Aphids are hella attracted to yellow, which is why you can by trap cards for them.

Thing is, they're stupidly (for the value) expensive in Australia for something you use and then throw away, so I made some reusable ones. Based on the "On-Guard Outdoor Protector" brand, and will fit in side their proprietary cages (will not be able to use clips at both ends as you can't fit a full size card on a standard bed, but the 2mm rigidity holds them in place)

Two versions, one with holes so it can be hung / mounted in the cage, the other a flat card that works great with Pippa666's Stand for sticky traps or can even just be nailed to a stick.

For the sticky element on the trap, I use Tree Guard Glue, although I believe in the US a good alternate is Tanglefoot tree glue. Once the card is full of bugs, simply clean off the old glue (and dead bugs) with soap and water and re-apply.

May eventually come up with a custom cage. Twist my arm.

Print in yellow (obviously)