eChapters

A number of insects infest seeds in storage. These insects infest seeds to fulfill their feed and shelter requirements, which result into qualitative as well as quantitative loss of seeds. Indian climate is very favourable for their multiplication and growth throughout the year. Storage pests move along with commercial products from one area to another and even to different countries in the world. Some adult insects are strong fliers and may spread from one to another place of storage or from source of infestation. Generally, all insects infesting seeds in storage belongs to insect order Coleoptera and Lepidoptera (Table 4.1). Some minor species belong to Pscoptera. These pests cause losses to man by destroying large quantities of grain, corn, legumes (beans, lentils and peas), milled cereal products, flour, bran, macaroni and other paste products, dried fruits, dried vegetables, cheese, nuts, candy and other food materials. They contaminate and thus eliminate for human consumption, far more food than they eat and either cause direct loss or transmit diseases to man and his domestic animals. These insects can be categorized as major or minor pests according to the loss of seeds caused by them. Similarly, on the basis of their feeding behavior, they can be grouped as follows:

Introduction

The increasingly precarious situation facing the world’s hill regions has been the focus of a growing level of awareness over the past two decades. The high altitude regions offer a challenge to agricultural development agencies which is shared by many hill areas of the world characterized by marginality, extreme diversity, environmental fragility and complex smallholder farming systems. There is justifiable concern relating to the conservation of hill and mountain ecosystems, to the extent that the concept of sustainability has been adopted as a broad slogan by the environmental movement (Lele, 1991).

Conditions specific to mountain regions, such as inaccessibility and diversity have placed a high premium on large families, encouraging population growth. Children are essential to family subsistence strategies offering free labour, and they are consequently considered to be a source of wealth. Population control measures in these regions have ignored this scenario (Sharma and Banskota 1990; Jodha, 1991).

DEFINITION

Pheromones are chemical produced as messengers that affect the behavior of other individuals of insects. The term pheromone was introduced by Peter Karlson and Martin Liischer (1959) and is based on the Greek pherein (to transport) and hormon (to stimulate) is a chemical that triggers a natural behavioural response in another member of the same species. There are alarm pheromones, food trail pheromones, sex pheromones. And many are others that affect behaviour or physiology. Their use among insects has been particularly well documented, although many vertebrates and plants also communicate using pheromones. Pheromones are chemicals released by an organism into its environment enabling it to communicate with other members of its own species.

Farmers still rely heavily on insecticides because of their efficiency, portability, and speedy returns on investment. Although synthetic organic insecticides are highly efficient, their widespread usage has led to toxicity to natural enemies, toxic residues in plants and the environment, insect resistance, and a resurgence in insect populations. Ripper (1956) first time recognized the problem of resurgence in plant protection.

Metcalf (1986) distinguished between two types of resurgence: primary insect resurgence, in which populations of target insects that had been suppressed by insecticide application quickly recover to excessive levels (Fig. 1.A), and secondary insect outbreak, in which non-target species develop into serious insect s after insecticide application (Fig. 1.B).

Primary insect resurgence

Primary insect resurgence occurs when the target insect population increases to at least as high (Hajek, 2004) or higher (Hardin et al., 1995) than in an untreated control or higher than before the treatment (Pedigo and Rice, 2006).

Secondary insect resurgence/ secondary insect outbreak (Type II resurgence)

The phenomenon known as replacement of a primary insect with a secondary insect, or secondary insect outbreak, occurs when the population of a non-target insect, which is harmful to the crop, experiences a surge following the application of a insecticide aimed at controlling the population of the primary insect. A second insect outbreak is also called resurgence. A secondary insect outbreak is the rise of a non-target species after an insecticide has been used.

19.1. Introduction

A wave of research on insect pheromones has been initiated in early 1960’s in response to public concern and alarm about chemical pesticides to develop an elegant and ecologically safe technology for the control of insect pests. Pheromones, a class of semiochemicals are considered as ‘Biochemical Pesticides’, belong to the subdivision of Biorational pesticides which include “Microbials” (Viruses, Bacteria, Pathogens etc.) and “Biochemicals” (insect plant growth regulators, semiochemicals etc.). The term biorational (biological + rational) pesticides can be defined as the use of specific and selective chemicals, often with a unique modes of action, that are compatible with natural enemies and the environment, with minimal effect on non-target organisms. Biorational control is based on a diversity of chemical, biological and physical approaches for controlling insect pests which results in minimum risk to man and the environment (Horowitz  et al., 2009).

History

• Aristotle (384-322 BC): A good beginning of taxonomy was made by Aristotle (Historia Animalium). He erected entomon. He could distinguish mandibulates and haustellates; winged and wingless forms. The insect orders like coleopteran, dipteral, psyche (Lepidoptera) were created by him. Hence, he was called as Father of Biological Classification.

• Linnaeus (1707-1778): Father of Taxonomy and Binomial Nomenclature. He coined the term Insecta. He used the term Systematics. His greatest contribution is Systema Naturae.

• Brawer (1885): Laid foundations for modern system of classification and responsible to divide class Insecta into Apterygota and Pterygota.

• Michael Anderson (1727-1806): Contemporary and rival of Linnaeus. Introduced Numerical Taxonomy and hence is called Father of Numerical Taxonomy. 

• Johan Christian Fabricius (1745–1808), the first systematist considered to specialize on insects, published in 1778 his Philosophia Entomologica (40), the first textbook of entomology.

• Fabricius had already set forth his system of insects in 1775 (Systema Entomologiae), his system of genera in 1776 (Genera Insectorum), and then numerous works on species, culminating in individual accounts of the species of each order

Onion production is constrained by insect pests and diseases that damage seedlings, foliage, roots and bulbs and reduce both yield and market quality. Important pests include onion thrips, leaf miners, cutworms, armyworms and onion maggots. Major diseases include damping-off, basal rot, downy mildew, purple blotch, white rot and pink-root rot. Some insects also transmit damaging viral diseases. This chapter presents integrated cultural, biological, botanical, behavioural and chemical strategies for managing these threats. Crop rotation, sanitation, healthy planting material, proper spacing, resistant varieties, traps, barrier crops, beneficial microorganisms, natural enemies and need-based pesticides are discussed as components of sustainable crop protection and resistance management.

Efficiency of pest control by insecticides is dependent on the correct type of pesticide formulation applied at the proper time and correct dosage, besides the good equipment. Equipment used to apply insecticides must be suited to the crop (or other situation in which the pest is to be controlled), to the scale of operation, and to the formulation of chemical to be applied. In the long run, it is good economy to buy the best equipment available.

Application equipment of high quality means not only good, durable construction but also good design that gives it a professional appearance. Because it is desirable and often necessary to utilize pesticides in a variety of ways, various types of dispensing equipment have been developed. This equipment is placed in the following categories: (1) Sprayers, (2) Dusters, and (3) Granule Applicators. In addition, specialised equipment of various sorts (such as mist machines and fog generators) are available for particular purposes. Since detailed consideration of pesticide application equipment is out of the scope of this book, only a brief consideration is given here to some important features of the main types of equipment.

Insecticide classification majorly divided into three categories. A. based on chemical group, B. mode of entry in the insect, C. based on toxicity.

A. Classification of Insecticides based on chemical group

Historians have traced the use of pesticides to the time of Homer around 1000 B.C. earliest records of insecticide use pertain to the burning of “brimstone” (Sulfur) as a fumigant. Pliny the Elder (A.D. 23-79) recorded most of the earlier insecticide uses in his Natural History and included among these was the use of gall from a green lizard to protect apples from worms and rot. Later, a variety of materials used viz., extracts of pepper and tobacco, soapy water, whitewash, vinegar, turpentine, fish oil, brine, lye and many others. At the beginning of World War II (1940), insecticide selection was limited to several inorganic compounds, arsenicals, petroleum oils, nicotine, pyrethrum, rotenone, sulfur, hydrogen cyanide gas, and cryolite. It was during World War II that opened the Chemical Era with the introduction of a totally new concept of insect control.

Introduction

Analysis of insecticide formulations are critical for the availability of quality insecticides in the market for ultimate benefit of farmers and ecosystem health. This chapter highlights the significance of comprehensive insecticide formulation analysis protocols, encompassing methods for determining active ingredient and assessing physical and chemical parameters. Employing advanced analytical techniques such as spectroscopy and chromatography for insecticide formulation analysis will eventually maintain the quality of insecticides for the sustainable management of pests.

In India, over 339 pesticides are registered that includes insecticides, fungicides, herbicides (DPPQS, 2024). The current market of non-genuine insecticide is INR 3,200 crores (USD 525 Million) which constitutes 25 per cent by value and 30 per cent by volume of the total domestic market of agrochemicals in India as per Industry reports, primary interviews, news articles and Tata Strategic analysis (FICCI, 2015). Monitoring registration and regulation of insecticides is governed by the Insecticide Management Bill 2020, which replaced the Insecticide Act 1968 (DPPQS, 2023). The Insecticide Act of 1968 established the Central Insecticide Laboratory, Faridabad, under section 16 with two regional insecticide testing laboratories at Chandigarh and Kanpur (DPPQS, 2023). Current Quality Control of Insecticides in States/UTs during the last five years shows that 68078 insecticide samples were analysed (DPPQS, 2023). In the beginning, these laboratories involved in analysing insecticide samples drawn by any officer or the body authorized by the Central or State Governments and submit certificates of analysis to the concerned authority. Regional Pesticide Testing Laboratories (RPTLs) had a huge target of analysis of 1550 samples per annum that necessitated the establishment of 71 State Pesticide Testing Laboratories (SPTL) spread across India of which 14 are NABL accredited (DPPQS, 2023).

Formulation is a word that can be used in a lot of different ways, but at its core, it means putting things together in the right way, usually by following a formula. Insecticides come in different forms, which are called formulations. A formulation is just the way a product is used. The chemical or biological makeup of a pesticide and its active ingredient (also called the active substance) determine how it works on living things. Most of the time, the active ingredient is mixed with other things, and the product as it is sold will need to be weakened even more before it can be used. Formulation makes a drug easier to handle, store, and use. It can also have a big effect on how well it works and how safe it is.

Insecticides come in many different forms because the active ingredients vary in how easily they dissolve, how well they kill pests, and how easy they are to handle and move. The pesticide is made up of both active and non-active (used to be called “inert”) chemicals. The manufacturer will need to know the identity of the pest, as well as details about its feeding behavior, reproduction, and life cycle, in order to create an effective formulation. Manufacturers also take into account factors including surface and equipment type, runoff and drift rates, pest habits, and safety when formulating insecticides. Inactive materials (adjuvants/ additives) are often added to insecticides to make them stick to the application surface or spread out over leaves. There are solvents (liquids) that dissolve the active ingredient, carriers (liquids or solids) that aid in the delivery of the active ingredient, etc.. Boosting the efficacy of active ingredients requires additives, such as spreaders, stickers, wetting agents, compatibility agents, foaming agents, etc.

Insecticide use for agriculture has increased along with food quality and quantity, but self-harm has also increased. Despite a high rate of insecticide poisoning and sometimes usage for homicide, little is known about insecticide management.

Insecticide poisoning kills up to 300,000 people around the world every year. According to hospital admission data, most estimates of insecticide poisoning in the short term have been based on numbers of people poisoned by insecticide s. This represents only a small part of the real number, as it includes only the most dangerous cases. IS 4015 is a standard guide for handling cases of pesticide poisoning.

INTRODUCTION

Insecticide resistance poses a severe threat to agricultural productivity in India and in other countries of the world. Humans have had the ingenuity to develop thousands of pesticides to protect foodstuffs, livestock, and health and the use of these poisons has triggered a rapid evolutionary response in many target species and some nontarget species of invertebrates, microorganisms, higher plants and vertebrates. Insecticide exposure led to nullify their toxic effects through genetic selection for individuals with the biochemistry or behaviour. Continual development of new compounds and its greater use and increase in input insecticide cost is mainly due increase in resistance. Reduction in insecticide efficacy from insect resistance has major economic, environmental and human health implications. Integrated Pest Management (IPM) is a convenient descriptor for wide range of still-evaluating pest control program that emerged from chemical prophylaxis practiced. IPM theory has fostered a transition from primarily chemical control to programs tempered with biological information and input tailored to each agro ecosystem, crop and pest situation in production.

Insecticide resistance to both fumigants and contact insecticides is an increasing problem in controlling stored grain and grain product insects throughout the world (Table 14.1). Hence, persons engaged in food commodity storage and preservation world over are concerned about the resistance of stored product insects to contact insecticides and fumigants. It is, therefore, necessary to work out strategies to delay or minimize the probability of resistance evolution. Resistance to pesticides is the ability of a strain of insects to tolerate doses of toxicants which would prove lethal to a normal population of insects of the same species. Resistance results when occasional resistant individuals arise in a population and survive the pesticidal treatment. These survivors then reproduce and confer the resistance to their offspring in succeeding generations. Resistance is the ability of a population (of insects) to survive a dose (of insecticide) that would normally kill 100 per cent of a susceptible population. Insecticide resistance is a dynamic phenomenon dependent on biochemical, physiological, genetic and ecological factors.

The chances of development of insecticide resistance in stored grain insect pest are more because of their life style, i.e., to remain confined in limited area. This results in more common inbreeding of the homozygous resistant strain resulting into homozygous resistant progeny. At the same time their management, once detected, can be easily achieved with the application of sufficiently acceptable sufficiently higher dose of the most appropriate insecticide to eliminate all the resistant survivors

The insect pest of stored grains can be conveniently divided into two groups, i.e., coleopterous and lepidopterous, therefore, the subject on these two groups has been pooled accordingly.

Insecticide mode of action is divided in to four major chapters 1. Nerve & Muscle 2. Growth & development 3. Respiration & Energy production 4. Metabolic process 5. Unknown or Non-Specific (multisite inhibitors) (Source: IRAC). To understand the mode of action of insecticides, it is necessary to understand the function of nervous system and how it works in insect. The nervous system functions transmits information throughout the body. This system has three components: 1) Peripheral nervous system (PNS) to receive and transmit incoming signals (taste, smell, sight, sound, and touch) and to transmit outgoing signals to the muscles and other organs, effectively communicating them how to respond, and 2) Central nervous system (CNS) to interpret the signals and coordinate the body’s responses and movements. 3) Visceral or sympathetic nervous system (VNS) directly connected with the brain that supplies nerves to the anterior part of the alimentary canal (foregut and midgut), heart, and spiracles. Some additional nerves arise from posterior compound ganglion of ventral nerve cord (VNC) which supply nerves to the posterior part of gut and reproductive system.

Insecticide resistance is a growing concern for those who need insecticides for medical, veterinary, and agricultural control of insect pests. In response to the introduction of DDT resistance in 1947, the incidence of resistance has increased annually by an alarming amount. Resistance is “the inherited ability of a strain of some organism to survive doses of a toxicant that would kill the majority of individuals in a normal population of the same species” (WHO, 1957).

As a result of continued insecticide application, the proportion of resistant insects increases compared to that of susceptible and the population becomes increasingly difficult to control

Above photograph theoretical example illustrating the increase of insecticide resistance levels in a pest population. Some individuals (black) with genetic traits allowing them to survive insecticide applications can reproduce; if the selection pressure is frequent, they easily become the preponderant part of the population (Fig. 1).

An adaptation to a pesticide leads to reduced susceptibility to it among the pest population targeted by that pesticide. In nature, pests develop resistance to chemicals through natural selection. In the most resistant organisms, their genetic traits are passed on to their descendants. Since 1945, at least 500 species of pests have developed resistance to pesticides (Anonymous, 2007), but other sources estimate as many as 1000 species (Miller, 2004).

General Aspects About Insects

‘Insects’ are almost ubiquitous. They are found all over the world, in the icy regions of the poles, deserts, forests, mountain peaks, oceans and even in oil wells. They can adopt themselves to any climatic conditions and can live in any habitat where food is available. Insects are mostly small, air-breathing organisms of the animal world. Most of the insects live freely in nature. Many species are wild and harmless to human beings. Many are beneficial because of their role in the ecosystem. Some are a part of the food chains of wild creatures, while others through predation and parasitism hold in check many other species of insects. Insects also play a vital role in pollination. Relatively only a few species are harmful to man and are his chief competitor on earth.

Integrated disease management (IDM) needs competence in three broad areas
I. Prevention
II. Monitoring
III. Intervention

Integrated disease management includes use of physical, cultural, biological, chemical and biotechnological for disease management. It may comprise computer aided sampling, decision making, improved farm tools & equipment.Farmers are the primary decision makers in Integrated disease management programs. They have to decide individually and collectively how to manage all diseases that may harm crops.

With some important exceptions, applied plant pathology was for many years rather single minded. It aimed at eradication or total exclusion of a plant disease , and it relied largely on a single control method, application of chemical poisons.