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The world has two powerful demand on the one hand we should meet the food demand for growing population and on the other hand we need to provide quality food. In order to fulfill the demand for the food production, commercial high intensive crop production is practiced which require large amount of chemical pesticides. This has negative impact on the quality of product and ultimately to the consumer. So, agriculture scientist needs to find the ways to reduce the application of the chemical pesticides inputs. Pesticides commonly use affect non target organisms and lead to loss of bio-diversity which can be natural predators to pests, pollinator and food producers (bees and honey). It also leads to the insecticides resistance by the pest and outbreaks of secondary pest which are normally controlled by natural enemies. Using chemicals to kill the pests or control the disease have alternative action on the natural predator and reducing or even eradicate from the certain location which leads to severe accident in the crop production. Along with this there are already ample of examples on pollution of the water source and the soil which force the governments of different parts of the world to think about the probable outcomes and started to act against it.
Continuous exposure to these chemical pesticides causes Chronic and severe health disorder in nervous system, reproduction system, kidney, possibility of various Cancer , birth defects( PANAP, 2010). Small children, pregnant women and lactating mothers are highly vulnerable to the toxic contamination of pesticides.According to the study conducted by UNDP in eight Asian Countries revealed that 66 percent of pesticides active ingredients are used in vegetables, cotton, paddy, rice and other crops are highly hazardous according to PAN International classification Criteria. Poor land management practices and the loss of agriculture lands to the economic activities lead to increase the use of chemical pesticides (Singh, 2009).It is predicted that 90 percent of applied pesticides donâ€™t meet the target and enter the marine environment via surface runoff, drainage, erosion, miss-application and atmospheric transportation in Caribbean Region (UNEP, 1994).Also, massive coral mortality and egg shell thinning has occurred in the same region. Also, fish mortality in coastal areas of Jamaica coincide with the period of pesticide application on coffee plantation (Chin Sue, 2002)
â€œMany pesticides that have been banned or whose use are severely restricted in the developed countries are still marketed and used in developing countries. These chemicals pose serious risks to the health of millions of farmer and the environment.â€ Said by Dr. Jacques Diouf, Former Director General, Food and Agriculture Organism (FAO) of the United Nations.
The emerging practices of integrated use of biological, organic methods, cultural practice of crop protection that is prevalent in different parts of the world can be effective in producing quality food. Even though it is not possible to ban all the pesticide but we can go on integrated approach to reduce the harmful effect i.e. Integrated Pest Management.
An Indian boy suffering from cerebral palsy and cannot walk or talk. His village suffer high incidence of neurological disorder linked to pesticide exposure
Integrated pest management(IPM) is an ecosystem based strategy that focus on long term prevention of pests or there damage through a combination of techniques such as biological control, habitat manipulation and modification of cultural practices. Pesticides are used only after monitoring indicates they are needed and pest control materials are selected and applied in a manner that minimizes risk to humans, non target organisms and the environment.(2009, UCIPM). It is the highest sustainable method for long term protection. This include consideration of economic thresholds, sampling technology, modeling, natural controls, geographic distribution , effects of pest migration and movement, host resistance and pesticides. The conservation of natural enemies is probably the most important as they are susceptible to pesticides and can lead to accidental eradication from the location.
Biological control proves much more sustainable one and be given top priority. It includes natural enemies such as parasites, predators, pathogens or competitors are the important factor for IPM. Successful biological control means that no further cost is required to control pest.
The four types of natural enemies are Predators, Parasitoids, Pathogens and weed factors:
PREDATORS: They feed on various types of pest and insects with choice of preying vary from the selective to the broad range of insect. They are the component of all agricultural ecosystem and have differ life cycle which is the important things to be noted when using them as useful predators. Some of the popular are Lady Beetles: They show predaceous habit on both larva and adult stage, feed on aphids, Scales, Mealy bugs, white Flies, spider Mites and even on the eggs of various insects. Robber Flies: They are even capable of predating on prey that are larger than themselves . Feed on Butterflies, Wasps, Bees, Dragonflies, Grasshoppers, Bettles , etc. Soldier Beetles: Their larva are of voracious feeding nature preying on Slugs, Millipeds, earthworms, Maggots, Locust eggs, etc.Ground Bettle: They are nocturnal predators feeding on gypsy moth larvae and pupae.Hover Flies: They are dark bees or wasps, eat fruit tree spider mites and small caterpillars. Dragonflies: They attack on mosquitoes. Also other predators are frogs, toads, lizards, hadge hogs, slow worms.
PARASITOIDS: Their immature stage develop on or inside the host ultimately killing the host when they mature. The eggs of parasitoids are laid inside the host and after maturation they emerge out of the host and continue the life cycle. Wasps or flies are mostly the parasitoids.They are specialized in the choice of the host and only female search for the host. They are more susceptible to insecticides than the host. Some of parasitoids are:
Ichneumonid wasps: Prey mainly on caterpillars and butterflies and moths. Braconid wasps: They are tiny wasp attack on caterpillars and others.Chalcid wasps: They parasitize greenfly, white fly, cabbage caterpillars, and scale insects. Tachinid Flies: Various insects like caterpillars, adult and larval beetles, true bugs and other are their prey
Pathogens of insect and weed pests:
Variety of entomopathogens (disease of insect- pests) are used for controlling pests in glass house, row crops, orchards, ornamentals. range ,turf and lawn, stored products, and forestry and for the abatement of pest and vector insects of veterinary and medical importance(Burges 1981; Tanada and Kaya, 1993; Lacey and Kay, 2000). They may be used to augment naturally occurring pathogens(augmentation), conserved or activated in nature(conservation),introduction into pest population as classical biological control agents to become established and exert long term regulation of pest or used inundately for rapid short term control( inundative release)(Lacey, Frutos, Kaya and Vail; 2001).Inundative Biological control refers to the release of overwhelming number of biological control in the expectation of achieving a rapid reduction of pest population.
Figure: Robber fly predating on spiderBacteria: Bacillus thuringiensis (Bt) is found naturally in the soil and plants and is most widely used as inundatively. Crystal protein that are produced by different varieties of this bacterium are toxic to the insects that feed in it. Bacteria (paenibiacillus popilliae) is another one which is used in small scale for control of white grubs. B. sphaericus which has has some advantages over Bt in the aspect of being more persistent in polluted habitats and may recycle under certain conditions, but have narrow host range(Lacey and Undeen, 1986;Hougard,1990; Charles et al, 1996; Nicolas ,et al ., 1994)
Virus:Large number of virus act as microbial control agents(Payne, 1982). The widely popular are Baculoviridae (nucleopolyhedroviruses(NPV) and granuloviruses(GV) )( Granados and Federici, 1986; Hunter-Fujita et al.,1998). Some of the drawbacks using entomopathogenic virus are their slow action, sensitivity to UV light and the requirement for living system. They are commonly used for controlling various insects like Bollworms, several loopers, moths( Indian meal moth, Gypsy moth, codling moth, etc), army worms , cotton leafworm, etc.
Fungi : Although 700 entomopathogenic fungi have been found only 10 have been currently being developed for insect control(Hajek and St. Leger, 1994) Species of Hyphomycetes demonstrate good against several range of pest including white flies, aphids, thrips, termites, grasshoppers, locusts, beetles and others(McCoy et al 1988; Goettel et al, 1995,2000)
Nematode : Large number of species of more than 30 families is associated with insects and other invertebrates(Poinar, 1979;Kaya and Stock,1997. For example, Phasmarhabditis hermaphrodita is used to suppress slugs , likewise D. siricidicola has been successful as a classical biological control agent for woodwasp(Bedding, 1993).
Protozoa: They are ubiquitous and play important role in the regulation of the insect population(Maddox,1987;Books,1988) . They are slow acting host specific with complex biology. Grass hopper pathogen Nosema locustae is the typical example.
There lies ample of opportunity for biological control techniques to fit them as important component of IPM. In most case no single organism can control the pest in sustainable way so integrated approach is needed for maximum effect. Also, providing extension network for farmer with latest finding of new biological control can be effective in ground level. Taxation on the chemicals pesticides can be helpful in the reducing their use. For example, in Denmark, strong regulation and taxation in pesticides reduce their usage to some extent. In order to maintain sustainable agriculture, there is an immediate need for alternative intervention for pest management techniques, which should be environmentally friendly and reduce the amount of chemical pesticide contact with human. There need to demonstrate that conservation of the biodiversity help opportunity to restoration of the biological control agents. The government and various organizations should focus on exploring about their interaction with pest and agro ecosystem, their effectiveness and their advantages. Still lots of works to be done to convince farmer that investing money on biological control methods which is expensive and slow process in the short term can lead us to sustainable agriculture in the long run.