B.Sc (Hons) Ag 3rd year, CPM

1. Lecture no. 8
Insect pests of Tobacco, Potato and
Sweet Potato
RK Panse
Asstt Professor (Entomology)
JNKVV-CoA, Balaghat
Subject: Pests of crop and stored grain and their Management

2. Potato tuber moth
S.N. Phthorimaea operculella
Family: Gelechiidae
Order: Lepidoptera
Distribution and status
World wide. It is the most destructive pest of potato. It is
a cosmopolitan pest, found in warmer countries.
Host range: Tomato, tobacco, brinjal, potato,
sugarbeet and solanaceous weeds.

3. Biology and Bionomics
Egg period: 3-6 days
100-150 eggs/ female
Eggs laid singly –the ventral surface of foliage and an
exposed tubers
Larval: 7-16 days
Yellow coloured caterpillar with
dark brown head
Pupal: 7-10 days
Pupation: within a cocoon among the trash, clods of
the earth in the field
Adult:
Small narrow winged
moth , greyish brown
forewings and hind
wings- dirty white
•5-6 generations/yr
•Introduced pest –from
Italy to India

4. Marks of Identifications
• Eggs are minute, oval
and yellowish in colour.
• Full-grown caterpillars
are pinkish-white to pale
greenish in colour.
• Pupation takes place in
rough silken cocoons.
• Adults are small moths
with silvery body. Fore
wing is greyish-brown
with minute dark spots
and fringes of hairs. Hind
wings are dirty white.

5. Damage symptoms
• Pest of field and storage.
• Larva tunnels into foliage, stem and tubers which lead to loss of
leaf tissue, death of growing points and weakening or breaking of
stems.
• In tubers, irregular shaped galleries are seen with excreta.
• ETL: 5% leaf damage

6. IPM
 Select healthy tubers and avoid shallow planting of tubers
 Adopt inter-cropping with chillies, onion or pea
 Earthing-up at 60 days after planting to avoid female moths
egg laying on the exposed tubers
 Install pheromone traps in the field @ 20/h
 Remove and destroy infested tubers
 Release egg-larval parasitoid, Chelonus blackburni@ 30, 000
adults/ha twice, 40 and 70 days after planting
 Keep pheromone traps in godowns also and destroy trapped
moths.
 Fumigate godowns in airtight condition with carbon
disulphide (CS2) or a mixture of carbon disulphide and carbon
tetrachloride or with Ecofume.

7. Cutworms
• S.N. : Agrotis ipsilon, A. segetum,
• Family: Noctuidae
• Order:Lepidoptera
Distribution and status
India, China, northern Europe, Canada, Japan down to South
America and New Zealand. They are cool climate pests. In
plains, they actively migrate to hilly regions.
• Hostrange
Ppolyphagous pests. Besides potato, they also feed on barely,
beet-root, cole crops, okra, linseed, lucerne, millets, oats,
peas, poppy, pulses, tobacco, wheat etc. They can cause
economic loss under favourable cold conditions in northern
plains.

8. Biology of A. ipsilon
Egg period: 4-7 days
Creamy white spherical eggs laid
singly or cluster on lower surface of
the leaves Larval: 21-35 days
Black with pale mid
dorsal stripes
Adult:
Pale brown forewings
with dark purplish
brown along costal end.
White hind wings with
brown tinge
Pupal: 10 days
Pupation: earthen cocoon in the
soil

9. Marks of identification
• Eggs: Creamy white, dome-
shaped eggs, laid on lower
surface of the leaves
• Larvae: Newly emerged young
larva is yellow in colour. The
full-grown larva is dark or dark
brown with a plump and greasy
body.
• Pupa: Dark brown pupae are
found in earthen cells lying
underground in the potato
fields
• Adult: Dark with some grayish
patches on the back and dark
streaks on the forewings.

10. Symptoms of damage
• Young larvae feed on
the epidermis of the
leaves
• Older larvae come out
at night and feed
young plants by cutting
their stems
• They also damage the
tubers by eating away
part of them

11. Management
Hand –pick and destroy the larvae – morning and evening
hours
on cracks and crevices in the field
Plough the soil during summer months to expose larvae and
pupae – avian predators
Light trap @ 1/ ha
Pheromone traps @ 12/ ha to attract male moths
Poison bait: Rice bran 12.5 Kg +Molasses or Brown sugar 2.5Kg
+ Carbaryl 50 WP 1.25 Kg – Mix the ingredients well – Keep
around the field in the evening hours
Irrigate in day time to expose larvae for avian predators
ETL: 2 larvae/ metre row
Insecticides: Chlorpyriphos 20EC @ 1 lit/ha or neem oil @ 3%

12. Aphid
• S.N. : Myzus nicotianae, Myzus persicae
• Family : Aphididae
• Order : Hemiptera
Aphids are pinkish to brown or green.
The winged forms are black or reddish with
transparent wings.

13. Sweet potato Weevil
S.N: Cylas formicarius
Family: Apionidae
Order: Coleoptera
Distribution: All over India
Host range: Sweet potato
Biology
Egg period: 5-7 days
Eggs laid singly- tubers and stem
Grub: 14-22 days
Whitish apodous grub with
brown head
Pupal: 7-11 days
Pupation: within the larval tunnel
Adult:
Black, look like ant with a
long snout
Reddish brown thorax and
legs and brownish red
abdomen

14. Marks of identification
• Adult weevils are ant-like, slender bodied having elongated
snout-like bluish-brown head with non-geniculate antenna,
bright red thorax and legs and brownish-red abdomen.
• Grubs are apodus, pale-yellowish white in colour.
• Pupation takes place in larval burrows.

15. Damage symptoms
• Grubs bore into stems, cause tunneling inside and feed on
soft tissues. Grubs and adults bore into tubers both in field
and storage godowns. Affected tubers develop dark patches,
which later start rotting. Pest is disseminated from field to
field through infested vines and is carried over from season to
season by breeding in damaged tubers left in the fields after
harvest.

16. Management
• Harvest immediately after maturity and
destroy the crop residues
• Install yellow sticky trap @12/ha
• In godowns, treat the bag surface with
malathion 5% or carbaryl 5 % dust.
• Dip planting material in fenthion 100 EC or
fenitrothion 50 EC or monocrotophos 36 WSC
@ 2 ml/ lit of water before planting

17. Tortoise beetle
• Scientific name: Cassida circumdata Herst
• Family: Chrysomelidae
• Order: Coleoptera
Geographical distribution
Throughout Africa, Southern China,
Southeast Asia.
Host range
Sweetpotato is the main host, Other
crops which have been established as
alternative hosts are coffee, beet,
potato and various flowers.

18. Biology and bionomics
• The mated female lays around 250 eggs as singly on either
surface of the leaf and covered with the translucent golden
brown membrane.
• Hatching of eggs occurs in 4 to 7 days.
• The insect undergoes 5 larval instars, each instar lasts 1 to 6
days. The total larval development ranges from 7-26 days.
• The pupa becomes firmly attached with silken threads by its
caudal end to either surface of the leaf.
• The pupal period is 4-8 days.
• Longevity of adults lasts 2-29 days.
• The total life cycle ranges from 15-41 days.

19. Marks of identification
• Egg The light green egg is covered
by translucent golden brown
membrane.
• Larva The larva appears green,
flattened, slug-like with two pairs of
branched lateral fleshy green spines
per segment.
• Pupa The body is yellowish green,
oval, flattened with prominent
prothoracic shield.
• Adult The adult is a small tortoise
beetle with metallic greenish yellow
body. The wings have 3 irregular
longitudinal black band with lateral
extension like a shield.

20. Nature of Damage
• Larvae and adult produce round holes.
• When feeding in groups, irregular holes are formed and
can totally defoliate the plant.
• However, usually damage does not affect yield.

21. Management
• Removal of convolvulaceous weeds in the surrounding area
may reduce their numbers.
• The wasp parasitoid Tetrastichus cassidus.
• Larvae and adults are easily controlled by application of
insecticides to the foliage