Keep monitoring the slug population – June is prime time for them and they can decimate a crop overnight! Brassicas, Lettuce and other particularly susceptible varieties can be covered with Extra Fine Insect Netting which will protect your vulnerable crops from a whole host of nasties including whitefly, aphids, carrot root fly, cabbage white butterfly, cutworm, birds and rabbits. It can lie directly on to the crop but better protection is offered if it is placed over a support. The mesh is re-usable and will last for years.
Biological Controls are very effective, Nemaslug consists of millions of tiny nematodes – microscopic worms which kill slugs above and below ground. You just water in and they are completely harmless to birds, animals and children. Nemasys has the same effect on the larvae of Vine Weevil – the scourge of the container gardener! Drench the compost with the Nematode solution and you will have protection until autumn. An autumn drench will destroy all larvae that hatched during summer.
Butterflies will be out and about now too, they may be pretty to look at but keep an eye out for the eggs on the undersides of your brassica leaves, that will quickly emerge as caterpillars and devastate the plant! You can squash them (not a very nice job!) or wipe them off at this stage. The simplest thing is to cover the plants with Insect Netting or alternatively try Nemasys Grow Your Own Pest Control which is a unique mix of different nematode species which targets a broad range of pests. Especially for the home gardener, it has been specifically researched to combat caterpillars, carrot root fly, cabbage root fly, leatherjackets, cutworms, onion fly, ants, sciarid fly, gooseberry sawfly, thrips, and codling moth.