I use a 2 gallon pump sprayer like this:
https://amzn.to/2PHukS2
I use captain Jacks dead bug juice:
https://amzn.to/2OpJo22
I get the 1 quart concentrate and add it to the sprayer.
I usually just spray this alone but I have added it to the foliar spray.
I tpyically use the juice whenever I see a leaf that has been munched on or caterpillar poop on a leaf.
It is also good for asian leaf miners which we have a problem with for citrus. this stuff works for a lot of different caterpillars or worms.