX Total $8208 US Total $18621 Sources: [2, 3] 14

15 Table 29.2 Areas infested with economically damaging levels of BCW and areas treated by state State % area infested % area treated % area untreated IL IN OH KS MO TX KY MS LA Note: Estimates for Texas area infested from [29] Source: [5,29] 15

16 Table Fall Armyworm damage and control in Georgia corn acreage harvested (000) Total Control Cost (000$/year) Total Insect Damage (000$/year) Acres Needing Control (000) % of acreage needing control infested % of acreage treated Year Note: data not available for Source: [42] Table Corn Earworm damage and control in Georgia corn acreage harvested (000) Total Control Cost (000$/year) Total Insect Damage (000$/year) Acres Needing Control (000) % of acreage needing control infested % of acreage treated Year Note: data not available for Source: [42] 16

17 Table Results of Cry1F trial on ECB Cry1F Isoline Guthrie Rating Total Number of Larvae Total Number of Tunnels Shank Feeding Average Larvae/Plant Average Tunnels/Plant Percent of Shanks Note: Average of 4 replications. Source: [22] 1 Amount of leaf feeding by 1 st generation. 2 Number per 20 plant sample. 3 Number of shanks with feeding out of 20 plants. 4 Percent with a larva or injury Table Early season observation of SWCB efficacy of Cry1F corn Hybrid Modified Guthrie Rating 0-9 scale Modified Guthrie Rating % plants 3+ 1 st Gen. SWCB/ Plant 1 st Gen. Tunnels/ Plant 1 st Gen. Tunnels Inches/ Plant 1 st Gen. % Plants Infested Cry1F 0.5 b 0 b 0.0 b 0.0 b 0.0 b 0 Non-Bt 7.8 a 100 a 2.7 a 3.2 a 7.6 a 100 MON b 0 b 0.1 b 0.2 b 0.1 b 10 Note: results followed by same letter are not significantly different. Source: [36] Table Late season observation of SWCB efficacy of Cry1F corn 2 nd Gen. Hybrid 2 nd Gen. SWCB/ Plant 2 nd Gen. Stalk Tun. No./Plant 2 nd Gen. Shank Tun. No./Plant 2 nd Gen. Stalk Tun. Inches/ Plant Shank Tun. Inches/ Plant 2 nd Gen. Total Tun. Inches/ Plant 2 nd Gen. % Plants CB Infest Cry1F 0.0 b 0.0 b 0.0 b 0.0 b 0.0 b 0.0 b 0 Non-Bt 1.1 a 2.6 a 0.7 a 12.2 a 1.1 a 13.4 a 100 MON b 0.0 b 0.0 b 0.0 b 0.0 b 0.0 b 0 Note: results followed by same letter are not significantly different. Source: [36] 17

18 Table Number of cut plants out of 8 plants, 10 days after infestation Trial #1 Trial #2 Cry1F Non-Bt 8 3 Source: [23] Note: Average of 4 replications. Table Percent of plants cut 17 days after infestation Treatment Percent of plants cut Untreated 20 Cry1F 3.3 Capture 2EC 0 Baythroid 2EC (0.025 lb/acre) 3.3 Source: [4] Table Efficacy of Cry1F to control Fall Armyworm Leaf Feeding Damage 1 7 days after 14 days after Ear Damage 35 days after silking 2 infestation infestation Isoline 3.8 a 5.7 a 5.9 a Yieldgard 1.2 b 2.6 b 3.1 b Cry1F 0.3 c 0.03 c 5.4 a Notes: results followed by the same letter are not significantly different 1 Leaf feeding damage was rated on a 0 to 9 scale where 0=no damage and 9=extensive damage 2 Ear damage rated on a cm scale where 0=no damage, 1=silk feeding only, 2=feeding to 1 cm below the ear tip, n+1=feeding to n cm below the ear tip Source: [35] Table Corn Earworm Efficacy Trial Results Average # of CEW larva Hybrid per ear tip Cry1F 0.28 Isoline 0.51 LSD (0.05) NS Source: [9] 18

19 Table Corn Earworm Efficacy Trial Results CEW Hybrid CEW larvae per ear CEW mean instar damaged kernels/ear % ear tips infested % ear bases infested Cry1F Non-Bt Cry1A(b) Source: [36] Table ECB, SWCB, FAW, CEW and BCW damage on Cry1F hybrids versus their non-bt isolines across multiple genetic backgrounds. SWCB ECB Leaf Feeding Rating 1 ECB Stalk Tunneling (inches/ plant) Stalk Tunneling (inches/ plant) FAW Leaf Feeding Rating 2 CEW Ear Damage Rating 3 BCW % Plants Cut TC Non-Bt Hybrid TC Non-Bt Hybrid TC Non-Bt Hybrid TC Non-Bt Hybrid TC Non-Bt Hybrid Note: TC1507 lines are Cry1F hybrids. 1 ECB leaf feeding rating scale: 1=long lesions common on most leaves, 9=no visible damage. 2 Rating scale for FAW leaf feeding rating scale: 0=whorl and furl leaves almost totally destroyed, 9=no visible damage. 3 CEW ear damage rating scale: 1=heavy damage to silks, husks, or eartips, with 5.1(+) cm kernels lost, 9=no damage to eartips or kernels, slight damage to silks or husks (i.e., a nibble or two) Sources: [40, 41] 19

20 Hybrid Table ECB, SWCB, FAW and BCW damage on Cry1F hybrid versus non-bt isoline ECB Leaf ECB Stalk SWCB Stalk FAW Leaf Feeding Tunneling Tunneling Feeding BCW % Rating 1 (inches/plant) (inches/plant) Rating 2 Plants Cut TC Isoline Number of Locations Note: TC1507 lines are Cry1F hybrids. 1 ECB leaf feeding rating scale: 1=long lesions common on most leaves, 9=no visible damage. 2 Rating scale for FAW leaf feeding rating scale: 0=whorl and furl leaves almost totally destroyed, 9=no visible damage. Sources: [40, 41] 20

21 Table Estimated Impact of Cry1F for Black Cutworm Control in Selected States Production increase on untreated acres (000 Bu) 2 Value of yield increase (000$) 3 Area with insecticide use reduction (000A) 4 Insecticide use reduction (lbs AI/Y) 5 Insecticide use savings Technology (000$) 6 State Adoption (000A) 1 fee (000$) 7 IL ,150 2,210 1,879 IN ,625 2,775 2,359 KS 384 4,160 8, , ,264 KY ,900 2,460 2,091 LA , ,650 1,110 1,573 MO ,410 6,094 5,180 MS 212 2,118 4, ,800 OH 330 4,851 9, ,805 TX , , TOTAL 2,560 12,929 25,739 1, ,185 15,479 21, Harvested acreage (Table 29.1) times % infested (Table 29.2) 2. A 10% increase in average yields (Table 29.1) is assumed on acreage untreated currently (Table 29.2) 3. Yield increase times average price per bushel (Table 29.1) 4. Percent acres treated (Table 29.2) times harvested acres (Table 29.1) 5. Calculated at 0.15 lb AI/A 6. Calculated at $10/acre 7. Calculated at $8.50/acre 21

22 Table Estimated Impact of Cry1F for Fall Armyworm and Corn Earworm Control in Georgia Impact Component Estimate Adoption (acres) 1 15,000 Production increase on untreated acres ( bushels) 2 Value of production increase (000$) 3 58 Area with insecticide use reduction (acres) 10,500 4 Insecticide use reduction (lbs AI/y) 5 5,250 Insecticide use savings (000$) 6 84 Technology Fee (000$) Net Benefit (000$) Calculated as 5% of 300,000 acres (Table 29.1). 2. Yield increase of 6% assumed of 107 bushel/acre average yield (Table 29.1) across 30% of adoption acreage. 3. Assuming price of $2.00/bushel (Table 29.1). 4. Insecticide use reduction assumed on 70% of adoption acreage. 5. Insecticide use reduction of 0.5 lb AI/acre assumed. 6. Insecticide treatment cost of $8/acre assumed on 70% of infested acreage. 7. Calculated at $8.50/acre. 22

23 Table State Volume (000 bushels) Estimated Impacts of Cry1F Corn by State Production (per year) Value Costs (000$) (000$) Net Income (000$/yr) Pesticide Use Reduction (lbs AI/yr) GA ,250 IL ,150 IN ,625 KS 4,160 8,528 2,624 5,904 9,600 KY ,900 LA 858 1, ,650 MO ,410 MS 2,118 4,023 1,800 2,223 0 OH 4,851 9,702 2,805 6,897 0 TX 942 2, ,409 2,850 TOTAL 12,958 25,797 6,322 19, ,435 23

24 References: 1. Babcock, J.M. and J.W. Bing, Genetically Enhanced Cry1F Corn: Broad- Spectrum Lepidopteran Resistance, Down to Earth, vol. 56, no. 1, pp , USDA, Crop Production 2000 Summary, National Agricultural Statistics Service, January USDA, Crop Values 2000 Summary, National Agricultural Statistics Service, February Shaw, John T., Efficacy of soil insecticides and seed treatments for the control of seed corn maggot in field corn in Illinois, 2001, Insect Management and Insecticide Evaluations, Illinois 2001, Center for Economic Entomology Technical Report No. 16, Illinois Natural History Survey and University of Illinois at Urbana-Champaign. 5. Pike, David R., et al., Biologic and Economic Assessment of Pesticide Use on Corn and Soybeans, USDA National Agricultural Pesticide Impact Assessment Program, Report Number 1-CA-95, Steffey, Kevin, More Intense Captures of Black Cutworm Moths Have Occurred, Pest Management and Crop Development Bulletin, April 12, Blair B.D., et al., Corn Pest Management for the Midwest, North Central Regional Publication Number Black Cutworm Factsheet, Minnesota Department of Agriculture, available on the internet at 9. Bob Wright, University of Nebraska, personal communication. 10. Fall Armyworm, North Carolina State University AG 271, available on the internet at Sparks, A.N., A Review of the Biology of the Fall Armyworm, Florida Entomologist, June Edwards, C.R., et al., Armyworm and Fall Armyworm, Purdue University Cooperative Extension Service Field Crops Bulletin E-57, October, Lippert, George and Randall A. Higgins, Black Cutworm in Kansas, Cooperative Extension Service, Kansas State University,

25 14. Ghidiu, G.M. and J.T. Andaloro, The Relationship Between Fall Armyworm (Lepidoptera: Noctuidae) Instar and Susceptibility to Insecticides Applied to Sweet Corn, Florida Entomologist 76(4): , Bessin, R. Fall Armyworm in Corn, University of Kentucky College of Agriculture Factsheet, available on the internet at Pitre, Henry, Chemical Control of the Fall Armyworm (Lepidoptera: Noctuidae): An Update, Florida Entomologist, vol. 69, no. 3, Alabama Pest Management Handbook, available on the internet at k Pest Management Handbook, Clemson University Extension, available on the internet at Georgia Pest Control Handbook, University of Georgia, available on the internet at Morrison, W.P., et al., Managing Insect and Mite Pests of Texas Corn, Texas A&M, Texas Agricultural Extension Service Bulletin B-1366, 1995, entowww.tamu.edu/extension/bulletins/b-1366.html. 21. Babcock, Jonathan, Herculex I Insect Protection: Dow AgroSciences Product and Stewardship Overview, presented to the National Grain and Feed Association Annual Convention, March 19, Dennis Calvin, Pennsylvania State University, personal communication. 23. Marlin Rice, Iowa State University, personal communication. 24. John Shaw, Illinois Natural History Survey, personal communication. 25. Santos, Luisa and Elson J. Shields, Yield Responses of Corn to Simulated Black Cutworm (Lepidoptera: Noctuidae) Damage, Journal of Economic Entomology, vol. 91, no. 3, pp , Rice, Marlin, Preventive Cutworm Treatments in Corn, Integrated Crop Management, April 30, Alabama Cooperative Extention System, Corn Insect, Disease, Nematode, and Weed Control Recommendations for IPM-428, /CORN.PDF 25

26 28. North Carolina Cooperative Extension Service, Cutworms, Corn Insect Pest Management Department of Entomology Insect Note, Plymouth.ces.state.nc.us/pubs/ent/crcutworm.html. 29. Roy Parker, Texas A&M University, personal communication. 30. Ric Bessin, University of Kentucky, personal communication. 31. Ken Ostlie, University of Minnesota, personal communication. 32. Bruce Eisley, Ohio State University, personal communication. 33. Larry Bledsoe, Purdue University, personal communication. 34. Ron Hines, University of Illinois, personal communication. 35. Robert Lynch, USDA-ARS, Tifton, Georgia, personal communication. 36. Lawrent Buschman, Kansas State University, personal communication. 37. USDA, Animal and Plant Health Inspection Service, Approval of Mycogen Seeds c/o Dow AgroSciences LLC and Pioneer Hi-Bred International, Inc. Request ( p) Seeking a Determination of Non-regulated Status for Bt Cry1F Insect Resistant, Glufosinate tolerant Corn Line 1507, Environmental Assessment and Finding of No Significant Impact, June 2001, U.S. FDA, Biotechnology Consultation Agency Response Letter BNF No , May 18, 2001, U.S. EPA, Biopesticide Registration Action Document: Bacillus thuringiensis Cry1F Corn, Babcock, John, et al., Supplement to MRID : Supplemental Data Public Interest Document for Cry1F-Protected Corn (Dow AgroSciences LLC), Study Number GH-C 5179, January 23, Babcock, John, et al., Supplement to MRID : Supplemental Data Public Interest Document for Cry1F-Protected Corn (Pioneer Hi-Bred International, Inc.), Study Number PHI , January 23, Georgia Agricultural Experiment Stations, Summary of Losses from Insect Damage and Costs of Control in Georgia, University of Georgia, various years. 26

27 43. North Carolina Cooperative Extension Service, Corn Earworm, Corn Insect Pest Management Department of Entomology Insect Note, Plymouth.ces.state.nc.us/pubs/ent/crearworm.html. 27