Hello, I’ve got a large old lemon tree that I want to prune back extensively. When is the best time to do this? It also gets severely effected by guava moth. What should I do to prevent this next year?

Hi David

Generally lemon trees do not require pruning unless they are getting too large or are misshapen. The best time to prune your lemons is early summer - avoid pruning in winter and in September/October as you run the risk of lemon borer laying eggs in fresh cuts. 

You can prune when your tree has finished fruiting but only in frost free regions. If you are in a frost prone area delay pruning as the soft new growth that regrows after pruning could get frosted and knock the tree back. 

Guava moth unfortunately can be a problem with lemons. At present no completely effective treatments exist. Guava moths lay their eggs on the fruit and the larva burrows into the fruit. It is very hard to treat once the plant is affected and is a big problem in warmer regions. Prevention is the best method of control. Cover your trees with fine netting immediately after flowering (when the petals have fallen) to protect the fruit. Secure with tape to the supporting branch. Remove fallen and rotting fruit, and dead leaves and mulch from under the tree as often the moths lay eggs in these areas.

Guava moth pheromone delta traps with sticky bases are available from garden centres and rural suppliers.

Thanks, Tui Team