Personally, I translated this to "The yellow fruit are tasty." The word 'fruit' can be either a countable or uncountable noun; therefore, I believe that it's acceptable without an 's.' I know what you mean, Marbleox, however, it is perfectly fine to think of 'fruit' as plural. Are there any other thoughts on this?
In general use (including here) "fruit" is uncountable, and so used with a singular verb. And we wouldn't say, for example, "those fruit", but "that fruit".
On the rare occasions when it is countable, it takes the normal plural form with an "s":
"They grow mainly citrus fruits"
I don't wish to argue but fruit is one of 'those' words. You would say (that e.g. ::you are going to eat apples, pears and bananas): I am going to have or eat some fruit. In English that could never be fruitS. I've had this discussion with a few anglophones, some of them linguists, and while you can say 'fruits of the forest' for example, the kind that you eat or buy or talk about collectively, although a plural noun, is singular, and you would not say 'he is a fruits farmer, even though there could be many different fruit involved. Could this be our revenge on all those brain busting Polish complications of plurals and genders? I wonder ...and then you have 'pair'...one pair is two items...but is singular; but you can have two pairs etc. and NEVER two pair, as is often incorrectly used. Duh... Nor would I say 'they grow mainly citrus fruits' but would say 'fruit' because by implication of citrus it is plural, as citrus implies lemons, oranges, grapefruit (no S there in grapefruit, either) etc. I am not learned or an academic but this sort of exception is drummed into us from a very young age and is instinctive.
In English the most likely translation of this would be "Yellow fruit is delicious / good". If you go for "yellow fruits are", the plural means you must be talking about multiple varieties of yellow fruit but while technically correct, this is less natural / common. "Yummy" is a more childlike word tham delicious and we wouldnt very often use "tasty" for fruit, it is more commonly used for savoury items