The document discusses major insect pests that affect cashew plants, including the tea mosquito bug, cashew stem and root borer, cashew leaf miner, red banded thrips, and mealy bug. It provides details on the identification, life cycle, damage symptoms, and management practices for these key pests. Some severe pests are the tea mosquito bug, which can cause 20-60% yield losses, and the cashew stem and root borer, which can kill trees by extensively damaging roots. Management involves monitoring, collection of damaged plant parts, and application of specified insecticides at particular plant growth stages.

1. Insect pests of Cashew and their
management
Dr M Thippaiah
Professor
Department of Entomology
University of Agricultural Sciences
GKVK, Bangalore- 65

2. Cashew (Anacardim occidentale) is very important foreign exchange
crop of India
It was originally introduced into India from Brazil by Portuguese
travellers during 16th century mainly for checking soil erosion on
the coastal regions
Now, India is the largest, producer, consumer and exporter of cashew
in the world
Pest infestation is a major constraint in cashew production
It is attacked by a number of Insect pests during different stages of
its growth and development
More than 50 species of insect pests are known to be infesting
cashew in India in different degrees of intensity
Dr. M. Thippaiah

3. Major insect pests of Cashew are
Tea mosquito bug Helopeltis antonii Miridae Hemiptera
Stem and root borer Plocaederus ferrugineus Cerambycidae Coleoptera
Cashew leaf miner Acrocercops syngramma Gracillaridae Lepidoptera
Thrips Selenothrips rubrocinctus Thripidae Thysanoptera
Mealy bug Ferrisia virgata Pseudococcidae Hemiptera
Aphids Toxoptera odinae Aphididae Hemiptera
Out which a half dozen of them cause serious damage when they
get favourable conditions.
Among all insect pests cashew stem and root borer and
tea mosquito bug pose a severe threat to cashew growers.
Dr. M. Thippaiah

4. Tea mosquito bugs : Helopeltis antonii
( Miridae : Hemiptera )
It is a major pest of Cashew and is widely distributed in
Karnataka, Goa, Maharashtra and TN
Other two species viz., H. theivora and H.bradyi also infests cashew
Dr. M. Thippaiah

5. Adult bug is slightly bigger than mosquito and reddish
brown in colour with long legs and antennae
Black coloured head and red coloured thorax and black to yellowish
coloured abdomen
A white bands is seen on the lower surface of the abdomen
A peg like projection on the dorsal side of the scutellum
Dr. M. Thippaiah

6.  The females are longer and measures about 8mm in length
 The males are smaller and measures about 6mm in length
 The males are abundant than females with a sex ratio 4:1 i.e.
Males are more numerous than females
Host plants : Tea, Neem, Moringa and Guava
 It is estimated that this pest alone cause 20-60% yield loss
 It causes more than 30 % economic loss by inflorescence blight
and immature nut fall down
Dr. M. Thippaiah

7. Eggs : are inserted into
epidermis of tender shoots,
axis of inflorescence,
the buds and the midribs
either singly or in groups of 2-6
Eggs are elongate and slightly curved with
a pair of breathing filaments which projected
from its operculum
A female bug can lay up to
259 eggs during its life time
I.P – 7-8 days
Nymphs : there are 5 nymphal instars that are reddish brown in
colour and ant like and feed on tender leaves which
later become necrotic
N.P - 14-16 days
The life cycle is completed in
22 – 25 days
The preoviposition period- 3-5 days
The oviposition period - 5-10 days
Dr. M. Thippaiah

8. Nature and symptoms of damage
The adults and nymphs suck the sap from tender flushes, petioles
tender shoots, inflorescence, panicles and growing young nuts
The tissues around the feeding punctures become brown in colour
as a result die and dry up due to the toxic action of the saliva of
the insect.
Then turn black colour and finally the shoot and inflorescence
dry up, giving burnt up appearance.
Symptoms
 Resin exudes from the feeding punctures.
 Blossom blight and die back symptom appears
 Wide spread drying of shoots, inflorescence and flowers
and shedding of nuts takes place.
 Feeding on tender leaves causes crinkling
 Affected shoots show long black lesions
Dr. M. Thippaiah

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12. Shoot and inflorescence dry up, giving burnt up appearance
Feeding punctures become brown in color Blossom blight and die back symptom appears
Dr. M. Thippaiah

13. Seasonal incidence
The condition becomes quite congenial for the multiplication and
feeding by nymphs and adults, when the cashew trees are in their
most active growth phase ( December on wards)
Trees with new flush and tender inflorescence are highly attractive to
the nymphs and adults
The pest population reaches its peaks, during the month of Feb – March
These periods the trees are in the full blossom stage
Young trees are getting affected more, because of the availability of
succulent throughout the year
Dr. M. Thippaiah

14. Management practices
 Remove the volunteer (Self sown) neem plants in and around
cashew plantations
 Proper monitoring of the pest situation is very important
 Collect and destroy the damaged plant parts
 The fungal pathogen, Aspergillus flavus causes 85-90% mortality.
 The nymphs are predated upon by the ant,
Crematogaster wroughtoni and reduviid bugs.
The eggs of the tea mosquito bug are naturally parasitized by
 Telenomus sp.
 Erythmelus helopeltidis Dr. M. Thippaiah

15.  Three spray schedules should be followed
1st spray with monocrotophos @ 1.5 ml / lit. ( 0.05%)
or
Lambda- cyhalothrin @ 0.003 %
During new flushing stage ( November – December)
2nd spray with dimetohate 0.05%
or
quinolphos 0.05%
or
malathion 0.1%
At flowering stage ( Dec – January)
3rd spray – Repeat the first spray at the initial fruiting stage
(Feb – March)
Dr. M. Thippaiah

16. Cashew stem and root borer: Plocaederus ferrrugineus
( CSRB) (Cerambycidae: Coleoptera)
The stem and root bore is a very serious pest of cashew tree in
karnataka, TN, kerala, AP and Maharashtra
 Adult is a medium-sized dark brown coloured longicorn beetle and
measures 25-40 mm long.
 The male antennae are twice as long as the body but in the
female they do not as long as the body Dr. M. Thippaiah

17. Eggs : A dirty white coloured eggs are laid into the live tissues in the
crevices of the loose bark on the trunk and on the exposed portion
of the roots above the soil.
A female beetle lays - 60-90eggs
Grubs : bore into the fresh tissues of the bark. They feed on the sap
wood tissues and make tunnels in irregular directions,
deepest in the middle and shallow at the sides.
Dr. M. Thippaiah

18.  The larvae are off - white in color.
 The grown up grubs measures about 60-75 mm in length.
 The fully grown grub descends to root zone through
tunnels bores into the heart wood and forms a chamber
tightly packed with fibrous tissues and frass providing
protection to the calcareous cocoon with in which the
grub undergoes pupation.
Pupa : Pupation takes place with in the
galleries inside the cocoon
Cocoon and pupa of Plocaedorus spp.
Grub
Dr. M. Thippaiah

19. Developmental periods of CSRB
Dr. M. Thippaiah

20. Nature of damage
 The grubs bores into the trunk near the soil.
 During the initial stages of pest attack, exudation of gum
and frass can be noticed in small quantities at the base of CSRB
infested trees.
 During later stages of attack, the infested tree canopy shows a
sickly appearance with yellowish leaves and premature dropping
of leaves occurs.
 During the severe stages of attack, the twigs dry off and the bark on
the trunk starts splitting.
 At this stage, large quantity of chewed fibres and gum, as well as
frass can be seen as huge lumps at the base of the infested trees and
the tree finally weak and death occurs Dr. M. Thippaiah

21. Sometimes, the unexposed stout lateral and taproots are extensively
damaged without any external symptoms and such trees may look
very healthy or with slight sickly appearance, and suddenly die
without any yellowing of leaves
Dr. M. Thippaiah

22. Gummosis and extrusion of chewed up
cashew trunk fibres by P. ferrugineus
Holes and cracks on cashew trunk caused by
P. ferrugineus infestation
Dr. M. Thippaiah

23. Symptoms:
 Small bored holes on the tree trunk or collar region
 Gummy exudation at the base infested trees
 Extrusion of frass (chewed up fibers and excreta)
through the holes at the collar region
 Yellowing and shedding of leaves
 Drying of branches and gradual death of the tree.
This pest is more severe in neglected plantations.
Dr. M. Thippaiah

24. A cashew tree killed by P. ferrugineus
Dr. M. Thippaiah

25. Management practices:
 Regular monitoring and early detection of the infestation are
essential to combat the pest.
 The dead trees should be uprooted and removed from the plantation
as they serves as natural source for multiplication of the borer.
 Prune the branches containing grubs and destroy.
 Avoid any injury to the stem and exposed portions of the root.
 The nematode cum bacterial culture DD-136 infect the larvae
(Neoplectna carpocapsae and Achromobacter nematophilus).
 Swab the exposed roots, tree trunk and shoots with chlorpyriphos
@ 2 ml / lit. after removing the affected tissues along with the
immature stages of the pest.
Dr. M. Thippaiah

26. This may be done twice a year
before the onset of south-west monsoon (March- April)
and
After cessation (stopping) of the monsoon (November).
or
 Swab the tree with neem oil 5 % ( thrice a year)
February
May – June and
Sept. – Octo.
 Plug the fresh bored holes with cotton soaked in monocrotophos
solution mixed @ 5ml/20ml of water.
 Inject dichlorvos 0.1% or monocrotophos 0.05% @ 10ml/bored
holes and plugged with mud mainly to kill the grubs.
Dr. M. Thippaiah

27. Cashew leaf miner: Acrocercops syngramma
(Gracillaridae: Lepidoptera)
Leaf miner is one of the serious pests of cashew during post monsoon
flushing period all over the country.
Adult is a minute silvery grey coloured moth
Dr. M. Thippaiah

28. Nature of damage:
The reddish brown caterpillar mines the leaf, the mined region
show white blistered patches in the older leaves,
These blisters dry and drop off leaving big holes, up to 8 larvae
are found to attack a single leaf
And up to 26% of the leaves on trees are damaged by larva more
severe on young trees.
Eggs : are laid on the tender leaves.
Larva: reddish brown color and measures 6mm in length, it drops
to the ground.
L.P - 2 weeks
Pupa : Pupation takes place in soil.
P.P - 7-8 days.
Dr. M. Thippaiah

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31. The reddish brown caterpillar mines the leaf, the mined region
show white blistered patches in the older leaves
Dr. M. Thippaiah

32. Management practices:
 Collect and destroy the damaged plant parts.
 Spray suitable insecticides during new flush formation stage
monocrotophos 0.05% ( 0.5 ml / lit.)
During the month of October – November at new flush emergence
stage
 Spray the crop with NSKE 5%, two rounds 1st
new flush formation stage
and 2nd at 20 days later.
 NSKE is quite effective against this pest.
Seasonality:
The incidence is most common in post monsoon flushes during
August- December reaching the peak during October- November,
but incidence can be seen up to April at low level.
Dr. M. Thippaiah

33. Red banded thrips: Selenothrips rubrocinctus
(Thripidae: Thysanoptera)
Nymph Adult
 Adult thrips are dark brown to black in colour and measures about
1 to 1.3 mm long.
 They have two pairs of narrow feathery wings which are folded
along the back when the insect is at rest.
 The nymphal stages are creamy yellow in colour with two
characteristic bright red bands around the abdomen.
 One band is directly behind the hind legs and the other is at the
tip of the abdomen Dr. M. Thippaiah

34. Nature of Damage
 Both immature and adult thrips suck sap from cells.
 The preferred feeding site for thrips is the tissue next to the midrib
on the undersurface of leaves, but in severe infestations fruit
is also attacked.
 The first sign of damaging is a silvering of leaves and fruit.
 In severe infestations, the silvering develops a pale yellow to brown
discolouration, speckled darkly with dried droppings.
 In severe cases there will be shedding of leaves and stunting of
growth of trees
Dr. M. Thippaiah

35. First sign of damaging is a silvering of leaves
Dr. M. Thippaiah

36. Management practices
 Spraying of monocrotophos 36WSC @ 1.5 ml / lit.
 Spraying dimethoate 30 EC
or
methyl demeton 25EC @ 1ml / lit. of water
Rasping and sucking activity the apples and nuts forms corky layers on the affected parts
Dr. M. Thippaiah

37. Mealy bug : Ferrisia virgata
( Pseudococcidae : Hemiptera)
 The mealy bug, Ferrisia virgata is a serious pest of cashew in all
cashew growing areas
 Other species of mealy bugs infesting cashew includes
Planococcus citri and Phenococcus solenopsis
 They are soft bodied, covered with milky white coating on the body
Mealy bugs on leaves Dr. M. Thippaiah

38.  They have reproductive potential of laying 100-300 eggs in masses
covered with cottony white mealy filaments
 The eggs are yellowish –brown in colour and within a day they hatch
into crawlers ( At this stage the chemicals are more effective )
 Nymphal period lasts for 26 – 45 days
 Adults lives for 15-20 days
 Total life period is 45-65 days
Nature of damage
The nymphs and adults of mealy bugs suck large amount of sap from
the tender plants parts results in withering of growing shoots,
inflorescence and developing fruits
It can be seen on the lower surface of tender leaves, twigs,
inflorescence, panicles and fruit peduncles
Dr. M. Thippaiah

39. Besides causing direct damage, the bugs excrete large amount of
honey dew on which sooty mould develops which impairs normal
photosynthetic activity
Heavy nut yield loss observed under severe out break conditions
Dr. M. Thippaiah

40. Management practices
 Conditions monitoring and early detection of infestation are essential
to manage this pest
 The cashew Plantation and neighbouring areas should be free from
weeds and alternate hosts
 The infested portion of the plant parts like leaves, inflorescence and
twigs with mealy bug colonies should be pruned and destroyed.
 Fallen leaves under the tree canopy should collected and burnt to
avoid further spread of the pest
 Spray of dichlorovas 76WSC @ 2.5 ml / lit.
or
methyl parathion 50 EC @ 1 ml / lit.
or
dimethoate 30 EC @ 1.75 ml / lit. in combination with fish oil rosin soap
@ 1.75 ml / lit. of water reduces bug incidence effectively
Dr. M. Thippaiah

41. Aphids: Toxoptera odinae
(Aphididae: Hemiptera)
Brown colored aphids infest tender shoots , inflorescence,
nuts and causes shedding of flowers.
Control measures for thrips and aphids:
Spray any systemic insecticides like monocrotophos 0.05%
or dimethoate 0.05%
Dr. M. Thippaiah