Puppy eating fallen loquat tree fruit, HELP!

Hey everyone, I have had my 3 month shep-pit puppy for about a week now and im growing concerned because of the loquat tree in my backyard. I rent a townhome with a quaint backyard and a loquat tree that covers at least half of the yard. The fruit fall from the tree constantly and my puppy will not stop finding them and eating them. Through research I’ve learned that the fruit itself is okay for consumption but the seeds are toxic… I have tried holding the sides of his mouth and making him spit them out but I’m struggling to catch him every time as the fruit are small and hidden in the grass… I have also checked his potty multiple times and i keep seeing the seeds in his poo so he is passing them. Overall, I’m not sure if it’s possible for me to stop him due to the amount of the yard this tree covers/drops fruit and because I’m renting but any ideas on how to train against or prevent him from eating these would be helpful!! I have a vet appointment In two weeks to discuss health concerns but training wise, I’m not sure how to stop him!