THE EFFECTIVENESS OF TOONA SINENSIS (MELIACEAE) AS INSECT REPELLENT

An experiment was conducted over a period of six weeks, to observe the effectiveness of Toona sinensis as insect repellent. Three other tree species from the same family (Meliaceae), namely, Toona sureni, Chukrasia tabularis and Swietenia macrophylla were used as test plants, as most meliaceous trees are susceptible to attacks by shoot borers. The percentage of leaf damage of test plants at six different distances from Toona sinensis was used as a measure of effectiveness of the latter in repelling insect pests. It was found that Toona sinensis was effective in controlling pest attacks, the more so the nearer this species was to the test plants. Swietenia macrophylla was least susceptible to pest attacks, Chukrasia tabularis, more susceptible and Toona sureni, the most susceptible. Toona sinensis placed among a mixture of the three test plants was effective in controlling pest attacks. Satu kajian telah dijalankan selama enam minggu, untuk mengkaji keberkesanan Toona sinensis sebagai pencegah serangga. Tiga lagi spesies pokok dari famili yang sama (Meliaceae), iaitu Toona sureni, Chukrasia tabularis dan Swietenia macrophylla telah digunakan sebagai pokok ujian, kerana kebanyakan pokok dari famili ini adalah rentan kepada penebuk pucuk. Peratus kerosakan daun pada pokok ujian yang diletak di enam jarak yang berlainan dari Toona sinensis telah digunakan untuk menilai keberkesanan spesies ini untuk mencegah serangga perosak. Didapati bahawa Toona sinensis boleh mengawai serangan perosak dengan berkesan, khususnya apabila pokok ini terletak lebih dekat dengan pokok ujian. Swietenia macrophylla kurang rentan sekali, Chukrasia tabularis lebih rentan, sedangkan Toona sureni paling rentan. Toona sinensis apabila diletak di antara campuran ketiga-tiga pokok ujian adalah berkesan dalam mengawal serangan perosak.