Morphology of Melanagromyza obtusa, Red gram podfly

1. ACHARYA N.G RANGAAGRICULTURAL UNIVERSITY
Agricultural college, Bapatla
Course No :ENT 501
Course Title :INSECT MORPHOLOGY
Topic :Morphology of Redgram Podfly
(Melanagromyza obtusa)
Submitted to,
Dr. B. Ratna kumari
Assistant professor
Department of entomology
Agricultural college
Bapatla.
Submitted by,
P. Vijay babu
BAM 18- 41.

2. RED GRAM PODFLY
Melanagromyza obtusa

3. Contents:-
1. Important notes
2. Taxonomic position
3. Morphology
• Head - sclerites, compound eyes, antennae,
mouth parts.
• Thorax - wing venation and leg modifications
• Abdomen - various structures and modifications of
abdomen.
4. Biology and management
5. References

4. 1. Importance notes:-
• In Agricultural Entomology, the pigeonpea pod fly appears in
a list of “the more notable pest species of Agromyzidae” (Hill,
1994).
• In Agricultural Insect Pests of Temperate Regions and Their
Control, the pigeonpea pod fly appears in a list of “important
leaf miner (Agromyzidae) pests” (Hill, 1987).
• The FAO document “Plant Pests of Quarantine Importance
to the Caribbean” mentions, “Can be very serious. Up to
100% pod damage and up to about 85% seed damage
reported in India.
• In Latin America, pigeonpea is both a backyard garden crop
and an export crop grown for canning green seeds (Shanower
et al., 1999).

5. 2. Taxonomic position
• Phylum : Arthropoda
• Class : Insecta
• Order : Diptera
• Family : Agromyzidae
• Full Name : Melanagromyza obtusa Malloch 1914
• Synonym : Agromyza obtusa Malloch (Sigh & Ipe, 1973)
• Common name: Pigeonpea Pod Fly (Shanower et al., 1999)
Bean Pod Fly; Pod Fly (FAO/RLAC, 1989)

6. 3. HEAD
• The head is distinct from the
thorax, with a marked
narrowing at the neck.
• Adult agromyzids can be
recognized by the
distinctive sclerotization of the
head.
• The upper part of the frons,
above the ptilinal suture is
lightly sclerotized and
lacks setae.

7. • The lower part of the frons and the dorsal area of
the head tends to be much more heavily sclerotized
and setaceous.
• Thus, the frontal vitta often forms a distinctive patch
on the head, different in colour and texture from the
rest of the head.
• The compound eyes are usually oval and fairly small,
although in some species, they are larger and more
circular.
• The chaetotaxy is well developed, especially on the
head.

8. • The post vertical orbital bristles
on the head are always present
and divergent, inner and outer
vertical bristles on the head are
well developed.
• They have ocellar bristles, frontal
bristles (two to eight pairs of
frontal bristles, the lower one to
three pairs curve inward, the
other pairs backward), vibrissae
(in some cases weakly
developed), and oral bristles are
always present.

9. Antennae:-
• The basal segment of the
antennae is very short; the
second antennal segment is not
grooved.
• The third antennal segment is
always large, usually round (not
elongated but sometimes with a
sharp point) and usually with
swollen, and the almost bare or
pubescent arista never is
plumose.

10. Mouth parts:-
• The mouthparts are sponging
type and proboscis is usually
short and thick, rarely
elongated and geniculated .
• The maxillary palps are single-
segmented and porrect.
• At the end of the labium, there
are large sponge like organs
called labella.

11. • The labella is a very complex
structure that contain many
grooves known as
pseudotrachea. This structure
is very important as it suck up
liquids like a sponge.
• Once liquid food is drawn by
the pseudotrachea, it will pass
through the food channel into
the oesophagus.

13. 2. Thorax:-
• The thorax has well-developed
dorsocentral bristles, postalar
bristles, supra-alar bristles, and
acrostichal and intra-alar
bristles. The scutellum has two
to four bristles.
• The chaetotaxy of the pleura is
also of taxonomic significance.

14. • The characters taken into consideration are presence
or absence, the number, and the position of setae
and groups of hairs on the,
• Mesopleuron – anepisternal or mesopleural bristles
• sternopleuron – sternopleural bristles
• proepisternum and proepimeron – proepisternal and
proepimeral bristles, or propleural bristles
• Pteropleuron – anepimeral or pteropleural bristles
• Hypopleuron – meral or hypopleural bristles.

15. Wings:-
• All Diptera are equipped with
only one pair of functional
wings, which are on the
mesothorax (front).
• The wings on the metathorax
are transformed into
the halteres or rocker arms.
• The halteres are club-shaped
organs, used to balance the
insect in flight

16. Wing venation:-
• Wing-veins are costa, subcosta, radial, medial and
cubital.
• The costa has one break which is at the end of the
subcosta.
• The subcosta is apparent (faint) and joins vein 1 well
short of the costa, or terminates before it (vein Sc is
complete or incomplete, apically ending in vein R1 .

18. Legs:-
• A few bristles are on the legs, but bristles on tibia 2,
are of taxonomic significance.
• Tibiae are without a dorsal pre-apical bristle.
• Hind tibiae are without strong bristles in the basal
4/5.
• The front femora are without a conspicuous spine
beneath.
• The relatively thin legs have precisely arranged
bristles which also function in chaetotaxy.

19. • The dorsum of the tibia (especially) and the femur is
often identified by a double line of very small bristles.

20. 3. ABDOMEN:-
• The morphology of the
abdomen is substantially
determined by morpho-
anatomic adaptation, in both
sexes, as a function of the
reproduction.
• In general, the 10 urites are
reduced to a lower number of
urites because of structural
modifications of the first urite
and the last.

21. • In females, the last urites
become thinner and stretch
forming a flexible telescopic
ovipositor.
• This morphological
adaptation is often
accompanied by sclerotisation
of the terminal eighth urite,
so that the ovipositor is able
to penetrate through the
tissues of the organism which
will accommodate the eggs
and larvae.

22. Eggs and larva:-
• The egg is oval-shaped, white
or yellowish.
• The Diptera larva is apodous
(with no legs).
• The head is usually devoid of
eyes, has chewing mouthparts,
modified antennae with up to
six segments, more or less
developed or reduced to
papillae.

23. PUPA:-
• The pupa is variable, from barrel
shaped, to a more elongated
shape (coarctate type).
• The outer surface can
segmentation and is more or less
smooth or wrinkled.
• The colour varies from black to
brown to yellowish white.

24. ADULTS:-
• The adult is a medium-sized
green species with a large
ocellar triangle (Spencer,
1973).
• On the abdomens of the
females, the basal cone of
the ovipositor is
conspicuously elongated
(Spencer, 1973).

25. • Females copulate within 24
hours after emergence and
oviposition quickly follows
(Spencer, 1973).
• When fed with honey, the
adult stage lasts for
approximately 12 days;
without feeding, only half as
long (Shanower et al., 1999).

26. DAMAGE SYMPTOMS:-
• Dark brown encrustation on
the pod wall
• Dry pods showing pin head
size hole,
• Seeds shrivelled, striped and
partially eaten

27. MANAGEMENT:-
• Chemical Control:
• Hill (1987) notes that several insecticides, such as
diazinon and chloropyrifos, are effective against
dipterans
• Several studies showed that two or three applications
are more effective in reducing pod fly infestations than
single applications of the same insecticide (Shanower et
al., 1998).
Because of
• (1) the high cost of insecticides used in repeated sprays,
• (2) the comparatively low value of the crops, and
• (3) the cryptic nature of the pest, control by insecticides
may not be feasible.

28. Cultural Activities:-
• Because of its restricted host range (Shanower et al., 1999)
crop rotation will probably influence populations of pigeon
pea pod flies.
• The maturation date of pigeon peas in India greatly
influenced the quality and quantity of damage caused by the
pigeon pea pod fly.
• Pigeonpea cultivars maturing at the end of November had 4%
seed damage; cultivars maturing in mid-February had 11%
seed damage.
• cultivars maturing in the last week of April had 35% seed
damage (Shanower et al., 1998).

29. Natural Enemies:-
• More than 14 species of parasitic
hymenoptera attack the larval
stage.
• The two most important taxa are
Euderus spp. and Ormyrus spp.
(Shanower et al., 1999;
Shanower et al., 1998).

30. PREDICTED CONSEQUENCES:-
• The ARS is seeking a pigeonpea variety that will mature in 120
to 150 days.
• This variety will be introduced into the wheat rotation.
• The pigeonpea variety will be planted just after the wheat has
been harvested (usually in June) and will be harvested before
the replanting of wheat (usually in October) (Weaver, 1998).
• In Latin America, pigeonpea is both a backyard garden crop
and an export crop grown for canning green seeds (Shanower
et al., 1999).

31. REFERENCES:
• Ahmad, T. 1938. The tur pod fly, Melanagromyza obtusa, a
pest of Cajanus cajan. Indian Journal of Agricultural Sciences
8(1):63-76.
• Delfino, M. D. and Hardy, D. E. 1967. A Catalog of thje
Diptera of the Oriental Region. The University Press of Hawaii,
Honolulu, HI.
• Hill, D. 1994. Agricultural Entomology. Timber Press, Portland,
OR.
• Shanower, T. G., Lal, S. S., and Bhagwat, V. R. 1998. Biology
and management of Melanagromyza obtusa (Malloch)
(Diptera: Agromyzidae).
• Singh. S. 1971. Agromyzidae Exploration in India. School of
Entomology, St. John’s College, Agra, India.

32. Submitted to,
Dr. B. Ratna kumari,
Assistant professor,
Dept. of entomology,
Agricultural college,
Bapatla.
Submitted by,
P. Vijay babu,
BAM-18-41,
Msc .Ag 1st year,
Dept. of entomology,
Agricultural college,
Bapatla.