Answer: If you select a hybrid developed specifically with disease resistance in mind, it is likely to be resistant to more types of problems than an heirloom. However, it does need to be resistant to the particular problem you are having in order to help in your situation. If it is a soil borne problem, then it will be diffiuclt to control it in a raised bed. Adding organic matter and compost and maintaining good plant vigor, a careful crop rotation program and meticulous cleanup of diseased plants (including roots) as well as each fall can all help. You might also want to discuss the problem with your county extension to see if they have any suggestions for you.
Slugs can be a problem in raised beds especially because they hide along the edging material. In some cases it can be helpful to disturb that soil around the edges in early spring to expose the overwintering slugs and their offspring to the elements. It may also be helpful to ring the outer edge of the bed with diatomaceous earth (DE) from the garden center to try to limit the number of slugs that reach your plants. Similarly, individual plants or planting areas can be outlined with DE. Repeat after watering or rain to keep the material effective. You might also try the beer baited traps and hand picking them at night.
I hope this gives you some ideas.
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