Insects are not kosher so some plant products can contain too many insects to be kosher or require careful washing and inspection to be kosher. Figs contain wasps and need to be inspected and the wasps removed before they can be consumed. Fresh strawberries with stems have a lot of tiny insects on them that need to be washed away before consumption.

Products derived from grapes have special rules as well. https://www.kosher.com/learn/about-kosher-laws/kosher-wine-a...