Example 5
This example describes the superior protection of plant comprising event MON 87411 from corn rootworm damage when compared to current commercial products (MON 88017 and DAS-59122-7) and negative control plants. Efficacy field trials were conducted comparing 135 plants each of event MON 87411, MON 88017, DAS-59122-7, and negative controls. Root damage ratings (RDR) were collected, and the percentage plants with an RDR less than the economic injury level (0.25 RDR) is shown in Table 8.
Table 8 shows that only about 4% of plants containing event MON 87411 exhibited RDRs greater than the economic threshold of 0.25 RDR. In contrast, 22% of the commercially available plants containing MON 88017 exhibited RDRs greater than the economic threshold of 0.25 RDR. And, 20% of the commercially available plants containing DAS-59122-7 exhibited RDRs greater than the economic threshold of 0.25 RDR. And, 96% of the negative control plants exhibited RDRs greater than the economic threshold of 0.25 RDR. The conclusion from these data is that event MON 87411 is clearly superior at providing protection from corn rootworm damage as compared to commercial products MON 88071 and DAS-59122-7, and a negative control.
Trial included 135 plants for each event tested.
Efficacy green house trials were conducted to test the performance of event MON 87411 with extreme infestation pressure of corn root worm. In this trial the following event were evaluated: event MON 87411, an event from transformation with DNA vector #890 expressing only the dsRNA; MON 88017; DAS-59122-7; and negative control. For these high-pressure efficacy trials, the corn plants under evaluation were grown in pots in a green house. Extreme infestation pressure was achieved by sequential infestation of each potted plant with approximately 2,000 WCR eggs per pot at their V2 growth stage, and, at 4 additional times occurring at 1 to 1½ week intervals with approximately 1,000 WCR eggs per pot per infestation for a total of approximately 6,000 WCR eggs added to each pot. Plant roots were removed, washed, and rated for RDR at their VT growth stage. The roots from all thirteen (N=13) negative control plants exhibited maximum root damage, or an absolute RDR of 3 RDR. These results illustrate that event MON 87411 is more superior to other corn events available for controlling corn rootworm (Table 9).
One measure of efficacy of corn rootworm transgenic events is by a determining the emergence of adult beetles from the potted soil of plants cultivated in a green house. To determine adult corn rootworm beetle emergence from the soil of event MON 87411 plants grown in pots, 10 to 15 plants were germinated in pots containing soil infested with WCR eggs, similar to that described above. Throughout the growth period, each corn plant was covered with mesh bag to contain any emerging adult beetles.
Counts of above ground adult beetles were made at 6, 12, and 18 weeks after plant emergence, and at the end of the trial the roots were evaluated for RDR. Plants containing event MON 87411 were compared to negative control plants, and other corn rootworm protective transgenic events. The results were that significantly fewer beetles were observed to emerge from soils in which event MON 87411 plants were potted compared to the other corn rootworm protective transgenic events, illustrating the superior properties of event MON 87411 to protect against corn rootworm damage.
