Plant Protection - Stored Grain Pest Nature of Damage, Diseases and their Control Measures.

1. Stored Grain Pests
and their control

2. Stored grain pest and their management
Cereal and pulses must be stored before being processed
and sown. In Nepal, a large proportion of grain is stored in the
home for domestic consumption and re-sowing. There are many
pests which reduce the quantity and quality of stored grain. A
number of stored grain insects, fungal pathogens, rodents and
birds can cause significant losses. Among the stored grain pests,
the following insect species, diseases and rodents cause post-
harvest losses of grain.

3. Insects
Primary Insects
1. Rice weevil (Sitophilus oryzae)
2. Maize weevil (S. zea mays)
3. Grainary weevil (S. granarius)
4. Angoumois grain moth (S. cerealella)
5. Lesser grain borer (Rhizopertha dominica)
6. Khopra beetle (Trogoderma granarium)
7. Pulse beetle (Callosobruchus chinensis)

4. Insects
Secondary Insects
1. Red-rust flour beetle (Tribolium castaneum )
2. Saw toothed grain beetle (Oryzaephillus surinamensis)
3. Rusty grain beetle (Cryptolester forugieus)
4. Indian meal moth (Plodia interpunctella)

5. Fusarium species of fungus are
predominant ones and can produce
mycotoxin in stored grains. The
predominant species prevailing in
Nepal are:
● Giberella fujikuni
● Fusarium graminearum
● Penecillus spp
● Aspergillus spp
Diseases

6. Rodents
 Rattus rattus (House rat)
 Bendicata bengalensis (Field rat)

7. Identification
Prominent beak which is known as snout. They
contain small dot-like grooves which are
scattered in the body. Rice weevils are
generally smaller than maize weevils.
Damage
Both adult and larvae cause damage by
feeding and contaminating the grains. The rate
of development of Sitophilus species
population varies with grain moisture content
and temperature. The developing larvae live
and feed inside the grain hollowing it out in the
process. The entire grain is usually destroyed by
the time adult emerges.
Rice weevils; Maize weevils;
Grainary weevils

8. Management
Store hygiene: In good storage
suitable site should be need. These site
should be airy, shady, cool and dry
locations. New and old lots of grains
should not be stored together.
Drying: A moisture content of not more
than 12-13 % depending upon the R.H. is
essential before grains are stored .
Drying helps to reduce grain moisture
content in grains.
Rice weevils

9. Management
Choice of variety: Nepalese farmers
prefers to grow maize varieties that
have hard intact teguments or tightly
closed husks. Modern hybrid maize
varieties often possess open husk
which don little to prevent the
infestation by weevils.
Time of harvesting: In general, farmers
do not harvest maize unless it is fully
matured because of the weevil
problem. Timely harvesting followed by
drying the grains can ensure that
weevils can’t easily bore into grains.
Rice weevils

10. Management
Use of botanicals: such as natural insecticides to
combat post harvest insects. For example:
● Use of fumeric powder @2%
● Use of commercial mustard oil @1%
● Use of timur
Use of household lime and wood ash.
Use of aluminum phosphide.
a. Volume basis:
under air tight condition @20 tablets/ 30m3
Under partial airtight condition @40-80 tablets/
30m3
b. Weight basis:
under airtight container @ 1 tablet/ metric ton.
Under partial airtight container @ 2-4 tablet/
metric ton.
Rice weevils

11. Management
Disinfecting the store room and container
with malathion dust.
Rice weevils

12. Hosts: cowpea, black gram, lentil and other
pulses.
Identification: Adult have long antennae,
and are strong fliers.
Nature of damage: Both adult and grub
(larva) damage the grain. They bore the
grain, feed it and make unsuitable for
consumption and germination. The
infested pods are then harvested and
taken into the farm stores where further
development takes place. The adult
produce spoiling more than what they
feed. The damage is peak at April- Sep. and
low in Oct.- Nov.
Pulse beetle

13. Management
Cultural control: can be effective in
growing vulnerable crops at least half a
mile away from farm stores which are the
primary source of infestation.
Storage hygiene
Drying
Choice of variety
Time of harvesting
Pulse beetle

14. Hosts: maize, wheat both in field and in
grain stores.
Nature of damage: during monsoon, the
damage is at peak. The larvae bore into the
grain and feed on their content. As larvae
grow, the extend the hole which partly get
filled with pellets of excreta. Usually, about
30-50% of the grain contents are consumed,
but sometimes the larvae finish off the entire
grain. With infestation the grains give out an
unpleasant smell and present an unhealthy
appearance, each grain being covered with
scales shed from the moths.
Angoumois grain moth

15. Management
Same as Rice Weevils
Angoumois grain moth

16. Host: maize, wheat, barley (crushed grain and
flour)
Nature of damage: larvae of the insects are of
destructing nature. They feed on stored products
and the infected products give terrible and off
smell which makes grain inedible. Beetles feed
whole grains but require flour or broken grains
for breeding purpose. Beetles are abundantly
present in broken grains and flour rather than
full grains.
Red-rust flour beetle

17. ● Use whole grain for storage.
● Storage area should be neat and clean.
● Low humidity, low grain moisture and low
temperature should be maintained.
● Use metallic bin and other modern storage
utensils for the storage.
● Storage the seeds after drying.
● Use aluminium phosphide or Celphos.
● Mix the seed with neem seed kernel extract
or with Bojho extract.
Management practices of stored grain
pests:

18. Thank You..