COCONUT palms (Cocos nucifera) are not susceptible to lethal yellowing disease1 until they are from two to three years old, reckoning from the time they are planted out from the nursery bed. Rare instances are known where palms have become infected at 18 months. No explanation for this unusual phenomenon has been offered, even though it is widely held that the disease is infectious. It presents a serious barrier to the study of the transmission of the disease, since palms 18 months old and older are difficult to grow under controlled conditions.