Conversely, many of the approved chemicals are not effective, as pests eventually build up a resistance to these products.
Ọtụtụ ihe ndị ọcha na-arụpụta ha na-ete n'ahụ adịchaghị mma n'ihi na ọ na-abụ e mechaa ọ kaa onye ahụ nka n'ike.