Ensure any raspberry stock you purchase is disease- and pest-free. Get the stock from a nursery or plant supplier. Old stock often carries bugs and worms with it, because many pests lay their eggs in the raspberry stalk itself.
Remove wild berry brambles from the area. Wild berries frequently carry disease and pests than can pass to garden raspberries. Clearing the area of wild brambles reduces the likelihood of infection of your crop.
Plant raspberries in well-drained soil or on hills so that water drains and does not stagnate. Additionally, keep raspberry plants in hedgerows no wider than 12 to 24 inches to allow the patch adequate sunlight and air movement to easily dry out after a rain or watering.
Trim back old growth in the fall with pruning shears. After the harvest season is over, cutting down old stalks to just an inch or two above the ground removes dead plant material that harbors harmful bugs. Burn the trimmings or remove them from the area.
Pick fruit when it becomes ripe and before it falls to the ground. Overripe fruit left on stalks or the ground attracts picnic beetles which feed on decaying fruit and can damage new fruit ready for harvest.