Attract beneficial insects and other predators to your garden by growing plants rich in nectar and pollen. Bumblebee Margin Mix contains Phacelia, Clover and Borage which are a positive magnet for all sorts of beneficial insects, some, like the bees will pollinate your beans and tomatoes etc and some will devour the aphids, whitefly and thrips which will be waiting until your back is turned to sneak up and feast upon your tender produce. Grow some in your border or on the edge of your vegetable patch.
It is easy to cover brassicas, lettuces and other particularly susceptible varieties with fine insect netting. This light-weight netting will protect vulnerable crops from a whole host of nasties including aphids, carrot root fly, cabbage white butterfly, cutworm, birds and rabbits. It is light enough to lie directly on to the crop but better protection is offered if it is placed over a support. A simple system is to use canes pushed into the ground with an inverted plastic pot over the top of the cane to support the net, pegging the sides into the soil to form a cage. The mesh is re-usable and will last for years.
If you prefer not to cover your crops Biological Controls may be the best approach for you. Aphid Control with Lacewing Larvae is a safe and natural way to help rid your plants of aphids. The larvae will also snack on thrips, red spider mite and mealy bugs and are totally harmless to other wildlife, humans and pets.