Macadamia Tree Health Initiative Act of 2017 This bill amends the Food, Agriculture, Conservation, and Trade Act of 1990 to authorize the Department of Agriculture to provide competitive research and extension grants for a macadamia tree health initiative to: (1) develop and disseminate science-based tools and treatments to combat the insect known as the macadamia felted coccid (Eriococcus ironsidei); and (2) establish an area-wide integrated pest management program in areas affected, or at risk of being affected by, the insect.