My pipfruit are in full blossom, which means I need to arm up against the codling moth. I am pretty relaxed in my orchard, with a ‘live and let live’ attitude to most and allowing nature to balance itself out, but codling is the exception. Though we have released several predators in New Zealand, none are prolific enough (yet) in my area to control it, and the codling multiplied and multiplied until there was barely a single apple without the telltale brown hole and rotten core. It was then I declared war.
I tried every folk tale and remedy short of chemicals, and now count the damage in one bucket. My successful strategy? I spray with a biological insecticide at 80% of petal fall. I use one called Madex 3 which contains a natural pathogen of the codling moth. Less specific but more economical for a tree or two, is a caterpillar biocontrol from Kiwicare containing Bacillus thuringiensis, a soil-dwelling bacteria that kills a range of caterpillars, including (although it is not listed on the packet) the codling moth. dose of compost given to each tree. I note what needs pruning, but I won’t prune yet as I don’t want to open any wood up until after the lemon tree borer moth stops flying in late summer. This column is adapted from the weekly e-zine, get growing, from New Zealand Gardener magazine. For gardening advice delivered to your inbox every Friday, sign up for Get Growing at: getgrowing.co.nz