Crop: Apple Why is it a problem? Tree lichens are common in all apple orchards. They are only a problem if allowed to cover branches and young shoots. In severe cases they cause drying of branches and reduce growth and fruiting. This normally only occurs in poorly managed orchards and …
Thanatephorus cucumeris (or Rhizoctonia solani) Crop: Rice Why is it a problem? This fungus can kill rice plants, or result in greatly reduced yields. Patches of dying rice can be very noticeable. However, the disease normally does not spread fast, and at present it is not a cause for …
Pyricularia oryzae Crop: Rice Why is it a problem? Severe epidemics of this fungus have resulted in large scale losses, including total loss by some farmers. However, it may not be as severe after widespread adoption of more resistant rice varieties following the epidemics during the 1990s. Where and …
Alternaria solani Crop: Potato. It has also been reported on tomato Why is it a problem? Early blight is a fungus that, looks like late blight, can defoliate and even destroy unprotected potato crops. However, treatment is not often required. Where and when is it a problem? Early blight co-occurs …
Potato Leaf Roll Virus (PLRV) and Mosaic Viruses (PVX and PVY) Crop: Potato Why is it a problem? Several potato viruses have been reported in Bhutan. Serious PLRV infections can greatly reduce yields, but can normally be easily avoided through good management practices, especially seed potato renewal and hygiene practices. …
Phytophthora infestans Crops:Potato and Tomato Why is it a problem? Late blight is the most important disease of potato in Bhutan. The pathogen is capable of destroying an entire unprotected potato crop within one to two weeks under the right weather conditions. Losses can be largely avoided through intensive management, …
Alternaria mali or Gloeodes pomigena Crop: Apple Why is it a problem? As the name suggests, premature leaf fall (PLF) disease of apple results in defoliation of parts or entire trees while apples are still developing. On rare occasions, it can also infect apples which become black by harvest …
Venturia inaequalis Crop: Apple Why is it a problem? The major economic loss through apple scab is the substantial reduction in fruit quality of scabbed apples. Considerable management, including the use of fungicide, is needed to prevent loss of fruit quality (“improve apple colour”) in susceptible areas. More severe …
Candidatus Liberibacter asiaticus Crop: Citrus Why is it problem? Huanglongbing (HLB), is one of the most devastating citrus diseases globally. There is no known cure for the disease. It probably entered Bhutan in the 1960s and has become the most serious threat to citrus production. Huanglongbing infection results in reduced …
Oidium citri Crop: Citrus Why is it a problem? This fungus is mostly a problem in nurseries and young orchards where it prevents growth, although new growth in older orchards can also be affected. Severe infections kill branches. It can also attack young fruitlets causing distortion and premature fruit drop. …
