Ilex forest is the west of Azeala town. Here you will help a boy find his Farfetch'd.The Farfetch'd is located in the northeast of Ilex forest. You will have to protect two rare candies to win. After you battle Farfetch'd, you talk to the boy(Is located where you enter Ilex forest) to get the HM Cut. There is only one trainer in Ilex Forest, which is a bug catcher who will send out a level 25 Ledian and Parasect.
You will battle a level 35 Farfetch'd and a few other types of pokemon, including Psyduck, Parasect, and Venonat. All except Venonat are level 25, Venonat being level 20.
The battlefield is U-shaped. Candies are put at the lower arms of the U. On the left is Farfetch'd, on the right are the other pokemon. Pokemon can pass through the bottom link to pick up both sides of candies.
Since Farfetch'd is walking fast and uses Sword Dance, use moves like Thunder Wave to slow down the movement as well as attack cooldown. Electric, Ice, and Rock type moves are super effective against it. Use Electro Ball if you have slowed down it for doubled damage.
For the other side, using Rock-type moves can tackle Venonat and Parasect well. Multi-target moves like Rock Slide, Stealth Rock are useful. Electric-moves can effectively harm Psyduck.