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 …
Panonychus ulmi Crop: Apple Why is it a problem? Prolonged, intense infestations weaken apple trees, seriously affecting the development of shoots, buds and fruit set in the following year. Where and when is it a problem? Mites can be a pest in most apple growing regions, but serious problems are …
Popillia species and Protaetia neglecta Crop: Apple Why is it a problem? The adults of six species of apple fruit beetles all feed on developing apples, making them unmarketable. Although feeding damage can be conspicuous, the economic impact is not important unless beetles arrive in large numbers. Where and when …
Myllocerus sp. nr chloris Crops: Apple, peach Why is it a problem? Adults feed in groups on small apples, causing rot and making them unmarketable. They can arrive in large numbers. However, as they normally feed in groups total fruit loss is generally quite low and they can be relatively …
Microserica sp. Crop: Apple Why is it a problem? Large beetle numbers can defoliate trees. This is mainly a problem with young trees and newly established orchards where it can retard growth. Where and when is it a problem? Problems have been recorded in Thimphu and Paro valley from late …
Linda rubescens Crop: Apple Why is it a problem? Larvae bore into stems, causing twig dieback. This is most damaging in seedlings, where the main leading shoot can be destroyed. Where and when is it a problem? Outbreaks are quite localized and rare. They have been reported in apple orchards …
Eriosoma lanigerum Crop: Apple Why is it a problem? Woolly aphids are a common pest of apple trees, causing damage to both the trees and the fruit. They feed by sucking sap from the tree, which can cause galls (swellings) on the roots and branches, weakening the tree and making …
Diaspidiotus perniciosus Crop: Apple Why is it a problem? When feeding on apples this scale insect leaves red spots, and in severe cases distorts the fruit. This affects sale prices, especially for exports. Complete coverage on twigs and branches can lead to dieback of affected parts and ultimately the decline …
