Production of Seed Potatoes in a Hot, Dry Climate

Abstract

AFTER Maldwyn Davies's demonstration1 that low temperatures and high relative humidities were needed to check the flight of the aphids that transmit potato virus diseases, it was widely accepted that these conditions were necessary for growing healthy seed potatoes. The absence of these conditions over most of South Africa, and difficulties in importing seed during the past few years, led to a review of the question, and it has been found beyond reasonable doubt that Davies showed only one side of the picture. Very high temperatures and low relative humidities are as effective as low temperatures and high humidities. At both ends of the scale there is an extreme at which the potato will thrive, but aphids not; it is in intermediate climates that heavy infestations occur.