Although there are no strict rules, some of the names of fruits are commonly written in katakana.
Click link to hear the pronunciation.
fruits
kudamono
果物
apricot
anzu
杏
banana
banana
バナナ
grapes
budou
ぶどう
strawberry
ichigo
いちご
fig
ichijiku
いちじく
persimmon
kaki
柿
melon
meron
メロン
Japanese orange
mikan
みかん
peach
momo
桃
pear
nashi
なし
orange
orenji
オレンジ
lemon
remon
レモン
apple
ringo
りんご
cherry
sakuranbo
さくらんぼ
watermelon
suika
スイカ
plum
ume
梅
