Weeds in paddy

Why is it a problem? Rice is the staple diet of the Bhutanese people. Weeds are one of the constraints to rice production. In a weed survey conducted in the rice growing areas of western Bhutan, at least 19 different species were found infesting transplanted rice (Dorji et al., 2013). …

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Wild boars

Sus scrofa Crops: All crops, but especially maize, rice and potato Why is it a problem? Wild boar are the main vertebrate pests of agricultural crops in Bhutan. Crop losses due to wild boar are one of the main constraints to alleviating poverty and increasing food security in the country. …

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Shochum

Potamogeton distinctus Crop: Rice   Why is it a problem? Potamogeton distinctus, locally called shochum, is one of the most serious weeds in transplanted rice in Bhutan. It is an aquatic plant so grows together with the rice. Yield reductions of up to 37% have been reported, even when farmers …

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Rice sheath blight

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 …

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Rice blast

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 …

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Hoppers on rice

Several species of Cicadellid and Delphacid bugs Crop: Rice Why is it a problem? Leaf hoppers and plant hoppers are sap-sucking insects that at high densities can desiccate and ultimately kill rice patches of rice plants (called hopper burn). However, it rarely if ever requires management in Bhutan.  Some species …

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Rice stem-borers

Four moth species Crop: Rice   Why is it a problem? There are at least four species of stem-boring moths affecting rice in Bhutan. They kill the central shoot at the vegetative stage and can result in seed loss at later stages. Rice plants can compensate for early damage, and …

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Rice leaf folder

Cnaphalocrocis medinalis Crop: Rice Why is it a problem? The rice leaf folder attacks tillering and booting stages. High densities can reduce seed production, but this is rare and management is normally not needed. Where and when is it a problem? It is a commonly encountered pest, in part because …

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Rice caseworm

Parapoynx stagnalis Crop: Rice Why is it a problem? This leaf-feeding moth causes most damage within 2-3 weeks of transplanting. They cut off leaf tips, thereby reducing plant growth rates. Where and when is it a problem? It is more serious in poorly drained fields, but damage is rarely serious …

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Armyworm

Pseudaletia separata (or Mythimna separata)        Crops: Rice, maize, wheat and buckwheat   Why is it a problem? Armyworms can cause heavy losses to rice nurseries, with caterpillars destroying seedlings. They also attack rice and maize fields and, to a lesser extent, barley and bitter buckwheat. Although not quantified in Bhutan, …

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