Instructions
Remove any dust from your GBA Game Pak by blowing gently into the opening. Push "Pokemon Emerald" into the Nintendo DS until you hear it click. Blow into the top slot of your Nintendo DS and insert the "Pokemon Platinum" cartridge.
Power on your Nintendo DS once you have inserted "Pokemon Platinum" and "Pokemon Emerald." Remove and reinsert "Pokemon Emerald" into your Nintendo DS if you do not see an icon for the GBA game. Touch the "Pokemon Platinum" icon with the Nintendo DS stylus.
Travel to Route 203, Route 204, Route 210 South, Route 229 or Eterna Forest. Look for a Pineco in the nearest patch of long grass. Run away from Wurmple, Budew, Silcoon, Buneary, Beautifly and any other Pokemon besides Pineco. Out of 100 Pokemon, you will encounter about eight Pineco.
Make the Pineco easier to catch by using Fire-, Flying- and Rock-type moves. These types of moves are very effective on Pineco. Inflict a status ailment onto the Pineco. "Will-o-wisp," "Glare," "Stun Spore," "Sing" and "Sleep Powder" are some moves that inflict status effects like "Burn" and "Sleep."
Throw Net Balls at the Pineco until you catch it. A Net Ball makes it easier to catch Water- and Bug-type Pokemon. Because Pineco is a Bug-type Pokemon, you will have an easier time catching it with a Net Ball instead of a Pokeball.