A nematode Meloidogyne incognita infects tobacco plants and reduces their yield. The specific genes from the parasite are introduced into the plant using Agrobacterium as the vector. The genes are introduced in such a way that both coding RNA and complementary RNA are produced. Since these two RNAs are complementary, they form a double-stranded RNA (ds RNA). This neutralizes the specific RNA of the nematode, by a process called RNA-interference. As a result, the parasite cannot line in the transgenic host, and the transgenic plant is protected from the pest.