Most years we get some whitefly on the allotment but this year there seems to have been a plague of biblical proportions. Every plot seems to have been affected and they are not just going for the usual suspects - brassicas but seem to be attacking anything that is green - even my courgettes have been affected. I understand that the whitefly can also spread diseases from plant to plant. I know that some people on the allotment have tried spraying with propriatory insectacides that are supposed to effective on them but without success. Has anyone else had a similar problem this year - if so any tips/advice as to how to deal with them? We could of cause wait and hope for a cold winter - but last year we got down to -18 and they survived!