In his attempt to warn Ophelia about Hamlet’s intentions, Laertes alludes to two common Elizabethan proverbs:

• “Envy shoots at the fairest mark,” meaning jealousy is always aimed at what’s most attractive. In this case, Ophelia’s virtue makes a good target for the “calumnious strokes” or rude remarks of others.
• “The canker soonest eats the fairest rose.” The canker worm is a pest that attacks plants. As this proverb suggests, it’s the most beautiful plants that get eaten first. In this case, Laertes tweaks the proverb to remind Ophelia that her youth makes her vulnerable.

Ophelia, painted by John William Waterhouse, c. 1894