A network that helps people worldwide obtain rapid advice and information on crop protection, including the identification and management of plant pests.
PestNet is a network that helps people worldwide obtain rapid advice and information on crop protection, including the identification and management of plant pests. It started in 1999. Anyone with an interest in plant protection is welcome to join. PestNet is free and is moderated, ensuring that messages are confined to plant protection.
November 2014. A large field of melons in northwest Cambodia are showings signs of severe wilt. The sender asked if members had seen such symptoms in SE Asia previously. It was also asked if the water-soaked brown lesion on the leaves might suggest a bacterial disease.
One suggestion was gummy stem blight, a problem in Pohnpei, Federated States of Micronesia, but the symptoms were more a wilt then a collapse of the leaves due to infections.
The images were sent to AVRDC, The World Vegetable Center, and this was the response: it is difficult to diagnose from photos such as this one.
Nevertheless, the following comments are given:
The distribution of symptoms looks so uniform in the field. Most diseases do not have a uniform distribution, unless they are seed-borne or air-borne (including insect transmitted diseases).
The symptoms look like developed at the later stage of the crop (after fruit-setting). This could mean that it takes time for the symptom to develop. Thus, it could be soil-borne diseases. However, they usually do not have uniform distribution.
Another member said that he agreed that it seems that the problem came late in the life of the crop after fruit formation. The lower leaves are not wilting, and the stems appear green and turgid which suggests this is not a root or vascular infection. Do all of the plants across the plot have the lower leaves remaining green or is it only the plants in the rows nearest the camera? What weather conditions have there been recently?