Journal of Biology and today's world 2013, volume 2, issue 5, pages: Efficacy of Various Biological and Microbial Insecticides

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1 CNB Scholar Journals Available online: Journal of Biology and today's world ISSN Review Article Efficacy of Various Biological and Microbial Insecticides Mohammad Mohammad Doost Chakoosari Department of Microbiology, Faculty of Science, Lahijan Branch, Islamic Azad University, Lahijan, Iran Received: 12 December 2012 / Accepted: 10 April 2013 / Published: 28 May 2013 Copyright 2013 Mohammad Mohammad Doost Chakoosari. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Synthetic chemical insecticides provide many benefits to food production and human health, but they also pose some hazards. In many instances, alternative methods of insect management offer adequate levels of pest control and pose fewer hazards. One such alternative is the use of microbial insecticides-insecticides that contain microorganisms or their by-products. Microbial insecticides are especially valuable because their toxicity to nontarget animals and humans is extremely low. This article focuses on microbial insecticide as a potential source of insecticide. Keywords: Microbial Insecticide; Bacillus thuringiensis; Insect 1. Introduction Microbial insecticides are especially valuable because their toxicity to non-target animals and humans is extremely low. Compared to other commonly used insecticides, they are safe for both the pesticide user and consumers of treated crops. Microbial insecticides also are known as biological pathogens, and biological control agents (Table 1) [1, 2]. Correspondence should be addressed to Mohammad Mohammad Doost Chakoosari, Department of Microbiology, Faculty of Science, Lahijan Branch, Islamic Azad University, Lahijan, Iran; Big_blue2456@yahoo.com; Tel: P a g e

2 Table 1. Microbial Insecticides Microbial Insecticides Product Name Host Range Bacillus thuringiensis Bactur, Bactospeine, Bioworm, Caterpillars (larvae of moths var. kurstaki (Bt) Caterpillar, Killer, Dipel, Topside and butterflies) Bacillus thuringiensis var. israelensis (Bt) Bacillus thuringiensis var. tenebrinos Aquabee, Bactimos, Gnatrol, LarvX, Skeetal, Teknar, Vectobac Foil, M-One, M-Track, Novardo, Trident larvae of Aedes and Psorophora mosquitoes, black flies, and fungus gnats larvae of Colorado potato beetle, elm leaf beetle adults Bacillus thuringiensis Certan wax moth caterpillars var. aizawai Bacillus sphaericus Vectolex CG, Vectolex WDG larvae of Culex, Psorophora, and Culiseta mosquitos, larvae of some Aedes spp. Beauveria bassiana Botanigard, Mycotrol, Naturalis aphids, fungus gnats, mites, thrips, Lagenidium giganteum Laginex larvae of most pest mosquito species Nosema locustae NOLO Bait, Grasshopper Attack European cornborer caterpillars, grasshoppers and mormon crickets Steinernema scapterisci Nematac late nymph and adult stages of mole crickets Bacillus popilliae and Bacillus lentimorbus Doom, Japidemic, Milky Spore Disease, Grub Attack larvae (grubs) of Japanese beetle Microbial insecticides are comprised of microscopic living organisms (viruses, bacteria, fungi, protozoa, or nematodes) or the toxins produced by these organisms. They are formulated to be applied as conventional insecticidal sprays, dusts, liquid drenches, liquid concentrates, wettable powders, or granules. Each product's specific properties determine the ways in which it can be used most effectively [3]. 2. Advantages of Microbial Insecticides The organisms used in microbial insecticides are essentially nontoxic and nonpathogenic to wildlife, humans, and other organisms not closely related to the target pest. The safety offered by microbial insecticides is their greatest strength. The toxic action of microbial insecticides is often specific to a single group or species of insects and this specificity means that most microbial insecticides do not directly affect beneficial insects (including predators or parasites of pests) in treated areas. 250 P a g e

3 Residues present no hazards to humans or other animals, microbial insecticides can be applied even when a crop is almost ready for harvest. If necessary, most microbial insecticides can be used in conjunction with synthetic chemical insecticides because in most cases the microbial product is not deactivated or damaged by residues of conventional insecticides [4, 5, 6]. 3. Disadvantages of Microbial Insecticides Heat, desiccation (drying out), or exposure to ultraviolet radiation reduces the effectiveness of several types of microbial insecticides. Consequently, proper timing and application procedures are especially important for some products. Special formulation and storage procedures are necessary for some microbial pesticides. Although these procedures may complicate the production and distribution of certain products, storage requirements do not seriously limit the handling of microbial insecticides that are widely available [4, 5, 6]. 4. Microbial Insecticide 4.1. Bacteria Bacterial pathogens used for insect control are spore-forming, rod-shaped bacteria in the genus Bacillus. They occur commonly in soils, and most insecticidal strains have been isolated from soil samples. Insecticidal products comprised of a single Bacillus species may be active against an entire order of insects, or they may be effective against only one or a few species. For example, products containing Bacillus thuringiensis var. kurstaki kill the caterpillar stage of a wide array of butterflies and moths. In contrast, Bacillus popillae (milky spore disease) kills Japanese beetle larvae but is not effective against the closely related annual white grubs [7, 8, 17] Viruses The larvae of many insect species are vulnerable to devastating epidemics of viral diseases. The viruses that cause these outbreaks are very specific, usually acting against only a single insect genus or even a single species. Most of the viruses that are nuclear polyhedrosis viruses (NPV's), in which numerous virus particles are "packaged" together in a crystalline envelope within insect cell nuclei, or granulosis viruses (GV's), in which one or two virus particles are surrounded by a granular or capsule-like protein crystal found in the host cell nucleus. These groups of viruses infect caterpillars and the larval stages of sawflies. Viruses, like bacteria, must be ingested to infect insect hosts. In sawfly larvae, virus infections are 251 P a g e

4 limited to the gut, and disease symptoms are not as obvious as they are in caterpillars. In caterpillars, virus particles pass through the insect's gut wall and infect other body tissues [9] Fungi Fungi, like viruses, often act as important natural control agents that limit insect populations. Most of the species that cause insect diseases spread by means of asexual spores called conidia. Although conidia of different fungi vary greatly in ability to survive adverse environmental conditions, desiccation and ultraviolet radiation are important causes of mortality in many species. Fungi used as insecticides include: Beauveria bassiana, Nomuraea rileyi, Vericillium lecanii, Lagenidium giganteum, Hirsutella thompsonii [10] Protozoa Protozoan pathogens naturally infect a wide range of insect hosts. Although these pathogens can kill their insect hosts, many are more important for their chronic, debilitating effects. One important and common consequence of protozoan infection is a reduction in the number of offspring produced by infected insects. Species in the genera Nosema and Vairimorpha seem to offer the greatest potential for use as insecticides [11]. 5. Bacillus thuringiensis (Bt) Bt is a gram-positive, rod-shape, aerobic, and spore-forming bacterium closely related to the omnipresent soil bacteria Bacillus cereus. The vegetative cells are 1 μm in width, 5 μm long, and have short hair-like flagellae. Bt is ubiquitous in the environment and can be isolated from soil, foliage, water and air. The species is distinguished from B. cereus by its ability to produce a protein crystal during sporulation. Bt was first isolated by the Japanese bacteriologist S. Ishiwata from diseased silkworm Bombyx mori (L.) larvae in In 1911, E. Berliner in Germany recorded the first scientific description of the bacterium. In 1916, Aoki and Chigasaki found that its activity was due to a toxin present in sporulated cultures, but not in young cultures of vegetative cells. Bt produces a parasporal inclusion body during sporulation usually referred to as a crystal. This crystal is made of proteins. A large number of related crystal proteins are known and more than one protein type can co-assemble in one crystal. In an effort to overcome a somewhat confused situation, a classification of crystal proteins and their genes was proposed. This classification is based on the crystal protein structure and on the host range. More than 14 distinct crystal protein (cry) genes are described, and recently additional insecticidal proteins have been identified. The genes specify a family of related insecticidal (Cry) proteins, and are divided into four major classes: Lepidoptera-specific (I), Lepidoptera- and Diptera-specific (II), Coleoptera-specific (III), and Diptera-specific (IV) genes. Bt has been applied to the environment since 1933, and first commercialized in France in However, it was not successfully commercialized until the 1950s, when the new technology of deep tank aerobic liquid fermentation was used to produce spore and crystal preparations. Major applications of Bt have taken place in North 252 P a g e

5 America for the control of over 40 pest species in field, forest, orchard, vineyard, park and gardens. The first commercial Bt formulations were available for field testing in the United States in In 1961, Bt subsp. kurstaki (Btk) was used as a biopesticide for the control of susceptible lepidopteran pests. New markets were opened by the discovery in 1976 of the israelensis subspecies, which is toxic to larval mosquitoes and black flies and the discovery of Bt subsp. tenebrionis, which is toxic to several beetle species. These discoveries stimulated sudden and dramatic commercial interest in Bt [12, 13, 14, 15, 16, 18]. 6. Conclusion Microbial insecticides offer effective alternatives for the control of many insect pests. Their greatest strength is their safety, as they are essentially nontoxic and nonpathogenic to animals and humans. References [1] Fuxa, J.R., Ecological considerations for the use of entomopathogens in IPM. Ann Rev Entomol., 32: [2] Harper, J.D., Present and future status of microbial control of arthropods. Crop Protection., 6: [3] Mansour. S.A., M.S. Foda, A.R. Aly, Mosquitocidal activity of two Bacillus bacterial endotoxins combined with plant oils and conventional insecticides. Industrial Crops and Products., 35: [4] Aly, C., M.S. Mulla, Effect of two microbial insecticides on aquatic predators of mosquitoes. J. Appl. Entomol., 103: [5] Regis, L., S.B. Silva, M.A. Melo-Santos, The use of bacterial larvicides in mosquito and black fly control programmes in Brazil. Mem. Inst. Oswaldo Cruz., 95: [6] Veena, P., A.K.Tripathi, K.K. Aggarwal, S.P.S. Khanuja, Insecticidal, repellent and oviposition deterrent activity of selected essential oils against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus. Bioresour. Technol., 96: [7] Thomas, W.E., D.J. Ellar, Bacillus thuringiensis var. israelensis crystal endotoxin: effects on insect and mammalian cells in vitro and in vivo. J Cell Sci., 60: [8] Hofte, H., Whiteley, H.R., Insecticidal crystal proteins of Bacillus thuringiensis. Microbiol Rev., 53: [9] Kurstak, E., (Editor), Microbial and Viral Pesticides. Marcel Dekker, New York. 253 P a g e

6 [10] Lacey, L.A., A.H. Undeen, Microbial control of black flies and mosquitoes. Ann Rev Entomol., 31: [11] Honee, G. B. Visser, The mode of action of Bacillus thuringiensis crystal proteins. Entomol Exp Appl., 69: [12] Aronson, A.I., W. Beckman, P. Dunn, Bacillus thuringiensis and related insect pathogens. Microbiol. Rev., 50:1 24. [13] Gill, S.S., E.A. Cowles, P.V. Pietrantonio, The mode of action of Bacillus thuringiensis endotoxins. Ann. Bev. Ent., 37: [14] Pearce, M., B. Habbick, J. Williams, M. Eastman, N. Newman, The effects of aerial spraying with Bacillus thuringiensis Kurstaki on children with asthma. Can. Jour. of Public Health., 93, 1. [15] Petrie, K., M. Thomas, E. Broadbent, Symptom complaints following aerial spraying with biological insecticide. N Z Med J., 14:116. [16] Binh, N.D., Reasearch, production and application of Bacillus thuringiensis in Vietnam. Biotechnology of Bacillus thuringiensis. Science and Technics Publishing House., 5: [17] Lacey, L., Bacillus thuringiensis serovariety israelensis and Bacillus sphaericus for mosquito control. J. Am. Mosq. Control Assoc., 23:133. [18] Lacey, L.A., M.S. Goettel, Current developments in microbial control of insect pests and prospects for the early21st century. Entomophaga., 40: P a g e

Microbial Insecticides 1

ENY275 Microbial Insecticides 1 R. Weinzierl, T. Henn, P. G. Koehler and C. L. Tucker 2 Synthetic chemical insecticides provide many benefits to food production and human health, but they also pose some