This just started, the yellow leaf in the picture took only a few days to go completely this colour! I've taken the plant out of the pot and it looks good, slightly moist and no evidence of pests or disease. Can you diagnose the cause of this, please? I've attached pictures of good leaves and the problem ones and, by the way, new leaves are coming on! Thank you, Murray
Murray, is that plant in full sun? You might want to move this thread to the Aroid section, where you will get some expert advice
The specimen in your photo appears to be a hybrid known as Alocasia Amazonica. Depending on the source, the hybrid was created by crossing Alocasia watsoniana x Alocasia sanderiana while another source indicates the parentage to be Alocasia watsoniana x Alocasia noblis. Alocasia Amazonica is often confused with Alocasia micholitziana (mik-oh-lit-zee-AY-nuh) which is often sold commercially with the trade name Alocasia 'Frydek'. Even though some websites claim Alocasia Amazonica is difficult to grow, in fact it is quite easy. The trick is you must provide the plant the conditions it requires. This plant specimen will not do well as a "house plant" on the interior of the home unless it is receiving at least moderately bright light. You also cannot forget to water the plant on a regular basis. This is a hybrid of rain forest specimens and requires damp (not muddy) conditions to prosper. However, like many Alocasia sp., if planted out doors Alocasia Amazonica will often go dormant when the temperatures drop much below 12.75C (55 degrees F) and you may not see it for some months until spring and warmer weather returns. In most cases the specimen will grow again once the temperatures rise and stabilize again. But this specimen will not tolerate a freeze! Recent reports from knowledgeable growers indicates the true parent species are often found growing in very bright light, almost direct sunlight. If grown in too low light the Alocasia often looses much of its green color on the upper surface of the leaf and becomes almost black. In low room light, especially without water, the specimen is likely to simply droop, loose the color, and die a slow death. However, it will grow well in medium filtered light. As a house plant, keep it near a bright window. If you wish to grow Alocasia Amazonica in direct, or near direct sunlight, this plant can require a great deal of water. However full sun may not be advisable in some areas where the summer sun is extremely hot
