Biological control is an environmentally safe method used in integrated pest management. It involves

suppression of pest population using two groups of living organisms referred to as Entomophaga and

Entomopathogens. Entomophaga comprise natural predators and parasites of the pest. Entomopathogens are

generally microorganisms that include virus, bacteria, fungi, nematodes and protozoa. This review gives an

account of various biological control methods including ecological engineering and push-pull strategy with

examples and discusses the advantages as well as challenges associated with them.

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injury (red palm weevil) or serve as vectors transmitting diseases (Banana aphid transmitting bunchy top

disease). Biological control is one of the widely adopted tools in pest management programme that targets

environmental and ecological stability by holding biodiversity together. Biological control involves suppression

of pests using other living organism which includes two major categories such as (i) Entomophaga

encompassing predators and parasitoids and (ii) Enomopathogens involving virus, bacteria, fungi, nematodes,

protozoa etc.

Biological control is one of the critical components of Integrated Pest Management programme and owing

of the encyrtid parasitoid, Acerophagous papaya from Puerto Rico. Under augmentative biological control, it

could be either inoculative with one time release of natural enemies (E.g., Release of green lacewing,

Chrysoperla zastrowii sillemi for the bio-suppression of sucking pests [Hopper, Amrasca devastans; aphid,

Aphis gossypii] of cotton) or innundative with frequent release of natural enemies based on the pest incursion

status (E.g., Frequent release of stage-specific parasitoids, Goniozus nephantidis or Bracon brevicornisin the

bio-suppression of coconut black

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headed caterpillar, Opisina arenosella). Though conservatory biological control is not so prominent and

successful in several cropping systems, its silent but significant role in the bio-suppression of two invasive

In general, predators kill the prey for itself and are usually larger than the prey. Predators are mainly free-living

species that directly consume a large number of preys during their whole lifetime. The first international

shipment of an insect as biological control agent was made by Charles V. Riley in 1873, delivering France the

predatory mites Tyroglyphus phylloxera to help fight the grapevine phylloxera (Daktulosphaira vitifoliae) that

was destroying grapevines in France. In 1888–1889 the vedalia beetle, Rodolia cardinalis, a lady beetle, was

introduced from Australia to California to control the cottony cushion scale, Icerya purchasi. This had become a

major problem for the newly developed citrus industry in California, but by the end of 1889 the cottony cushion

scale population had already declined, and this successful bio-suppression strategy is termed as “Miracle of

Entomology”.

predator of rhinoceros beetle, Oryctes rhinoceros (Figure 1a). A wide array of spiders is recorded as predators

of black headed caterpillar, Opisina arenosella of which Rhena, Sparassus and Cheiracanthium are the major

ones. Many predatory mites including Amblyseius largoensis, Neoseiulus paspalivorus and Bdella distincta

were reported as potential predators of coconut eriophyid mite, Aceria (Figures 1b and 1c).

A parasite and its host belong to two different classes taxonomically and usually a parasite will never kill the

host but could cause extreme level of parasitism. For example, head louse on humans is a parasite. On the other

the pupal parasitoid Brachymeria nosatoi (Chalcididae) are the most promising ones which are extensively

used for augmentative releases for pest suppression (Figure 2c). The major desirable attributes of these

parasitoids are their greater host searching ability, production of higher proportion of females, occurrence

throughout the year and their distribution in all pest infested areas. A large area field validation of the bio-

suppression technology of

cent reduction in O. arenosella population in a period of two years. Very recently the natural bio-suppression of

(Figure 2d) is a classic example of conservatory biological control which could parasitize the pest to more than

85% in a pest prone area. In this backdrop, a pesticide holiday is advised for the natural buildup of the

parasitoid, E. guadeloupae.

This category includes microbial pathogens such as virus, bacteria, fungi, protozoa and nematodes used in

biological pest suppression. [1-6]

non-occluded types based on the occlusion of virion particles. Virus infection begins in the insect’s digestive

system but spreads throughout the whole body of the host in fatal infections. The body tissues of virus-killed

insects are almost completely converted into virus particles. The digestive system is among the last internal

organ systems to be destroyed, so the insects usually continue to feed until they die.

The occluded viruses such as Spodoptera litura nuclear polyhedrosis virus, Helicoverpa armigera nuclear

polyhedrosis virus, Cydia pomonella granulosis virus are very effective and commercially used in biological

pest suppression. In coconut, the use of non-occluded virus, Oryctes rhinoceros nudivirus (OrNV) is very

effective and kills the O. rhinoceros grub in 15 -20 days’ time significantly suppressing the longevity and

indicated that OrNV infected grubs become less active and stops active feeding. As a result of virus

translucency in the abdominal region which is an important exopathological symptom of the OrNV infection

and mortality in grubs. The infected beetles disseminate the virus through faecal matter into the surroundings

after 3-9 days of inoculation at the rate of 0.3 mg virus adult-1 day1. Introduction of OrNV in Minicoy and

Androth Islands of Lakshadweep, Chittilappilly, Thrissur, Kerala and Sipighat, Andaman Island successfully

reduced the population of O. rhinoceros and its damage potential on coconut.

A small number of entomopathogenic bacteria have been commercially developed for control of insect pests.

These include several Bacillus thuringiensis sub-species, Lysinibacillus (Bacillus) sphaericus, Paenibacillus

spp. and Serratia entomophila. B. thuringiensis sub-species kurstaki is the most widely used for control of pest

in soil, insects and their habitats, stored products, plants, forest, and aquatic environments. It produces a

When toxins are solubilized, protoxins are released through the action of proteases resulting in active proteins of

microvilli of the apical membranes of the columnar cells of the lepidopteran gut. The binding of Cry toxins to

the apical microvillus of the membrane vesicles of the insect determines the specificity of the Cry toxins. The

Cry toxins cross the peritrophic membrane by binding to specific receptors on the apical membranes of

intestinal cells causing opening or pore formation followed by vacuolation of the cytoplasm by osmotic

imbalance between the intracellular and extracellular environments and cell disruption. This destroys the

microvilli, causing the insect to stop feeding, leading to its death.

two decades. The Bt genes used in insect-resistant transgenic crops belong to the Cry and vegetative insecticidal

reducing the amount of broad-spectrum chemical insecticides used while being safe for consumers and non-

target organisms. Despite successes, the adoption of Bt crops has not been without controversy. In addition to

discovery of more efficacious isolates and toxins, an increase in the use of Bt products and transgenes will rely

on innovations in formulation, better delivery systems and ultimately, wider public acceptance of transgenic

plants expressing insect-specific Bt toxins.

Entomopathogenic fungi do not require per os infection and could enter insect system through the cuticle.

Examples include Metarhizium anisopliae, Verticillium lecanii, Beauveria bassiana, Nomuraea rileyietcwell

exploited in pest management. Metarhizium anisopliae (Metchinkoff) Sorokin is an entomopathogenic fungus

mode. Mass production technology of M. anisopliae was standardized in semi - cooked rice grains yielding a

spore count of 3x107cfu / g of the culture.

Searching for natural enemies of coconut eriophyid mite A. guerreronis, ICAR-CPCRI could collect more than

The word ‘nematode’ means "thread-like” and they are also known as thread worms or round worms.

Nematodes are numerically the most abundant metazoans on earth and second only to insects, in terms of

insect pathogens that possess potential as biological control agents. These nematodes, working with their

symbiotic bacteria (Xenorhabdus for steinernematids and Photorhabdus for heterorhabditids), kill insects within

24 to 48 hour (Figure 6). They are safe for the plant health, human health, soil and the environment. There is a

huge potential for the utilization of these nematodes for the management of many coconut pests like white grub,

rhinoceros beetle, red palm weevil etc.

Protozoans are one-celled forms. One group the Microsporadia, contains many species that have promise for

biological control. Microsporidian infections in insects are thought to be common and responsible for naturally

occurring low to moderate insect mortality. But these are relatively slow acting organisms, taking days or weeks

to debilitate their host. Infected insects may be sluggish and smaller than normal, sometimes with reduced

feeding and reproduction, and molting problems. Death may follow if the level of infection is high. Nosema

locustae is the only commercially available species of microsporidium, marketed under several labels for the

Emergence of the exotic rugose spiraling whitefly (RSW), Aleurodicus rugioperculatus (Figure 7a) on coconut

their abundance on the protected resource, for example, a crop or farm animal. The pests are repelled or

integrated pest management programs reducing pesticide input.

Plant health management (PHM) is the science and practice of understanding and overcoming the

ornamentals, timber trees, or other uses. Although practiced as long as agriculture itself, as a science-based

concept, PHM is even younger than integrated pest management (IPM) and includes and builds upon IPM; but

is not a replacement for IPM. PHM is a moving target, like a football game, where one team is science and

technology and the other is nature, where the S & T team is only beginning to know nature's rules while playing

itself with the three sets of rules written to, respectively, satisfy the laws of economics, protect the environment,

and gain social acceptance. In a nutshell, PHM includes integrated pest, disease and weed management,

integrated nutrient management and soil health management in a holistic manner as system approach.

From the ecological engineering concept, health management is revered as holistic and at the same time

sustainable providing continuous income and employment as well. Systematic care would thus make you cheer