Plant diseases


One of the best known pests that can attack crops in agriculture is the weevil. It is a fairly small insect whose scientific name is Sitophilus granauris. It usually lives and reproduces in areas where food is in the form of grains. Therefore, it seriously affects corn, rice and oat crops. It can form really annoying pests and you have to know what to do to treat them correctly.

In this article we are going to talk to you about the characteristics of the weevil as well as its life cycle and what you should do to eliminate a pest of this type.

Main features

This insect has become a very harmful pest in many agricultural ecosystems where grain-based plantations such as corn, rice, and oats are planted. This is because it has great speed when it comes to reproducing and damages the sowing completely. Because it reproduces so quickly, you have to act fast or else we will allow it to destroy all the crops.

Around 86,100 different varieties of weevils are currently known. All these varieties come from the Curculionidae family. These are small beetles that come from Asia. Its main food is vegetables. Although it is considered a pest in most of the world, they have quite interesting medicinal properties. They act in the cure of certain diseases such as diabetes, asthma, strengthen the immune system and have helped a lot in some cancer treatments.

It has a very tiny body of only 1.5 to 35 millimeters. Throughout its life cycle, the body undergoes a series of changes that are divided into four stages: egg, larva, eruption and adult. The eggs of the weevil are light in color and oval in shape. They are more rounded at one end of the egg while at the other they are flatter.


The embryos are also of different sizes depending on the variety. We can find measurements between 0.7 and 0.8 millimeters. These embryos burst in just a couple of days . The expulsion depends on the variety of weevil and the environmental temperature.

When the embryos manage to open, the worms begin to emerge. They are very primitive worms that do not have any limbs. They have a color that varies between white and yellow. The head, however, has a somewhat darker color. His jaw is somewhat stronger and is used to bite hard at the food he is eating. This is important since their main food is grain plants and they need strength to be able to bite food solidly.

Weevils that attack corn crops usually take 6 to 8 weeks to grow. Those called red weevils take between 12 and 14 weeks. When they develop, they go from the pupal cycle to the adult stage. Normally, this transit usually lasts between 5 and 30 days, depending on the variety and the ambient temperature. When the cocoon ends up bursting, the weevils sprout up and are already adult. This means that they are of reproductive age and that they can mate between males and females.

Reproduction of the weevil

Let’s take a closer look at the reproduction of this insect. As we mentioned at the beginning of the article, it is an insect that multiplies with great speed. They usually adapt well to the environments where they are, so they do not have survival problems. They generally like to be in fairly dry environments. The females are capable of laying between 300 and 500 eggs. Their annual reproduction cycles usually repeat between 3 and 6 times. This depends on the variety.

For example, the variety of the wheat weevil, are capable of reproducing up to 6 million offspring in just 12 months. This makes it a pest that seriously threatens crops. To protect the eggs, the females place them in specific places. For example, in the internal part of grains and cereals such as wheat, rice, barley, rye, corn, etc. They can also place them at the end of the petiole of the leaves and in the cracks that we have in the bark of the trees.

The life span of these insects varies depending on the species. There are some that can only live between 45 and 90 days and others that can last up to 3 years.

Weevil plague

Due to the high speed of reproduction, this insect becomes a harmful pest for thousands of crops around the world. It is capable of ending the entire life of plants and not just damaging it. Normally they invade the cupboards and stay to live inside the grains and cereals. This causes its continuous deterioration. They lay their eggs, the worms hatch, they empty all their excrement, etc.

Detecting that a grain is not suitable for consumption is by seeing a whitish powder that covers food. To eliminate the weevils, strong insecticides are used that help eliminate most of the populations that are affecting crops.

To prevent weevils at home that may appear in some grains you have, it is best to eliminate possible wet areas. These areas are their favorites and tend to attack grains that have been stored in humid areas for the longest time. Usually attacks in pantries.

If at home you usually have enough packages of flour, rice, oats, etc.  It is best to put the packages in the fridge for a few days. This low temperature will be able to kill both them and the eggs. In this way, we ensure that the product does not spoil.

For prevention, a product called diatomaceous earth comes in handy . This product is placed in bags in the areas where the insect may appear and serves to dehydrate them. It also acts against cockroaches. Therefore, these bags are essential if you have large pantries where you store a lot of product in the form of grain.

I hope that with this information you can learn more about the weevil and its treatment.

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