Major crop and vegetable insects pests; scenario of the damage level in the research thematic areas for the major stable agriculture.

1. Mrs. Sunita Adhikari Poudel, S1 RARS, Lumle
Major crops and vegetables insects pests
In western hills and mountain, recent most devastating havoc in crops and vegetables found
caused by three insects army worm(Spodoptera frugiperda), locust and red ant. The army worm
is in barley and seasonal while other are broad spectrum most prevalent in all seasons.
1. Army worm (Spodoptera frugiperda)
In barley crops, chewed leaves, heads and awns can be apparent,
although the first sign of armyworm damage is usually barley heads on the ground. As barley
matures, part of the stem often remains green and appetizing after other parts have dried.
Armyworm caterpillar has the three longitudinal white lines, especially on the collar, which help
to distinguish it from other pest caterpillars of cereal crops. At mature, the armyworm caterpillars
burrow in soil to form pupae. Adult moths emerge from the pupae. Adults generally dull
coloured moths with some species having metallic-looking markings on their wings. Other
similar species armyworm can be confused with cutworms are also smooth caterpillars but are
usually only pests of cereals at the seedling stage and appear at a different time of the year. They
do not climb and sever heads from the stems. Cutworm caterpillar, Helicoverpa puntifera, feeds
only on individual grains and is not usually as damaging in barley as the armyworm. It damage
individual grain.

2. Barley crops heads extensively damaged by armyworm. Spodoptera mauritia, Mythimna separate,
(noctuidae) ear cutting caterpillar are more obvious than swarming. It’s distribution is across South
Asia, Australia, China, Japan,West Africa, Tanjania, Madagaskar, Mauritius, Arjentina, Hawaii,
Urope, Northern America.It causes damage from seedling to harvest. In green parts, it completes
life cycle- in one spot 300 no of brown eggs, more than 2-4 eggs laid. 4-9 larvae ear / day from
one entry for 4-5 weeks and moulds 5 times. Pupate in earthen cocoon for 5-14 days. Constitutes
40- 50 days life cycle (Egg, larvae, pupae and adult) of armyworm and the speed of development
depends on temperature. Eggs are greenish-white in colour. Young larvae are pale green and
move. Older larvae are greenish-brown with numerous white, orange and dark brown stripes which
run the length of the larvae. The head is pale brown with a green tinge and mottled brown
appearance. Larvae feed on leaves, stripping the leaf margins and move up to feed on the panicles
and flowers, stripping off awns and kernels. Lodged plants provide a favourable environment for
all stages of the armyworm. The adult/moths are concealed, lay eggs and larvae flourish in the
high humidity underneath the dense crop. Pupae are reddish brown with fine black speckling.
Adult moth is 25 mm long with a wingspan of 35-45 mm. uniformly light brown in colour with a
small, prominent white spot in the centre of each forewing. For management, monitoring picked
up using sweepnets. Armyworm caterpillars may be confined to only small portions of a crop.
Thresholds in barley: late maturing barley crops need to have three large caterpillars or more per
square metre, before insecticide spraying. Control; biological control agents include parasitic flies
and wasps, predatory beetles and diseases. Chemical control ; synthetic pyrethroid insecticides are
registered for the control. Insecticide withholding periods is important in late sprayed crops.
Natural enemies; lacewings, ladybeetles, and hoverflies. They contribute to suppress armyworm.
Damage symptom looks like encroached by livestock and rat damage.
Pre-emergence to flowering and grain development to ripening are the damaging critical growth
stages however, armyworm are most damaging in barley close to harvest. Monitor crops regularly
at least fortnightly at vegetative stage; weekly nears maturity. Use a sweep net, beat tray, or beat
sheet, a trowel to examine the soil between rows.Traps, containing lures (10% port, 15% raw
sugar and 75% water), can be used. Around 20 species of predators and parasitoids have been
recorded attacking armyworm; predators include predatory shield bugs, ladybeetles, carabid
beetles, lacewings and common brown earwigs. Parasitoids include tachnid flies and a number of
wasp species (e.g. Netelia, Lissopimpla, Campoletis). Viral and fungal diseases can cause
armyworm mortality. In cultural control remove alternative hosts, ryegrass before moving into
cereal crops. Windrow or dessicate barley as an alternative to spraying for armyworm if rapid
drying conditions are forecast.Armyworm are active at night- spray alpha-cypermethrin and
chlorpyriphos 1 to 2 ml per 1 l. of water late afternoon or early evening. Considering withholding

3. periods when chemical control is used close to harvest. Control of armyworm in early crop
development can have off-target impact on other cereal pests e.g. Helicoverpa, aphids and mites.
In addition, manual picking, deep plough, stagnate the field with water without drainage for 4 days
to plug the places of the worms are effective.
2. Red ant of potato( Dorylus orientalis Westwood )
Red ant (Dorylus orientalis Westwood) has long been known as an important pest of potato in
western mid to high hills of Nepal. Red ants ( Dorylus orientalis), is one of the most important soil
pests of potato reducing the yield 35-40%. The pest made hole on the surface of tuber which
reduced tuber yield as well as market quality. The insect is reported causing 70-90% damage at
harvest to potatoes in farmer’s fields. Dorylus orientalis has long been known as an important
pest of potato in middle and higher hills of Nepal and it causes serious damage to potato, radish,
carrot, cauliflower, cabbage and many solanaceous and cruciferous vegetables in Nepal. Causing
more than 10% of the damage in irrigated potato crops. High temperatures and dry weather favor
population build-up. The pest damages mainly the potato stems and tubers by chewing holes and
in severe wilt in direct sunlight and will eventually dry up. The pest appears during December and
remains active until April. Highest 90.3 % infestation was found by numbers, while by wt. the
highest 54.91 % infestation was recorded from red ant damage. Botanicals (Artemisa, Eupatorium,
Agave, Justicia, and Azadirachta) @ 1.44 kg/plot with chloropyriphos will check further spread.
Plant resistant varieties Janak dev, Khumal Ujjwal , Khumal Laxmi manage the pests. Pesticides;
Dursban 20 EC and Sevin 85 WP, Furadan 5G @ 40 kg/ha , Neem oil cake @ 300 kg/ha, poultry
manure @ 3 ton/ha, kerosine @ 5 ml/lit water, mixture of carbaryl and lindane , chlorpyrifos EC
with sand granules and at the rate of (2000 -2500g a.i./ha) are effective to control red ants. Sugar
based bait, honey with boric acid, molasses with boric acid, at tuber formation, tuber maturity and
harvesting stage, and thus collect red ants and remove.
2. Desert locusts swarm in Nepal (Schistoceera gregaria Forsk)

4. Three different types of locust found solitary and in swarm; Desert locust Schistoceera gregaria
Forsk, Migratory locust Locusta migratoria Linn, and Bombay locust Patanga succinct Linn.
There were about 8 million locusts when they entered Nepal in the beginning. The swarm can fly
up to but according to migratory nature and dictintive morphology differentiated from grasshopper
and known short horned. It has 2 phases solitary and swarm/ migratory. Color changes brown in
alone, pink brown pale in migratory/swarm stage. (The Locust Information Center) There are
200,000 locusts intact with the swarm. Meanwhile, a total of 1,118 hectares of land has been
affected by the locust swarms in Makwanpur, Dang, Pyuthan, Arghakhanchi and Palpa. The center
has mentioned that despite locusts’ presence in 52 districts. The PQPMC, the Plant Quarantine and
Pesticide Management Center (PQPMC), immature swarm, mix of mature and immature adults
had entered Nepal in June. Till last June, Locusts’ infestation has expanded to 28 districts in just
two days of swarms of the insect entering the country and found locusts’ infestation damaging
crops in 12 districts; Cornfield in Makwanpur alone, Tarai region to mid-hill region including the
Kathmandu valley. According to Locusts Information Center, Rupandehi, Bara, Parsa and Sarlahi
Dang, Pyuthan, Kathmandu, Lalitpur, Bhaktapur, Makwanpur and Kailali districts.are also
infested. Though locusts have appeared in a group of just 200-400 in some hilly areas but little
in a swarm. Pressurized direct the provincial governments to immediate management
implementation. Plant Quarantine and Pesticide Management Centre. Not to use chemicals
regarding human health hazards, preferring sound producing, smoking devices and net to repel.
Minister for Industry, Commerce and Supplies concern poor laboratory facility at each entry port.
The Food and Agriculture Organization (FAO) is reported that FAO had trained 100 Nepali
agriculture specialists in locust control after the swarms came to India. Likewise Nepal's
Ministry of Agriculture and Livestock Development confirmed the entry of the locusts in a
statement after farmers of a few districts in Province 2, Province 5 and Bagmati Province in Bara,
Parsa, Sindhuli, Sarlahi and Rupandehi. Management of locust; during early stage, drenching/
dusting/ spraying tunnel with pesticides. Spray the hosts with appropriate pesticides. Netting,
beating mannualy in night swarm, flaming in tree swarm. Repelling with white clothes, smoke
repel the swarm. Carbaryl and malathion, cyfluthrin or other pyrethroids toxic to bee and natural
enemies (NEs) are effective against desert locust. Organophosphates and systhetic pyrethroid can
control desert locust.
Conclusion

5. All three insects are prevalent nowadays in western hills and mountains of Nepal. However
armyworm is seasonal according to barely season in Marpha and Lumle. While potato red ant
and desert locust are broad-spectrum in western mid hills to high hills, Nepal. All stakeholders
must execute prompt management strategy.