Hello my fellow grower. Well I will try my bestest,lol. Remember there is beneficial nematodes. I was freaking out in my DWC because I was seeing crazy things . What will help is if you study about the Rhizosphere. It's like the area all around roots. Where all the microbial stuff goes down.Are job as growers is to try and make the root area as much as possible like soil. In my book it says nematodes are microscopic round worms that live in grow media or soil. Find out if u have good or bad. If they bad there is a fungus called myrothecium verrucaria . It's a fungus. I AWSOME book I got is called what's wrong with my marijuana. See if u can find it on line because it has a lot of stuff about nematodes. One more thing the oil is just from your Neem,not a bad thing unless you much. Some people put Neem in feeding schedule. I use it spraying once a week,if see love bugs soap water kills faster then Neem. Remember preventative is better that's what Neem does best. Neem is not a fast kill on contact,it's a preventative. Well my fellow Grower blessings on all u grow. I hope my special Ed self helped!