I have fruit trees, vegetable garden, flowers, native plants and bees (of coarse).
I am using a "complex" approach:
- sometime just relatively strong jet of water from the house washed out aphids and other "soft-body" insects. It works great on roses and other plants, who could stand the pressure of the water. As any "treatment" (not good for treatment-free forum), it needs to be repeated - I would say at least every week.
- soapy water works good too. In extreme case you may add a little bit vegetable oil into warm soapy water and energetically shake it - this will kill even scales, but, probably not good on eatable parts (never tried). Note - this mixture may kill bees - apply in the evening, when bees are at home.
- I usually plant garlic and marigold flowers between other vegetables. Garlic and marigold (probably some others) creates no insects flying zone and therefore protects other plants nearby. I did not notice that it affects honey bees.
- in our area (beach side SoCal) the fungus is a real problem. It is not possible to eliminate it completely, but timely early spring spray with copper solution helps to control it. It is very clear that time of applying solution is critical, but I did not get how to determine this exact time. It looks like, the best time is when plant is just starting kicking up and juices are pushing, buds swelled, but are not opened yet.
- I also find that native plants are beneficial to the garden - my understanding is that they do attract native insects who protects the garden. I do not know how it works, but I noticed that we have much less problems with pests since our native garden has been established. Natives attract also birds, may be they helped as well. Natives also good for bees.
- Ladybugs and other good insects/creatures - of coarse!
- for slugs - Budweiser beer and cover made of small branches of the Christmas tree, which was kept for this occasion.
- ANTS - they create aphid's and scale's plantations on your plants for their own needs. If you want to control aphids, scales etc., you need to control ants!
- some plans are less defensive against pests if deficient in micro-elements such as magnesium, zinc, silica (water-soluble), vanadium, some others.
Sergey