Possible Clues:

• Citrus fruit essential when climbing
• Mandarin tests? I don't know answer!
• Fruit that's a necessity when up?
• Fruit may see small areas full of mould returning
• Christmas fruit?
• School tests, I'm thinking, are in Mandarin
• Fruit, it's a necessity when retired
• Perched adult will consume whole grub in segments
• Food devoured by hippopotamus tastes revolting
• Fruit is a necessity when growing up