beneficial nematodes for sweet potato

Hi all,
last year many of my sweet potatoes had tiny worms inside, I think wireworm? They dig tunnels.  I have never used nematodes and dont know when to buy them and apply to the soil since I hear they may not survive in some conditions, I live in central texas where it gets hot and I will plant my slips in may. Do I just water nematodes into the soil?  When?
Any help appreciated.
sophia

I don't have experience with nematodes or wireworms.

I have seen them online for sale.

Here are some threads that you or others might find helpful:

https://permies.com/t/146481/perennial-vegetables/Perennial-root-veg-wireworms

https://permies.com/t/130344/Wireworm-issues

I don't know a lot about this. I work for a Co-op. We kind of sell them.  We have cards we sell. You fill it out, and send it to the company, and they send you the nematodes. I went to a seminar for  work, and they had a representative of this company. It sounds easy and they say it works well. Yes you mix them with water, and spray them in the infected area. I would like to use them for fleas ( probably a different nematodes). The problem is they are pretty expensive.  I do know this company sends detailed instructions. I'm sure you can order them online. I would think there will be reviews.  
Good luck, let us know if you try it, and if it works