Weevils, the small beetles that belong to the Curculionidae family, exhibit a large range of features. This family has a number of species than in any other family. According to recent studies, more than 1000 Curculionidae species are expected to be present in the northern United States alone.
- 1 Different Types of Infestation Causing Weevils
- 2 Infestation
- 3 Control Methods
Different Types of Infestation Causing Weevils
There are many types of beetle that are considered pests, like, some are considered plant pest, whereas some are considered as grain pests and flour pests. Thus, controlling each and every species has to be done in a different manner. Some of the most common weevil pests are:
Anthonomus Grandis, commonly known as Boll weevil is a beetle that is quite popular as a pest in the cotton field. It causes tremendous damage to the cotton plant. It attains an average 6mm length. It primarily eats the flower and bud of the cotton plant.
The flour weevil from the Tenebrionidae family is a type of beetle that stays and feeds on flour, thus contaminating it. It is mostly found in a metallic color or reddish brown shade, and attains a length of 3-4mm.
Boll Weevil – Photo by: Photo by: Olaf Leillinger
Rice weevil, technically known as Sitophilus Oryzae is a serious pest that harms the crops like rice, wheat and maize. It attains a length of 2mm and possesses a big snout. It has a brown or black body with four red or orange colored spots on the cover of the wings.
Bean Weevil – Photo by: Clemson University – © Bugwood.org
The bean weevil is the name of a subfamily of beetles, present in the Chrysomelidae family. It is again a serious pest that can infest the seeds or beans, and mostly it prefers to live its whole life inside one seed. Its size ranges between 1 and 22 mm, and mostly has a black or brown body.
Wheat Weevil – Photo by: CSIRO
Wheat weevil is commonly referred as Granary Weevil, which has a scientific name, Sitophilus Granaries. The adult feeds on whole grains like rice, rye, wheat, corn, oats, etc., and thus infects the grains. It attains a size of around 5mm, and has a typical black or brown body.
Black Vine Weevil
Black Vine Weevil – Photo by Denny Bruck.
Otiorhynchus Sulcatus, commonly referred to as Black Vine Weevil is a type of beetle that is considered a serious pest due to the damage it causes to the garden plants. As the name suggests, it has a black body and attains a length of ¾ of an inch.
Rose Weevil – Photo by: Ingrid Taylar
Merhynchites bicolor, also known as Rose weevil, is a dangerous pest to all horticulture plants. It drills through the buds of the flower, thus causing a great damage to the flower petals. It has a red and black colored body that attains a length of 5 to 6 mm.
White Pine Weevil
Pine Weevil – – Photo by: Arnstein Rønning.
The white pine weevil species, biologically termed as Pissodes Strobe are a destructive pest that infests white pine and spruce trees. It has a rust-colored body that attains a length of 4 to 6 mm.
Cowpea Weevil – Photo by: Carl Davies, CSIRO.
As the name suggests, this weevil, also known as Callosobruchus Maculatus is a beetle that infests stored cowpeas and soya bean. It has a reddish brown colored body with gray or black colored elytra.
Weevils invade home, attack crops, flowers, seeds and other food stuffs. Some plant feeders enter houses for shelter during harsh weather. Some species like Asiatic oak weevil invades houses, because they are attracted towards light. You can find them in clusters outside the house. As they get a chance to enter through doors or windows, they will invade the house. They also enter through cracks, holes or attic vents. They also have the ability to crawl under the door. If they reach inside, then they will go on infesting every room of the house. They hide in clusters on the window panels. They also crawl through the ceiling, walls, window sills, and then drop on the floor. Seed feeding species are usually brought inside the house by one or the other seeds that we purchase from the market. Many other species can also be found in rice, wheat, nuts, cereals, popcorns, beans and other food stuffs. They also feed on fruits like apple, grapes and pears. The other plant destroying pests infests the plant”s fragile parts like leaves, flowers, buds, or roots and cause damage. Many agricultural yields are also destroyed by some species of weevils.
It is a very convenient method to examine the weevils. There are many different types of weevil traps that can be used in numerous ways. Most traps make use of pheromone to lure and attract the weevils, present in the area. This pheromone scent is very similar to the one produced by the weevils itself. This smell tricks weevils to get caught in the trap. This method is most commonly used by the farmers to protect their yield from this pest. The population caught in the trap reveals the actual population of weevils grooming around. It helps the farmer to decide, whether to apply insecticide to the crops or not. The eradication program for the cotton boll weevil also made use of traps in the field of cotton. Such traps are also helpful to destroy other weevils like the White Pine Weevil, Plum Weevil and Rose Weevil. This method is also a success to trap the weevils preset in the stored product, by using pheromones to attract rice weevils, bean weevils and other granary weevils. It is also commonly used in grocery stores, warehouses, storage facilities for grains and plants for food processing.
Vacuum cleaners can be used by the house owners to get rid of those weevil that take shelter in the houses. They come in groups and invade the houses. Vacuum cleaners help to get rid of them through walls, hiding place in windows or other cracks and floor.
Heating Or Freezing
Weevils can be killed with cold. They will die when kept in a freezer; hence some foodstuffs like flour, oats, grits, corn meal, etc. can be frozen as soon as you bring them home. If you have enough space, then you can keep those foodstuffs in the freezer, or at least keep for 3 to 4 days, so that any larvae, egg or adult weevil present in the foodstuff will die. If you don”t prefer freezing all your foodstuffs, some can also be heated to kill these insects in nuts, peas or corns etc..
Weevils that are pantry pests can be controlled using Pyrethrins. It is because these insects live and feed on your foodstuffs that cannot be sprayed with insecticides. Hence, this is the best method of getting rid of this creature from your food stuffs. There are many types of Pyrethrin sprays and mild aerosols available in the market that are safe to use indoors, and especially near food handling places, but still, spraying directly to your food is not recommended. Once you clean your shelf and cupboard, you can spray it, and then replace with your containers consisting food stuffs.
The outdoor weevils can be best controlled with insecticides that can be applied over your crops, plants, or trees. It will discourage any development of eggs, larvae or adult weevils. But care must be taken while using it, as insecticides are very poisonous.