I have noticed that the beetles are particularly fond of fruit plants, my dwarf peach tree is under attack and certain vegetable plants they seem to destroy, like my sweet corn, also I have noticed them covering a wild grape vine growing nearby. Maybe if you put a plant nearby for them to consume and keep up the sevin dust, they may be more inclined to leave your baby alone! Seems to work for mine, but I had stuff like that nearby anyway. There is a product called milky spore that works really well on dastardly jap beetles.
However this is a natural product that only kills the grub larvae of the beetle, so buzzing beetles will need another method. Milky spore is a mold that feeds on grass roots but does not harm grass in anyway, when the beetle grub which feed in adolescent phase exclusively on grass roots they eat the spores which causes them to basically blow up and explode spreading the spores further. After 4 years, I notice every year the beetle population tends to get smaller around my house, but as I live on lots of land.... they still keep up around the property. Try it, it works, but is a long term solution.
best of luck with the beetle scourge!
were in it together