Sunan Abi Dawud, Hadith 3465 ⓘ
Yahya b. Sa'id said: Blight is not effective when less than one-third of goods are damaged. Yayha said: That has been the established practice of Muslims.
حَدَّثَنَا سُلَيْمَانُ بْنُ دَاوُدَ، أَخْبَرَنَا ابْنُ وَهْبٍ، أَخْبَرَنِي عُثْمَانُ بْنُ الْحَكَمِ، عَنْ يَحْيَى بْنِ سَعِيدٍ، أَنَّهُ قَالَ لاَ جَائِحَةَ فِيمَا أُصِيبَ دُونَ ثُلُثِ رَأْسِ الْمَالِ - قَالَ يَحْيَى - وَذَلِكَ فِي سُنَّةِ الْمُسْلِمِينَ .
also referenced under: Hadith 3472 (DarusSalam)