1,206. What Renders the Four Species Invalid

Hilchos Shofar, Succah v’Lulav 8:1

Each of the four species is invalid if: it has dried out; it was stolen – even after the rightful owner has given up hope of it being returned; it came from an idolatrous asheira tree, even after its idolatrous worship has been nullified; it came from a city condemned for idolatry. If one of the four species belonged to an idolator, one should not take it for the mitzvah. After the fact, if one did so, he has fulfilled his obligation. If one of the four species is wilting but it has not yet dried out completely, it is still valid. In extenuating circumstances or times of danger, a dried-out lulav may be used but this is not the case with the other species.

Hilchos Shofar, Succah v’Lulav 8:2

An esrog that comes from orlah (produce of the first three years), ritually-impure terumah or untithed produce (tevel) is unfit for use. An esrog from doubtfully-tithed produce (demai) is permitted because one could conceivably declare his property ownerless. This would render him a needy person, enabling him to eat demai. An esrog that comes from ritually-clean terumah or from second tithe in Jerusalem should not be taken out of concern that one might render it susceptible to ritual impurity. After the fact, if one took it, it is valid.