Biopesticides for Sustainable Crop Protection and Improvement

M. MADHAVI1’, CH. ARUNA KUMARI1, V. RAM REDDY2,

B. LAXMI PRASANNA2, K. MANOHAR3, and A. NAVATHA4

department of Plant Pathology, Agricultural College,

Professor Jay ashankar Telangana State Agricultural University, Jagtial 505529, India

department of Genetics and Plant Breeding, Agricultural College, Professor Jay ashankar Telangana State Agricultural University, Jagtial 505529, India

  • 3 Plant Pathologist, College of Agriculture, Rajendranagar, Hyderabad 500030, India
  • 4Agricultural College, Administration Section, Professor Jayashankar Telangana State Agricultural University, Jagtial 505529, India

'Corresponding author. E-mail: This email address is being protected from spam bots, you need Javascript enabled to view it

ABSTRACT

The chapter deals about the biopesticides which are natural substances to control different biotic stresses in an ecoffiendly manner.

It discusses briefly with the strategies of biological control, impact of synthetic pesticides on environment, different components of integrated pest and disease management, concepts, development, usefulness of biopesticides, different types and success of biopesticides in controlling the economically important pests, and pathogens as an integral component in sustainable agriculture.

INTRODUCTION

In recent years, and production of agricultural crops are greatly hampered because of many biotic and abiotic factors; besides these the changes in climatic/weather conditions have still worsened the productivity.

The fanners, who are helpless against natural conditions like climatic factors, focus on biotic stress to save the crop for increasing the yield and productivity. As a part of this, disregarding the future ill effects, farmers started using chemical pesticides. From the past decades, over and extensive usage of these synthetic organic chemicals led to a number of adverse long term enviromnental problems including extinct of natural flora, fauna, and so on. The conventional chemical pesticides though enhanced the food production, have adversely affected the environment and nontarget organisms.

Continuous accumulation of chemical fertilizers and pesticides in the environment is resulting in increase of pollution and harming the ecosystem. Many of the pesticides being used today are remaining within the plants for long duration and these residues are entering food chain, as they are also persistent as residues in soil and ecosystem. Therefore, in the present situation high priority may be given to adopt the usage of biopesticides in an ecofriendly manner for sustainable crop production. Biopesticides are a powerful tool in creating new generation sustainable agricultural products.

They are best alternative against few of the most problematic synthetic pesticides that are currently in use. In nature, several organisms including predators, parasitoids, microbial agents act as natural enemies to various pest infestations. Variety of insects belonging to arthropod taxa namely, ladybird beetles, ground beetles, spiders, and lace wings act as predators and are polyph- agous. Parasitoids have specialized life styles that allows them in finding their host and thereby attacking/killing, though the host specific parasites are variable, parasites may attack only one life cycle of a host (egg or larva).

APPROACHES OF BIOLOGICAL CONTROL

These are the three biological pest control strategies—importation, augmentation, and conservation.

14.2.1 IMPORTATION

Introduction of an exotic or co-evolved biological control agent for permanent and long term control of the pest (Eilenberg et al., 2001). It includes introducing a pest natural enemies into new localities where their presence is lacking. Generally, the government authorities will be practicing this type of approach.

Few splendid importation programs are cited below.

  • 1. The pest cottony cushiony scale Icerya purchasi, which devastated citrus industry in California, was totally checked with the instigation of Rodolia cardinalis, a predatory insect pest and also by a parasitoid fly that was introduced from Australia in late 19th century.
  • 2. After 20 years of introduction of natural enemies nearly 75% of alfalfa weevil Hypera postica population was brought down in Northeastern United States.
  • 3. From China, a wasp Trichogramma ostrininae was introduced for the control of Ostrinia nubilalis a European corn borer, the most destructive pest of North America. (4) During 1920s under classical bio-control program the population levels of Levuana iridescens an important serious coconut pest was controlled.

Important exotic pests of India:

  • 1. Two Parasitodis (Acerophagiis papyae, Pseiidleptomastix inexicana) imported from Puerto Rico USDA and quarantined at NBAH were used for the control of Paracoccus marinates, the mealy bug of papaya that caused serious damage in economically important crops and standing crop of mulberry in Coimbatore.
  • 2. During the year 2009-2010, the parasite Quadrastichus mendeli was introduced from Australia and released in Bangalore and nearby areas of Karnataka and Orissa for the control of Eucalyptus gall wasp Leptocybe iiivasa a pest introduced from southeast Asia in 2006 which later became established as a serious pest in South India, Uttar Pradesh, and New Delhi.
  • 3. Parasitoids Einytoma erythrinaea and Aprostocetus exertus were introduced during 2008 from South Africa to control Erythrina gall wasp Qiidastichns erythrinae which produces galls in different plant parts of Erythrina sp (coral tree) in Karnataka and Tamil Nadu. The classical biocontrol approach is mostly effective against exotic insect pests.

The drawback for failure though not thoroughly understood they might be attributed to the poor adaptation of natural enemies to the introduced environmental conditions and locations, lack of appropriate syncing between the life cycle of the pest and natural enemy.

14.2.2 AUGMENTATION

The two perspective of augmentation biological control are namely, (1) Inundation, and (2) Inoculation

1. Inundation biological control: it utilizes living organisms in the control of pests by the introduced organisms itself (Eilenberg et ah, 2001). When the pest population crosses the economic injury level, then the bioagents are released in huge amounts for early control of the pest. If, once after release, the population of pest has further increased, after over a period the bioagents will be reintroduced. The timescale is weeks or months as the events are often limited to one cropping season.

Ex. Predators such as Lacewings, lady bird beetles and parasit- oids Trichogramma are released more frequently in large number.

  • 2. Inoculation biological control: intentional release of biocontrol agent that multiplies and control the pest in an extended period of time (Eilenberg et al., 2001). The underlying objective is to let the natural enemy to increase their population size and may control the pest in due course of time. Different events of biological control are limited to one cropping period. The greenhouse White fly and the spotted spider mite were controlled with the periodical release of Encarsia formosa (parasitoid) and Phytoseiuhis persimilis (predatory mite).
  • 3. Conservation: conservation refers to enhancing and maintaining of natural enemies that are already present in the landscape. Various methods namely, alteration of the management practices, adoption of strip cropping or polyculture, provision of hosts to get predators thr ough times of lack of food, provision of nonlrost foods like sugar, nectar sources as crucial sources for attracting and retaining most of the parasites and predators, and so on.

Examples of successful biological control agents of India are briefly mentioned below:

  • 1. Control of cottony cushion scale, Icerya purchasi on fruit trees by its predatory vedalia beetle RodaJia cardinalis in Nilgiris which was imported from California (1929) and from Egypt (1930). The predatory was multiplied under in vitro and when released had effectively checked the pest within one year period.
  • 2. During 1983-84, the water fern Salvinia molesta in Bangalore was biologically suppressed by the weevil Cyrtobagous salviniae imported from Australia (1982).
  • 3. For control of Water hyacinth (Eicchomia crossipes) three exotic natural enemies namely, Neochetina eichhomiae and N. brnchi and Ortlioga- lunma terebrantis were introduced from South America in 1982.
  • 4. The apple wooly aphis, Eriosoma lanigerum was controlled in Coonor area with the introduction of parasitoid Aphelinus mali. The egg parasitoid v. Trichogramma australicum @ 50,000/ha/wk was released for 4-5 weeks from one month after planting for the control of shoot borers of sugar cane, cotton boll worms, stem borers of paddy, and sorghum.
  • 5. Cryptolaemns montrouzieri was effective in suppression of Centro- coccus isolitus on brinjal, Pulvinaria hirsutus on grape, and Pseudo- coccus carymbatus on citrus.

BIOPESTICIDES HISTORY

The earliest agricultural biopesticides were the plant extracts wherein, the history says the natural insecticides rotenone (roots of derris plant), pyre- thrum (flower heads of chrysanthemum) and nicotine (leaves of tobacco) were used before 1940s to control various pests and diseases. Later, during 1940s use of synthetic chemicals was started for pest control.

In 18th and the beginning of 19th centuries, the theme of biological control was to use birds and entomophagous insects; where microbes were properly not known during that time. The wider aspects of microbe-based biological control were known with discovery of Bacillus thuringiensis (Bt) bacteria (Aronson et al., 1986; Martin and Traverse, 1989; Siegel and Shadduck, 1990; Marrone, 1994; Joung and Cote, 2000).

The Japanese biologist, Shigetane Ishiwata isolated Bt from diseased silk worm. The bacteria B. thuringiensis (Spores) was the first widely used biopesticide developed during 19th century. Later, Ernst Berliner, a German biologist rediscovered it from diseased caterpillar of flour moth. In 1911, Bt is classified as type species, that is, B. thuringiensis. The main concept of microbial pest control, its selective action on specific pest attracted the attention of many researchers.

In France, early in 1920s Bt was used as biological insecticide and have developed Sporeine, the first commercial Bt product, in 1938. In the United States, extensive usage of biopesticides began in the 1950s and also, they have even published the research studies on Bt efficacy and soon registered Thuricide the first commercial Bt product in 1961 (USEPA, 1998). Since then, different subspecies, varieties, strains of Bt were identified that are effective against various insect pests (Gonzales et al., 1982; Carlton, 1988). Thereafter, Bt has covered nearly 90% of biopesticide market (Chappie et ah, 2000; Chattopadhyay et ah, 2004; Romeis et ah, 2006), and at present several Bt strains have registered as biopesticides globally (Glare and О Callaghan, 200). During 19th century usage of mineral oils have started as plant protectants among the biological control experiments and by 20th century, soil microbiology and ecological studies had led in identifying different soil microbes which are antagonist to pathogens and insects pests, by different mechanisms (antagonism or hyper parasitism or antibiosis or competition etc).

Even though most of them have proven under field conditions, only few of them were commercially developed which could sustain the situation at that point of tune against usage of synthetic pesticides.

During mid of 20th century, there was a predominant adoption of toxic chemical insecticides in different crop ecosystems because of which the research and developmental activities of biological control were come down. However, during this period the utilization of new products developed were restricted to niche markets only where the synthetic chemicals were not economical. As a first viral insecticide, Heliothis NPV has received Elcar label in the year 1975.

The biocontrol pathogen, B. thuringiensis var. israelensis discovered in 1977 was toxic against flies and the strain tenebrionis against beetles in 1983. During 1979, U.S. EPA registered first insect pheromone to mass trap Japanese beetles. In early 1990s, research studies were started on kaolin clay as an insect repellent in organic fruit orchards and made available in commercial form in organic systems. Similar transformation was seen in Biopesticides development and their usage for the control and management of plant diseases.

During 1980 and 1990, success stories on commercial basis was seen from the products containing Agrobacterium radiobacter against crown gall of woody crops, Pseudomonas fluorescens against fire blight in orchard crops wherein the over usage of streptomycin had resulted in development of resistant pathogen populations. In greenhouses and pot mixing industries, products with variety of microbes with suppressive nature against soil borne pathogens were introduced into the market. Increased cost on over usage of chemical pesticides has led in resurgence of academic and industrial research for biopesticides development.

The organic agriculture had rapidly expanded from the past decade, thus there was a prompt increase in adoption rates and paved a way for the increase in development of new biopesticides during mid-1990s. Under U.S. EPA Biopesticides division, nearly 100 biopesticides active ingredients were registered and available commercially in different products.

The pioneer workers all the world who has worked on biopesticides has stated that the antagonistic microbes can be used as an alternative to synthetic chemical pesticides in the control of crop pests (Le Conte, 1874; McCoy et al., 1988). Later, these pioneer Works and further researches had become breakthrough for the development of microbe-based pesticides (Sundheim and Tronsmo, 1988). The pioneer workers who have worked on biopesticides had stated use of antagonistic microbes is a best alternative against synthetic pesticides for the control of insect pest. Boverin, (Beau- veria bassiana) the first fungal product developed in 1965 from former Union of Soviet Socialist Republics (USSR) for control of Colorado potato beetle and also the codling moth (De Faria and Wright, 2007). Heliothis nuclear polyhedrosis virus (NPV) is the first viral biopesticide declared in 1973 (Szewczyk et al., 2011).

 
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