Grain Weevil — Pest Control

Grain Weevil

Scientific name: Sitophilus granarius
Family: Curculionidae

There are 3 different species:

  • Sitophilus granaries (Grain Weevil)
  • Sitophilus oryzae (Rice weevil)
  • Sitophilus zeamais (Maize Weevil)

Each of these species varies considerably in size but has a distinctive elongated snout which is adapted to the size of its preferred grain. Typically, they reach 2-4mm in length and have a long cylindrical body which is dark brown or nearly black in colour.

Grain weevils are encountered in all temperate and warm-temperate climates. They are widely distributed around Europe. Both adults and larvae are cold-hardy.
Rice and Maize weevils are widely distributed in tropical and sub-tropical areas and will be carried to temperate areas on imported commodities.
The maize weevil breeds on maize in the field but the Rice weevil only breeds in stored grain. Both insects will not normally overwinter in unheated premises or grain stored at normal temperatures.

Grain weevils do not fly but instead, infestations often occur after being imported in grain and cereal products, also from the fabric of vehicles used to transport grain or buildings to store it.
The female will lay a single egg inside the grain, where larva and pupa stages will occur, once developed, the weevil bores its way out leaving a hole in the grain.

The Grain weevil can only breed in grain with moisture content of more than 9.5% and at temperature within the range 13-35C.

Grain weevils are primary grain pests, infesting undamaged grain and attacking other hard cereal products such as macaroni and spaghetti. Weevil-damaged grain is readily recognised by the presence of large holes which are the exit holes of the emerging adults.

Both the adults and the larvae feed on the grain causing holes and also contamination with their excretions. Grain quality and marketability is reduced.

See also:  Do Ladybugs Bite People

Recommended products

AquaPy Micro

For ULV application. A water-based, ready-to-use.

Beetles & Weevils

Turf wars with Beetles and Weevils
Beetles and weevils are classified in the Order Coleoptera. They represent some of the most significant turf insect pests. Beetles which damage turfgrass are known as Scarab beetles. During their larval stage, they cause the most damage to turf.

Commonly known as white grubs or curl grubs, the larvae live in the soil. They feed on turfgrass roots and high infestations cause significant turf damage. The most important species are the African Black Beetle, the Argentinian Scarab and Pruinose Scarab.

Weevils have pronounced snouts and 2 species cause significant turf damage. The Argentine Stem Weevil is a noteworthy pest of bentgrass/Poa golf greens. Ryegrass is also susceptible to damage from Argentine Stem Weevil. Billbug can be very damaging on warm season grasses. Kikuyu is especially susceptible to this pest.

Chemical control options generally include a programme of adulticides and larvicides to control the different stages in the lifecycle.

Other Problems


Bed bugs are parasitic insects of the cimicid family that.

UK Plant Health Information Portal
An online hub for plant health information, data and resources

Alternatively, use additional searches based on risk register priorities for actions or try an image based search

About the UK Plant Health Information Portal

Defra recognises the additional challenges being presented to industry as a result of the current COVID-19 outbreak. We aim to support businesses involved in the trade in plants and plant products, to help ease pressure on the food supply chain without compromising the safeguarding of UK biosecurity. We are also contributing to central initiatives, for example, on how Defra can best support the UK’s food supply chain through this period. For guidance and support for businesses and employers, visit

There are many pests and diseases that can seriously damage crops and plants in the UK. Assessing and understanding these threats is essential to informing the actions needed to protect plant health set out in Protecting Plant Health — A Plant Biosecurity Strategy for Great Britain .

See also:  Parasites - Types, Diseases They Cause, Prevention and More

As the Strategy makes clear, tackling threats to plant health is not just a matter for government; success is dependent on partnership working between all those with a role to play. To this end the Portal is a shared resource providing information about plant pests and diseases, including the assessments of risk undertaken by government and the data underpinning those assessments, with links to other sites of interest, including non-government sites, as well as information on the plant health controls and services provided by government.

The smarter rules for safer food (SRSF) package is a set of EU regulations for the protection against animal disease, plant pests, and for the organisation and performance of official controls. SRSF brings major changes to the UK plant passport system, and the importing and exporting plants and plant products. The PHR and OCR became applicable on the 14 December 2019. Use the ‘Smarter Rules for Safer Food (SRSF)’ page to find out more.

How to Get Rid of Weevils – Weevil Control

Weevils, also known as flour bugs and grain bugs, can cause damage in a wide range of habitats, from grain silos to household plants. There are many different species and lifecycles of weevils, but they can all be controlled with our weevil control products. Do it yourself using the same products the pros use to combat a weevil infestation and prevent further problems.

Shipping Zip Code:

General Weevil Control – How To Get Rid of Weevils

Many species respond well to beneficial nematodes and residual pesticides. However, these measures need to be applied at the proper time of year. Some species need control of adults, some of the larvae, and emergence and egg-laying times are crucial for treatment. Sometimes weevils wander into homes. They don’t cause any damage indoors (besides grain-invading species) and often just need to be vacuumed or swept up. You can use an aerosol spray to kill live adults and apply an insect growth regulator to inhibit juveniles to reproduce. Essentially, the only way you can know how to get rid of weevils is if you identify your weevil species.

See also:  Controlling Colorado Potato Beetle - How To Prevent Potato Beetles

Weevil Identification

In general, weevils are very small, about ¼ to ½ inch long. The body shape is similar for all species: they are light bulb shaped with “snouts” or nose-like protrusions from their head, and are usually a dark color. Larvae are grub-like in appearance. Some species, like black vine weevils, do not fly, but crawl from plant to plant or are transferred via people or animals. Often times you will be able to identify the weevil that is causing you problems based on where you find them. For example, if you are finding damage and weevils on spruce trees, white pine weevils are probably the culprits. Getting rid of weevils is dependent on the identification of the species.

Common Weevil Damage

Root weevils, including black vine weevils and strawberry root weevils, cause notching damage, while white pine weevils cause terminal growth to wilt and die. Some weevils invade stored grain in farms and even in home pantries, where people will find weevils in food. These bugs in flour or other pantry grains can cause problems in homes, and are part of the pantry pest group. For weevils this includes grain weevils, rice weevils, maize weevils, and bean weevils. Control measures are dependent on the species, as timing is usually a key component in all control measures. You can contact your local extension office to talk to the master gardener to help you identify the different species of flour bugs species and determine the proper time to begin control measures.

Can’t find the product you are looking for? E-mail us and we’ll get it for you!

We sell professional do it yourself pest control (diy), exterminator and
extermination insecticide, pesticide, chemical and bug killer treatment
products to spray, eliminate and exterminate pests.

Many of our products are not available in stores
such as Home Depot, Walmart or Lowes.

No comments

Добавить комментарий

Your e-mail will not be published. All fields are required.