Beneficial insects contribute to agriculture by controlling plant pests and pollination. Beneficial insects can be divided into two groups: predators and parasitoids. Predators consume more than one prey and are usually larger than their prey. Furthermore, predators are generalists and may be omnivorous. On the contrary, parasitoids are smaller than …
Aceria litchi Crop: Litchi Why is it a problem? Lychee erinose mite destroys leaves, flowers, and fruits. Heavy infestations prevent flower and fruit setting and reduce the photosynthetic ability of leaves. Overall, LEM weakens the tree. Where and when is it a problem? It is commonly observed in Sarpang and …
Spodoptera frugiperda Crops: Maize Why is it a problem? The fall armyworm (FAW) is a polyphagous pest that damages more than 350 plant species belonging to 76 plant families (Montezano et al., 2018). The higher damage is found in maize and sorghum, which are their primary hosts (Casmuz & Juárez, …
Tuta absoluta Crop: Tomato Why is it a threat? Although not yet detected in Bhutan, the tomato leaf miner is a devastating pest of tomato. Tomato plants are attacked in all the growth stages in both open fields and greenhouses. Although using pesticides is now thought to be an effective …
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 …
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 …
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 …
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 …
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, …
Diaphorina citri Crop: Citrus Why is it a problem? The Asiatic citrus psyllid (ACP) is the primary vector of the devastating disease, huanglongbing (HLB). Management of the vector is important to slow the spread of the disease within and between orchards. At high densities direct feeding can also damage plants, …
