This document discusses insect pests that affect forest nurseries and their management. It begins by explaining the importance of forest nurseries for forest regeneration and how insect pests can cause losses. It then categorizes different types of insect pests that affect nurseries based on factors like frequency of association, life stages affected, and type of damage caused. Specific pests discussed include armyworms, cutworms, white grubs, scarab beetles, grasshoppers, defoliating caterpillars, and more. Management strategies covered are prophylactic cultural methods, curative cultural/mechanical/biological/chemical methods, and integrated pest management. Examples of pests and their management in different forest nursery

1. Tropical Nursery & Plantation
diseases: Symptoms, Agents,
Remedial measurements, IPM
Vikas Kumar
vkskumar49@gmail.com
PhD Scholar

2.  Forest nurseries are integral part of forest regeneration since a nursery contributes to
successful forest regeneration.
 In spite of the best efforts made nurseries suffer losses due to insect pest damage.
 Insect pests occur in mother bed or in the transplant beds and even after out-planning
them in the field.
 Such field losses starts with the improper management of pest problems in seedling in
nurseries, paving way for carrying over of life stages of pests of field.
 So the pest problems do not confine only to nurseries.
 Nursery managers must analyses the damage or losses caused by insects and the
costs involved in preventing such pest problems.
 There is very great demand for seedlings of various tree species for different
plantation programmes.
 In order to produce quality-planting materials, the nursery has to be managed properly
against pest insects, which may assume serious proportions resulting in partial or total
loss of planting material.

3. TYPES OF INSECT PESTS
No. Pest
Category
Frequency of association
with the plant species
Examples
a Persistent
pests
Present throughout the year on
seedling
Myllocerus sp., and thrips on Elangi
b Regular pests Occurrence most frequently on
seedlings and have close
association with that species
Aphids and Psyllids on Albizia lebbeck and
Cirtrus butterfly Papilio on Aegle and wood
apple
c Occasional
pests
Occur rather infrequently
without a close association
with the particular plant
species.
Bag worms on Acacia and Scale insect
Megapulvinaria on Neem
d Seasonal
pests
Appear mostly during a
particular season of the year
Ghamar defoliator, Calopepla, Teak
defoliator Hyblaea, skelectonizer, Eutectona
and parnara on Pongamia
e Sporadic
pests
Appear infrequently in the few
isolated localities
Scale insects on Albizia and larva of
Catopsilia butterfly on Cassia.

4. CATEGORIOZATION OF INSECT PESTS
NO PEST
CATEGORY
STAGE OF INSECT TYPE OF INJURY ON PLANTS EXAMPLE
a Seed feeders Both adult and
immature stages
complete their life
cycle fully or in part
in seeds
Feed on seeds of trees either in the
field or during seed storage
Tamarind seed
feeder Carryedon
serratus
b Defoliators Adults and/or
immature stages
Feed on the leaves and cause
damage by loss of young and
mature leaves.
Teak defoliator,
Ailanthus defoliator
c Sap feeders Both adults and
immature stages
Insects pierce the plant tissue with
the help of pointed mouth parts and
feed on the plant sap.
Scale insects,
plant bugs.
d Borers adults or immature
stages
Insects bore into the stem or roots
of plants for feeding and shelter
Pouch gall on
Pongamia
e Gall makers Adult phase, the
immature stages or
entire life cycle is
spent inside the galls
Sustained feeding
by the insects leads to the
development of abnormal structures
called galls
Pouch gall on
Pongamia
f Sub-
terranean
pests
Colonies of termities
or larval stages of
some insects
Insects remain underground and
feed both on roots and the above
ground plant parts of plants.
Termities,
White grubs

5. Hoplocerambyx spinicornis

6. INFESTED PLANT
- Galls on midrib, petiole, young shoots
- Initially green, turns pink and finally red
- Deformed and branched seedlings

7. Shoot gall on Tectona grandis caused by Asphondylia tectonae

8. Marginal gall on leaf of Terminalia sp. Whole leaf rolled into a gall like structure
Nymph of Trioza hirsuta Adult of Trioza hirsuta

9. TYPES OF INJURY ON PLANTS BY INSECTS
NO TYPES OF INJURY DESCRIPTION EXAMPLE
1 DEFOLIATION
1. Free feeding Consume the whole leaf and minor veins, leaving large veins untouched Teak defoliator
2. Leaf mining Build tunnels inside the leaf tissue in between the upper and lower epidermis
resulting in irregular linear or round patches.
Pongamia blotch minor
3. Skeletonizing Feed on the leaf tissue leaving the veins intact leading to a skeletonized
appearance.
Teak skeletonizer
4. Shelter feeding Make shelter out of the plant parts like leaves, stem or flowers and then feed on
the plant
i. Leaf webbing Web leaves together for protection and feed on the enclosed foliage. Leaf webber in Elengi
ii. Leaf folding or
rolling
Roll an entire or part of the leaf, fasten it with silk and feed on it by remaining
inside
syzygium leaf roller
beetle
iii. Leaf tying Tie up leaves, debris or needles to prepare a bag with the help of silk secreted and
feed by remaining inside the bag.
Bag worm in Acacia
II STEM OR ROOT
BORING
Bore into the roots or stem and feed on the internal pith resulting in tunnels in the
affected region.
Teak borer
III GALL Making Feeding by an individual insect or group leads to the production of galls. In many
cases, adult or immature stage of the insect uses this gall as a shelter and derive
nutrient from the tissues.
Mite gall in Pongamia
IV BARK FEEDING Feed on stem surface leaving irregular or continues girdling on the surface. Bark feeding catepillars.
V SAP FEEDING Damage plants by making punctures and desapping resulting in chlorosis,
weakening and drying
Scale insects and plant
bugs
VI ECG LAYING
DAMAGE
Punctures or slits made during egg laying make the shoots dry. Cow bugs in Acacia

10. MAIN PEST TYPES IN FOREST NURSERIES
ARMYWORM
 These are larvae of noctuid moths.
 These lay eggs on the lower surfaces
of the leaves of the host.
 Defoliators
 Losses of 40% of seedlings by
Spodptera sunia in nursery of Pinus
caribea, P. tropicalis and Casuarina
in Cuba (Mellado, 1976).
 56% of seedlings of teak lost:
S. litura (Roychoudhury et al., 1995)

11. CUTWORMS
11
 Larvae of noctuid moth.
 Soil inhabiting pests, and they cut-off
seedlings at ground level and drag
them into shallow burrows in the soil.
 Moths active at night and lay eggs in
moist, recently cultivated soil, stems
and leaves of plants.
 Young cutworm caterpillars climb
plants and either skeletonize the leaves
or eat small holes in them.
 Agrotis ipsilon and A. segetum are
cosmopolitan and important pests of
conifers in nurseries (Sen-Sarma,
1987)
 Damaged 20% seedlings of Albizia
lebbek and Eucalyptus tereticornis- A.
ipsilon (Chaturvedi, 1996, Bihar)

12. WHITE GRUBS
 Larvae of scarab beetles damage trees
by feeding on roots, often ring-barking
and severing the stem below ground
level.
 Live in soil, feeding on organic plant
matter when young and later on plant
roots.
 Injury is recognized when patches of
previously healthy seedlings begin to
exhibit drought-like symptoms, thus a
faded green to brown colour and die.
These seedlings are easily pulled out
of the soil with a gentle tug.
 Damaged 30% seedlings of Acacia
nilotica, Azadirachta indica and
Tectona grandis- Holotrichia serrata
and (Ali and Chaturvedi, 1996) H.
consanguinea

13. SCARAB BEETLES
 Scarab beetle adults, and their
larvae (white grubs), defoliate
seedlings and girdle stems.
 Thakur and Sivaramkrishnan
(1991) reported that 70-80 % of
the seedlings are defoliated by
cockchafer swarms in April to
May in nurseries of Eucalyptus
tereticornis, Dalbergia sissoo,
Syzygium cuminii, Peltophorum
ferrugenium and Santalum
album in Southern India.

14. GRASSHOPPERS AND CRICKETS
14
 Grasshoppers browse the foliage of
young plants, and may break or sever
twigs and stems.
 Crickets sever stems at ground level and
drag the plants into their burrows for
feeding.
 In Ghana, there have been regular
outbreaks of Zonocerus variegatus
every year in various localities (Wagner
et al., 1991).
 Mole crickets cause a great damage by
tunneling, which disturbs the soil and
sometimes uproots seedlings (Bacon and
South, 1989).
 In Venezula, Gryllotalpa sp. Caused
losses of 20 % of young Pinus caribea
seedlings in a nursery within a month of
sowing (Vale et al., 1991)

15. DEFOLIATING CATERPILLARS
15
 Species of Lepidoptera.
 In India, the larvae of Pyrausta
machaeralis (Pyralidae) and
Hyblaea puera (Hyblaeidae) are
major pests of seedlings of teak.
 Eligma narcissus is a major pest
of Ailanthus triphysa and A.
excelsa.
 Young caterpillars eat the
chlorophyll tissues of leaves or
the tender areas near margin and
older larvae leave only the mid-
rib.
 According to Sivaramakrishnan
and Remadevi (1996), almost
100% defoliation of nursery
stock of A. triphysa.

16. LEAF TIERS ON ROLLERS
 Eggs are laid on the upper surface
of leaflets and newly emerged
caterpillars combine to web two
overlapping leaves together to
make a nest.
 The caterpillars feed gregariously
and skeletonize the surface of the
leaves which then wither. The
larvae then crawl out of the
damaged leaves to the nearest pair
of suitable fresh leaves and repeat
the process. Pupation occurs in the
rolled up, withered leaves.
 Damage in one Eucalyptus nursery
in Ghana exceeded 50% in some
beds (Wagner et al.,1996).

17. LEAF BEETLES
 Chrysomela populi, a pest of
popular, beetle that chew foliage
of nursery plants causing growth
setback, deformity or mortality.
 Eggs are laid in cluster on the
lower surfaces of leaves and
emerging larvae feed
gregariously at first,
skeletonizing the leaf and finally
consuming large pieces of it.
 Nodostoma waterhousie, showed
infestation levels ranging from
less than 10% to almost 60%
(Singh and Singh, 1995)

18. WEEVILS
 Weevils like Myllocerus sp. Cause
heavy injury to Acacia senegal and A.
tortilis in the Thar Desert of India (Vir
and Parihar, 1993).
 Aesiotes notabilis, in Araucaria
cunninghamii seedlings, cause tunneling
in the main roots, chewing away woody
tissues as well as bark and finally
forming cocoons at or near ground level
( Brimblecombe, 1945; Elliott et al.,
1998)

19. LEAF CUTTING ANTS
 Atta sexdens caused 71.3%
damage to rubber trees, Hevea
spp. in Brazil (Calil and Soares,
1987).

20. PSYLLIDS
20
 Sap-sucking psyllids cause
stunting, distortion, wilting,
tissue, tissue necrosis, loss of
vigour and plant death.
 Their sucking causes the
periphery of the leaves to curl,
roll and later turn yellow or
brown.
 Attack can result in die-back,
stunted growth, defoliation and
death.
 In India, gall formation and
stunting by psyllids has been
the main problem for Albizzia
odoratissima and Pterocarpus
marsupium in nurseries in
Kerala (Mathew et al., 1991).

21. MEALYBUGS, SCALES AND APHIDS
 MEALYBUGS- free-living insects
and their bodies may be covered with
fine powder or meal. The females are
sap-sucking and attack roots, stems,
leaves and fruits of plants.
 SCALES- In TN, seedlings of the
Rhizophora mucronata were infested
by the scale Aspidiotus destructor
causing the leaves to wither and fall
(Kathiresan, 1993).
 APHIDS- Cinara and Pineus are
important examples.

22. TERMITES
22
 They damage the root system
belowground level by
hollowing out or ring-barking
the tap-root, ultimately causing
death of seedling.
 Thakur (1992) records 80%
mortality of Casuarina seedlings
and 10-30% mortality of Acacia
nilotica.

23. MANAGEMENT PRACTICES
 Pest management is reducing pest problems by careful
manipulation and adoption of selected control methods.
Prophylactic
methods
•Cultural methods
•Field sanitation
•Treatment with
chemicals
Curative
methods
•Cultural methods
•Mechanical methods
•Biological methods
•Chemical methods
•Types of Insecticides
•Botanical pesticide
Integrated
Pest
Manageme
nt
•Monitoring and evaluation
•Cultural and mechanical
methods
•Biological control
•Chemical control

24. INSECT PESTS IN FOREST NURSERIES
Type Occasional pest
Description Larva occurs inside a bag made up of silk threads
secreted by larva and other extraneous materials,
mostly the spines of Acacia nilotica. Pupates within
the bag. The adult female remains inside the bag and
it is an apodorus and apterous from (without
appendages and wings) and only the male emerges as
winged moth.
Injury Defoliation
Damage The bag worm usually strips the sapling off foliage.
They prune off twigs, growing shoots and buds for
making the bags.
Occurrence May, September to October
Alternate host Tamarindus indica and Cauarina equisetifolia
Natural enemy Sinophorus psycheae
Management
measures
Mechanical
Hand picking bags and destruction can reduce the
pest
population.
Chemical : 0.05% monocrotophos spray.
Acacia nilotica

25. INSECT PESTS IN FOREST NURSERIES
Type Occasional pest
Description Minute light brown scales with a row of white filaments
all around the scale, occurring underneath the leaflets,
petiole and stem region
Injury Feed on plant sap
Damage Loss of plant vigor and wilting
Occurrence September to October
Management
measures
Mechanical
Plucking and destruction of affected leaves. During
early infestation stages, affected seedlings can be
segregated from the main bed and pesticides can be
applied.
Chemical: 0.06% dimethoate or 0.05% methyl demeton
can be applied during severe infestation.
Second round of spray after 15 days can be given if the
problem reoccurs.
Acacia mangium

26. INSECT PESTS IN FOREST NURSERIES
Type Regular pest
Description The larva, a hairy caterpillar remains concealed below
the leaves. It is bright yellow in colour with black
bands which become more prominent as it grows.
Pupation occurs in a boat shape pupal case attached on
the stem of Ailanthus seedlings. Adult is also a brightly
coloured moth with dark brown and bluish fore wings
and orange hind wings having black borders
Injury Larvae are voracious feeders and defoliate the nursery
bed
Damage Complete defoliation of seedlings result in slow or
retarded seedling growth
Occurrence October to December
Alternate host Ailanthus malabaricus, Ailanthus triphysa
Management
measures
Mechanical
integrated pest management measures
Ailanthus excelsa

27. INTEGRATED PEST MANAGEMENT
 It involves the combination of all appropriate pest management
practics into a package which reduces the economic losses caused by
insects to tolerable levels.
 Speight et al., 1999 made an attempt to summarize the types of
management that might be employed in a general IPM system for
tropical forestry.
 Accordingly, the strategy consists of some stages.
 Stage A deals with planning and decision making, carried out before
a tree seed is ever planted.
 Stage B and C must be fully implemented as an assurance against
failure of stage A.
 Stage D, the actual hands-on manipulation of insect pest
populations, comes into play once the previous stages have been
implemented.
27

28. STAGE A Site choice, avoid low
tree vigour; consider
life history and
previous cultivation
Tree sp or
genotype choice;
consider end-use
and economics
Location choice;
proximity to
older stands and
natural
vegetation
Silviculture choice;
mixed vs
monoculture, shade
resistance and
enrichment
STAGE B Inventory major pests
and diseases in locality;
consider history of
problems
Research
biology and
ecology of major
pest and diseases
sp; host-pest
relationships
Inventory major natural enemies in
locality-pathogens, predators and
parasitoids
STAGE C Determine potential impact damage, with
economic thresholds
Monitor pest levels during vulnerable
growth period; relate to economic
thresholds
STAGE D Ecological control:
sanitation, thinning,
nursery treatment,
establishment
Biological
control:
parasites,
predators and
parasitoides
Chemical control: insecticides, growth
regulators, pheromones
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29. RESEARCH AND MANAGEMENT PROBLEMS
OF USING IPM IN FORESTRY (CLARKE,1995)
PROBLEMS USING IPM IN FORESTRY
•Defining economic injury levels (EIL) of pests.
•Defining economic thresholds (ET) of pest damage.
•Carrying out monitoring procedures.
•Implementing management tactics.
•Operating under tight economic constraints
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