General Purpose spray for Fruit trees?

Hi everyone
I was wondering if anyone on here can advise of a spray for fuit trees that covers most pests and most types of tree.

Both my son and I have fairly new trees (his planted last year) and ours this year. They are all growing well and he has quite a bit of fruit this year - apples, cherries & plums. Ours wont do anything until next year but we also have apples, cherry, plum & pear trees.

Both lots are suffering from a variety of pests and the leaves on his apple tree are looking very sick indeed. All curled up and dead. I took all the green fly off every time I watered and thought I had managed to beat them but now are trees are also looking poorly.

When looking up the conditions on the web you are bombarded with a variety of pests & diseases and potential cures which as total amateurs trying to be organic is bewildering.

Is there such a thing as a 'general purpose' spray which would help our trees to survive and can we use it now or is it too late as we go into August?

Any help much appreciated.

MA.