Lemno tree problem

Question: All,

Our lemon tree suddenly started to show these leave problems. Do you know what it is and how to treat it?

Henri

responder: Kevin K.  Replied June 13, 2023, 6:03 PM EDT
response: Hello Henri, Thank you for your inquiry to "Ask Extension". We know it can be very frustrating to have to answer more questions, but... it would be really helpful to have a bit more information as we work to figure out what is wrong with your lemon tree! A lot of very different problems can cause signs that look alike. How long have you had the tree? Have you had this problem in the past? Do you see any signs of insects on your tree, especially on the affected leaves? We can see a big insect on a healthy leaf in the image you sent, but we're wondering about little ones that feed by puncturing the leaves. Can you send us a photograph of the backside of one of the affected leaves?  If you could also send along an image of the whole tree that shows where the affected leaves are on the tree, that would be very helpful as well. Thank you very much! Deb K & Jennifer G

responder: The Question Asker Replied June 13, 2023, 7:33 PM EDT
response: Hi all, Thanks for the response. No problem with questions!   We had this tree about ten years, never an issue before. Produces good limes.  I attached a picture of the whole tree (tree3), and one leave at both sides (tree1,2). I did see an insect (tree4) and some punctures and spots (tree5). Happy to take more pictures when needed!  Henri  On 6/13/2023 3:03 PM, Ask Extension wrote:

responder: Kevin K.  Replied June 15, 2023, 11:13 AM EDT
response: Hi Henri,  Thanks for the additional pictures. Lemons and limes can be a challenge to grow in our climate, congratulations for keeping yours healthy and producing for 10 years! I can not give you a definite diagnoses with the pictures only, but I can give you some possibilities and options   The tree might have been stressed this spring from irregular watering or from getting too hot or too cold, or damaged while being moved outdoors. The stress made the tree more susceptible to insects and or diseases. Another possibility is that there has been a build up of salts over time from fertilizing.  Here are my recommendations:  1.Water until water comes out the drain holes to flush possible fertilizer salt build up.   2. Remove and destroy all yellowing leaves (including the ones that have dropped to the ground or into the pot). Look for and prune out tree branches and twigs that have dark lesions.   3.The insect in the provided picture is a predatory bug which would indicate the presence of aphid, thrip or scale. I don't see any insects on the leaves in the pictures, but the resolution may not be high enough for that kind of detail. Keep a look out for small insects or bumps on the leaves. Check the underside of the leaf with a magnifying glass. If you see some scrape them off with your fingers or spray them off with a stream of water   4. Contact us if problems persist or worsen.  Or for more information now, Bring a small branch that has both healthy and necrotic leaves to the extension office where we can take a closer look. Wrap the cut end with a wet paper towel and put in a plastic bag.  The Master Gardener help desk is located in the Benton County extension office (Sunset Building). The office is open Monday - Friday 8am - 5pm. (Closed federal holidays)  Benton County 4077 SW Research Way Corvallis, OR 97333<personal data hidden> <personal data hidden> Happy Gardening! Deb K & Jennifer G

responder: The Question Asker Replied June 15, 2023, 3:09 PM EDT
response: Thanks! We will try these approaches.  On 6/15/2023 8:13 AM, Ask Extension wrote: