Among the biggest challenges the present world is going through, producing enough food for its vast population is a vital one. The explosion of population forces the modern agriculture to produce the minimum amount of food required to feed the living human population without leaving too many scopes for the agronomists to think much about the environment and people’s health. You must protect your crops from the damages caused by pests, any animals or plants that are harmful to humans and human interests such as- harmful insects, mites, nematodes, etc., to ensure a good crop production. Farmers of many countries around the world have been using different types of chemical pesticides indiscriminately to protect their crops from various pests. Though chemical pesticides bring them temporary relief, but at the very moment, they introduce many long-term and persistent disasters.
Chemical Pesticides Are Poisons
Indiscriminate use of chemical pesticides is highly hazardous to the environment and human health. When pesticides are applied to a field they don’t remain confined to their targeted field, rather travel to a vast area outside the targeted field by air, water, and soil. This widespread movement of applied pesticides brings surface and ground water contamination. Soil and air contaminations also take place from inappropriate pesticide use. These pollutions produce complicated human diseases like – skin irritation, nausea, cardiovascular illness, etc.
Besides humans, the toxic residues of chemical pesticides produce many harmful impacts on various animals (e. g., birds, fishes, amphibians, etc.) and plants.
The above-mentioned problems are not all pesticides are responsible for, there is another terrible and irreparable problem that pesticides introduce that is ‘Making the Pests Resistant’. The indiscriminate application of pesticides has been making the pests resistant to pesticides and thus making them stronger and more damaging gradually by the following ways-
• When a pesticide is applied to a crop field that kills many beneficial insects, the insects which are a natural enemy to the pests and suppress the pests directly or indirectly, along with the target pests. As pesticides cannot completely eradicate the whole pest population, the pest population resurges to higher levels than the standard before treatment. This incidence is known as pest resurgence.
• Sometimes pesticides kill the susceptible pests allowing the naturally resistant ones to survive. Thus, the genetically determined resistance traits of the survivors are passed to their offspring, and a more resilient pest population than the previous one is evolved. This is known as pest resistance, and it increases the number of resistant pests gradually.
• Pesticides may bring another problem called replacement or secondary pest outbreak. This problem takes place when a pesticide controls a target pest but afterward a previously insignificant pest replaces the target pests and appears as an economic problem.
Pests must be controlled to ensure our food safety, but the above mentioned numerous problems don’t leave any option for us to rely entirely on pesticides. A more efficient, long-term, eco-friendly and safe technique must be adopted to control pests.
IPM has some fundamental ways to work-
• IPM prevents pests from turning into a problem. It works with approaches which target long-term prevention of pests without producing environmental hazards.
• IPM pays much attention on the correct identification of pests to decide the most suitable controlling approach.
• Careful monitoring of pests and considering all information of their biology and environment are critical in IPM, as they enable us to decide whether the pest can be tolerated or should be destroyed.
• IPM programs manage pests effectively by combining many management approaches; a combination of various approaches works better than a separate approach.
Pest Controlling Methods of IPM
Different methods for managing pests efficiently and permanently can be grouped into the following categories-
Pests like weeds, nematodes, invertebrates, vertebrates and plant pathogens have many natural enemies like predators, parasites, pathogens and competitors. Biological control of pests refers to the eradication or suppression of various noxious pests by encouraging, artificially introducing or increasing their natural enemies. The natural enemies or biotic components of natural control of pests are diverse and have different mechanisms to control pests.
• A good number of pathogenic bacteria, fungi and viruses attack insects and cause diseases to them. These microorganisms can be used practically to control pests by culturing them in artificial media and introducing them in large number into the affected area.
• Parasitic insects or parasitoids live on or within the body of many living insects. They feed on the body of their hosts and ultimately kill them. These parasitoids are used to control many pests, e.g. Encarsia Formosa Gahan is effective in commercial controlling of whiteflies.
• Predaceous insects like Praying Mantis and Lady Beetles attack and kill many pests to eat them as food. These predator insects consume many pests during their lifetime and play an important role in controlling many plant-feeding insects.
• Predatory vertebrates like fishes, birds, amphibians and reptiles utilize many insects as their food and can be used to control pests.
Cultural controls are the farming or cultural practices used to reduce the establishment, reproduction, growth and survival of pest species by making the environment less favorable to pests. Many cultural practices are used to control insect pests.
• Certain plant varieties are highly resistant to many insect pests. As pests fail to attack them successfully, planting these resistant varieties suppresses many pests.
• Different insects prefer different crops. Only some rare pests can survive on almost all plants.
Therefore, crop rotation is useful to suppress the pest population which was damaging to the previous crop.
• Residues of some crops can act as a media for the insects to survive. Burning out those residues would create a difficult situation for those pests.
• Shifting the plantation time of a crop from the period of activity of its pests is a good technique to avoid pest infestation.
• Plants must be nurtured with required fertilizers to ensure their good health. Healthy plants are more resistant to pest attack.
• A small scale plantation of a trap crop before planting the main crop will divert the attention of pests from the principle crops.
• The immature stages of some pests are aquatic. Proper water management will prevent water logging conditions and consequently suppress those pests.
• Cultural practices like Introducing fall plow and use of clean seeds are sufficient to control many pests.
Mechanical and Physical Controls
These are the most ancient methods of controlling pests and involve with killing a pest directly or making the environment unfavorable for it. Weed management mulches and steam sterilization are two physical controls while rodent traps are examples of mechanical control. Many mechanical and physical controls with their unique controlling techniques have been controlling pests for ages.
• Hand picking off pests and destruction is a pest controlling technique which simply pick the noticeable destructive stages of pests and destroy them.
• Many internal and cryptic feeders produce conspicuous symptoms of their infestation; collection and destruction of those infested plant parts is an effective technique to suppress those pests.
• Some insects, such as beetles, inhabit on the foliage of plants. The systematic shaking of the infested plants in the evening will dislodge the pests from the plants. The dislodged pests then can be collected by spreading cloth below the plant and eventually killed.
• A number of light traps are used to catch unwanted insects to kill them.
• Many insects have distinct preferences for particular color. Taking advantage of this tendency of many harmful insects color traps, like Yellow sticky traps, yellow pan water, etc., are used to catch insects, like aphids, flies, etc., during day time.
• Banding of fruit trees with banding material, like grease, is effective in controlling pests like caterpillars and ants which crawl up the trunk from the soil.
• Spiking of the pests in their bore holes is a method used to kill the damaging borers.
Chemical control in IPM refers to the use of pesticides either to kill pests or to inhibit their development in the way that possesses the minimum risk to human health and the environment. In IPM, pesticides are used only in those worst infestations where no other control methods work. IPM allows you to use only the most selective pesticide that will destroy the pest population without deteriorating the quality of soil, air, and water. In IPM, pesticides are used in combination with other controlling approaches to ensure efficient and long-lasting control. Using pesticides in bait stations rather than sprays is an example of chemical control.
Pheromone Trap-An Interesting Weapon
Pheromones are chemical factors secreted by insects to trigger social responses in members of the same species. A special character of pheromone is that it can act outside the body of the secreting insect and attract the receiving insect, and this is the basis for a pheromone trap. In a pheromone trap pheromones are used to lure and trap insects. This trap consists of a glue trap which is impregnated with sex pheromones. The sex pheromones applied in the trap are hormones secreted by the female insects as a signal to mate. Thus, when the male insects are lured and drawn into the trap with the intention of mating, they are caught and destroyed.