What Are The Drone Anti-jamming Systems Technology?
3010320004.ento.4.3.pptx management of beneficial insects
1. COLLEGE OF AGRICULTURE
ANAND AGRICULTURAL UNIVERSITY
JABUGAM-391155
MANAGEMENT OF BENEFICIAL INSECTS
Ag. Ento. 4.3
Submitted By:
Jainil Bhoya
Submitted To:
Dr.M.R.Dabhi
4. • Silk is a fibrous protein of animal origin. A number of organisms
secrete silk, which is used by them for anchorage (mussels),
entangling their prey (spiders), or forming a protective sheath with
or without other materials (Lepidopteron cocoons).
• Nearly 400-500 species are known to produce silk but only very few
are commercially exploited. Based on the organisms producing it, silk
is classified into insect silk and non – insect silk.
• Insect silk is commercially more important. The majority of silk
producing insects belong to the order: Lepidoptera, Super family.
Bombycoidea and Families. Bombycoidea and Saturniidae
TYPES OF SILKWORM
5. • Nearly 95 per cent of commercial insect silk comes from the mulberry
silkworm Bombyx moti and is known as mulberry silk. The
commercial silk from all other sources is collectively called Non-
mulberry silk. Hence the major insects species producing silk are,
1.Mulberry silkworm
Bombyx mori Linnaeus
9. Classification of Silkworm
1. Basedon voltinism
• Voltinism is a term used in a biology to indicate the number of broods
Or generation of an organism in a year.
• It is a genetically determined character which exerts its effect through
hormones.
• Based on voltinism,three kinds of races are recognized in mulberry
silkworm, Univoltines, biovoltines and multivoltines.
10. • Number of moults during the life cycle is a hereditary character
determined by Mendelian genes
• On the basis of the number of moults which they undergo during
larval life, B. mori is divided into three races – tri moulters, tetra
moulters and Penta moulters. Most of the commercially exploited
races are tetra-moulters with five larval instars.
2. Basedon moultinism/ No.of larval moults
11. Based on their place of origin, B. mori is classified into Chinese,
Japanese, European and Indian races. The races can be distinguished
from one another on the basis of
• Morphological characters of egg, larva, cocoon and adult
• Biological characters like duration of life cycle, diapause, number of
larval moults and resistance to diseases as well as other
environmental factors and commercial characters like length of
filament, denier, defective cocoon percentage, reelability etc.
3.Based on geographical distribution
12. • Based on genetic nature, silkworm races are classified as pure races
and hybrids.
4. Based on geneticnature
Characters of silkworm races
1. Multivoltine races :
2. Bivoltine Races:
13. • Multivoltines or polyvoltines have more than three generations per
year. The larval duration is short.
• Larvae are resistant to high temperature and high humidity. They are
well adapted to tropical conditions where mulberry sprouts
throughout the year.
• Larvae and cocoon are small in size. Commercially these cocoons are
poor quality. The adults lay non-diapausing eggs.
• Multivoltine races of tropical region generally produce coloured
cocoons – greenish or golden-yellow.
1. Multivoltine races
14. • This was originally a Japanese bivoltine race which was imported and
introduced in the state of Mysore.
• Due to continuous rearing by seed producers, this race has now
degenerated to a multivoltine race.
Nichi
Nistari
• This is one of the indigenous multivoltine races which is continuously
being reared not only for producing cross breed hybrids, but also as a
commercial indigenous race.
• It was introduced in 1881 from China and continues to dominate
commercial rearing in the entire North India, especially in West Bengal.
15. • It was imported from China in 1895. The main demerit of this race is
its long larval period (about 27-28 days).
Pure
Mysore
Sarupat
• This race belongs to the North – Eastern part of India.
16. • Some multivoltine races of India are able to produce white cocoons.
Tamil Nadu Sericulture Department isolated the race called TNW in
1975.
• Other races are, Kolar Gold, Kollegal Jawan, Mysore princess, Hosa
Mysore, MY 1, MY 2, BL 23, BL 24 and BL 67.
Tamil Nadu
white
17. • Bivoltine races have two generations per year, the first generation
adults developing from eggs hatched in spring lay non-diapausing eggs.
• The second generation adults developing from these eggs lay eggs
which remain dormant till next spring. The larval duration is longer as
that of univoltines.
• Larvae are robust and tolerate environmental fluctuations they are
used for summer and autumn rearing in temperate regions. By careful
manipulation of artificial breaking and incubation, a third crop can be
raised using late summer and early autumn leaves.
• The bivoltine cocoons are commercially superior. Japanese and Chinese
races have both uni and bivoltine varieties.
2. Bivoltine Races
18. • Mulberry silkworm Bombyx mori is holometbolous insect and passes
through four morphologically different stages in the life cycle – egg,
larva, pupa and adult.
Biology of silkworm
Egg
• Eggs are tiny and 2000 eggs weigh about 1 gram. Races producing
white cocoonslay pale yellow eggs and races producing yellow
cocoons lay deep yellow eggs.
19. • The eggs are ovoid, spherical or ellipsoid in shape and are flat on one
side. This is called egg dimple. This side is attached to the substratum
and receives a gluey secretion from the accessory glands as they pass
down the common oviduct prior to oviposition. It measures 1.2 mm.
Egg period of silkworm is about 10 days
20.
21. • The larva is eruciform or polypod type with abdominal prolegs. The newly
hatched larva is about 3 mm long, black in colour and is covered with
bristles.
• The bristles or setae are situated on four pairs of tubercles in each segment
of the body. As the larva grows, it moults and enters into the later instars,
the cuticle becomes smooth and stretched and the setae are shed and
tubercles become less prominent. The colour also becomes pale.
• The last instar larva is 10 cm long. The body of the larva is divided into
three regions (tagmata) – head, thorax and abdomen.
• The head is formed by the fusion of six segments, the thorax has three
segments and the abdomen eleven segments.
Larva
22. Sex differences in the larva
FEMALE Male
A pair of sex marks on the ventral
side of the 8th and 9th abdominal
segments called Ishiwata’s Fore
glands and Ishiwata’s Hind glands,
respectively. Fore glands later
modify to form the ‘Bursa
copulatrix’ and ‘Receptaculum
seminis’. Hind glands become part
of the posterior region of the
oviduct and the accessory glands.
A single median opening at the
junction of the 8th and 9thsegments
called opening of Herold’s gland. It
becomes the seminal duct and
Ejaculatory duct of the adult.
• These can be seen clearly only in the freshly moulted 4th and 5th instar larvae.
23. • The full grown larva pupates inside the cocoon and pupa is obtect
type. In about 10 days’ time it transforms into a winged adult.
• The adult moth makes an opening in the cocoon and escapes through
it.
Pupa
24. • The cocoon is formed from a secretion from two large silk glands
(actually the salivary glands), which extend along the inside of the
body and open through a common duct on the lower lip of the
mouthparts.
• The larva moves the head from side to side very rapidly (about 65
times per minute) throwing out the secretion of the silk glands in the
form of a thread.
• The secretion is a clear viscous fluid, which on exposure to the air
gets hardened into the fine silk fibre.
The
cocoon
25. • The filament forming a cocoon is continuos and ranges in length from
700-1100 metres.
• The cocoons from which moths have emerged are called pierced
cocoons. These are of low value because continuous thread cannot
be obtained. Pieces are removed by instruments and spun into a
thread.
26. Sex differences in the pupa
FEMALE MALE
1. Pupa is larger with a broader
abdomen.
2. There is a vertical line in the
centre of the 8thabdominal
segment on the ventral side.
1. Pupa is thinly built with
narrower abdomen.
2. There is a small round spot on
the 9thsegment.
27. • The moths have lost their flight due to several centuries of
domestication. It does not feed during its short life span of 3-6 days.
• The size of the moth is 4 x 2 cm. the entire body and the wings are
covered with epidermal scales. The body is divided into head, thorax
and abdomen.
Adult
28. Sex differences in the adult
Character Female Male
Colour Paler Darker
Activity Less active More active
Antennae Small large
Body size Large small
Abdomen Large and flat with 7
segments
Long, narrow with 8
segments.
External genitalia The caudal end has a
median knob – like
projection with secondary
hairs. This knob is
protruded and retracted to
expel
the pheromone
The caudal end has a pair
of kooks known as harpes
helping in copulation
