Q Is there a way of ridding my lemon tree of scale organically? It keeps coming back!
Kerry Brazier, by email
A BOB SAYS Wiping off the scales is one way, but the difficulty is that you only need miss one for it to multiply. Each scale is a minute sap sucker. When young, they’re tiny and often go unnoticed under leaves.
As they grow larger, their shells harden. From underneath these, white powdery masses of eggs ripen and reinfect your plant. When wiping off scales you might inadvertently help to distribute them, so drench your cloth in soapy water to mop them up. Then remove the top layers of compost on which many will have dropped, and wipe over pots and supports and ties.
Repeat this cleaning regime regularly to stop scale infestations continuing. But be vigilant – scale affects a wide range of plants, so do investigate and clean other plants nearby, particularly any that have become sickly.