Garlic has strong anti fungal properties and is effective against many issues that plague fruit trees. Planted near the base of apple trees, garlic protects against apple scab. Planted near the base of peach trees it protects from leaf curls.
Many of the same issues that affect Apples and Peaches also hamper pear and cherry trees so naturally garlic is helpful to them as well.
It also has properties that help repel many insects, borers are a major problem with some fruit trees, garlic repels them. It is a natural organic pest control. It doesn’t kill the insects, it just keeps them away. Garlic is a cost effective and fairly simple garden hack for pest control.
In addition to borers Garlic helps ward off aphids, flea beetle, Japanese beetle, fungus gnats, codling moths, cabbage loopers, ants, snails and spider mites. There is also some proof that it deters mammalian herbivores such as rabbits and deer.
Grapes – While garlic will benefit the grapes in the area of pest and fungus suppression there is some evidence that planted too close to the grapes it may actually impede their growth. They can still be planted at a safe distance, I would just avoid having them so close that they are drinking out of the same trough.
Blueberries – Garlic grown near blueberries can benefit the blueberries in the area of pest and fugal suppression. It also helps condition the soil for the unusual requirements of blueberry plants.
Raspberries Benefit from being planted with garlic for the same reasons as other fruits, an added plus is that raspberries are preyed upon by Japanese Beetles which garlic helps to repel.