Integrated Pest Management with Reference to INM

Among various pest control methods, Integrated Pest Management (IPM) has gained importance as it is eco-friendly and helps in sustainable production. IPM is defined as the selection, integration and implementation of available pest control methods. The common and major components of IPM are cultural, physical, chemical and biological control. IPM packages have to be developed based on the crop, the environment and it should be region specific. Information technology helps in IPM programs [1]. Success of IPM depends on sharing and transferring the technology to the farmers. IPM deals with economic profitability, human health and environmental risk [2]. The ideal objective of IPM should be to maximize profit while minimizing human health and environmental risks. In late 1950’s IPM concept is evolved due to the hazardous effect of the pesticides on the environment and this has led to the re-discovery of the value of biological control and helps in the conservation, preservation and protection of biodiversity. Later, the innovative and traditional methods such as cultural control, physical and mechanical control, need based use of pesticides, hostplant resistance, transgenic plant etc. [3] reduced the hazardous effects of pesticides and supported IPM practices until today [4].

Integrated Pest Management (IPM) has been defined in many ways

It consists of the development, use and evaluation of pest control strategies that result in favourable socio-economic and environmental consequences [5].

It is a system approach to reduce pest damage to tolerable levels through a variety of techniques, including predators and parasites, genetic resistance hosts, environment modification and when necessary and appropriate, pesticide.

The Food and Agriculture Organisation (FAO) described this concept as a pest population management system that utilizes all suitable techniques in a compatible manner to reduce pest populations and maintain them at levels below those causing economic injury [6].

It refers to an ecological approach in pest-management in which all available necessary techniques are consolidated in a unified programme, so that pest populations can be managed in such a manner that economic damage is avoided and adverse side effects are minimized [7].

The following basic principles has been suggested for practice of pest management

Determine how the life-system of the pest needs to be modified to reduce the number to tolerable limit. Apply biological knowledge and current technology to achieve the desirable modification i.e., applied ecology. Devise procedures for pest control suited to current technology and compatible with economic and environmental quality aspects i.e., economic and social acceptance.

The proper utilization of this approach involves the following steps

To develop an integrated programme against any pest, it is essential to have possible effective methods for its control. To establish economic threshold and economic injury at which the control operation should be initiated. To bring about the possible effective control methods in such a way that the integrated components should hold the nematode pests below damaging threshold level and avoid environmental disturbances.

IPM can be divided into seven components [8]. Biological monitoring, environmental monitoring, the decision maker, decision support system, the decision, procedure implementation and the system. Integrated nematode management (INM) is not an isolated approach from IPM, rather a component of it hence should match the convergent objectives of trans-disciplinary mode of implementation [9]. Integrated pest management includes research, development, technology transfer and implementation needed to integrate two or more control measures to manage one or more nematode species. INM must be imposed in conjunction with broader objectives of IPM. Nematode management is important for high yields and quality that are required by the high cost of modern crop production [10]. Therefore, the idea of keeping the nematode population below the economic damage level by adopting different available tactics is advised to the growers [10]. The young tender seedlings of various crops are very much vulnerable to attack by nematode while the older plants achieve some degree of tolerance.

Chemical control with the application of nematicides is the most effective means of nematode management. However, most of the effective nematicides have been withdrawn from the world market. At present, a fewer insecticides having nematicidal property are so far available to the farmers and many of them are not cost effective and environmentally acceptable [11]. Despite their inherent drawbacks, chemical nematicides could be applied judiciously so that the doses and cost are reduced drastically. The applications of nematicides through seed treatment, bare-root dip treatment and nursery bed treatment have been proved to be effective to protect the young seedlings from nematode attack. In spite of the problems associated with nematicides, they comprise an important tactic for many of the nematode IPM systems especially for high-value crops [12].

The modern concept of pest management is based on ecological principles and involves the integration and synthesis of different components /control tactics into a pest management system. IPM is a component of the agro-ecosystem management technology for sustainable crop production. An increase in the area of cultivation, intensive cropping, use of heavy amounts of chemicals and fertilizers and introduction of high yielding varieties etc. [13] resulted in the increase of pests (including nematodes) and pathogens. Plant-parasitic nematodes, hidden enemies of crops are microscopic, invertebrate animals often called as threadworms, eelworms or roundworms. They are distributed all over the world in different kinds of habitats and found in nearly every biological niche that supports life. They damage the crops not only by feeding on plants but also by interacting with various other organisms. They cause severe losses to economically important crops like vegetables, cereals, pulses, oilseeds, fruit crops, etc. Ref. [14] have indicated an annual crop loss due to phytonematodes on worldwide basis to the tune of $100 billion [15]. In a world-wide survey conducted by Sasser [16] the 10 most important genera of plant parasitic nematodes revealed were Meloidogyne, Pratylenchus, Heterodera, Ditylenchus, Globodera, Tylenchulus, Xiphinema, Radopholus, Rotylenchulus and Helicotylenchus causing damage to agricultural crops. In India also, there are some reports which indicate heavy crop losses due to nematodes [17].

A committee in 1971 on the estimation of crop losses constituted in USA and estimated 6 per cent loss in field crops, 12 per cent loss in fruit and nut crops, 11 per cent loss in vegetable crops and 10 per cent loss in ornamental crops which gives an annual monetary loss of 1590.7 million dollars due to nematodes. Losses estimated due to nematode attack to different cultivated crops all over the world by FAO is around 400 million dollars. Thus, nematodes either alone or in combination with other pathogens constitute an important constraint to world agricultural production. However, the nematode control problem is rather very tricky, especially because the majority of nematode pests are soil-borne and thereby necessitate a careful study of the situation and proper selection of strategy [18].

A complete understanding of the behavior of nematode species involved, host plant and the ecological constraints is essential before an appropriate method could be applied. In the current agricultural scenario, INM have been emphasized due to the social, economical and environmental status in the agricultural society. INM programs developed so far have already contributed to a decline in chemical inputs on many crops. Integrated management for nematodes requires: 1) determining whether pathogenic nematodes are present within the field 2) determining whether nematode population densities are high enough to cause economic loss and 3) selecting a profitable management option [19].

Attempts to manage nematodes may be unprofitable unless all of the above Integrated management procedures are considered and carefully followed. Similarly, some management methods pose risk to people and the environment. Individual methods of nematode control have either proved ineffective or uneconomical approach against plantparasitic nematodes [20]. Therefore, integration of various suitable tactics [21] may be an eco-friendly, economically viable and practically feasible approach for managing nematode problems in different crops.

The approach of an integrated nematode management should be according to Ref. [22]

Minimization of environmental and health hazards, Utilization of several compatible measures, Maximization of natural biotic and abiotic environmental resistance, Understanding and counteracting nematode survival strategies, Minimum use of drastic control measures, Increased reliance on location specific and resource compatible management strategy, Minimizing input costs in harmony with potential gains and Maximizing of profit to the grower.

Integrated nematode management strategies can be applied sequentially or simultaneously. The first approach includes season to season or year to year integration of strategies and is particularly relevant to annual cropping cycles [18]. The second major approach to INM involves simultaneous application of two or more strategies. This approach may be utilized for both annual and perennial crop production [23,24]. The integration of different strategies for nematode management is not a new concept. Kuhn [25] used crop rotation and following for the control of nematodes. Tyler [26] proposed combination of two or more control strategies into an overall management programme is the only sound and sustainable approach for the effective control of rootknot nematode (Table 1).

Validation and demonstration of INM technologies

On soybean: A field trial was laid out at the Farm of IARI, New Delhi during Kharif season in 2 m × 2 m plot with the following treatments as: Lantana camara chopped leaves @ 400 g/4 m² (T1), seed Treatment with Kalisena @ 2% (T2), Triazophos @ 1.5 l/ha (T3) and combinations T4=T1+T2, T5=T1+T3, T7=T1+T2+T3 and T8=control. Seeds of soybean cv. Pusa-24 were sown in well infected plots in lines. Population of R. reniformis was estimated before treatment, at the time of harvest and yield (plot weight) per plot were recorded. Data presented in Table 2 revealed that the combinations of more ten one treatment were efficient in managing reniform nematode, R. reniformis thus resulted more growth of soybean as compared to control. Significant increase in yield was recorded in all combinations (T4, T5, T6 and T7 treatments) as compared to single application (T1, T2 and T3 treatments) [28].

Table 2: Nematode population and yield of soybean as influenced by various INM treatments.

On mungbean: A field trial was undertaken during 2005 crop season in plots of 4 m², replicated thrice with following treatments: T1=Multineem (0.03% Aza) @ 2 l/ha, T2=T. harzianum, T3=Phorate @ 1 kg a.i/ha, T4=T1=T2, T5=T1+T3, T6=T2+T3, T7=T1+T2+T3 and T8=Control. All the treatments were applied in rows before sowing mung crop cv. Pusa ratna. Soil samples before the treatment at harvest were recorded for R. reniformis population (Table 3). Yield was also taken at the end of the experiment. All the treatments either alone or combination were effective in reducing R. reniformis population under field condition. However, maximum reduction was recorded in treatment where all three components of INM was used. This in turn enhanced the yield of mung bean crop. Maximum yield was recorded in T7 (Multineem+T. harzianum+Phorate) treatment as compared to control [29].

On pea: A Field trial was conducted in IARI field, New Delhi having good population of reniform nematode. Plots of 2 m × 2 m were prepared and Pea cv. bonville were sown in lines. The treatments were: Calotropis procera chopped leaves + twigs @ 2 l/ha (T1); Trichoderma viride @ kg/ha and Triazophos 40EC @ 1 l a.i/ha and their combinations in RBD design and replicated thrice. Observations on nematode population before treatment and at harvest were taken with yield of pods/plot (Table 4). Results revealed that higher yield was observed in T7 treatment where combination of all three was taken in the experiment.

Table 4: INM on Pea.

The success of integrated nematode management will depend on a wide range of appropriate expertise on research/demonstration/training projects. It requires a strong research base, to provide information on nematode pests, crops, agronomic practices related to the crop and their interactions [30]. Once the various integrated control programme are developed, it is necessary that they should be put to practice [12,31]. The implementation of these programmes will require scientists/trained technicians and efficient extension media [32]. In addition to these, they should also possess communication skills which are needed to work with the farmers. Similarly, farmers with their available resources could follow integration of cultural, biological [32,33] chemical methods and resistant varieties in suitable combination for each crop cultivation system [34,35].

Intensive and extensive surveys on the presence of parasitic nematodes infesting agricultural crops should be conducted. Use of cultural practices should be emphasized depending on area/locality. Emphasis should be given on the integration of nematode management practices by adoption of cultural practices, resistant varieties, nematicides, organic amendments, biological control agents, etc. Role of secondary organisms in causing diseases along with nematodes should be studied and nematode management practices be evolved. Need to develop varieties, which are resistant or tolerant to nematodes. Varietal screening and subsequent breeding programmes should be intensified. Attempts should also be directed towards biological control. Paecilomyces lilacinus, Trichoderma harzianum, Verticillium chlamydosporium and VAM fungi have been identified all over the world as potential biocontrol agents against plant parasitic nematodes. The possibility of using these bacteria and fungi as biocontrol agents against nematodes infecting crops should be explored.