National Plant Protection Centre

Department of Agriculture, Ministry of Agriculture & Forests

Nppc-Header-Dzongkha

National Plant Protection Centre

Department of Agriculture, Ministry of Agriculture & Forests

Insects & Mites

Insects & Mites

 

[table colalign=”left|left|center|left”]
Pest | Description | Crops/Host | Management | Image
Army Worm |Adult moths are pale and brick-red to pale brown with a very hairy body covered with dark specks and patches.The freshly hatched larvae are dull whitish with brown-black head. Larvae feed in the upper portion of the rice canopy on cloudy days or at night; Adult feeds, mates, and migrates at night and rests in daytime at the base of the plant.| Rice, Maize and Wheat| Place ashes in the trenches. Place branches around fields (congregate and handpicked). Avoid killing natural enemies of armyworms such as Wasps and spiders. Insecticides spray (cypermethrin@1ml\1 L water) should be the last resort for armyworm control.Armyworm

Chinese fruit fly |The Chinese Citrus Fly (Bactrocera minax) is almost 1½ cm long and yellowish- brown. It has dark spots at the tips of the wings and the general appearance is wasp-like.Female flies lay their eggs in mandarin fruits from June to August and  causes fruit drop in October and November | Citrus |Dropped fruits should be collected every 3-5 days and destroyed. For burial, fruits should be thrown into pits of about 2 meters deep. First Spray Cypermethrin 10 EC (1ml\1L water). Mid altitude: Mid-June (marble  sized fruit). Lower altitude: Early June (marble size fruit). Second Spray Dimethoate 30 EC (2ml\1L water)  Two weeks after first spray. Third Spray Cypermethrin 10 EC (1ml\1L water). Two weeks after  second spray |

 

Citrus Trunk Borer | The Citrus trunk borer is a longhorn beetle and is ash-grey with transverse rows of small black spots.The matured larvae tunnel into the centre of the trunk, where later they turn into adult. The Citrus Trunk borer causes tree decline, especially in neglected orchards. |Citrus | The lower part of the trunk should be applied    with the chemical Chlorpyrifos mixed with the sticker Sandovit at four week intervals starting from mid-April to August. Poke with an iron wire in holes producing fresh frass in order to kill the older larvae. Then plug these holes with some cotton soaked in kerosene or petrol. | citrus trunk borer

Potato tuber moth | The adult tuber moth has a narrow silver grey body and grayish-brown wings patterned with small, dark specks. The oval eggs are laid singly on the underside of potato leaves and exposed tubers. Young larvae are grey or yellow-white: mature, healthy larvae are tinged with ping or green. All instars have a dark brown head. | Tomato and Potato | Crop rotation with solanaceous host crops. Hilling up to cover the soil cracks and exposed tubers will prevent PTM from reaching the tubers. Early harvest date i.e. harvest as soon as possible after the tubers have matured. | Potato tuber mothlarva

Rice case worm | Adult is a tiny delicate moth  measuring about 1.5cm in  length. Wings are white and speckled with pale brown markings. The young larva cut the leaf blade  into small bits and  constructs a tubular case and larva remains inside the case. | Rice | Draining the field for at least 3 days will kill most of the larvae because they are highly dependent on water for oxygen. Use of older seedlings reduces the duration of the susceptible stage of the crop. Trichogrammatid wasps, several species of ants and spiders are reported as a parasite of caseworm eggs. | rice case wormrice case worm larvae

Stem borer | Destroy rice at any stage of the plant. Feed upon tillers and causes dead heart or drying of the central tiller, during vegetative stage; and causes whiteheads at reproductive stage. The hatching larvae are negatively geotropic and crawl upward toward the tip of the plants where they stay for only short periods. | Rice | Raise level of irrigation water periodically to submerge the eggs deposited. Encourage biological control agents: braconid, ants, lady beetles, staphylinid beetles, carabid ants, and mites,  earwigs, bird, wasp, dragonflies, damselflies, and spiders. Apply nitrogen fertilizer in split following the recommended rate and time of application. |stem borer

Plant hopper | High population cause leaves to initially turn orange-yellow before becoming brown and drying. This condition, called hopper burn, kills the plant. Suck sap form the plant and feeding damage predisposed the plant to fungal diseases and honey dew secretions encourages sooty molds. | Rice | Draining fields for 3-4 days during infestation can help reduce population populations. Crop rotation- can provide effective control in areas where one rice crop per year is grown. Judicious use of nitrogenous fertilizers-split application. |zig zag  rice plant hopper

Rice leaf folder | Caterpillars fold a rice leaf around them and attach the leaf margins together with silk strands. They feed inside the folded leaf creating longitudinal white and transparent streaks on the blade. | Rice | Reduce density of planting. Use balanced fertilizer rates. | rice leaf folder

Cabbage white butterfly | The adult is a large white butterfly with a wing span of 5-7 cm. The forewings have black tips. Two black spots are present on the upper side of the forewings in the females, while in the males these spots are on the underside of the wings The caterpillars are about 25mm when fully grown and are with three longitudinal yellow trips with many black spots. | Cabbage,Cauliflower,  Spinach and  Mustard | Eggs are easily visible and should be handpicked and destroyed. The larvae feed in groups they can be easily located and destroyed. In case of serious problems, contact insecticides like Cypermethrin can be used at recommended dosages (1 ml per liter of water) (2-7 days safety interval should be maintained). | Cabbage whilte buterfly

Ginger shoot borer | Eggs are pink, oval, flat and lay singly or in group on the tender part of the plan. Larva are long, pale greenish with a pinkish was dorsally, head and pro-thoracic shield brown in colour and body covered with minute hairs arising onwards. Adult are medium sized moth, the wings are pale yellowish with black spots on the wings.The larvae bore into pseudo stems and feed on the growing shoot resulting in yellowing and drying of infested shoots. | Ginger | Pruning and destroying freshly infested pseudo stems will reduce the infestation level. Spot out the shoots infested by the borer and cut open the shoot and pick out the caterpillar and destroy them. The shoot borer can be managed by spraying malathion (0.1%) at 21 day intervals during July to October. The spraying is to be initiated when the first symptom of pest attack is seen on the top most leaves on the pseudo stem. | Ginger shoot borer moth

Chili pod borer | Large larvae  have white hairs around the head; and have black hairs around the head. It is stoutly built, large brown or yellowish brown moths with conspicuous black spot in center of forewings. | Chilli | Maintain proper Spacing between the plants(Damage due to H. armigera was more in closer spacing of 20 x 5 cm in comparison to wider spacing of 40 x 20 cm. Pheromone traps for mass trapping. |Chili pod borer larva

Cut worm | The caterpillars are clay-colored with faint dark lines along the sides of the body. The pupa is smooth and shiny brown in colour. The adult is a medium-sized moth with grey-brown forewings. | Chili, Cabbage tomato ,Maize. | Weeds act as the preferred site for oviposition and food for the first instar larva, hence clean weeding of the field. Hand collection of larvae is quite effective. Deep ploughing will bring larvae and pupae to the soil surface for exposure to natural enemies and the sun for desiccation. Seedlings of vegetables like Chilli and Cabbage can be dipped in a solution of Chlorpyrifos (4 ml in 1 litre of water) before transplanting. Where infestation is serious, cover sprays during the susceptible stage of the crop can also be carried out with Chlorpyrifos at the above rate. |Cut worm larvae  [/table]

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Program Director

Program Director

Mrs. Yeshey Dema

Mrs. Yeshey Dema joined the civil service on 26th February 1996. She headed the Soil Fertility Unit, NSSC from 2008 till 2013. In 2013, she was transferred to the National Plant Protection Centre as the Program Director. She holds M. Phil in Soil Science from the University of Reading, UK.

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