Cleistocactus strausii
The cactus prefers free draining soils, strong sunlight, but not high temperatures — in fact it can withstand hard frosts down to -10 °C. In its natural habitat it receives plenty of water during the summer, but almost none over the winter. In cultivation, watering too much in winter often leads to root rot.
Pitaya
Overwatering or excessive rainfall can cause the flowers to drop and fruit to rot. Also, extended over-watering can cause maturing fruit to split on the branch. Birds can be a nuisance. The bacterium "Xanthomonas campestris" causes the stems to rot. "Dothiorella" fungi can cause brown spots on the fruit, but this is not common. Other fungi known to infect pitaya include "Botryosphaeria dothidea", "Colletotrichum gloesporioides" and "Bipolaris cactivora".