Japanese Beetle

Beetle control in the garden is a constant battle during the month of July. They appear in large numbers seeming to eat everything in the vegetable and flower garden. Daily scouting for damaged plants and adult beetles helps win the war against them and salvage the plants. The first line of defense is to identify the enemy. Just which beetle is eating the specific species and is it eating different plants is clue to controlling the different beetles.

The life cycle of all beetles have four stages: egg, larva, pupa and the adult beetle. Japanese, Asiatic garden and Oriental beetles lay eggs on the soil, where they hatch into white grubs and feed on plant roots. Pupation takes place under the soil, too. The adult beetles emerge after pupation, rising out of the soil in large numbers, looking to feed and mate, and then females will lay the next generation of eggs back on to the soil. There is one generation per year for most of the garden pest beetles. The most common garden pest beetles are also lawn pests as white grubs feeding on grass roots, but grubs can also be found in the vegetable and perennial gardens. Control grubs in the lawn by using conventional grub control. Organic options are parasitic nematodes and Bt galleria. Milky spore disease will only kill the Japanese beetle grubs. Bag traps to catch and contain adult beetles are available. They are specific to each variety of beetle and use a pheromone lure as an attractant. Place the trap away from the garden to keep the beetles from finding your plants. The organic options are a good choice for the soils in a vegetable garden. Other natural control measures are already in the environment. Tiphia wasps feed on the grub stage killing them. Hand pick beetles and drop into a container of soapy water. Attract birds to the garden to feed on the beetles by providing lots of perching spots with sticks and plant supports. Place a saucer of water or birdbath in the garden to invite them for a visit and meal. Floating row covers can be used to keep beetles off until plants flower and need pollinators to reach the flowers.

Japanese Beetle in hand

Japanese Beetle

Japanese beetles are cosmopolitan feeders. They have over 300 different host plants, but prefer some over others. Roses, sunflowers and beans are favorites of this metallic green and cooper colored winged beetle. The white grub is C-shaped with a tan head. The adults are active during the day and hide nearby at night.  Japanese beetles were brought to New Jersey accidentally in 1916 from Japan, and have spread up and down the eastern states. They are steadily moving westward. Japanese beetle feeding results in ragged foliage and distorted flowers. They are even known to chew on fruits and vegetables. Their damage can be extensive, especially when there is a large population.

Oriental beetle retry

Oriental Beetle

Oriental beetle is a mottled tan and dark brown beetle, active during the day also. They are native to Asia and are in many eastern states. They feed on a wide range of plants, especially the blossoms. Oriental beetles are most active in the afternoon and early evening before it gets dark.

Asiatic Garden Beetle 2

Asiatic Garden Beetle

Asiatic garden beetle are cinnamon brown in color and a little smaller than Japanese beetles. As the name implies, they are native to Asia, brought here around 1920. These beetles feed at night and hide in the soil below plants during the day. Scraping through the soil below night damaged plants will reveal the sleeping beetles. Flooding the area with a good soaking will also bring them to surface for capturing and killing.

Favorite plants for Asiatic garden beetles  are basil and roses.


Squash beetle and damage

Squash Beetle

Squash beetle eggs

Squash Beetle eggs.

Squash beetles are another big pest in my garden. They are yellowish-orange with 14 black spots. Their life cycle is different than the other three beetles mentioned above.  Adults overwinter in leaf litter and under loose tree bark, flying to the garden during the end of June. Squash beetles lay their eggs on the underside of squash, pumpkin and cucumber leaves and hatching out into a yellow, spiny larval grub to feed directly on the leaves. The adult and larval stage can destroy a crop quickly. Monitor daily for adults and turn over leaves to look for eggs which can be crushed or removed with sticky tape. I find clear packing tape and blue painters tape wrapped around my hand with sticky side facing out works well without ripping the leaves. Less eggs means less larva and adults eating the plants.

-Carol Quish

frass on leaf

Frass left on leaf after beetle feeding. Frass is insect poop!






Photo: Joseph Berger, Bugwood.org

When you think of beetles, an image like the photo to the left probably comes to mind first. This is a common ground beetle. These are only one type of many in the diverse order Coleoptera.  The beetles come in a wide array of sizes, colors and forms. In addition, they occupy diverse habits, have food preferences ranging from dead organic matter to plants and other animals and even fungi, and have a variety of both harmful and beneficial roles, depending on your perspective. The ground beetle pictured here is a beneficial predator of other insects and small prey. One of the very interesting groups of beetles are the blister beetles in the family Meloidae.

The common name blister beetle refers to the skin irritation resulting from contact with an exudate produced by these beetles when they are alarmed or injured. It contains the toxin cantharidin, an odorless chemical found only in this and one other beetle family, Oedermeridae (false blister beetles). Skin contact in humans can result in blisters but they are reported to be only minimally painful if at all and to clear up on their own in a reasonable amount of time. There is a much greater risk associated with consumption of beetles (and the toxin) in hay by livestock, especially horses. Some blister beetle species are attracted to alfalfa, especially during bloom, and when cut for hay during this time, beetles can be killed and inadvertently fed to animals. Different blister beetle species produce varying levels of toxin and therefore have different levels of severity when ingested. Reports indicate that if a horse ingests only 5-10 beetles (or their toxin) it may be fatal.

Striped blister beetle (Epicauta vittata)Photo: Clemson University – USDA Cooperative Extension Slide Series, Bugwood.org

What do blister beetles look like? They have a unique appearance. Wing covers (elytra) are generally shorter than the abdomen (note this in the photos featured in this blog). The neck (between the head and thorax) is very narrow and the thorax is wider at the abdomen than at the neck. Antennae are pretty long and look serrated or segmented. The striped blister beetle shown above is found in the eastern part of the US and southern Canada and the adults feed on some common vegetable plants and weeds, sometimes congregating in large numbers and causing damage. These and some other blister beetles are attracted to lights. As a group, the blister beetles are not nocturnal but are also not strictly diurnal.


Meloe sp. by Joan Allen, UConn

So that’s the bad side of blister beetles (well, one of them anyway). An explanation of the life cycle of some of them in the genus Meloe (common name oil beetles) will shed some light on another somewhat negative impact. In blister beetles, the larval stages are typically predaceous while the adults feed on flowers or leaves. The earliest larval stage is called a triungulin. In many species, eggs are laid on or near the flowers of the host plant of the adult. After hatching, the triungulins attach to a male bee as it visits a flower and catch a ride to a female bee.  In some cases, large numbers of triungulins cluster together on flowers and emit a chemical attractant that mimics one emitted by the female of the target bee species to help attract males. Once transported to a female bee, the triungulins move from the male to her and accompany her to where she is building a nest, laying eggs and providing provisions for her young. There they leave the female and consume bee eggs, larvae and their provisions.  Adult Meloe sp. are easy to identify: their elytra are much shorter than their large abdomens as shown in the image above (possibly M. impressus or M. campanicollis).

As mentioned above, the adults are typically herbivores, feeding on plant material. Sometimes they will aggregate in large groups and cause significant but localized damage to food crops including those in the Brassicaceae, Amaranthaceae, Asteraceae, Fabaceae and Solanaceae. A couple of years ago there was a localized outbreak of Meloe campanicollis on Brassicas on farms in Connecticut (shown below).

Meloe campanicollis on Brassica leaves. Photo: Jude Boucher, UConn

Another type of blister beetle can be considered a bit more beneficial. Many in the genus Epicauta lay their eggs on or in the soil and the young feed on grasshopper eggs or even on the eggs of other Epicauta sp. The margined blister beetle (E. funebris) and the black blister beetle (E. pensylvanica) are examples of these beetles that occur in the northeast (and are widely distributed in the U.S. and southern Canada). Adult host plants preferred by the margined blister beetle include alfalfa, beet, eggplant, tomato, potato, and soybean. Black blister beetles are often found on goldenrod but will feed on many other plants too. See pictures below.

blisterbeetlemarginedPCooper 8-13-11

Margined blister beetle (Epicauta funebris) by Pamm Cooper, UConn


Black blister beetle (E. pensylvanica) on goldenrod by Whitney Cranshaw, Colorado State University, Bugwood.org

Pest - Colorado Potato Beetle Adult, www.uwm.edu

Pest – Colorado Potato Beetle Adult, http://www.uwm.edu

Colorado potato beetle larvae, www.agriculture.purdue.edu larvae

Pest – Colorado potato beetle larvae, http://www.agriculture.purdue.edu larvae

Beetles are fascinating insects with a wide variety of colorful families and species. Some are beneficial, feeding on other insect, while other species are just plain pests. All beetles are in the order Coleoptera. Common among all adult beetles are two pair of wings, with front wings being thickened and leathery that completely cover the membranous hind wings. Adults have large compound eyes and chewing mouth parts.

Beneficial Predator as Adult - Eyed click beetle Photo by Pamm Cooper

Beneficial Predator as Adult – Eyed click beetle Photo by Pamm Cooper

Pest - Wireworms, maine.gov

Pest – Wireworms, maine.gov


Beetles have complete metamorphosis containing four life stages; egg, larva, pupa and adult beetle. Larvae have chewing mouth parts, and simple eyes which detect light, dark and movement, but cannot see as well as adult stage with the compound eyes. Different species of beetles differ in larval form. Some are c-shaped grubs with six legs, and others are wireworms with no legs. The common grubs found in the lawns will develop into beetles.

Pest - Japanese Beetle umass.edu

Pest – Japanese Beetle umass.edu

Pest - Japanese Beetle Adult

Pest – Japanese Beetle Adult

Control of all beetles can be achieved by hand picking adults and larval stages. Grubs in turfgrass are treated when grubs are newly hatched during the end of May through July by using Imidacloprid or Chlorotraniliprole as the active ingredient. Parasitic nematodes can be applied to lawns to infect the grubs, eating their insides so they never develop into adult beetles. Milky spore is a bacterial disease that affects only Japanese beetle grubs, although it has limited efficacy here in Connecticut.

In the vegetable garden, monitor known host plants by turning over leaves to look for eggs to crush them by hand. Insecticidal soap sprayed directly on any larvae will kill them by suffocation. Spinosad is an organic insecticide that will kill larval stages, too. Monitor for natural predators that would keep the pest population under control. Using broad spectrum insecticides will kill the good guys as well as the pests.

Carabid beetle Lebia grandis are voracious predators of Colorado potato beetle eggs and larvae. photo by Peggy Greb, extension.psu.edu

Carabid beetle Lebia grandis are voracious predators of Colorado potato beetle eggs and larvae. photo by Peggy Greb, extension.psu.edu

Colorado Potato Beetle Eggs, umass.edu

Colorado Potato Beetle Eggs, umass.edu


-Carol Quish




Tiger beetles are among the many beetles I like to watch and I look forward to seeing them every year. They are easy to find once you know their habitats and the time of year they are out and about. These predatory beetles are fast on their feet and are also among the quickest of the beetles to take flight. Walking along open trails, you may see something fly off just ahead of where you were going and land not too far away. If you don’t get a good look at it, you may mistake it for a fly because both insects are quick to take off in  flight and because they are often found in the same habitat.

As of 1996, there were fourteen species of tiger beetles in Connecticut, seven of which are on the state’s protected list. They are members of the Carabidae family, which are the ground beetles. Like most ground beetles, the larval stage is spent in the ground and some tiger beetles take two years to complete their life cycle. Most tiger beetles are found in habitats featuring low or sparse vegetation and sandy soils. If you want to see adults in action, look for them on sunny days as most become inactive if clouds block the sun for any length of time.

To identify a beetle as a tiger beetle look for three things- bulging eyes, long legs and crisscrossed mandibles that are formidable in appearance. When standing still, they have a distinctive posture where the head is up, the rear is down, and the body is held high off the ground on stilt- like hairy legs. These insects are built for speed both on the ground and in the air.


Typical tiger beetle posture

A tiger beetle is predatory in both the adult and larval stage. The larva is an ambush predator, similar to the ant lion, which lies in wait beneath the ground. It lives in a vertical tube in the soil and you may see its head just inside the tube as it waits for prey to amble on by. When that happens, the larva pops out and grabs its victim with its powerful jaws and then pulls it into the burrow. Larvae can survive for weeks without food and are also able to survive temporary flooding.

Adults have powerful sickle- shaped overlapping jaws which they use for capturing prey such as ants, spiders and other arthropods. They can catch prey both on the ground and in the air. They are so fast when pursuing oblivious ants that I have sometimes seen them overrun them and have to do an about- face. Their vision appears acute, and while they perch, they will suddenly turn in the direction of any movement. This can make it very difficult to approach them if you are trying get a closer look. A tip is to crouch down, with the sun ahead of you so as not to cast a shadow that will trigger flight. Then move slowly toward the beetle. Tiger beetles are also preyed upon by dragonflies, robber flies, birds, and small vertebrates, so they are approachable to some extent.

Look for tiger beetles in open sunny areas that have low or sparse vegetation with scattered rocks and sandy soils. Some are found along woodland trails and forest edges. Once you have found a tiger beetle, you will probably be able to find it the next year. Note the time of year and the exact area you saw it. They are reliably found, if not in almost exactly the same spot, then within ten to twenty yards of it.  If disturbed, most tiger beetles will fly only a short distance away and may be found by simply walking ahead in the direction you saw it fly. The adult may sit and wait for some small insect to scurry by and then use its speed to run it down. Or it may run forward and stop repeatedly as it checks out any promising activity.

There are several species in Connecticut that are of special concern. One is the federally threatened and state endangered species Cicendela puritan, the Puritan tiger beetle. This beetle is found in two small areas in the country-  periodically flooded sandy beach habitats along the Connecticut River and similar areas along the Chesapeake Bay in Maryland. The small area in Connecticut where this was found is now protected from human access both from the water and from land.


Tiger beetle Cicindela repanda on my thumb.

Cicindela rufiventris  is a species commonly found in dry upland rocky and eroded areas but can also be found in areas of sparse vegetation such a trails , power lines or forest clearings. I have found populations in several areas where stones have been brought in by the local governments or power companies to help stop erosion caused by both maintenance vehicles accessing the land and all-terrain vehicle activity that can cause greater damage of a more permanent nature. Whether the stones helped keep the ground from being destroyed or just allowed a better habitat for both larvae and adults to survive, rufiventris appear to be doing well in these areas. Look for adults in July and August.


possibly a C. rufiventris as the abdomen just showing below elytra is orange- red.

There is a small spit of tidal flooded land along the Connecticut River where the ferry comes in on the Glastonbury side where there is a large colony of Cicindela repanda can be found. These common beetles are very similar in appearance to the endangered Puritan tiger beetles. In August there are hundreds of them running along the water edges and among the rocks of this spit- the ground seems to come alive with their activity. When the tide is in, the area shrinks in size, and if you sit down on the sand, you will be surrounded by beetles rushing around. They even venture into shallow water to catch the flies that are abundant there. Take care not to step on any of these industrious, beautifully patterned creatures.


 Cicindela repanda August 2012 Glastonbury in sand at the ferry landing.


Ct. River ferry landing area in Glastonbury showing tiger beetle C. repanda habitat. Picture taken at low tide.

I have found the six- spotted tiger beetle, Cicindela sexguttata, year after year on the same power lines, along the same gravel roads and in the same areas  bordering woodland edges. I look for them in mid to late April during warm springs, but normal activity begins in early may. Adults are readily seen through July and sometimes into August. These beetles are bright metallic green and have three white spots on each elytra. They can be found perched on logs and rocks or bare soil either in the sun or shade. Their bright color will make them easy to spot if they have landed in any open area. A slow approach is in order if you want to get close enough to take a picture or just watch them for a while. If you lost sight of it, just walk on for a while, and if nothing appears, turn around and head back to where you first saw it. Often it will have circled around gone back near where it was before.


Six- spotted tiger beetle- Cicindela sexgutatta– found on a restaurant window in Cold Spring, New York June 28, 2011. The restaurant was surrounded by rocky cliffs and a large disturbed area bordering woods.

So next spring and summer if you are out and about hiking along nature trails, power lines or dirt roads, be alert to the possibility of tiger beetles being on the hunt nearby. And don’t forget to bring your camera! I would not have had the opportunity to take any of the pictures you see here if my camera had been left at home ( or in the car! ).

Pamm Cooper                                                      All Photos Copyright 2013 Pamm Cooper

I have been finding leaves of some of my plants with holes in them and some shredded with only veins left. One surprising plant being eaten is the leaves of my rhubarb. I do notice the damage is being done during the night. This clue tells me the insect doing the chewing is a nocturnal one. A little scouting with a flash light in the dark reveals the Asiatic Garden Beetle( Maladera castanea) voraciously munching away! During the day they hide in the mulch and soil just below the plants. Carefully pull the mulch away and scrape small amounts of soil to reveal the beetles sleeping quarters during the daytime. I hand squish the ones I can find during the day or drop them into a jar of soapy water. I am finding about 20 per plant every few days. They must be flying in during the night from other areas. Other plants they seem to feed heavily on are basil and peppers. Tomatoes are not being damaged at all. The pink petals of my coneflowers are completely missing thanks to these beetles’ nocturnal foraging.

Asiatic Garden Beetles are reddish-brown beetles a little smaller than the Japanese beetles. I like to call them cinnamon colored so people don’t confuse them with the bright red lily leaf beetle. All beetles have complete metamorphosis, four very different stages of life. They start off as an egg, hatch into a white grub typically found in lawns, then pupate under ground, then change into the adult beetle.

Here in CT there is one generation per year. The adult beetles emerge from the soil  July through August. They feed on above ground plant parts, mate,  and the female lays eggs in  the soil. The eggs hatch into grubs during the next few weeks  and  feed on plant roots until the cold weather triggers them to move deeper into the soil. The grubs overwinter until the spring warms the soil at which time the grubs move up the begin feeding on the plant roots once again.  Around June the grubs will  pupate to become adult beetles rising out of the soil in July and cycle begins again.

Control measures are handpicking from the soil during the day or from the plants at night. Row covers of remay will exclude the beetles from landing on the plants but will need to be removed if your plants need to be pollinated to let in the bees.

The grub stage is easiest to kill by applying grub control to lawns. Merit (Imidacloprid) is a commonly used in grub killer formulations. If you kill these grubs, they will not grow up to be next year’s beetles.

To kill the adults presently eating the garden, chemical controls recommended are pyrethrin, rotenone or Sevin (Carbaryl).

photo by Peter Cristofono