Susceptibility of the Asian Corn Borer, Ostrinia Furnacalis, to Bacillus Thuringiensis toxin cry 1 Ac

EI, Aye Kyawt Kyawt, Prof.Dr.Ir. Y. Andi Trisyono, M.Sc

2007 | Tesis | S2 Ilmu Hama Tumbuhan

Kepekaan larva instar 1, 2, 3 dan 4 penggerek batang jagung Asia, Ostrinia furnacalis (Guenee) [Lepidoptera: Crambidae], terhadap protein Bacillus thuringiensis Cry1Ac diuji dengan metode celup pakan. Larva berasal dari KP-4, UGM di Kalitrito dan dikembangbiakkan di laboratorium menggunakan pakan buatan (InsectaLF), tiga generasi sebelum digunakan untuk penujian. Instar O. furnacalis yang diuji dipaparkan pada pakan buatan yang telah diperlakukan dengan berbagai konsentrasi Cry1Ac selama satu minggu. Nilai LC50 pada hari ketujuh setelah perlakukan untuk instar 1, 2, 3, dan 4 berturut-turut adalah 0,79; 21,12; 113,66; dan 123,17 ppm. Hal ini menunjukkan bahwa instar yang semakin tinggi tingkat kepekaannya terhadap Cry1Ac semakin menurun. Larva yang baru menetas dan diberi pakan yang telah dicelupkan pada konsentrasi sublethal Cry1Ac sebagian akan mati. Larva yang hidup, pertumbuhan dan perkembangan larva terhambat. Fekunditas dan vialibitas serangga betina hasil dari larva yang diperlakukan dengan Cry1Ac menurun. Penelitian ini menunjukkan bahwa Cry1Ac toksik terhadap larva O. furnacalis dan juga mempunyai efek kronik terhadap larva yang tetap hidup setelah memakan toksin.

The susceptibility of the Asian corn borer, Ostrinia furnacalis (Guenee) [Lepidoptera: Crambidae], to a Bacillus thuringiensis protein (Cry1Ac) was evaluated using insect feeding bioassays against 1st, 2nd, 3rd and 4th instars. The population of O. furnacalis was originally collected from the experimental station of UGM at Kalitirto and had been reared in the laboratory using an artificial diet “InsectaLf”. The tested instars were exposed on diets treated with a series of concentrations of Cry1Ac for one week. The LC50 values on the seventh day after treatment for 1st, 2nd, 3rd and 4th instars were 7.79; 21.12; 113.66; and 123.17 ppm, respectively, showing that the higher the instars the lesser the susceptibility to Cry1Ac. When the neonates were exposed to sub-lethal concentrations of Cry1Ac as 0, 0.0583, 0.116, and 0.5830 ppm, growth and development of larvae were inhibited. The fecundity and viability of females produced from treated larvae decreased with increasing the concentrations. These findings indicate that application of sub-lethal concentrations of Cry1Ac not only cause larval mortality but also alter their reproductive abilities of the survivors.

Kata Kunci : Hama Tanaman,Penggerek batang Jagung,Bacillus Thuringiensis, Bacillus thuringiensis; Cry1Ac, Ostrinia furnacalis, toxicity