No guarantees, but...
Fleas & Ticks:
Cedar is a natural repellent for fleas: Scatter cedar shavings inside the "dog house" if you have one. Or, fill a dog bed with them. The kind they sell in the pet stores work fine.
Flea & Tick Spray: Combine ingredients in a spray bottle: 1/4 C Witch Hazel, 1/4 C Aloe Vera Juice, 10 drops of Lavender and Lemon Oils, 20 drops Cedar Oil. Do not spray this on the dogs face, avoid getting it into their eyes.
Homemade Flea Bath: Mix 1/4 C White Vinegar, 1/4 C Dawn Dish soap, and 1/2 C water. Lather up dog with solution (avoid face, eyes, ears, mouth, nose). Wait 5 minutes. Rinse thoroughly. Dry pup well.
Heart worms are passed to the dog by mosquitoes who have bitten an infected dog. This concern is less prevalent in NY than in other eastern locations. It may be a concern if you are traveling south during the summer months. Mosquitoes require a mere tablespoon of water to breed, but the cold winter months tends to kill off the mosquito population. I do not know of anything that would be effective in preventing mosquitoes from biting an animal. Being a coastal NC resident, I swear by Avon's Skin So Soft spray. I do not know if this is safe to use on an animal.