JERUSALEM (JTA) — Israel’s unusually extreme summer heat has seriously damaged this year’s etrog crop, growers say.

Strong heat and winds caused many more of the fruit, one of the four species required for the Sukkot holiday starting Wednesday night, to fall off trees prematurely, a grower told Haaretz.

In addition, while in most years 10 percent of the harvest is designated of highest quality, this year only 1 percent received the designation, another grower told Haaretz.

Israel’s 15 large-scale etrog growers and numerous small-scale ones produce about 1.5 million of the citron fruits each year, of which 300,000 are exported.