Polyphagous pest - Locust

Arun R Rankawat

1. POLYPHAGOUS PEST LOCUST Presented by :- Arun RAnkawat

2. 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.

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

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

5. 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.

6. -: Host Plants :-

7. -: 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.

8. -: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

9. Gregarious Nymph : Yellow or pink with distinct black markings. Adult : Pink on emergence, gradually turn grey finally yellow when sexually mature. When numbers rise, they become gregarious and migrate in dense groups. Behave as a Cohesive Unit. Attracted to nonspecific. Walk rapidly. Active mostly at day. Diet broad.

10. -: 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.

11. Adult:- Large size about 45-60 mm in length. Hind wings have no markings. Adult flight is strong and stedy . Nymph :- An immature locust is called a nymph or hopper . Miniature to adults but wingless. Lighter in color than adult. Desert Locust Migratory Locust Bombay Locust

12. -: Life Cycle :-

13. 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 .

14. 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.

15. -: 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.

16. 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.

17. -: 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 .

18. 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.

19. -: 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.

20. 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.

21. Chemical Control The adult beetles can successfully be controlled by treating the trees with the following insecticides : Carcaryl 0.1% Monocrotophos 0.05% Chloropyriphos 0.05% The grubs may be controlled by the soil application of following insecticides : Phorate 10 g @ 25 kg/hac. Ekalux 5 g @ 25 kg/hac. Carbofuron 3 g @ 35 kg/hac. 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.

22. Locust Warning Organization

23. “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 .

24. Thanks for your time