Q: Iβm experiencing leaf curling on my mature lemon tree, most notably on the new leaf growth. Most of the new growth is also much larger in leaf size than on the established limbs. This tree flowered wonderfully last month and there is a nice crop of fruit growing. I havenβt found any signs of insects on the leaves but there is a definite veining occurring which I tried to capture on the attached photos. Iβve been deep watering this tree every three to four weeks trying to keep moisture at the 36-inch depth and am fertilizing every three months (first dose at the beginning of February each year). Can you please help me with some of your sharp analysis and provide recommendations for treating?
A: Your citrus leaves are being eaten by tiny insects called citrus thrips (Scirtothrips citri). The females lay their eggs in new leaf tissue and when the young thrips feed, they cause curling, distortion and scaring. They may also lay eggs in and scar the rind of the fruit. The good news is they donβt do enough damage to warrant any concern unless you own an orchard and want to sell the fruit to a grocery store. The leaves are still photosynthesizing despite their contorted appearance and the fruit are as numerous and tasty as the ones you buy at the grocery store without any scars.
Peter L. Warren is the Forest Health Program Coordinator for the Arizona Department of Forestry and Fire Management. Questions, photos and videos may be emailed toΒ tucsongardensage@gmail.com
