Tag Archives: Pest Watch

Pest Watch: Bagworms!

by Susan Ndiaye, Community Horticulture Educator

pinecone like structure hanging on an evergreen tree

Have you ever noticed one of these structures hanging on a Colorado blue spruce or an arborvitae?  They kind of look like pine cones, but not exactly.  Well, they aren’t pine cones, but silken bags spun and decorated by bagworms (Thyridopteryx ephemeraeform).

Bagworms are moths whose larvae feed on evergreens such as spruce, juniper, pine and arborvitae.  The larvae can also feed on deciduous trees such as maple, elm, birch and sycamore.  Bagworms defoliate the trees and shrubs they infest.  In large numbers, bagworms can cause significant defoliation, which can lead to the death of the plant.

Bagworm Lifecycle

In late spring, bagworm eggs, which overwinter in their mother’s silken bag, hatch and caterpillars emerge.  These caterpillars begin to form new silk bags, and as they eat, they cover it with bits of leaves.  As the caterpillar grows, it expand its bags.   Then in late summer the caterpillar firmly attaches its bag to the plant and pupates.

Adult male bagworm - clear winged moth with furry brown body
Adult male bagworm

Complete metamorphosis from caterpillar to moth takes about four weeks.  Adult male bagworms emerge from their bags as clear winged moths and begin to search for a mate.  Adult female bagworms are wingless moths and never leave their bags.  After mating females produce 500-1000 eggs before dying.  Their eggs overwinter inside their mother’s silken bag and the whole cycle begins again.

Management

Because bagworms are protected by their silken bag, management can be tricky.  For smaller trees and shrubs the best tactic is to remove and destroy the bags by hand.  Unfortunately, this is not possible in all instances, especially on larger trees and shrubs.  Insecticides are most effective right after bagworm eggs hatch, when the caterpillars are small.

But how does one know when the eggs are going to hatch?  Well, it turns out that there is a “Bagworm Forecast” that you can check in the spring to determine  the best time to apply insecticide.  The maps provided by this forecast are updated daily and available six days in the future, so you can plan ahead.

For recommendations on pesticides, check out the resources below.  And as always, make sure you read and follow all the instructions on the pesticide label including the use of personal protective equipment.  The label is the law!

If you need to spray a larger tree, you may need to contact an arborist.  Click here to find a certified arborist near you.

Fun Facts

As females don’t fly, you may wonder how bagworms spread.  Bagworm caterpillars can balloon, or use their silk threads to catch the wind and travel long distances.

Despite relatively little protection for overwintering bagworm eggs, research at Purdue University found that it takes a 24 hr period at -0.6 ° F or below to kill the eggs.  So if you live in Orange County New York don’t expect a cold winter to kill off your bagworms.

Here is a video of a bagworm feeding!

Video from Purdue University Landscape Report (https://www.purduelandscapereport.org/article/824/)

Resources

Bagworm – Penn State University

Bagworms – Cornell University

Bagworm Forecast – USA National Phenology Network

Bagworms on Landscape Plants – University of Kentucky

Cold weather in January 2018 may have killed bagworms in some parts of Indiana – Landscape Report, Purdue University

What kind of insect is destroying my plants?

Biting / Chewing vs. Piercing / Sucking

By Susan Ndiaye, Community Horticulture Educator

This article appeared in the July 2019 Issue of Gardening in Orange County. Click here to subscribe!

Insects can cause a lot of damage to your plants.  Determining what insect is causing damage to your plant is key to developing an effective management strategy.  The first step is to examine the damage.

Biting/Chewing Insects

A leaf covered with holes and a small grasshopper
Chewing damage

Biting/chewing insects create holes in plant leaves.  The size and shape of these holes varies by  insect.  The three most common types of insects with biting/chewing mouthparts you may find in your garden are: grasshoppers, butterfly/moth larvae, and beetles (adults and larvae).

 Grasshoppers

Two mating diffrentail grasshoppers, the male sitting on top of the female
Differential grasshoppers (Melanoplus differentialis)

Grasshoppers are a sporadic pest and rarely cause substantial damage to garden plants.  During dry years when other plants dry out, grasshoppers may seek refuge and food in your lush green garden. Unfortunately, because grasshoppers are highly mobile they are difficult to manage.  If you have an ongoing problem with grasshoppers, you can reduce populations, by fall tillage as grasshoppers overwinter as eggs laid in the soil.

Imported Cabbageworm (Pieris rapae)

Imported cabbageworm larvae, a velvety green caterpillar with a faint yellow strip down the miidle of the back, hanging out on a leaf
Imported cabbageworm larvae
Imported Cabbageworm adult, a white butterfly with three black spots on the forewings perched on a rasberry bloom
Imported cabbageworm adult

Those beautiful white butterflies you see fluttering around your garden, may seem innocuous, but their larvae, the imported cabbageworm, can cause extensive damage to plants in the brassica family also known as cole crops.  These plants include broccoli, cabbage, Brussel sprouts, collards, kale, radishes, and turnips.  The caterpillar is bright green with a yellow stripe down the center of its back.  They start out chewing little holes in the leaves of the plants, but eventually consume the entire leaf leaving only the midrib behind.

A very holey head of cabbage a result of feeding by the imported cabbageworm
Imported cabbageworm damage on cabbage

To monitor for these pests, look for dark green frass or poop near feeding areas.  Once you discover a population of imported cabbageworm, depending on how numerous they are you can hand pick them off your plant.  The use of Bt (Bacillus thuringensis), a microbial insecticide is also highly effective on younger caterpillars.  This particular pest spends the winter in the pupal stage, so to prevent future infestations you can eliminate overwintering sites in your garden by removing plant debris.

Stripped and Spotted Cucumber Beetles (Acalymma vittatum and Diabrotica undecimpunctata howardi)

A single stripped cucumber beetle, black and yellow vertical striped with an orange thorax, a black head and black legs and filiform antennae, on the orange flesh of a pumpkin
Stripped cucumber beetle

Although they are called cucumber beetles, these insects feed on much more than cucumbers.  The stripped cucumber beetle prefers plants in the cucurbit family (squash, pumpkins, melons, etc.) feeding on leaves, flowers, stems and fruits.  They can be especially detrimental to young seedlings.

Spotted cucumber beetle, a yellow beetle with black spotts, a back head, legs and filiform antenna
Spotted cucumber beetle / Southern corn rootworm

The spotted cucumber beetle is more of a generalist and feeds on cucurbits as well as beans, tomatoes, and ornamentals. The larvae of this beetle can do substantial damage on the roots of corn plants hence its other name, the southern corn rootworm.

 

A cucumber plant sith bacterial wilt, there is a scetion of health plant and a two foot vine with shriveled brown leaves
Bacterial wilt of a  cucumber plant

Cucumber beetles vector or transmit bacterial wilt (Erwinia tracheiphila), a common disease in cucurbits in which bacteria clog up the vascular system of the plant preventing the flow of water and causing the plant to wilt and eventually die.

One way to protect your plants from cucumber beetles is by using row cover.  This can be put on at planting and kept on until female flowers appear, then it must be removed to allow for pollination.

Sucking/Piercing Insects

Squash bug damage on a squash plant - edges of the leaf are brown with a yellow line between the brown area and the green center of the leaf
Squash bug damage on a squash plant

Sucking/piercing insects can cause of variety of symptoms including leaf malformation and leaf discoloration. The most common types of insects with sucking/piercing mouthparts are from the Order Hemiptera, also known as the “true bugs”.  This order of insects contains, stink bugs, squash bugs, cicadas, leaf hoppers, scale, aphids and many more.

Brown marmorated stink bug (Halyomorpha halys)

A brown shield shapped bug with white and black marmoration on the edge of the wings
Brown marmorated stink bug adult

Many people are familiar with this invasive species because the adults invade their home every fall looking for a nice warm place to spend the winter.  Although it can be an unwelcome house guest it also can cause major damage on fruits and vegetables.  Some of the brown marmorated stink bug’s favorite snacks include apples, peppers, beans, tomatoes, and sweet corn.

About 20 orange and black colored brown marmorated stink bug nymphs clustered around their egg mass
Brown marmorated stink bug 1st instar nymphs clustered around an egg mass

Controlling the brown marmorated stink bug can be quite difficult because they are highly mobile, feed on a large variety of plants, and adults are highly resistant to insecticides.  Monitoring for these pests is the best way to start.  Bunches of about 28 eggs are laid on the underside of leaves and should be removed and destroyed if found.  When the eggs hatch the 1st instar nymphs cluster around the egg mass making them an easy target for removal.  The bugs usually drop down when startled, so for hand removal, you can knock them into a container of soapy water.

Lots of research is being done to develop effective management strategies for brown marmorated stink bug.  One of the most promising avenues of research is on biological control.  A stingerless wasp known as the Samurai Wasp (Trissolcus japonicas) destroys 60-90% of brown marmorated stink bug egg masses in its native range in Asia.  This tiny wasp has found its way to the United States and as of 2018 has been found in twelve states, including New York.  Research is now being done to determine the effectiveness of rearing and releasing this tiny parasitoid.  Check out this video about brown marmorated stink bug and the samurai wasp.

Potato Leafhopper (Empoasca fabae)

Potatoe leaf hopper adult on a leaf
Potato leaf hopper adult
Neon green leaf hopper nymph on the underside of a leaf
Potato leaf hopper nymph

Despite their name, potato leaf hoppers feed on over 200 hundred different kinds of plants including potatoes, snap beans, cucumbers, pumpkins, egg plants, rhubarb, squash and sweet potatoes.  The nymphs are neon green and are usually found crawling around on the underside of leaves.  The adults only reach ⅛ inch in length. They are pale green and wedge shaped and fly away when disturbed.

hopper burn on bean leaves, edges of leaves are yellowing, entire leaf is distorted
Hopper burn on bean leaves

These little pests do not overwinter in our area, but instead overwinter down south and the adults are brought up each year by the winds arriving in late-May / early-June.  Although small, a few individuals can cause hopper burn on your plants.  Hopper burn reduces yield and is characterized by chlorosis, or yellowing, of the leaf edges.  Eventually these leaves begin to curl and turn brown.

It is easiest to combat these pest as flightless nymphs using insecticidal soaps or horticultural oils on the undersides of leaves.  Dusting plants with diatomaceous earth can also help deter these pesky bugs.

Squash Bug (Anasa tristis)

Squah bug nymphs, green with black legs
Squash bug nymphs

Squash bugs are pests of all cucurbits, but prefer squash (summer and winter varieties) and pumpkins.  Adults are a little over a ½ inch long and are dark brownish while nymphs are black, pale green or gray with black legs.  These insects feed mainly on the leaves and the stems of squash plants, but can also feed on the fruits.  Initially they cause a stippling on the leaves, but after heavy feeding the leaves begin to look tattered.

Squash bug adult laying eggs
Squash bug adult laying eggs

Squash bugs overwinter as adults, so at the end of the season cleaning up plant debris and mulch will remove overwintering sites.  Eggs are bronze colored and usually laid in clumps on the underside of leaves.  Removing and destroying egg masses can help keep squash bug numbers down.  Adults and nymphs are known to hide in mulch around the base of the plants, laying down a board or piece of cardboard will provide a hiding place for these bugs.  You can then remove the shelter and destroy all the bugs underneath it.  There are also some cultivars of both summer and winter squash that are resistant to squash bugs.


Of course there are lots of non-insect pests that can wreak havoc on your garden as well and whose damage can sometimes be confused with insect damage.  Snails and slugs have rasping mouth parts that create holes in plant leaves much like insects that have biting/chewing mouth parts. Spider mites having piercing/sucking mouth parts that cause stippling on plant leaves like the “true bugs”.

So as you try to determine what is causing damage to your plants keep in mind that different kinds of insects cause different kinds of damage and that determining the cause is essential to developing a solution.

Note: Pesticide recommendations are not a substitute for pesticide labeling.  Remember to read the label before applying any pesticide.  The label is the law!

Helpful References

Vegetable Insect-Mite Pests

https://extension.umd.edu/hgic/topics/vegetable-insect-mite-pests

Brown Marmorated Stink Bug

https://www.stopbmsb.org/stopBMSB/assets/File/BMSB-in-Vegetables-English.pdf

https://extension.umd.edu/hgic/topics/stink-bugs-vegetables

 Grasshoppers

https://extension.umd.edu/learn/grasshoppers-life-cycle-and-control

Imported Cabbageworm

https://extension.umd.edu/hgic/topics/imported-cabbageworm-vegetables

http://idl.entomology.cornell.edu/wp-content/uploads/Imported-Cabbageworm.pdf

Potato Leafhoppers

https://extension.umd.edu/hgic/topics/potato-leafhopper-vegetables

Squash Bugs

https://extension.umd.edu/hgic/topics/squash-bug-vegetables

Striped and Spotted Cucumber Beetles 

https://extension.umd.edu/hgic/topics/cucumber-beetles-spotted-or-striped-vegetables

 

Citizen-Science Training

Stop the Spread: Scout for New Forest Pests

Adult Spotted LanternFLy measuring 1 inch in length
Spotted lanternfly adult

Help survey the Hudson Valley Region for potential new forest pests. Reports of invasive pests newly detected in New York are causing great concern. These include spotted lanternfly (Lycorma delicatula), Asian longhorned tick (Haemaphysalis longicornis) and jumping worms (Amynthas sp.). Reporting their presence and stopping their spread are urgent needs. You can help.

Spotted lanternfly (SLF) is an invasive planthopper that can feed on a wide variety of plants including grapevines, hops, maples and fruit trees. It is established in neighboring states and may be moving into our region.

This workshop will prepare interested individuals such as gardeners, hikers, landscapers and forest managers to scout for and identify SLF. Trainees will be asked to be “boots on the ground” to assist in the detection of the pest, to report it to NYS DEC and to help prevent its spread in our area. The biology, identification, potential damage, methods of spread, monitoring and management of SLF will be described. The Blockbuster Surveyor protocol and iMapInvasives app will be reviewed to track the current distribution and abundance (or absence) of SLF.

Identification information will also be provided for Tree of Heaven, Ailanthus altissima, the SLF’s favorite host; an emerging pest, Asian Longhorned Tick, Haemaphysalis longicornis; and Jumping Worms, Amynthas sp., which are in our region but under-reported.

CCE offices in the region will host the trainings in May. Register with the links below:

Questions can be addressed to Joyce Tomaselli, CCEDC, jdt225@cornell.edu, 845-677-8223 ext. 134

Lower HUdson PRISM LogoThis program is part of the Lower Hudson Partnership for Regional Invasive Species Management’s efforts to stop the spread of invasive species in the Lower Hudson Valley. Visit www.lhprism.org for more information on how the LHPRISM strives to address invasive species issues through its partnerships. Click on “Upcoming Events” or “Get Involved” to learn more.

Black-legged Ticks and Lyme Disease

May is Lyme Disease Awareness Month!

The black-legged tick, also known as the deer tick, is a very common in Orange County and is the only species of tick found in our area  known to transmit Lyme Disease.

In the spring months you are most likely to find black-legged tick nymphs. These poppy seed sized immature ticks can easily go undetected if the proper precautions are not taken.  This results in a  the highest number of  Lyme disease cases being confirmed in June and July.

Bar graph showing confirmed cases of Lyme Disease by month. January - April cases are below 10,00. May climbs to almost 20,000 with a peak in June and July with over 50,000 cases. August fall back to about 20,000 and Sept. - Dec. continues to fall starting a little about 10,000 in Sept. and falling to below 5,000 in Dec.
Confirmed Cases of Lyme Disease by Month of Disease Onset in the United States 2001-2017

In the fall adult deer ticks are more abundant.  Even though these  blood suckers are about twice as likely to carry Lyme disease then the nymphs, they are much larger and therefore  more easily detected and less likely to feed long enough to transmit Lyme disease.

The presence of ticks should not prevent you from enjoying the out-of-doors.  By avoiding tick habitat whenever possible and doing a daily tick check, you can minimize your risk of being bitten and contracting a tick borne pathogen .  Ticks usually hang out on shrubs and tall grasses, no higher than knee height.  Black-legged ticks prefer cool humid place like the woods, but can also survive in tall grasses and even on lawns.

Even if a tick gets on you, it usually doesn’t latch on immediately.  It first searches for a nice warm place such as behind your ears, in your armpits, or even in your belly button.  Conducting a daily tick check can help prevent tick bites.  Make sure you do daily tick checks on children as they are not likely to check themselves, which contributes to higher incident rates of Lyme disease among children than  adults.

Bar graph comparing confirmed Lyme diesease cases by age and sex. The highest incidence is for males age 5-9.

To safely remove a tick, use a point set of tweezers to grasp the tick as close to the skin a possible. Do NOT grab the back end of the tick.
How to safely remove a tick

If you find an embedded tick, it should be removed promptly.  To properly remove a tick, use a very pointy pair of tweezers to grasp the tick as close to the skin as possible.  Avoid squeezing the abdomen (large back part of the tick) as that can cause the contents of the tick be pushed into your body.  Although it is commonly thought that if not removed properly the head of the tick will remain lodged in your skin, this is false.  A tick uses its barbed mouth parts to puncture your skin and latch on.  The head is never embedded.  If you leave the mouth parts behind when removing a tick, it is similar to having a splinter and does not increase your risk of contracting a tick borne pathogen.

Don't Get Ticked NY LogoTo learn more about how to prevent tick bites check out the Don’t Get Ticked New York website.

Black-legged ticks can also transmit several other diseases including Anaplasmosis, Babesiosis, Powassan Virus, Borreilia miyamoti and Ehrichiosis.  For information about the symptoms and treatments of these and other tick borne diseases visit the Center for Disease Control and Prevention’s website or the Orange County Department of Public Health’s website.

For free tick identification contact the Orange County Department of Public Health.

You can also bring specimens to Cornell Cooperative Extension of Orange County, 18 Seward Avenue, Suite 300, Middletown, NY 10940. (There is a $7.00 fee for up to 10 ticks.)

Neither Cornell Cooperative Extension or the Orange County Department of Health test ticks for disease.  For more information on where you can get ticks tested for disease visit the Tick Encounter Resource Center. (Tests cost about $50.)

Pest Watch: Spotted Lanternfly

Spotted Lanternfly: a new, unwelcome invader!

by Jen Lerner – Senior Resource Educator, Cornell Cooperative Extension of Putnam County

Adult Spotted Lanternfly with spread wings measuring 1 inch in length
Spotter lanternfly adult with spread wings

Here in the Hudson Valley, we have weathered waves of invasion . . .  Insect invasion that is. Think of the multicolored Asian lady beetle buzzing around your house, soon replaced by the brown marmorated stinkbug dive-bombing your reading light at night. The emerald ash borer followed, and we see our native ash trees, their bark chipped away by woodpeckers foraging for larvae, standing as reminders that our actions have far-reaching impacts. Enter the newest invader. . .

Spotter lanternfly adult on a tree trunk
Spotted lanternfly adult

The spotted lanternfly (Lycorma delicatula) is a colorful insect in the planthopper family that congregates in large numbers to feed on the sap of trees. As it feeds, it excretes “honeydew” a nice name for what is essentially a sticky excrement. That honeydew sometimes alerts people to the presence of the pest.

While the honeydew is a nuisance, the strain placed on the trees’ resources by the insects feeding often kills the tree. The spotted lanternfly’s preferred host, the Tree-of-Heaven (Ailanthus altissima), is also an unwanted invader despite its heavenly moniker. Great, you say? Maybe the lanternfly will polish off the Tree of Heaven? Well these gregarious insects have a few more tricks up their spotted sleeves.

Why are we worried?

Thousands of Spotted Lanternfly adults clustered togeth on the base of a tree
Spotted lanternfly adults are know to aggregate on host trees

Like the brown marmorated stinkbug, spotted lanternflies are a pest of some important agricultural crops. They feed on and harm many fruit producing plants, including apples, peaches, plums, blueberries and grapes, as well as approximately 70 other plants. Besides the far-reaching economic impacts, there are ecological considerations too. Many of these trees and shrubs have relatives in our native ecosystem. For example, our native Shadblow or Serviceberry (Amelanchier sp.) is a close relative of the apple. It provides important forage for migratory birds who return to their nesting sites expecting to find its nutritious early fruits. Imagine the hole their loss would make in our ecosystem. We simply do not know yet how many host plants this insect can survive on or how wide their impact will be.

How can You Help?

Spotted Lanternfly life cycle - Eggs (October - June), Hatch and 1st Instar - black with white spots (May-June), 2nd instar - black with white spots (June-July), 3rd instar - black with white spots (June-July), 4th instar - red with white and spots (July-September), Adult (July to December), Egg Laying (September-Decemeber)Keep on the lookout and report your observations. Learn to recognize the insects themselves as well as  the signs of the spotted lanternfly. While the insect may be easy to spot because of its bright spots, the egg clusters are harder to spy. They are tan to light grey, laid in row and sometimes covered with a mud-like protective layer. If you see the insects or spot the egg clusters, please report the sighting to the NYS DEC ( spottedlanternfly@dec.ny.gov ). Digital photos or dead insects are helpful too. While sticky honeydew is another signs of these sap-feeding insects, many other insects also excrete honeydew in quantities sufficient to make cars, fences and deck surfaces feel tacky.

Don’t help them spread!

Though spotted lanternflies may hitch a ride on a boat, trailer, or vehicle, their egg clusters pose the most insidious risk because the female will lay them on just about anything!

Hitchhiking egg masses can be found on pallets of stone, firewood shipments, Christmas trees, and outdoor furniture. Remember . . . never take firewood from your home to a favorite campground or weekend retreat. Similarly don’t pick up wood from far away and bring it home: you may be bringing a hidden invader with you. Observe the “Don’t Move Firewood” rule.  Inspect boats and trailers for hitchhiking egg masses.  If purchasing used outdoor furniture, or items frequently stored outside like garden tools and wheelbarrows, check all surfaces for egg masses. Yes, the adult insects can fly, but they spread much more quickly when humans help them along.

How did they get here? And how far have they spread?

Spotted lanternfly is native to China, India, and Vietnam. This insect was introduced into South Korea and spread throughout the country (approximately the size of Pennsylvania) in 3 years. On this side of the world, an initial infestation was found in Berks County, Pennsylvania, in 2014. This first infestation is thought to have arrived on a shipment of stone in 2012. Currently the insect is found in 13 counties in South Eastern Pennsylvania and these and many other PA and NJ locations are under NYS quarantine. Historically we know from Korea’s experience that this insect spreads fast. In 2017, one dead was insect found in Delaware County, NY. In New York, 2018 saw spotted lanternfly adults or egg masses in Albany, Chemung, Monroe, Suffolk and Yates Counties, as well as Brooklyn and Manhattan– all thought to be hitchhikers.  So far, there are no known New York infestations. Let’s work hard to keep it that way!Map of NY, MA, CT, PA, NJ, MD, DE and VA showing counties where spotted lanternfly infestations have been found as well as counties in which spotted lanternflies have been found, but where there is no infestation.

Sources:

NYS DEC: https://www.dec.ny.gov/animals/113303.html

NYS IPM: https://nysipm.cornell.edu/environment/invasive-species-exotic-pests/spotted-lanternfly/

You can find photos of adults, nymphs and eggs here: https://www.aphis.usda.gov/aphis/resources/pests-diseases/hungry-pests/the-threat/spotted-lanternfly/spotted-lanternfly