We generally don't experience many pest problems, however we do keep an eye out when the Cabbage White butterflies are in flight.
Pieris brassicae - Cabbage White
Pieris brassicae - the large white, also called cabbage butterfly or cabbage white have been flying since early June - always a clear signal to watch out for their eggs on the underside of our Brassica crops which this year include Kale, Borecole and Kohlrabi. One adult female can lay up to 600 eggs and a small batch of the larva (20-30) can obliterate a 40 x 20 cm leaf in a few days so this is one potential pest we pay careful attention to.
Large White - Pieris brassicae eggs and new hatched larvae on underside of Kohlrabi leaf
We grow our crops in polycultures and one advantage of this is that it's more difficult for the butterflies to locate our crops among the other crops and they spend more time in flight where that are more likely to be caught by one of the many birds that use the garden as a feeding ground. Some butterflies do manage to mate and lay eggs so we check the underside of leaves every 4-7 days. If we fail to remove the eggs and the larvae emerge they need to travel around various other plants before they can locate another brassica food plant and are again more likely to to be located by the teams of pest predators we work with on the site i.e birds, frogs, toads, ground beetles, predatory wasps etc.
Our Permaculture Market Garden Polycultures
The cabbage white butterfly is second only to slugs as my major pests in the garden.
Picking off manually just about keeps them under control - but I really need to get some netting on next year.
Having perches for birds and tree cover around the garden seems to encourage birds in our garden. Shrikes and Flycathchers hunt the cabbage whites all day long this time of year to feed their young.