I recently had an interesting experience with liquid compost and am
wondering if anyone has an explaination for it.

On 2 occasions this autumn some roses in the garden were infested with
aphids and thrips (and maybe mites) and what I think is black spot. On both
occasions I sprayed the top and bottom of the leaves with a general liquid
compost (a combination of organic material including seaweed but nothing
made to a specific recipe). Within 1-2 weeks most of the aphids and thrips
were dead or had migrated and the black spot seemed to be less prolific.

I thus deduced either:
a. there was some good biological activity being transferred to the roses
which knocked out the pests
b. I drowned the bugs with enough liquid and the black spot somehow solved
itself or didn't in fact recede
c. the smell of the compost (rank) was enough to drive off the pests

Liquid composts are reputed to be beneficial to plants however I am not sure
whether I am a beneficiary of this or some other plausible explaination.

rob