Polyphagous pest - Locust

About Locust
• Locusts are the major agricultural pests of the
world.
• Out of 5000 different species of grasshoppers,
those which can live in two different phases viz.
solitary & gregarious phase are called locusts.
• Of these, only nine species have been recognized
as locusts, three species belonging to Indian
sub-continent.
• Economic losses due to locust plagues estimated
as 30 million tone/year.

-: Systematic Position :-
Phylum :- Arthropoda
Class :- Insecta
Order :- Orthoptera
Family :- Acrididae

-: Species of Locust :-
 Desert locust
(Schistocerca gregaria)
 Migratory locust
(Locusta migratoria)
 Bombay locust
(Patanga succineta)

Distribution
• Major agricultural pests of the world.
• Desert locust :- Desert locust is considered
the most important pest all over India.
• Migratory locust :- Important only in
Maharashtra, Gujarat, and Rajasthan.
• Bombay locust :- Mainly Maharashtra
& South Indian zone.

-: Identification :-
• Large size insect.
• Body length from 35-50 mm for males & 45-55
mm for females.
• Wings are colorless and exceeding clearly the
abdominal extremity.
• The color can vary but is usually green, brown,
yellowish-green or grey.
• The mandibles are dark purple to black.

-:Phases :-
Nymph : Color varies according to surrounding
vegetation.
Adult : Greenish grey throughout life.
Behave independently.
Repelled from other locusts.
Walk slowly with creeping.
Active mostly at night.
Diet restricted.
Solitary

-: Life Stage :-
Eggs :-
• Eggs are yellowish – brown in
color and 7-8 mm long.
• 1-3 egg pods per female with an
average of 60-80 per pod.
• Egg pod is large slightly bent, 50-
85 mm in length, 7-10 mm in
diameter.
Incomplete metamorphosis.
Three developmental stages, egg, nymph(hopper)
and adult are found.

Desert Locust Migratory Locust Bombay Locust

Female lays eggs in a hole in damp, warm or sandy soil
called a Pod usually at a depth of 2-10 cm.
Each pod contain 60-80 pale yellow rice grain shaped eggs
5-6 mm long.
Covers the eggs with frothy liquid to protects from
enemies, dehydration and contamination.
Collection of egg pods laid by a number of locusts is
termed as Egg Bed.
Egg beds may vary from a few square meters to several
hundred square meters and scattered throughout a region.
Egg hatch in 14-20 days.
Afterwards the nymphs move by crawling or hopping
along ground they have no wings.
5 wings nymph instars and nymphs take 4-8 weeks to
complete development Adult is the final stage.

Locusts at this level have fully pledged
wings and can fly without problem.
Adult appear from June to early July.
2-4 weeks after fledging, mating start and
females start laying eggs 2-3 weeks later
(usually at the end of July ).
Lifespan of adult is almost eight weeks.
Univoltine in the considered area but can
have up to five generations tropical zones.
Overwinter in the form of eggs.

-: Groups :-
Two types of groups are found.
1. Swarms are composed of winged adults.
2. Bands are composed of hoppers (nymphs).
3· One swarm can cover an area of 1000 sq. km.

PLAGUES:
Swarms or bands remained in many countries
for periods lasting several years called plagues
causing great damage to crops.
 Duration of plague lasts for 5-10 yrs and
recession period 1-8 years.
 Both swarms and bands rest on crops and trees
at night, morning they hop and fly to form a
swarm when temperature rise.
They are voracious feeders; feed on any
vegetation often causing famine.
Calotropis, Datura spp. are not fed by locusts.

-: Damage :-
Many formed in Rajasthan and Sind, fly north east and
south, thus invade all parts of India and damage kharif
crops.
 some swarms overwinter in North Western India and
become active when temperatures are suitable and
damage ‘rabi crops’.
Swarm :-
• If numbers are sufficient, locusts form dense groups.
• Swarms infested areas that are usually 5-50 km.
• There can be 40-80 millions locust in each square
kilometer of swarm.
• Swarms can travel about 5-130 km or more in a day.

During outbreaks, swarms damage to pasture,
hayfields, cereal crops, various crops ass well as
plantations of volatile oil bearing plants, many
tree species, young plants of many fruit, vines,
fruit, forest and bush trees.

-: Control :-
Cultural control
•Ploughing, digging and harrowing of
places where eggs are laid on large scale
and destroying-laborious.
Mechanical control
•Collecting hoppers with catching machine.
•Killing tem with flame-throwers.
•Crushing them with rollers.

Natural enemies
•Rose-colored and common
starlings (Pastor roseus and
Sturnus vulgaris)
•Blister beetle, Ground beetle
and Crickets are eggs predators.
•Flesh flies, Tachinid flies, and
Tangled veined flies are nymph
and adult parasitoids.

Chemical Control
The adult beetles can successfully be controlled by treating the
trees with the following insecticides :
a) Carcaryl 0.1%
b) Monocrotophos 0.05%
c) Chloropyriphos 0.05%
The grubs may be controlled by the soil application of following
insecticides :
a) Phorate 10 g @ 25 kg/hac.
b) Ekalux 5 g @ 25 kg/hac.
c) Carbofuron 3 g @ 35 kg/hac.
d) Oftanal 10 g @ 25 kg/hac.
The sprinkling of Chloropyriphos 20 EC @ 5 lit/hac offers of
economic and effective control of grubs.
Spraying the crop with Neem seed kernel powder suspension (1%)
has been found to be very promising.

“Locust Warning Organisation (LWO)”
established in 1939 and later amalgamated
with the Directorate of Plant Protection
Quarantine and Storage in 1946.
Locust Warning organization (LWO) is
responsible to monitor and control the locust.
Field Station for Investigations on Locusts
(FSIL) situated at Bikaner.

Polyphagous pest - Locust

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Polyphagous pest - Locust