Pests and their Importance

Welcome to agrifunda today post on topic on Pests and their Importance  So before actually getting into understanding the pests of various crops and their management, so it is necessary to look at what exactly is a pest and what is the importance of the pest. And this post deals about the pests and their importance.

Pests and their Importance

Pests and their Importance:

1.what is a pest?

 So how do you define a pest?  See the word ‘pest’ is basically derived from the French word as ‘peste’ or Latin as ‘pestis’, meaning that it is a plague or a kind of contagious disease. So according to the Food and Agriculture Organization(FAO), which has defined the pest as any species or the strain or the biotype of a plant or an animal or a microorganism; so which causes a damage to either a plant or the animal, including human beings and his belongings. So as per the word pest definition, it can be anything. Say for example as a birds, like any vertebrate pest or the mammals, okay, and the insects and as well as closely related groups like mites. So anything which causes nuisance to the human being, or to the plant, or to the environment can be called as a pest.

In this pos, which is mainly related to insect group and the mites closely, as and when we deal with each of the crops. However so we have for the other non-insect pest category, so where the larger mammals and as well as the birds and also the other invertebrates such as snails and slugs. So can is going to be covered in a separate class. Now how important the pests are. So if you look at the pest. So the type of damage that they are going to cause, and the kind of destruction that they are going to do it to the crop. So this explains their importance.

So pests are known to cause two major types of damage to the crop. So basically they cause, we categorize them as the direct damage or the indirect damage. The direct damage in the sense, where this pest actually feed on the plant. Any of the plant parts and causes a complete reduction in the plant vigor or the yield of the crop. The indirect damage is in a way that they act as vectors. So such as transmitting various microorganism diseases, like related to virus, bacteria, mycoplasma etc. As a result the plant vigor is going to be reduced and also its yield. So in these two ways the pests are mainly going to cause the damage.

In the third way also they can be quite pestiferous, which mainly comes in the stored grain situations, where apart from directly feeding on the foodgrains. So they contaminate the foodgrains, through the excreta, the catskins and the dead bodies. So which reduces the quality of food grains and as well as contaminate the food grains. And how much loss the pest is going to cause. This is also very important. So according to one study, so if you look at the pie chart here. Out of the total the organisms which cause the damage, the insect group alone; so causes around 26% of the damage when compared to the otherproblems. This indicates the importance of insects as a pest in the cropping ecosystem.

So according to one study so which is published in the Indian Journal of Entomology. So around 15.7% of the food grain loss is alone caused by insect pests. Which amounts to around 2,37,600 crore rupees of these things. So it is very essential to understand, so their nature of damage and how you are going to manage it. And the next one would be very interesting is that why these pests. So why they are very so dominant on the crops. And if you look at or analyze the situation of the Indian agriculture for the last 70 or 80 years, then we a very drastic change in the pest scenario in each and every crop. So there could be several reasons, and we are going to look at one by one.

 The first major reason is going to be the kind of the destruction of the forest, and also bringing that forest under cultivation. So imagine a situation where thousands of hectares of forest land is going to be what is called cut and so that has been brought under the agriculture. So what happens to millions and millions of species of insects and animals which are living in those forest eco-system. So the major thing is that they all get destroyed. Whereas few species of the insects are capable of shifting their hosts from the forest plants to the agriculture crops. When they shift, then they becomes very pestiferous. As they get the food so plenty for their multiplication.

second reason:

Then the second important reason would be that the destruction of the natural enemies. So one of the important biotic components, so in regulating the any pest population is the natural enemies. So which is going to bring down the pest population to what’s called a certain lower level. However with our several agronomic practices such as indiscriminate use of pesticides or chemicals which ultimately leads to destruction of the natural enemies. The natural enemies which includes like predators, parasitoids and even pathogens. So when that biotic force is taken off, then the pest outbreak is naturally going to happen.

 third reason:

 The third reason would be the intensive and extensive cultivation of the crop. So nowadays we are seeing that the large area of the agriculture are brought under a single cropping system. So if that kind of is a case, then what we call that as a mono-cropping. So this mono-cropping will actually leads to what is called as an extensive area under a single crop. So as a result, the pests are going to get their food for in a larger area and it actually helps them in multiplication, and by becoming quiet troublesome. At the same time if you grow the same crop, season after the season, then that same crop is going to be available to the pest throughout the year. So which again leads to the plentiful availability of the food, and easy for their multiplication.

fourth reason:

 Then the fourth reason would be the introduction of the new crop or the cultivar. Since the green revolution, so there was an introduction of the hybrids as well as the new high yielding varieties. So which are highly fertilizer responsive. Which actually has led them to a very vigorous growth in order to get a very high yield. But at the same time, these plants or the hybrids or the varieties, were found to be highly susceptible to the pest, because of their succulency and as a result, so they are highly vulnerable and leading to the outbreak of the pests.

fifth reason

Then the fifth reason would be the improved agronomic practices. As I told you earlier, these high yielding varieties are the cultivators, which are responsive to the various agronomic practices, such as the fertilizer application. So as they are very responsive to it; farmers will saw to the indiscriminate or the excess application of the fertilizer. So as a result the plant vigorously grows, but at the same time becomes susceptible to the pests. So for example the excess use of the nitrogenous fertilizer, especially in the rice eco-system. Which has led to the outbreak of the yellow stem borer and as well as the mini sucking pest. Similarly in cotton if you look at it, again the excess use of fertilizer, has led to the outbreak of the many of the sucking pest. And as well as the closer planting in case of the forest eco-system. So which actually, especially in the not in a forest eco. I mean the plantation or the mango eco-system increases the leaf hopper population so very much.

So these kinds of practices is going to help the pest to be quiet multiplied. And another important reasons for their outbreak would be the accidental introduction of the pest into new area, or what we call it as an invasive pest. So in recent times we are witnessing a lot of insurge of these invasive pests in our country. So in spite of a very very effective regulatory or legal quarantine practices, some of the pests are capable of getting introduced into our area. And when they actually come into the new area, due to the favorable condition, as well as the lack of natural enemy on them. So these pests multiplies large number and so they become very pestiferous.

 Some of the important which are listed here like: 

 Serpentine leaf miner
 • Coffee berry borer
 • Spiraling white fly
 Coconut eriophyid

Which are quite old. But of recent you can see the
 • Tomato leaf miner
•Then fall army worm which has come recently, last year are causing huge losses to our agriculture crops.

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