Hi, I put this plant outdoors in the summer as it loves the heat. I recently noticed in the sunlight around it what looked like tiny specs of dust, but then I noticed they moved back and forth like tiny mites. Some of the leaves got brown spots which I’ve removed most of them and sprayed the plant with soapy water. It’s also dropping a lot of oranges, some of which are pictured. Some of the leaves are mottled. Now that it’s wet I can see fine webs on the plant. Is there a particular solution that will get rid of them, or is soapy water treatment ok to continue with?
Thank you for contacting the Toronto Master gardeners concerning your citrus tree.
Orange trees along with lemon trees are susceptible to spider mites. Spider mites look like really tiny spiders – you probably need a magnifying glass to see them. Or shake your plant over some paper and look for tiny moving specks that have fallen out of the plant. Spider mites also suck the sap from a plant. Their initial damage is light coloured spots on the leaves, progressing to yellowing of leaves and leap drop. They also create webbing on the plant. Spraying your plant (not just a mist) with a hose during the summer when it’s outside or placing it in the shower and using a hand held sprayer for four or five days could be enough to knock them off. Make sure that you hose off the underside of leaves.
Alternatively, if you have a serious infestation this may require several applications of insecticidal soap, which is readily available from your local nursery. When using insecticidal soap or horticultural oil (both available from your local nursery) be sure to follow the directions carefully, and spray the undersides of leaves as well.
Spider mites are attracted to plants that are under stress. Your plant might be stressed due to a change in it’s environment. During the summer the plant received full sun and high humidity it currently resides in a home where the light levels are significantly lower with less humidity.
Central heating which makes our homes warm, dry and cozy during the winter can put the citrus tree under a great deal of stress and cause serious leaf drop. During the winter months, your plant needs 4-8 hours of direct sunlight a day and likes temperatures between 60-70 degrees F [16-21 degrees C] (and no drafts). Temperature drops of 5-10 degrees F [3-6 degrees C] at night are fine. If it’s too hot, especially around the roots, the plant may drop its leaves.
Citrus plants like slightly acidic soil. For example, 1/3 sterile potting soil, 1/3 peat moss, 1/3 organic matter would be a good mix when you repot. Make sure the soil drains well – soggy soil could rot the plant’s roots. Allow the soil to dry out between waterings.
Finally, we receive a number of inquires concerning the care of indoor citrus trees. One of our earlier posts entitled:Help me save my indoor lemon tree contains detailed information on soil, fertilizing, insect prevention along with additional reference material which you may find of use.
December 31, 2021