Desiree M. Hautea

The objective of this study is to evaluate the effects of event 'EE-1' Bt eggplants on the survival, growth and development of second (II) and third (III) instar larvae of two EFSB populations using detached terminal shoot and fruit disc assays.

• Restricted access to the BL2 and P2 Entomology Laboratory Room. All authorized personnel are required to sign in the logbook.
• Bagging of flowers will be done prior to flower opening to prevent unintended transfer of pollen to non-transgenic plants. Any open flowers not baged will be immediately removed.
• All plant parts will be disposed in the area at the end of the experiments. Fruits will be chopped, boiled/autoclaved and buried inside the BL2. Whole plants will be chopped and buried inside the area.
• Contingency plans are available in case of typhoons, flooding and other possible destructive cases of the BL2 facility.

The event 'EE-1' Bt eggplant is a genetically-engineered eggplant expressing a single insecticidal protein derived from Bacillus thuringiensis (80 that is active against the target lepidopteran insect pest, the eggplant fruit and shoot borer (EFSB), Leucinodes orbonalis Guenee (Lepidoptera:Crambidae). Promising Bt eggplant OP and F1 hybrids field tested in multiple sites demonstrated very high efficacy against EFSB (Hautea et a1.,2016). However, insects have been demonstrated to possess high capacity to develop resistance to a wide array of chemical insecticides, and the possibility that insects might evolve resistance to Bt-transgenic plants is a serious concern (Cao et al.,1999). Bt crops provide a constant selection pressure on insect populations, which may accelerate the development of resistant insect populations. To ensure durability of Bt transgenic crops, and delay the development of rare resistant individuals, appropriate resistance management strategies the Insect Resistance Management Team (IRMAT) of the Philippine Department of Agriculture-Bureau of Plant Industry have developed guidelines for IRM strategy for Bt corn with single, stacked and pyramided traits targeting the Asiatic Corn Borer (DA-IRMAT, 2014). An IRM strategy that is appropriate for event 'EE-1' Bt eggplants against EFSB must also be developed as part of product stewardship.

In almost all the reports related to bioefficacy of Bt toxins, only the neonate mortality data are considered because they are naturally very susceptible to the toxins, and therefore represent what narurally occurs in the field (Halland et al. 2011). Studies on survival of larvae up to late instars were done through bioassays (Hallad et a1.,2011 ; Venkatesh et a1.,2017) and suggest less susceptibility and toxicity to the protein that would lead to enhanced damage and acquisition of resistance. Results from field trials of event 'EE-l' Bt eggplants showed that larval counts were significantly reduced in event 'EE-l' Bt eggplants compared with non-Bt near-isogenic comparators and no first instar larvae (neonates) of EFSB were observed to survive in the Bt eggplants plots. A few late instar larvae (mostly 2nd and 3rd) were collected iu Bt plots but it cannot be ascertained if those larvae that survived in the Bt plots just moved from the adjacent non-Bt plots. Unlike in Bt cotton and Bt corn, there are no published studies done on survival of late instar EFSB in Bt eggplants. This study is proposed to evaluate the effects of event 'EE-l' Bt eggplants on the survival, growth and development of first (I) and second (II) instar larvae of two EFSB populations using detached terminal shoot and fruit disc bioassays. Together with information already available, the information that will be generated from this study will be used in designing the appropriate of IRM plan specific for Bt eggplant in the Philippines. Studies done on survival of late instar EFSR in Bt eggplants. The objective of this study is to evaluate the effects of event 'EE-1' Bt eggplants on the survival, growth and development of first (I) and second (II) instar larvae of two EFSB populations using detached terminal shoot and fruit disc bioassays. Together with information already available, the information that will be generated from this study will be used in designing the appropriate of IRM plan specific for Bt eggplant in the Philippines.

The terminal shoot and fruit assays will be done in the IPB Entomology Laboratory P2 Rooms while the Bt and nonBt hybrids and OPVs used in the assays will be grown and maintained in the IPB BL2 Facility. The genotypes that will be used
include: Bt eggplant hybrids: XEH 4 and XEH 16, Bt eggplant OPVs: D2 and M1 and non Bt eggplant comparators, 'Sulit' and 'Tanyag' (hybrids) and DLP and Mara 32 (OP checks). The reaction of 1st and 2nd larval instars of Laguna and
Pangasinan EFSB will be tested when given terminal shoots and fruits of Bt and nonBt hybrid and open pollinated eggplant varieties. Mortality data will be taken three and seven days after release. The longevity and fecundity (female moths) of adults from the surviving larvae will be recorded. Samples of terminal shoots and fruits used in assays will also be analyzed for Bt protein expression and correlated with mortality. There will be three replicates with replication done over time. Time will serve as block and the design to be used will be RCBD in split plot.

The study will be done from April l, 2018 to October 31, 2018