Integrated Pest Management (IPM) in Rice
Rice is the staple food of at least half of the world's population and is grown in approximately 148 million ha of land globally. Nearly 90 per cent of this area falls in the Asian region. Integrated pest management (IPM) is a broad ecological approach for pest management which employs all available skills, techniques and practices such as cultural, genetic, mechanical and biological methods including application of chemical pesticides as a last resort in a harmonious and compatible manner with a view to suppress pest population below economic injury level, based on regular crop pest surveillance and monitoring. The IPM is a dynamic approach and process which varies from area to area, time to time, crop to crop and pest to pest etc., and aims at minimizing crop losses with due consideration to human and animal health besides safety to environment. Live and let live is the philosophy behind IPM. IPM approach has been globally accepted for achieving sustainability in agriculture. IPM has been enshrined as the important principal of plant protection in the overall crop protection programme under the national agricultural policy of the government of India.
Rice is attacked by insect - pests, diseases, weeds, rodents and nematodes. Some of the pests are of national significance, while others are pests of regional significance. Insect pests like gallmidge (Orseola oryzae), white backed planthopper (Sogatodes oryzae), white backed planthopper (Sogatella furciferra), yellow stemborer (Sciropophaga isertalas), leaffloder (Cnaphalocrosis medinalis), and brown planthopper (Nilaparvata lugens) and diseases like rice blast (Pyricularia oryzae), bacterial leaf blight (Xanthomonas campestris pv. Oryzae) and sheath blight (Rhizoctonia solani) and weeds like Panicum spp., Cyperus spp. and Echinochloa spp. and rodents such as smaller bandicoot (Bandicota bengalensis), field mice (Musa spp.) and soft furred field rat (Millardia meltada) are pests of national significance.
Agro ecosystem analysis (AESA)
AESA is an approach that can be used to analyze field situations with regard to pests, predators, soil conditions, plant health, the influence of climatic factors and their interrelationship for growing healthy crop. The methodology of AESA is as under:
Enter the field at least 5 ft away from the bund. Select a site with a dimension of 1 sq. mt. visual observations are recorded on flying insects (both pests and defender), pests and defenders which remain on plants, pests like stem borer that remain under soil. Disease incidence, insect damage, types of weeds, their size and population density in relation to crop plant, soil conditions are also recorded. Rodent live burrows are observed and climatic. Factors viz. sunny, partially sunny cloudy, rainy etc. for the preceding week are also recorded.
Draw pest and defenders on the chart. Indicate the soil condition, weed population, rodent damage etc. draw healthy plants with green color, and diseased plants with yellow color. Pests and defenders are drawn at appropriate part or the plant where they are seen at the time of observation.
Group discussion and decision making
The observation recorded in charts discussed among the farmers. The extension functionaries during their visit to the village mobilize the farmers, and critically analyze the factors such as the pest population defender population, the influence of prevailing weather, soil conditions on the likely build up of defender/ pest population. Decisions are taken regarding release of defenders, application of safe pesticides to be used for specific pest situation.
Cultural practices are integral part of IPM. Summer ploughing, selection of healthy seeds, timely planting, raising of healthy nursery, removal of weed from field, balanced use of fertilizers as per recommendations are the important cultural practices that are followed for pest management in paddy.
Mechanical practices comprise of removal and destruction of pest infested plant parts, clipping of rice seedling tips and collection of egg masses and larvae of pest and their placement in bamboo cages for conservation of biocontrol agents.
Biological control practices
Biocontrol agents like coccinellids, spiders, damsel flies, dragonflies should be conserved. Chlorpyriphos is used for root dip treatment of rice seedlings. Egg, masses of borers are collected and placed in a bamboo cage cum percher till flowering. It permits the escape of egg parasites and trap and kill the hatching larvae.
Pheromone traps are installed at the rate of 20 traps/ha to trap yellow stem borer at 10 days after transplanting.
Chemical control measures
Chemical control measures are used under IPM as a last resort. Application of pesticides has to be need based and proper crop health monitoring, observing ETL and conservation of natural biocontrol agents has to be ensured before deciding in favour or use of chemical pesticides.
Economic threshold levels (ETLs) of major insect pests of rice.
Stem borer: Moderate to severe in nursery, 5% dead hearts or one egg mass/m2 at planting to tillering stages or one moth/m2 at panicle initiation to booting or flowering stages.
Gall midge: One gall/m2 in endemic areas or 5% affected tillers in non-endemic areas. 5% affected tillers is the ETL at mid tillering stage.
Whorl maggot: 20% damaged hills up to 30 days after planting.
Case worm: 1 to 2 cases per hill.
Leaf folder: One damaged leaf per hill or one larva per hill at planting and 1-2 freshly damaged leaf per hill at mid tillering or panicle initiation to booting stages.
Hispa: One adult or one grub per hill at planting to pretillering stages or one adult or 1 to 2 damaged leaves per hill at mid tillering stages.
Green leaf hopper: 2 insects per hill in tungro endemic areas, 10 insects per hill in other areas at tillering stage and 20 insects per hill at mid tillering to panicle initiation to booting stages.
Brown planthopper: 5 to 10 insects per hill at tillering stage. At panicle initiation to booting stage 20 insects per hill, while 5-10 insects at flowering stage and after flowering.
White backed planthopper: 10 insects per hill at tillering stage and 5-10 insects per hill at flowering stages and after flowering.
Gundhibug: One or two bugs per hill.
Submitted by vivek on Wed, 07/01/2009 - 12:49