Ridge gourd leaves - spotted and dying

Question: Hello.  I grow hydroponically in a greenhouse.  I have a  ridge gourd plant.  It started fine but now the leaves are getting spots, discolouration and drying.  I was wondering if it is because I had sprayed them with neem oil but I don't think that is it. They are under a white grow light for 5-6 hours daily.  The other plants (two bottle gourd) and two dill plants are doing fine.  They are separated, fans are operating all the time, and temperature of 68 degrees.  The plants are growing in perlite in a bato bucket.  Photos attached. Thank you very much.
We live in Hopkins/Minnetonka.

responder: MJ Replied April 28, 2024, 6:52 PM EDT
response: Hi, Why did you spray the plants with neem oil? Did you spray all the plants, or just the ridge gourds that are showing damage?

responder: The Question Asker Replied April 28, 2024, 8:28 PM EDT
response: Thank you for responding.  Yes, I sprayed all the leaves of all the plants because the Malabar spinach had red spots.I treated all the Malabar spinach plants growing in towers with the neem oil and that seems to have workedI then sprayed the two bottle gourd plants and the one ridge gourd plant.All the plants except the ridge gourd are fine.I am ar<personal data hidden> if you prefer to talk.Thank you very much. Ajay Gupta  From:ask=<personal data hidden> <ask=<personal data hidden>> On Behalf Of Ask ExtensionSent: Sunday, April 28, 2024 5:52 PMTo: Ajay Gupta <<personal data hidden>>Subject: Re: Ridge gourd leaves - spotted and dying (#0136118)

responder: MJ Replied April 28, 2024, 9:11 PM EDT
response: Thanks for the additional information, Ajay. I suspect the ridge gourd has been burned by the neem oil and is more sensitive to the spray than your other plants.  From the University of New Hampshire: "Regardless of the type of plant being treated, neem oil can damage plants by burning their foliage. Do not use on recent transplants or otherwise stressed plants. Though plants must be completely covered with neem oil for the pesticide to be effective, it is a good idea to test the product on a small area first. If no toxicity symptoms occur in that spot, then the entire plant can be treated." Here's the entire fact sheet: https://extension.unh.edu/blog/2020/01/what-should-neem-be-used-plants Check the packaging to make sure the neem oil doesn't need to be diluted. It should be applied every seven to 10 days. Don't use it more often than that. I hope this helps. Thanks!

responder: The Question Asker Replied April 29, 2024, 7:32 AM EDT
response: Hello.  Thank you for being so responsive and helpful.I too thought the leaves were burnt and so I stopped using the neem oil on the ridge gourd plant and turned off the grow lights.Before I sprayed the neem oil on the leaves, the edges of the leaves were red and some necrosis was visible.I will send you photos of the leaves if I see further issues.I am also monitoring the pH and the nutrition level in the water. With best wishes and thanks.Ajay Gupta   From: ask=<personal data hidden> <ask=<personal data hidden>> On Behalf Of Ask ExtensionSent: Sunday, April 28, 2024 8:11 PMTo: Ajay Gupta <<personal data hidden>>Subject: Re: Ridge gourd leaves - spotted and dying (#0136118)

responder: MJ Replied April 29, 2024, 10:35 AM EDT
response: Your plan sounds good. Hope it works!

responder: The Question Asker Replied April 29, 2024, 10:44 AM EDT
response: I will keep you posted. I appreciate how responsive you have been.If you are interested in looking at an all-weather hydroponic greenhouse, let me know.  Ajay Gupta From: ask=<personal data hidden> <ask=<personal data hidden>> On Behalf Of Ask ExtensionSent: Monday, April 29, 2024 9:35 AMTo: Ajay Gupta <<personal data hidden>>Subject: Re: Ridge gourd leaves - spotted and dying (#0136118)

responder: MJ Replied April 29, 2024, 10:54 AM EDT
response: Thanks!