Hi, my oranges are being stung and falling off the tree. Each orange has a light coloured spot on the skin with a sting mark in the middle. Cut open reveals a blackish spot about the size of a match head in the pulp. Which insect is causing this? Thanks.

Hi Tim, without a photo it is hard to say for sure what is affecting your fruit on your orange tree, it could possibly be guava moth larvae. Guava moth are a recent introduction to New Zealand and cause tiny pin-prick holes in fruit, the larvae causes the inside of the fruit to rot and it is inedible. Unlike other insect pests such as codling moth, guava moth are active year round as they move from host to host, one host they over winter on is Eugenia or lilly pilly tree. Guava moth are hard to control due to the caterpillar being inside the fruit. Collect up fallen fruit and dispose of in the rubbish or burn, some gardeners are freezing fallen infected fruit before disposing of to ensure the caterpillar is no longer alive. There are pheromone traps that can be hung in the trees to attract the male to help break the lifecycle, they are available from garden centres and hardware stores.