Stored Grain Pests and their Categories



Hi, welcome to agrifunda today post  on ‘Stored Grain Pests and their Management’. So in this post we are going to look at, what are the stored grain pests, how they are being categorized and their nature of damage,
the symptoms of damage and how best these stored grain pests can be managed. And in this post we will look at, what type of or the categories, which were actually present in the stored grain pests.

Stored Grain Pests and their Categories

Stored Grain Pests and their Categories


I. BASED ON IMPORTANCE

II. BASED ON FEEDING HABIT



Primary feeders : They attack fresh grains & their products

e.g. Rice weevil, pulse beetles, angoumois grain moth, rice moth etc.
 Secondary feeder : They feed on left over materials of damaged grains by the primary
primary feeders e.g. Saw-toothed beetles, long head flour beetle etc.

INTERNAL FEEDERS :

  They feed on internal content of the grains / kernels / seeds

e.g. Rice weevil, lesser grain borers, pulse beetles, angoumois grain moth,
tamarind beetle, drug store beetle, cigarette beetle etc.

 EXTERNAL FEEDERS : 

They feed on surface of the grains & their products externally

e.g. Red flour beetles, Indian meal moth, rice moth, khapra beetle etc.


stored grain pests are an insect groups, which are specialized in attacking the grains stored. Or the
finished products of the grains of food which could be of the normal field grains, or it maybe of pulses,
oilseeds or some commercial products and as well as the finished products, such as the sweets,
condiments, the spices and as well as the animal products also. So like the stuffed animal stuffs etc.
So if you look at the importance of the stored grains. So it is always there is a saying that ‘one grain
saved is one grain produced’. That means so if we take so much pain in producing one grain.

So it is
always important also to save that grain from these pests. So it has been estimated, that out of the total
food production happening in India; nearly 8 to 10% of the food grains are going to be affected or lost by
the stored grain pests. As a result, it is always our high priority to look at; so what are these stored
grains, and what kind of damage that they are going to cause. How to detect them? And how to prevent
initially not to make them to get into the storage. Or how to make curative measurements in order to
protect our grains from the storage pests.
So basically we can categorize the stored grains based on their nature of damage. Whether those pests

which attack the fresh grains, or which they have already attacked or attack already infested grains, or
categorize the pest which they actually act as an internal feeders, or they simply feed externally. So the
classification if you look at it. Now based on the importance we primarily classify them as primary
feeders and secondary feeders. The primary feeders are those that attack the fresh grains, and as well as
their products. So they belongs to such as the rice weevil, the pulse beetle, angoumois grain moth, the rice moth etc. Whereas the secondary feeders, they always feed on the leftover material so which comes to the saw toothed
beetle, long head flour beetle etc.

Now based on the nature of damage also, we can classify these insects as internal borers or the external
feeders. The internal borers are those which actually get into the grains, and then feeds on the internal
content. Whereas the external feeders are those which do not bore into the grains, but however they
scrape the surface of the food grains and then feed externally. There are only few groups of insects
which actually had mastered in causing the damage on the stored grains. Basically the insects which
belongs to the order Coleopteraand Lepidoptera are the major groups which are known to cause a
serious damage on the stored grains. Apart from that we get non-insect pest also, like mites and other
mammals like rats and squirrels are also referred as the stored grain pests.

If you look at the Coleopterans. So we normally have common coleopterans such as rice weevil, then
lesser grain borer, or cigarette beetle/tobacco beetle, drug store beetle, and the pulse beetle; which is
quite serious and tamarind/groundnut beetle.And these are normally the internal feeders. Means they
get into the seed and then feed the internal content. Whereas the red flour beetle and the khapra
beetle are usually the external feeders. And all these are also known as the primary feeders. That means
they feed on the fresh grains. Whereas the saw toothed grain beetle and the long headed flour beetle.
They are referred as the secondary feeders.
Then we come to another important group, that is the Lepidopterans. And usually we have the rice
moth, the Indian meal moth, fig/almond moth, then Mediterranean flour moth and cocoa moth. And these are called as the external feeders. And whereas the angoumois grain moth is referred as the
internal feeder. And rats and mice are the other non-insect pests which are attacking the stored grains.
And how these stored grain pests are getting into the storage structures, or in the storage condition attack them.

There are two important ways in which the stored pests are going to infest on the fresh grains. So one is
the infestation from the field, where some of the pest, whose activity starts right in the field. And after
harvesting when they are taken into the storage condition. These inoculum will get carried into the
storage structures, and thereby they multiply rapidly and become the stored grain pests. For example
the pulse beetle. And the another way of infestation is the cross infestation. That means the pests that
are already thriving on the stored grains in one storage structure, in a warehouse or a godown. So is
going to be carried to a new structure, when these infested materials are transported from the infected
building to the new building. So which we call it as a cross infestation.
In these two ways the stored grains are going to be carried from one place to another and then become
very serious. In the coming lectures we will start looking at the external feeders as well as the internal
feeders in separate lectures and look each of the pest which comes under these categories and look at it
in detail as how that can be managed.
Thank You.

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