Peter James writes
Does anyone on this NG have an effective control of whitefly and aphids
on sweet peppers. My plants are crawling with the wrtetched things, and
it seems that a lot of the aphids/whitefly are tolerant of a lot of the
control sprays and chemical treatments.

Whitefly - you can reduce a great deal by vacuum cleaning - use the
small brush that you'd use for delicate things so you don't damage the
leaves. Biological control - Encarsia - widely available.
--
Kay