Black ground beetle photo description danger and ways of fighting

Facts, Identification & Control

Latin Name

What Are Weevils?

Weevils are actually beetles. There are more species in this family than in any other beetle group. Scientists estimate that there are over 1,000 species of Curculionidae in North America.


Weevil species occur in a wide range of colors and body shapes:

  • Size: Many are slender or oval-shaped insects. Depending on the species, weevils range in size from about 3 mm to over 10 mm in length.
  • Color: They are usually dark-colored (brownish to black).
  • Head: The most distinctive feature of weevils is the shape of their head. An adult weevil has an elongated head that forms a snout. The mouth is at the end of the snout. Some weevils have a snout that is as long as the body. Another family of beetles called Bruchidae, such as the cowpea weevil, have a different appearance from the typical weevil. They lack the elongated snout found in the Curculionidae.

How Did I Get Weevils?

While weevils can find their way into a home from the yard, these pests usually come indoors inside packaged foods or bulk products. Weevil eggs are almost invisible to the naked eye, so it’s easy to buy tainted goods without realizing those goods are infested. Weevils usually infest grains and starches like rice, flour, pasta, and cereals.

Weevil infestations that start outside may be the result of fruit trees or gardens, which are also food sources. The insects often gather on the sides of homes and move into cracks and gaps that lead inside.

How Serious Are Weevils?

Outdoors, weevils can kill garden plants. Indoors, the pests are more of a nuisance than a danger. Weevils contaminate infested food with their feces and cast skins, causing more damage than they eat. So, an infestation may render entire packages or pantries of food inedible. Stored product weevils do not bite and they do not cause damage to dry, decay-free wood inside homes.

Stored Product Weevils

A few weevils attack stored grains and seeds. They can be very destructive, and their damage is often very expensive. The most common stored product weevils are:

  • Cowpea weevils, Callosobruchus maculatus (F.)
  • Granary weevils, Sitophilus granarius (L.)
  • Rice weevils, Sitophilus oryzae (L.)

Structural Pests

Some weevils can become structural pests. These are the weevils that upset homeowners because they invade homes often in great numbers. Some of them invade in the fall. They hide during the winter and leave in the spring. Others invade in the summer when the weather starts turning hot.

Signs of Infestation

Homeowners might not notice weevils when they are gathered on the outside of the home. But if the weevils manage to find an opening and invade the home, the homeowner often finds hundreds of insects crawling on the walls and windowsills.

How Do I Get Rid of Weevils?

Most likely, homeowners seeing weevils are dealing with the stored product species. The most important control methods are to find the infested material and eliminate it. Careful inspection of items before purchasing can help prevent getting a new infestation. Products with holes or signs of damage on the packaging should not be purchased.

A vacuum cleaner is a quick way to remove weevils from the walls and furniture. Be sure to take the vacuum outside to empty it so the weevils don’t reinfest the home.

What Orkin Does

The Orkin Man™ can help homeowners manage weevils. He will use Orkin’s exclusive A.I.M. system—Assess, Implement and Monitor. He will design a treatment plan for your home’s situation. By focusing on the source of the problem—outside or inside of the home—he will be able to help keep weevils from invading again.

When weevils invade, they can come in large numbers. Homeowners often feel more confident calling the local Orkin branch office to get The Orkin Man™ to help get weevils out of their home and keep them out.


If weevils haven’t invaded, there is time for some prevention. Check outside for any openings that weevils could use to get inside. Look around doors and windows for missing caulk and damaged weather stripping. Check attic vents and crawl space vents for torn screens.

Biology, Diet, & Habits

Weevils feed on plants in the larval stage and as adults. Some can be very destructive to crops. For many years, one of the most destructive weevils was the cotton boll weevil. The black vine weevil, Otiorhychus sulcatus (F.), is found in many parts of the United States. It feeds on a variety of plants, including hemlocks and rhododendrons.

Where Do They Live?

Most weevils are found in

Life Cycle

Weevil life cycles depend greatly on the species. For some, in spring, adults lay their eggs on the ground near host plants. When the eggs hatch, the larvae burrow into the ground and feed on the roots. Since the larvae are underground, people seldom see them.

Many of the larvae spend the winter in the ground and emerge as adults the following spring. However, the adults that emerge during the summer or fall may invade homes for shelter. Some, like the Asiatic oak weevil, are attracted to light, so they are drawn to homes at night. Others may be attracted by the warmth from the house.

Asparagus Beetle

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There are two types of asparagus beetle. Both target their namesake plant and do harm to newly emerged spears as well as late season foliage.

The common asparagus beetle (Crioceris asparagi) attacks both garden variety and wild plants. Originally a European species, it has spread throughout the United States. Adult beetles (1/4 inch long) are metallic blue to black with creamy yellow spots and reddish margins on their wing covers.

The adult spotted asparagus beetle, looking somewhat like a lady beetle, is red-orange with 12 black spots. Their damage can be problematic, but they are not as destructive as the common asparagus beetle.

The plump larvae (1/3 inch long) of both asparagus kinds of beetles are slug-like in appearance. The common beetle has a black head and visible legs and are gray or greenish in color. The spotted beetle larvae is orange.

Detailed descriptions of both types as well as definitive photos of beetles, larvae, and eggs — and a fascinating picture of a parasitic wasp violating an asparagus beetle egg — see the University of Minnesota Extension page here.

Life Cycle

Adults of both types overwinter in plant debris and garden trash. The common asparagus beetle emerges early, at the same time as the asparagus spear. Within a week of its appearance, the common beetles begin laying brown eggs in rows of three to eight on the new spears.

The larvae emerge within a week and begin to move upward as the plant grows, feeding as they go. After a couple weeks of intense feeding, they fall to the ground where they pupate for a week. Then the adult beetles crawl from the soil and the cycle begins again. Two life cycles are common in most regions but as many as five can be produced in areas with longer growing seasons.

The spotted asparagus beetle appears somewhat later, allowing the growth of fronds on which they deposit a single green egg. Larvae prefer to feed on the berries of mature asparagus plants. Within two weeks, they drop to the ground, entering the soil where pupation takes place. Ten days later the new adults emerge. Their reproductive season ends most places by late July.

Both adult and larval stages of common asparagus beetles feed on spears during the spring and early summer months. Their presence is often announced when spears take on “shepherd’s crook syndrome,” the twisting of the asparagus head giving the spear an uncharacteristic hook.

The beetle’s feeding can cause visible scarring and staining as they chew and deposit frass, the excrement left of their feeding. Often, spear tips will turn brown. In summer, asparagus beetles move to feed on the ferns. Significant defoliation at this point can weaken the plants, making them more susceptible to Fusarium wilt and other pathogens. Beetle damage may also limit the amount of nutrients plants can take in for the next growing season, causing fewer and less vigorous spears.

Asparagus Beetle Control

Some asparagus growers report a small but ongoing presence of asparagus beetles in their patches, a presence that doesn’t result in much damage or larger infestations. Finding the odd spotted asparagus beetle — their bright coloring makes them easy to see — may not portend disaster. But finding a few common beetles, either in larvae or adult stage, probably means there are a lot more on the way. Distinguishing the two types of beetles will help protect your crop. The sight of even one common asparagus beetle should alert you to take action.

  • A little attention goes a long way in beetle management. Removing adults as they emerge from the soil and climb up stalks of the still small plants can prevent larger outbreaks later. Begin scouting plants in April and early May, as soon as asparagus spears emerge.
  • Hand pick the adults and larvae from plants and drop them in a pail of soapy water. Wipe spears of eggs when you harvest.
  • Early harvest of spears cuts short the beetle’s life cycle. When cutting asparagus for the table, make it a habit to check for adults, larvae and eggs in what you gather and what you leave. Adult beetles are most attracted to asparagus with foliage. Early and thorough harvesting will discourage them.
  • Some gardeners recommend using a bristle broom or soft counter sweep to brush larvae from the spear. Larvae brushed to the ground usually won’t be able get back to the stalk and will expire in the dirt.
  • A multi-faceted, Integrated Pest Management program that combines a variety of natural controls will stop problems before they start.
  • Beneficial insects, especially ladybugs and lacewing, will consume the eggs and small larvae. Anything you can do to encourage these insects in your garden will help keep a variety of pests in check.
  • The best control is offered by a tiny wasp (Tetrastichus asparagi) that is not commercially available. The wasp lays its eggs on the larval stage of the asparagus beetle, destroying it from the ins >

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Coconut Rhinoceros Beetle (CRB)

Coconut rhinoceros beetle adults chew big holes through the growing tops of palm trees to feed on their sap, making distinct zig-zag shaped cuts in their leaves. This is a big beetle to battle, but Frankie knows that cleaning up palm debris and compost piles prevent its larvae from growing inside them. He’s on the lookout!

Printable Field Guide: PDF

Top view of a coconut rhinoceros beetle (Oryctes rhinoceros) adult. The beetle is named for the horn on its head! They are large (about 2 inches long) and are shiny black with rusty-colored hairs around their faces. Females also have similar hairs on their back ends. Photo Credit: Pest and Diseases Image Library,

S >Photo Credit: Pest and Diseases Image Library,

Bottom view of a coconut rhinoceros beetle (Oryctes rhinoceros) adult. Like all insects, rhino beetles have six legs. The spines on the front legs are an adaptation to help with digging. Beetles have flexible, segmented feet (called ‘tarsi’) with claws on the ends for a super grip! Photo Credit: Pest and Diseases Image Library,

Coconut rhino beetle larvae (called grubs) are yellowish white with reddish brown heads and legs. Insects breathe through tiny holes called ‘spiracles,’ which are the reddish dots down the s >Photo Credit: Hawaii Department of Agriculture,

The coconut rhinoceros beetle (Oryctes rhinoceros) has six distinct life stages. Female rhino beetles lay their whitish brown eggs in decaying palm trunks or compost. The eggs hatch into 1st instar grubs. There are three grub or larval stages, each bigger than the last, that feed on decaying plant material. Third instar grubs dig chambers in the compost and turn into pupae. After about 20 days, they emerge as new rhino beetle adults and can fly off to find mates. Photo Credit: Dr. Aubrey Moore, University of Guam Cooperative Extension Service,

A coconut rhinoceros beetle pupa found on Guam by “rhino hunters” for the Coconut Rhinoceros Beetle Eradication Project. Photo Credit: Aubrey Moore,

A coconut rhinoceros beetle (Oryctes rhinoeros) adult. That’s one big beetle! Photo Credit: Aubrey Moore,

The coconut rhinoceros beetle has three immature stages, called larval instars. By the time they reach the third stage, they can be 3 inches long! Photo Credit: Hawaii Department of Agriculture,

These healthy coconut palms (Cocos nucifera) are beautiful landscape trees, and can grow in sandy and exposed areas where many species can’t. Photo Credit: Forest and Kim Starr, Starr Environmental,

The large green fruits near the center of this tree are coconuts, which are the fruits of the coconut palm (Cocos nucifera). Coconut palms are one of the favorite foods of the coconut rhinoceros beetle. Photo Credit: Charles T. Bryson, USDA Agricultural Research Service,

Date palms (Phoenix dactylifera), like those seen here, are vulnerable to damage by the coconut rhino beetle. The clusters of dates are contained within mesh bags in this photo to protect them. Photo Credit: Patti Anderson, Division of Plant Industry,

These are dates, the fruit of the date palm. The coconut rhino beetle threatens the trees that grow these sweet treats! Photo Credit: Patti Anderson, Identifying Commonly Cultivated Palms, USDA APHIS ITP,

Screwpine trees (Pandanus sp.) are important salt-, drought-, and heat-tolerant species on many Pacific islands and may be attacked by the coconut rhinoceros beetle. Photo Credit: Forest and Kim Starr, Starr Environmental,

The fruit of the screwpine (Pandanus sp.) tree looks similar to a pineapple! Photo Credit: Forest and Kim Starr, Starr Environmental,

These are fan palms (Pritchardia sp.), or Loulu, growing in Hawaii. These kinds of palms are the only ones native to Hawaii, and many species are already endangered or threatened. Damage by the coconut rhino beetle could make them go extinct! Photo Credit: Forest and Kim Starr, Starr Environmental,

Fan palms (Pritchardia sp.) have clusters ofl fruit located near the top. Some species of fan palms are only found on certain islands in Hawaii! Photo Credit: Forest and Kim Starr, Starr Environmental,

Close-up of the leaf of the fan-shaped leaf of a fan palm (Pritchardia sp.). Photo Credit: Forest and Kim Starr, Starr Environmental,

Banana trees (Musa sp.), such as these, are sometimes attacked by the coconut rhinoceros beetle. The clusters of ripening bananas are ins >Photo Credit: Gerald Holmes, California Polytechnic State University at San Luis Obispo,

Banana trees (Musa sp.), such as these, are sometimes attacked by the coconut rhinoceros beetle. The clusters of ripening bananas are ins >Photo Credit: Charles T. Bryson, USDA Agricultural Research Service,

These oil palms (Elaeis guineensis) are one of the favorite foods of the coconut rhinoceros beetle. Photo Credit: Whitney Cranshaw, Colorado State University,

Fruit of an oil palm (Elaeis guineensis), which is used to make palm oil for cooking and industry. The coconut rhino beetle threatens the health of these palm trees, which are a very important agricultural species in many parts of the world. Photo Credit: Manfred Mielke, USDA Forest Service,

The large holes seen here at the base of the fronds of this palm are feeding damage caused by coconut rhino beetle adults. They burrow into the growing top of the palm to feed on the tree’s sap. Photo Credit: Hawaii Department of Agriculture,

When coconut rhinoceros beetle adults feed on coconut tree sap, they often create very distinct zig-zag or diamond-shaped cuts on the palm fronds. Photo Credit: Hawaii Department of Agriculture,

Diamond-shaped patterns cut into palms fronds mean that coconut rhino beetle was here! Photo Credit: Hawaii Department of Agriculture,

Traps for coconut rhinoceros beetle that contain an attractive pheromone are used to monitor beetle numbers and to capture and kill adults. Photo Credit: Hawaii Department of Agriculture,

Pigs love to eat juicy rhino beetle grubs! Although pigs themselves are invasive species on many islands, like Hawaii, they are very good at rooting out grubs living under rotting logs and in compost piles. Photo Credit: The Nature Conservancy Archive, The Nature Conservancy,

In the coconut rhino beetle’s native range, a fungus called Metarhizium anisopliae infects and kills rhino beetle grubs and adults. The fungus has been used as an effective biocontrol in some areas where the beetle has been introduced. After the fungus kills the beetle, it produces green spores all over the bug’s surface, as seen in the photo. Photo Credit: Fred Brooks, University of Hawaii at Manoa

Although rats are often invasive themselves, especially on island nations, they are important predators of both rhino beetle larvae and adults. Photo Credit: Wikimedia Commons,

Scientific Name: Oryctes rhinoceros

Description: Coconut rhinoceros beetles are quite large (1 ¼ – 2 ½ inches) and shiny black. They are called rhino beetles because both males and females have a horn on their heads that looks like a rhino horn! The male’s horn is larger, and they sometimes use these horns to battle one another for food or mates. Larvae of the CRB are large, off-white grubs with brown heads.

Native Range: South and Southeast Asia, from Pakistan to the Philippines

Introduced Range: CRB has been introduced throughout the South Pacific, and is now found in American Samoa, Bismarck Archipelago, the Cocos Islands, Fiji, Guam, Manus Island, Mauritius, Micronesia, Papua New Guinea, Saipan, Tonga, Wallis Island, and Western Samoa. It has most recently been discovered in Hawaii.

Habitat: Natural forests, palm plantations, and planted landscapes.

Host Trees: Adult CRBs attack coconut, oil, and date palm trees. They also attack other species of palms, such as Hawaii’s only native palms, the endangered fan palms, or Loulu. CRBs also sometimes feed on Pandanus (screwpine) trees, banana trees, sisal, sugarcane, and pineapple.

The Facts: This big bug is bad news for palm trees! The adult beetles burrow into the bases of palm fronds to drink the tree’s sap. When CRBs burrow in to feed, they create large holes near the top of the palm’s trunk, which can allow other bad bugs and fungi to enter and damage the tree. Because palm trees only grow from one central point at the very top, the beetles’ burrowing can also damage the tree’s ability to make new leaves and may kill it. They chew through the new palm leaves that are folded up within the top of the tree, making “v” shaped cuts in the leaves when they extend. Unfortunately, when one beetle finds a tasty tree, it calls in its friends for a mass attack!

Female rhino beetles love to lay their eggs in rotting wood, compost piles, and manure heaps, and the larvae eat this dead material when they hatch from the eggs. Coconut palm logs that have fallen to the ground are especially good places for CRB larvae to hide and feed. In areas where CRB is found, it is important not to move piles of branches or yard waste, or you could be taking rhino beetle grubs with it!

Natural enemies of the CRB include rats, pigs, other beetles, birds, and ants. In the CRB’s native range, a fungus and a virus are present in the environment that make the larvae sick and control their numbers, but these natural enemies are not present where this bug has been introduced. Beetle battlers in Guam and Hawaii are trying very hard to rid their island nations of CRB through a combination of trapping adult beetles and cleaning up piles of tree waste that may breed more of these bad bugs.

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