Green gardening and chemicals do not mix.

In the past 50 years we have been in a state of chemical heavy gardening, being constantly bombarded with new sophisticated chemical weapons. Every gardening website and magazine advertise chemical sprays for just about any pest you can think of, there is an unlimited amount of substances that eradicate pest full stop. There are also multipurpose, all-in-one killer sprays. There are weed-killing chemicals that are plant specific and potions to combat fungal disease.
 
It takes great mental strength to stop using these chemicals as they do turn your garden into a wildlife (and pest) free place with perfect flowers and green green grass. It is especially hard to resist grabbing your insect killer when pests go on the offensive. But if you keep spraying and killing, you will never solve the problem.
 
What you are actually doing is making the situation worse and sometimes irreversible, whilst spending large chunks of money on all manner of plastic-bottled chemicals.

Your garden is a habitat, it was before you were there and it will be after you have gone. It is an amazing mix of interdependent, symbiotic organisms. Biota living side by side in perfect balance. You have to conserve this balance not blow it up with chemical warfare on pests. You have to start thinking of the bigger picture if you want to become a gardener who is at one with nature. A wildlife gardener, a green gardener. You will have to realise how your contribution to the garden habitat  can effect all manner of insects, animals and plants.
 
If you think of a food chain where smaller creatures are eaten by larger creatures then that is how it works in your garden. Small insects like aphids feed larger insects like ladybirds. They then feed a bird like a Thrush. If you can grasp this is the garden then you will learn how to encourage insects into the garden not repel them.
 
Looking at the bottom links of the food chain can help you to understand how to best cater your garden to suit all wildlife. Looking at aphids. If you grow sweet peas, make sure you do not spray them with chemicals, instead make sure your garden has many places for aphid predators to live and breed. Aphid problem sorted!
 
Spraying chemicals is the worst possible corse of action you can take as a responsible gardener. Every bug you kill is food for another organism, once that pest is killed you are, in effect, wiping out the natural predator of the pest.  Even worse still, if you spray pests so much over time they will build of a resistance to that chemical. Then once it is not effective you will have killed all the pests natural predators and be left with a useless chemical that no longer works. Then you are in the worst situation, a pest resurgence.
 
Pests usually breed much quicker than their predator so when a pest predator is killed, the pests will multiply and ruin your garden further. Chemicals are not the answer at all.
 
If you put down the all-in-one spray, grit your teeth and let the pests attack you will be rewarded. Within a few days the predators will move in, killing hundreds of pests an hour. Think of it as delegating or outsourcing your garden pest control back to nature.  
 
Another problem with chemical killers is that they can remain poisonous in the carcass of the pest. Wildlife that you would normally welcome into your garden could be put at risk for example, by chemical Slug Pellets that remain poisonous in a dead slug or snail. They can poison BIrds, Hedgehogs and even Dogs!