Not sure what is wrong with my lettuce

Question: I a m growing different types of lettuce in a greenhouse. I am noticing black dots and scratching marks on some leaves. I have been able to harvest some leaves for now most of my leaves are being affected. I have sent pictures but not sure what it is, how to get rid of it.

responder: An Ask Extension Expert Replied June 15, 2024, 8:08 AM EDT
response: Hi Jonette, thanks for the question. This is most likely thrip damage.  The dark spots would be frass.  These guys are pretty small. Check out the following links: Guidelines for Managing Western Flower Thrips in California Lettuce - Salinas Valley Agriculture - ANR Blogs (ucanr.edu) High Tunnel Management - Thrips | USU I hope this helps.

responder: The Question Asker Replied June 15, 2024, 8:18 AM EDT
response: Is this something that I can get rid of or should I pull the plants? Thanks Jonette  On Sat, Jun 15, 2024, 8:08 AM Ask Extension <<personal data hidden>> wrote:

responder: An Ask Extension Expert Replied June 16, 2024, 7:11 PM EDT
response: Hi again, Managing/controlling thrips could be challenging, if the infestation is high, pulling the plants could be a good option to reduce the population.  If there are parts of the plants that are salvageable, then you may want to treat the plants. Another consideration is that the thrips may migrate to other plants.

responder: The Question Asker Replied June 17, 2024, 7:48 AM EDT
response: Thank you again for your help but ot looks like I have another issue if you don't mind. I did some ph readings and my beds are ranging from low to mid 4.0 to low to mid 5.0. I put these plant in on 5-3 so they are somewhat established plants. I know either lime or baking soda can increase the oh, but how do I apply this without damaging any of my plants or should I just wait until next season before I plant.  On Sun, Jun 16, 2024, 7:12 PM Ask Extension <<personal data hidden>> wrote:

responder: An Ask Extension Expert Replied June 17, 2024, 8:54 AM EDT
response: Hi Jonette, With pH ranging that low, one would expect the plants would show some severe signs of nutrient disorders. If you are not seeing any problems with these plants, those pH readings could be suspect.  A couple of questions - What plants are in these beds?  How are you measuring pH (type of meter)?

responder: The Question Asker Replied June 17, 2024, 9:27 AM EDT
response: I have grape & beef steak tomatoes, variety of lettuce, peppers, onion & green onion. I am using a meter you stick in the ground. My reading this morning are 4.1 - 5.3, depending on the bed I am testing. I have peppers growing but they are not getting tall and have been the same size for weeks. I fertilize every 3-4 weeks with a 10-10-10 fertilizer. I have the thrip & tipburn on the lettuce and have just notice what I think is septoria leaf spot on my tomato leaves. Both have been treated with Bon-Neem spray. I do have tomatoes growing too. If you would rather talk I can be reached at<personal data hidden>. Thanks.  On Mon, Jun 17, 2024, 8:54 AM Ask Extension <<personal data hidden>> wrote:

responder: An Ask Extension Expert Replied June 17, 2024, 7:42 PM EDT
response: Hi, There are few plants that will grow well in soils with a pH in that range.  Blueberries and azaleas are two that like the acidic soil.  Although home meters usually can give you a ballpark pH, I would strongly suggest you get a professional soil test (you can order one here: Home | MSU Soil Test).  Sampling should come from several spots in your bed and mixed together.  More reasons for soil testing - Agriculture (msu.edu)