White flies have a two year predator prey cycle. This is the second year of their cycle here. They were very bad last year and while they are still around this year and have pretty much peak numbers now, it is still better than last year.
They are extremely pesticide resistant. A product of how to build a better bug.
They are ultimately controlled by their predators. The best one here is an imported purple lady bug. Believe me everyone laughed when the state Ag dept decided to release a total of 9 ladybugs to control millions of white flies. There were even jokes about the fat lady bugs, but they multiplied and naturalized and they work. They aren't as nice as the nine spotted ladybugs though, these guys bite.
The white fly population rises more lady bugs are born to eat the white flies. When the population of ladybugs starts to exceed the supply of white fly food, the lady bug population declines and the white fly slowly recovers and the cycle begins a gain.
That is why, I choose to use water and cut back the common hosts rather than spray. I grow corn, because I like to eat corn but also because corn is the best attractor I know of for the purple ladybugs at least in my yard. The state does not allow the import of predators here, not even beneficial nematodes. Besides, ladybugs follow the food. Even if you buy them, they will only hang around if they have water, habitat and food.
I limit spraying so as not to kill beneficial insects and especially the predatory mites and parasitic wasps, and hover flies.
I will have to use bait for slugs and snails because I don't have a toad, not that I really want one. I do have to fungicide but I try to select cultivars with disease resistance whenever possible.
It is probably why I don't have as much of a problem with white flies. I know which plants are the preferred hosts and I check them for the first signs of problems. I cut back the host plants if they can take it and use water on light infestations. I let the predators take care of the rest and I try not to kill them.
Happy gardening in Hawaii. Gardens are where people grow.