BIOLOGY OF COTTON FLOWER BUD MAGGOT, DASINEURA GOSSYPII FLETCHER – AN EMERGING PEST ON Bt COTTON IN KARNATAKA, INDIA

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BIOLOGY OF COTTON FLOWER BUD MAGGOT, DASINEURA GOSSYPII
FLETCHER – AN EMERGING PEST ON Bt COTTON IN KARNATAKA, INDIA
Pritam Chakraborty, S. T. Prabhu, R. A. Balikai and S. S. Udikeri
Department of Agricultural Entomology, University of Agricultural Sciences, Dharwad-580 005, India.
e-mail: pritamchakraborty36@gmail.com, prajostp@yahoo.com
(Accepted 28 December 2014)
ABSTRACT : A laboratory experiment was carried out at the Agricultural Research Station, Hanumanamatti, UAS, Dharwad
to study the biology of cotton flower bud maggot, Dasineura gossypii Fletcher. The present study revealed that the different life
stages of D. gossypii viz., eggs, first instar maggot, second instar maggot, third instar maggot, pupal period, adult stage (male)
and adult stage (female) was of 1.5 ± 0.5, 1.2 ± 0.4, 1.7 ± 0.45, 2 ± 0.0, 4.4 ± 0.66, 1.2 ± 0.4 and 1.3 ± 0.45 days, respectively. Both
adult male and female are minute, soft bodied, orange in colour, weak flier and short lived. Males and females can be easily
distinguished by the presence of ovipositor or by intensity of hairs in antennae which were more in males compare to females.
The peak mating period was observed between 12.00 to 13.00 hours, though maximum oviposition was observed between 09.00
to 11.00 hours. Number of females use to lay eggs in a same square. From field collected samples 30.6 ± 3.77 numbers of eggs
per square have been traced. In laboratory condition fertility, sex ratio (female: male) and per cent adult emergence was
recorded as 30 per cent, 1.45:1 and 85.71, respectively. The number of generations per year was recorded as 8-10.
Key words : Dasineura gossypii, incubation period, sex ratio, fertility.
J. Exp. Zool. India Vol. 18, No. 1, pp. 143-146, 2015 ISSN 0972-0030
INTRODUCTION
Cotton is the term used to describe cultivated plant
species of genus Gossypium. The English word comes
from Arabic “qutum” or “kuntum”. It is also known as
“White gold”, “Queen of fibre” and is an important cash
crop. It supplies 75 per cent of total raw material needed
by textile industry in our country. About 60 million people
depend on activities relating to cotton cultivation, cotton
trade and it’s processing for their livelihood. In India, it
provides employment to 25 per cent of total industrial work
force and earns export of more than 60,000 crores,
which is 30-35 per cent of total export earnings (Gumber
et al., 2008).
Cotton is vulnerable to pest and diseases. Totally, 162
insect pests attack on cotton, out of which 15 are very
serious. Among the insects, thrips, aphids, leaf hoppers,
whitefly, cotton bollworms are some of the important pests
of cotton which cause 70-80 per cent damage to cotton.
In India, these insects cause annual loss of at least US$
300 million. Insecticides valued at US$ 660 million are
used annually on all crops in India of which about 55 per
cent are used on cotton alone (Manjunath, 2005; Rai et
al., 2009).
Array of some emerging pests like mealy bugs
(Phenacoccus solenopsis Tinsley), mirid bugs,
Creontiades biseratense (Distant) and flower bud
maggot, D. gossypii Fletcher are occurring seriously in
southern part of India especially in Karnataka (Udikeri et
al., 2011).
Flower bud maggot, D. gossypii (Cecidomyiidae:
Diptera) has appeared as potential pest for first time during
2009 in Karnataka with severe incidence in farmer’s field
at Hesarur village (Taluk: Savanur, District: Haveri). It
has been reported that the females of D. gossypii
preferred to lay eggs in square tips, where they lay 42-45
eggs. There are 3 instars in the life history and pupation
takes 4-5 days on bracts extending total lifecycle up to
10-13 days. The incident of flower bud maggot is
increasing day by day in Karnataka. Currently more than
90 per cent fruiting body damage has been recorded in
largely cultivated Bt cotton cultivars viz., Kanaka and
Neeraj. At present, better insecticide and other options
of management are also not available for this pest (Udikeri
et al., 2011).
MATERIALS AND METHODS
The biology of cotton flower bud maggot was carried
out in laboratory condition. Fully matured larvae were
collected from the field and kept in small petri dishes (5
cm diameter) for pupation. After pupation the pupae were
collected and kept in rearing cages for emergence. Five
pairs of newly emerged male and female were introduced
in to the rearing cages at the rate of one pair per cage.
Cotton wad soaked in ten per cent honey solution was
kept in the petri dishes to provide food for the adults. The

144 Pritam Chakraborty et al
ellipsoidal shape.
Larval stage
The larvae of cotton flower bud maggot, D. gossypii,
underwent three instars. The total larval period ranged
from 4 to 5 days. The newly hatched, first instar larvae
were white, transparent, elongate, slightly oval. The length
and width of first instar larva was found as, 0.66 ± 0.03
mm and 0.12 ± 0.02 mm, respectively, and the first instar
larval period was of 1.2 ± 0.4 days. The second instar
larvae were milky white to slightly cream coloured, the
length and width was recorded as 1.28 ± 0.05 mm and
1.15 ± 0.03 mm, respectively. The second instar larval
period was of 1.70 ± 0.45 days. Third instar larvae were
orange in colour, spindle shaped and length and width was
recorded as 1.72 ± 0.08 mm and 0.35 ± 0.04 mm,
respectively and the third instar larval period was of 2.0
± 0.0 days.Similar studies on larval stage was made by
Bosio et al. (1998) who reported there were three larval
instars and in blueberry gall midge, D. oxycoccana, each
successive instar larvae became darker in colour, going
from white to orange. Mature larvae ranged from 1.75 to
1.85 mm in length. Under laboratory conditions larvae
required approximately ten days to develop. Mahr (2005)
reported that blueberry gall midge, D. oxycoccana, later
instar larvae were 1.5 to 2 mm long, eyeless and legless.
Maia and Vasquez (2006) reported that the larval body
length of Dasineura theobromae varied from 1.9-2.1
mm. Udikeri et al (2011) reported that the cotton flower
bud maggot (D. gossypii) had 3 instars in its life cycle.
Mihaela et al (2012) reported that the larvae of blueberry
gall midge (D. oxycoccana) developed through 3 instars,
first instar was whitish and leg less and less than 1 mm in
length, second instar 1.75-1.85 mm length and orange in
colour, third instar represented the pre-pupal stage, during
which the larvae dropped to the ground to pupate in the
soil. Each instar lasted for 2-4 days.
Pupal stage
Pupae are orange in colour and covered by a white,
silken cocoon. Pupation usually occurs inside the bract
but sometimes in soil also. The pupal period lasted for 4.4
± 0.66 days. The length and width of pupae was recorded
as, 1.64 ± 0.06 mm and 0.30 ± 0.08 respectively. Similar
studies on pupae were made by Bosio et al (1998) and
they reported that the pupae of D. oxycoccana, blueberry
gall midge were approximately 1.1 to 1.3 mm long and
orange in colour and the pupal period varied for 8 to 10
days.Maia and Vasquez (2006) restudied the biology of
D. theobromae and reported that pupal length varies from
1.6-2.4 mm. Udikeri et al. (2011) reported that the pupal
period of cotton flower bud maggot (D. gossypii) takes
squares were replaced after every 24 hours until the
cessation of egg laying. Longevity and fecundity was
studied by enclosing ten pairs of adults at the rate of one
male and one female per cage. Number of eggs was
counted till the death of the female. The egg bearing
squares of cotton were collected and kept in separate
petri dishes (10 cm diameter) daily for making
observations on percentage of hatching. For instar studies,
immediately after hatching individual maggots were
transferred to specimen tubes and fifty such tubes were
kept. During this study the larva was provided with fresh
flower buds daily. Number of days required by each larval
instar, pupal period was recorded in the laboratory. Egg
measurements were made with ocular micrometre after
calibrating with stage micrometre. In each instar length
and width of 15 larvae was measured by using millimetre
scale. In addition to this the length and width of 15 pupae
and wing expanse of 15 adults was measured by using
the same scale. Following observations were recorded
namely; fecundity, incubation period, number of instars,
total larval period, total pupal period, adult longevity (with
food and without food for both male and female), mating
details, differences in male and female morphological
characters, dimensions of egg, larva, pupa and adult,
colour of egg, larva, pupa and adult, per cent adult
emergence and sex ratio.
RESULTS AND DISCUSSION
The results pertaining to the duration of various life
stages, fecundity, fertility, sex ratio and per cent
emergence and measurement of various life stages of
cotton flower bud maggot, D. gossypii are presented in
Tables 1, 2 and 3.
Incubation period
Freshly laid eggs of cotton flower bud maggot, D.
gossypii, were white, hyaline, elongate, and cylindrical
to ellipsoidal, with one end round and the other end rather
pointed. The incubation period observed was 1.5 ± 0.5
days. The eggs were minute, measured 0.29 ± 0.02 mm
in length and 0.10 ± 0.01 mm in width. Eggs are inserted
inside the tender squares by the female flower bud maggot
with its long, sharp ovipositor. Similar findings on incubation
period was made by Bosio et al (1998) and they reported
that a female of blueberry gall midge, Dasineura
oxycoccana deposits 10-15 eggs per blueberry bud and
a bud contain eggs from more than one female when the
infestation level is high. The eggs have a cylindrical-
elliptical shape and are approximately 0.25 mm long.
Mihaela et al (2012) studied on biology of blueberry gall
midge (D. oxycoccana) in Croatia and found that eggs
are small 0.25 mm in length and have a cylindrical to

ovipositor. Females are having a long (sometimes
as long as body), sharp ovipositor and the
abdomen is swollen. Females are usually larger
than males in size. Another distinguishing
character between male and female is the
intensity of hair like structures in antennae.
Usually antennae are moniliform type, and the
males are having more number of hair-like sensory
receptors in antennae. The body length and width
of male was recorded as, 1.82 ± 0.05 mm and
0.42 ± 0.03 mm, respectively, and the body length
and width of female was recorded as, 2.21 ± 0.06
mm and 0.44 ± 0.05 mm, respectively. The length
of the ovipositor was recorded as, 0.88 ± 0.06
mm. The longevity of male, with food and without
food was recorded as, 1.2 ± 0.4 days and 1.1 ±
0.3 days, respectively. The longevity of female,
Table 1 : Details of biology of cotton flower bud maggot, Dasineura gossypii.
Duration (in days)
Parameters
Maximum Minimum Mean±SD
Incubation period 2 1 1.5 ± 0.5
Duration of first instar larvae 2 1 1.2 ± 0.4
Duration of second instar larvae 2 1 1.7 ± 0.45
Duration of third instar larvae 2 2 2 ± 0.0
Pupal period 6 4 4.4 ± 0.66
Adult longevity of male with food 2 1 1.2 ± 0.4
Adult longevity of male without 2 1 1.1± 0.3
food
Adult longevity of female with 2 1 1.3 ± 0.45
food
Adult longevity of female without 2 1 1.2 ± 0.4
food
Table 2 : Fecundity, fertility, sex ratio and per cent emergence of
flower bud maggot, Dasineura gossypii.
Parameters Number/per
cent/ratio
Number of eggs per female (fecundity) 9.20 ± 2.35
*Number of eggs per female damaged bud 30.6 ± 3.77
Fertility 30 %
Sex ratio (Female:male) 1.45:1
Per cent emergence 85.71%
Number of generations per year 8-10
*Field collected damaged squares.
Table 3 : Measurement of various life stages of cotton flower bud
maggot, Dasineura gossypii.
Stage Length (mm) Width (mm)
Egg 0.29±0.02 0.10±0.01
1st instar maggot 0.66±0.03 0.12±0.02
2nd instar maggot 1.28±0.05 0.15±0.03
3rd instar maggot 1.72±0.08 0.35±0.04
Pupae 1.64±0.06 0.30±0.08
Adult (male) 1.82±0.05 0.42±0.03
Adult (female) 2.21±0.06 0.44±0.05
Length of the ovipositor 0.88±0.06 (mm)
4-5 days on bracts. Mihaela et al (2012) reported that
the pupae of blueberry gall midge (D. oxycoccana) were
1.1-1.3 mm long and orange in colour and development
lasted 8-10 days.
Adult stage
Both adult male and female are minute, soft bodied,
orange in colour, weak flier and short lived. Males and
females can be easily distinguished by the presence of
with food and without food was recorded as, 1.3 ± 0.45
days and 1.2 ± 0.4 days respectively.The peak mating
period was observed between 12.00 hours to 13.00 hours,
though maximum oviposition was observed between 09.00
hours to 11.00 hours. Adult activity starts from 08.00 hours
itself. The copulation period varied from 2 minutes to 10
minutes, though 20 minutes of copulation was also
observed in a rare case. One male used to mate with
number of females. Number of females use to lay eggs
in a same square. From field collected samples 30.6 ±
3.77 numbers of eggs per square have been traced. In
laboratory condition fertility of cotton flower bud maggot,
D. gossypii, eggs were recorded as 30 per cent.Female
to male ratio was recorded as, 1.45:1 and percent
emergence of adults was recorded as 85.71 per cent,
under laboratory conditions.The number of generations
per year was recorded as 8-10.
Similar studies on adult stage were made by Bosio et
al (1998) and they reported that the adults of D.
oxycoccana were 2 to 3 mm in length with females being
slightly larger than males. Females had expanded
abdomens, which are orange in colour and terminate in
an elongate ovipositor. When the ovipositor extended was
as long as the body. Males had slender abdomens, which
were yellow in colour and terminated in a forceps structure
which was part of the genitalia. Hallett and Heal (2001)
studied the sex ratio of olive midge and reported that the
male to female ratio of Olive gall midge was 1:2. Mahr
(2005) reported that the adults of blueberry gall midge,
D. oxycoccana, were approximately 2.00 mm long, short-
lived and weak flier. Females are easily identified by their
orange, pointed abdomen. Adair (2002) studied the biology
of Dasineura dielsi and reported that the adult longevity
of D. dielsi male was 1.35 ± 0.2 (n=9) for and 1.66 ± 0.2
Biology of cotton flower bud maggot 145

146 Pritam Chakraborty et al
(n=16) for females. Maia and Vasquez (2006) reported
that adult body length of D. theobromae varied from 1.75-
2.3 mm (male) and 2.2-2.5 mm (female). Mihaela et al.
(2012) reported that the adults of blueberry gall midge
(D. oxycoccana) were 2-3 mm long and females were
slightly larger than male. Females had exposed abdomen,
which were orange in colour and terminated in an
elongated ovipositor. When extended, the ovipositor was
nearly as long as the body. Males had slender abdomens,
which were yellow in colour and terminated in a forceps
like structure, which was part of the genitalia. The
antennae were moniliform and bear hair like sensory
receptors. Liburd et al (2013) reported that blueberry gall
midges D. oxycoccana, were very small insects,
approximately 3 mm in size. They had slender legs,
globular cylindrical antennae and transparent wings with
long black hair-like structures and reduced venation.
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