Title: Rice Plant- and Leaf Hoppers
1Bio-control and Biopesticides in Rice IPM
Introduction Pest management is known as an
ecological approach to tackle pest problems
because here emphasis is on containing pests in
such a way that other biotic components of the
system such as natural enemies, human beings and
wild life are not harmed and environment is
preserved in general. Pest management also
underlines that pest control tactics should be
socially acceptable and within the reach of
farmers.
Earthworms victims of pesticide use
2In IPM different methods of pest control such as
resistant varieties, cultural methods, physical
methods, Biological and pesticides are integrated
to suppress pest populations. An IPM programme
should be basically based on conservation of
native natural enemies, cultural methods and
resistant cultivars and other management tactics
should be incorporated based on availability and
need.
IPM Concept
3Biological Control
- Biological control refers to use of natural
enemies of pests such as parasitoids, predators
and pathogens to suppress pest populations. Rice
ecosystems are replete with natural enemies but
these need to be conserved against harmful effect
of pesticides. - Likewise, biopesticides like plant extracts or
pathogens are also used to contain pests.
Parasitoids such as Trichogramma are also used to
suppress borer pests.
Spider- Prolific predator
4- Predators
- Spiders, predatory bugs, predatory beetles,
predatory crickets and grasshoppers take heavy
toll of rice pests. - Spiders Spiders are dominant and most common
predators in rice ecosystem. They are voracious
feeders of leaf and planthoppers, leaf eating
caterpillars and adult stem borers. Spiders
consume 5-15 insects a day depending upon their
size.
Spiderlings in rice field
5Water strider Adults and nymphs of water strider
prey on rice hoppers, moths and larvae that drop
on to water surface. Each water strider consumes
5-10 prey daily.
Water strider
6- Predatory beetles
- Ground beetles feed on larvae of leaf folder,
and planthoppers. Each predator can consume 3-5
larvae per day. Rove beetles feed on larvae of
leaf folder and hairy caterpillar, and
planthoppers. Likeiwse, lady bird beetles prey on
leaf folder larvae and planthoppers. -
Rove beetle
7Predatory crickets and grasshoppers Sword-tailed
crickets are egg predators and consume eggs of
several rice pests. Likewise meadow grasshoppers
feed on eggs of rice bug and stem borer, and
nymphs of planthoppers.
Predatory cricket
8- Vertebrate predators Predators like sparrows,
mynahs, ducks, frogs and fish are also reared in
rice fields and they heavily consume planthoppers
and other pests, besides providing extra income
to farmers.
Sparrow
9- Parasitoids
- Parasitoids are tiny insects which feed on eggs,
larvae or pupae of pests. Eggs parasitoids of
stem borer and leaf folder such as Trichogramma,
Telenomus and Tetrastchus egg parasitoids of
leaf and planthoppers like Gonatocerus and
Anagrus, and larval parasitoids such as
Apanteles, Bracon, Stenobracon play very
important role in pest suppression under natural
field conditions.
Stenobracon parasitoid
10- Inundative releases of insectary reared egg
parasitoid Trichogramma (Trichocard) are also
undertaken to contain stem borer and leaf folder
incidence. Trichogramma japonicum and T. chilonis
is released against yellow stem borer and leaf
folder, respectively _at_ 1-1.5 lakh/ha/week for 6
weeks starting 30 days after transplanting. - These releases act like application of
insecticides and control is achieved through
released individuals only and not through their
progeny.
Braconid wasp
11- Pathogens
- Entomopathogenic fungi like Beauveria,
Metarhizium, Entomophthora also play important
role in suppressing populations of planthoppers
and other pests. Likewise, entomogenous nematode,
Steinernema carpcapsae and nucleopolyhedrosis
virus (NPV) have been found to be effective
against rice pests.
NPV infected insect larva Courtesy
http//butterflybreeders.com
12- Biopesticides
- Bacteria, Bacillus thuringiensis (Bt) is
effective against lepidopteran pests. - Neem products like neem seed kernel extract
(NSKE) is effective against planthoppers and
other foliage feeders. - Conservation of natural enemies
- Ensure need based application of pesticides
- Avoid use of broad spectrum pesticides
- Dont treat area having natural enemy abundance.
Conserve natural enemies
13- Lets Sum up
- Biological control refers to use of natural
enemies of pests to suppress pest populations. - Predators like spiders, predatory bugs, predatory
beetles, predatory crickets and grasshoppers take
heavy toll of rice pests. - Parasitoids are tiny insects which feed on eggs,
larvae or pupae of pests. Trichogramma is an
important egg parasitoid of rice stem borer and
leaf folder. - Inundative releases of insectary reared
Trichogramma (Trichocard) are also undertaken to
contain stem borer and leaf folder incidence. - Fungi like Beauveria, Metarhizium, Entomophthora
play important role in suppressing populations of
planthoppers and other pests. - Nematode, Steinernema carpcapsae and
nucleopolyhedrosis virus (NPV) have also been
found to be effective against rice pests. - Biopesticides such as Bacillus thuringiensis
(Bt) and neem seed kernel extract (NSKE) are
effective against rice pests. - Conservation of natural enemies can be ensured
through need-based application of selective
pesticides.