Hi Tui, why is the new growth on some of my newly planted citrus (mandarin trees) yellow and stunted whereas others are fine? Thanks.

Hi William, it looks like insect damage and likely to have sucking insects attacking the new growth, these could be scale insect, white fly or aphids. You can spray with a pyrethrum based insecticide which has a low toxicity, but cannot be sprayed while plants are flowering as it is toxic to bees, or spray in the early morning or late afternoon when bees are not foraging. Alternatively, a botanical plant spraying oil is also affective, this is safe for foraging bees and other beneficial insects, talk to your local garden centre or DIY store for a suitable control. Repeat sprays may be required to break the life cycle of these insects. Make sure your citrus is well watered, fertilise in early spring and again in late summer, early autumn with a specially blended citrus food such as Tui Citrus Food. Mulch around the tree to help conserve soil moisture and keep it actively growing during the growing season. Apply Tui Organic Seaweed Plant Tonic, or, even better, Seaweed & Fish. Seaweed is a good tonic to stimulate growth and also helps protect plants from pests and diseases. The Tui Team.