Course Code: AGB503
Course Title :Pest of Crops and stored Grain and
their Management
Program: B.Sc. (Hons.) Agriculture
Semester V
Academic Year 2023-24
Dr Tufail Ahmad
Outlines
Introduction
Pest of maize
Pest of millets
Pest sorghum
Sorghum shoot fly
Termites (Polyphagous pest)
Exercise
Learning Outcomes
References
Pest of maize and sorghum
Insect pests Of Maize , Sorghum and Millets.
The following are the major insect pests that attack maize sorghum and
millets:
Major pests:
1-Corn Leaf Aphid, Rhopalosiphum maidis ; Order :Hemiptera,
family:Aphididae.
2-Sorghum shoot fly, Atherigona soccata ;Order:Diptera Family-Anthomyidae
3-Maize and sorghum stem borer: Chilo partellus(Swinhoe)
Order: Lepidoptera Family-Pyralidae.
4--Pink stem borer, Sesamia spp. Order: Lepidoptera Family-Noctuidae.
5-Sorghum midge; Contarenia andropogonis=Stenadiplosis sorghicola ;Order-
Diptera Family-Cecidomyidae.
6. Fall armyworm Spodoptera frugiperda Order: Lepidoptera Family-Noctuidae
Pest of maize and sorghum
Sorghum shoot fly
Classification:
Scientific Name-Atherigona soccata.
Order-Diptera
Family-Anthomyidae
Host plant:Its preferred host is sorghum. Besides sorghum it also attack
maize. Wheat , smaller millets and Sudan grass is also attacked if the
preferred hosts are not available.
Distribution:
It is widely distributed in Europe Australia and Asia. It is a very serious pest
of sorghum in Eritrea.
Pest of maize and sorghum
Sorghum shoot fly
Identification:
It is a small size fly much smaller than the house fly. It has 3 pairs of black
spots at the end of abdomen.
Eggs are shining white about 2 mm in size round or oval. Maggots are
creamy white in color measuring from 5 to 8 mm depending on the age
and the hosts. Pupa are small dark brown in color measuring < 6 mm in
size.
Nature of Damage:
The damage is caused by the maggots. One maggot damage only one
seedling. After hatching from the eggs the maggots enter in the whorl of
the small seedlings and cut the growing point. It results in the dead-heart
formation. Tillers may arise from the attacked plants but they do not bear
the cobs. Plants up to the age of 3 weeks are attacked by the fly . Older
plants are not preferred. In severe conditions the pest may cause 100 %
loss of the crop.
Pest of maize and sorghum
Sorghum shoot fly
pupa
Adult Larvae
Pest of maize and sorghum
Life History:
Life cycle is completed in 17 to 21 days, Metamorphosis is complete .
Female lays about 40 eggs. 1 to 5 eggs are laid every day. The eggs are laid
singly on the lower side of the leaves. In the case maize the eggs are
mostly laid on the first (lower) rounded leaf. These eggs hatch in 1 to 3
days and maggot jump into the whorl of the plants where after feeding for
6 to 9 days pupate into the damaged plants or in the soil. Pupal period is
about 1 week.
Total life cycle is completed in about 14 to 21 days. The pest remain active
all the year round. In the off season the pest may survive in the damp
places on the grasses or wild sorghum. In the absence of the host pest
over winter in pupal stage. There may be 10 to 15 generations in a year.
Pest of maize and sorghum
Management:
Use increased seed rate.
Rouging of infested plants and thinning of extra plants.
Grow resistant varieties.
Seed treatment with systemic insecticides like carbafuran, carbaryl,
dimethoate, oxydemeton methyl, or Nuvacron may be useful in
protecting the early seedlings from the pest injury.
Carbafuran granules applied at time of sowing 3g/m row lenth or placed
near plant whorl 5-15 days after germination.
Removal or destruction of the alternate hosts like Sudan grass , wild
sorghum or other grasses from the vicinity of the field reduce the pest
incidence..
Maize and sorghum stem borer
Maize and sorghum stem borer
Classification: Scientific Name: Chilo partellus(Swinhoe)
Order: Lepidoptera
Family: Pyralidae
Host: Sorghum, maize and to some extent pearl millets and minor millets.
Distribution:Occur all over the world wherever the sorghum and maize
crops are grown. Besides, it may also attack other graminaceous crops.
Identification:
Larva is dirty yellowish white with 4 dotted dark colored stripes on the
dorsal side. Pupa obtact reddish- brown in color. Male pupa is invariably
smaller than the female pupa. Adult moths are straw colored with dark
scales on the fore wings Fore wings have dark colored spots at the outer
margin. Hind wings are clear white in color.
Maize and sorghum stem borer
Nature of Damage:
Damage is done by the larvae .The first instars’
larvae after hatching from the eggs feed on the
epidermis of the tender leaves in the whorl of the
plants. Later the larvae enter in the midrib and
make its way down in to the stem and tunnel the
stem through the nodes and internodes. The
stalks become weak and break- down when the
heavy winds blow, such stalks breaks from the
nodes. The cobs on such plants dry before grain
formation and maturity of the grains in the cobs.
The loss to the yield may vary depending on the
stage of the crop attacked and the intensity of
the pest. In severe incidence losses up to 50%
have been recorded.
Maize and sorghum stem borer
Life history:
Female moths lay eggs on the lower side of the leaves in clusters of 20
to 100 eggs. A single female may lay 200 to 600 eggs.
The freshly laid eggs are creamy white in color.
They become brownish and later black at the time of maturity.
The eggs hatch in 3 to 4 days. The larvae become full grown in about 14
to 28 days.
The larvae make tunnel in the stem and finally pupates in the pupal
chamber in the stem. The moths emerge from the pupae in about one
week.
Maize and sorghum stem borer
Life history:
Moths come out of the stem through the exit hole in the pupal chamber.
One life cycle is completed in 3 to 4 weeks.
Five to six over lapping generations are found during the crop season.
In the month of October, the insect, undergo diapause in larval stage
during the off season in dry stalks of host plants.
The diapausing larvae, in the stalks or stubbles regain activity in the
moths of coming June –July when the rains start.
The larvae then pupate in the stalks and moths emerge in a week’s time.
These moths mate and female lay eggs on the fresh crop.
In case the maize or sorghum crop is not available ,it may lay eggs on the
wild hosts or grasses and repeat the cycle.
When the crop is available the pest may again infest it.
Maize and sorghum stem borer
Maize and sorghum stem borer
Management:
Increase the seed rate and up root the damaged plants . It will compensate
the loss of the plants due to the incidence of the pest.
Cultural control: Usually the control method used stem borer are
Timely sowing
Crop rotation
Tillage
Fertilizer management
Removal of dead heart
Management of crop residue
Field sanitation
Intercropping
Maize and sorghum stem borer
Management:
Spraying of contact insecticides 2 to 3 times at the time of pest incidence
will kill the fist instar larvae.
Application of lindane or carbofuran granules in the plant whorl has been
found effective in the control of the pest.
Destruction of alternate hosts like wild sorghum, Sudan grass from the
vicinity of the field should be carried out.
The stubbles left in the field after the harvesting of the crop should be
collected and burnt as they may carry diapausing larvae of the pest.
The maize and sorghum stalks which the farmer store for animal fodder
should be stored after chaffing into small pieces with chaff cutter. It will
destroy the diapausing larvae.
Natural enemies or biological control agent, they belong order
hymenoptera:
Egg parasitoids-Trichogramma minutum , Bracon chinensis
Larval parasitoids.- Apantalis flavipes, Microbracon chinensis
Maize and sorghum stem borer
Difference between shoot fly damage and stem borer damage
Shoot fly Stem borer
Dead heart in sorghum is caused by shoot fly at Stem borer cause dead heart after 20 days germination
seedling stage <30 days plant upto 50 days old plant
Shootfly cause damage only to the most central shoot Stem borer cause dead heart to the two central leaves
of the crop.
Larva do not make tunnel and eat decaying material Larvae make tunnel towards downwards.
of plant.
