I have a few vegetable plants (kale, broccoli) that have been badly infested by aphids. I was wondering if I can remove those plants and put them in the compost bin or I should discard them some other way. I want to make sure they are gone and done reappear next year (I am sure new ones will appear but want to get rid of these for now)
It shouldn't be an issue to add aphid-infested plant matter to your compost. If your heap gets up to the right temperature, they'll burn to death anyways. If they lay eggs, those eggs will probably be eaten by the composting bacteria as well.
I've added aphid-infested stalks in without any problems with the resulting compost.
When I have an aphid infestation outpacing my ladybugs, I use my homemade pesticide spray of Dawn, water, and baking soda. (1 gallon water, 2 teaspoons Dawn, 4 teaspoons baking soda) Good for insects and fungus. Coat liberally.
When aphids first moved in on my gardens, I bought a few thousand ladybugs. (Despite my region being thick with Asian Lady Beetles, they can't gain a foothold on my lot BC of all the ravenous birds).
The initial release, when done properly, is like dropping an anti-pest nuke on your garden. Enough should stick around to keep you covered for the year. (I keep a dish with rocks & water for them, and built them a house - but that's probably a little overboard.)
Dill and Radishes are great for attracting ladybugs. This is mostly because they attract aphids - BUT they're so aroma-intense that ladybugs will come to the area because they know that where there's Dill and Radishes, there's aphids.
Summary: spray the infestation. Entice predators to the area. Maybe buy an initial population. Build/buy them a house if you're a psycho like me.