Microbial insecticides: Food security and human health

Abstract

Sustainable agricultural systems must be adopted to increase the food and fiber production keeping in view of human health and increase in population; the number of undernourished has increased to almost 20% (The state of food insecurity in the world economic crises - impacts and lessons learned. In Food and Agriculture Organization of the United Nations, Rome). Insect pests have been causing serious damage in the fields and stored grains and their products. Interventions is required to limit the losses, therefore, synthetic insecticides have played a significant role in their management for more than 60 years. Indiscriminate use of insecticides have left undesirable residues in the environment, which are toxic to human beings and non target organisms as well as insects have developed resistance against them and resurgence of pests that lead to find a suitable, sustainable and efficient method of management. Microorganisms: bacteria, viruses, fungi and protozoa form the most abundant and diverse groups, which offer a vast resource for exploitation to use in the management program. Bacillus thuringiensis is a gram positive, occurs in soil and ubiquitous in distribution. It produces parasporal crystalline body which contains one or more cry proteins that can be toxic to a number of insects. cry proteins are encoded by cry genes and 200 of them are identified. Similarly, a number of insect pests are also vulnerable to viral diseases. Nuclear Polyhedrosis and Granulosis Viruses are commonly used against the Lepidoptera. They are highly species specific and safer to human beings. Fungi, often act as important natural control agents that limit the insect population. Promising results are obtained by Beauveria bassiana and Metarhizium anisopliae against many insect pests. B. bassiana grows naturally in soil throughout the world and causes white muscardine disease. Therefore, intensive work is required to improve the efficacy of microbial insecticides through molecular biology and genetic engineering to enhance their role in the insect management for better food security.