Insects and Diseases

Emerald ash borer
Emerald ash borer (EAB), Agrilus planipennis, is a buprestid or jewel beetle which feeds on ash trees. It was first confirmed in Canada when it was detected in Windsor, Ontario in 2002. Since then it has spread to more locations in Ontario and was detected in Quebec in 2008. In December of 2017 it was detected in Winnipeg, Manitoba.

EAB is a forest insect pest that is native to China and Eastern Asia. It is a very destructive insect, killing true ash trees (Fraxinus spp.). “It has already killed millions of ash trees in Ontario, Quebec and the United States”…
Emerald ash borer confirmed in Winnipeg - Canada Food Inspection Agency

How to identify EAB:


The adult beetle is a small metallic green, flying insect about 8.5—14.0 mm long. After emerging in the spring they feed on the ash leaves for about two weeks (before mating and laying eggs).   Adult beetles are difficult to find so looking for the beetle is not the best way to determine if your ash tree is infested with EAB.

Eggs are laid in the crevices/under bark scales on the trunk or branches of the tree. They hatch one to two weeks later and the larvae bore through the bark and feed on the wood beneath the bark.

The larvae are creamy white with a, somewhat, flattened body. They create S-shaped feeding galleries/tunnels under the bark of the infested ash trees. The gallery shape is unique to EAB and is one of the easiest ways to tell if you tree has EAB.
The larvae pupate under the bark overwinter.

When the adult beetle emerges, it chews a D-shaped exit hole in the bark of the tree (May to early June). The exit hole is also a very good diagnostic tool for identifying if your ash tree is infested with EAB.

Tree symptoms include thinning of the tree canopy, growth of epicormic shoots (suckers) along the tree trunk or base of the tree, bark splitting and woodpecker activity.
Emerald ash borer - Canadian Food Inspection Agency

Why should we be concerned?


EAB… “ poses a major economic and environmental threat to urban and forested areas in North America.”
EAB Threat - Canadian Food Inspection Agency

“The City of Winnipeg is at risk to lose all of its ash trees over a 10-year period, resulting in a loss of at least 30% of our boulevard and park trees valued at approximately $437 million. Many ash trees on private property are also at risk of becoming infected over the next decade.”
http://www.winnipeg.ca/publicworks/parksOpenSpace/UrbanForestry/EmeraldAsh.stm

As an Island we are somewhat buffered by the fact that it is a bit more difficult for pests to get here on their own and we have fewer points of entry but introducing EAB (and/or other forest insect pests and diseases) is as simple as someone bringing an infested piece of firewood to our Island.

Ash is fairly rare on PEI and is a culturally important species for the Mi’kmaq people.

For Charlottetown specifically, we have 313 public ash trees and there are likely many more growing on private property. These all contribute significantly to our urban forest canopy, provide environmental benefits and make our City more beautiful.

What has the City been doing?


Street Tree Inventory - The City has created a street tree inventory that lists all the public ash trees and their locations. The City will start looking into getting an inventory of the private ash trees in Charlottetown.

Monitoring Program - All of the public ash trees in the City will be monitored annually for EAB as part of the City's tree management program.

EAB Survey - Working with CFIA and the Province to put up sticky traps in a few locations to help detect the presence of EAB.

Raising Awareness – Publish informational material on the City website and in social media to help residents identify their ash trees and look for signs of EAB.

Diverse Tree Planting Program - The City’s tree planting program includes a diverse number of tree species. This diversity makes the urban forest healthier and more resilient (a forest with low diversity in tree species are more susceptible to losing large numbers of trees in an invasive insect or pest are introduced).

Communicating with other Municipalities - The City has been talking to other municipalities about EAB - what they have done or what their plans are if/when EAB arrives.

Province-wide Discussions on EAB - Stakeholders on PEI will be coming together to discuss EAB and what will happen if/when it comes to PEI. Charlottetown and the PEI Invasive Species Council (which the City is a member of) will be a part of those discussions.

What can individuals do to help prevent the spread of EAB?


Don’t move firewood! Firewood is one of the highest risk pathway for moving insects pests and diseases around.

“Burn it Where you Buy it”. Buy your campfire wood near your campsite and leave any wood you don’t burn there. If you are purchasing wood to heat you home or cottage, source your firewood as close to home as possible.

Plant a number of different tree species in your yard.

Become familiar with the signs and symptoms of EAB and report any ash trees you see that are in decline.

The Canadian Food Inspection Agency (CFIA):


In an effort to prevent their spread, CFIA regulates pests such as EAB by identifying and regulating an area around the location where the pest is found. Restrictions are put on that regulated area: the movement of ash wood and firewood out of this regulated area are restricted - ash logs and branches, ash lumber, wood packaging materials with an ash component, ash wood or bark, ash wood chips or bark chips, firewood from all tree species, yard waste.

Current regulated areas for emerald ash borer in Canada.

Regulated Areas for Emerald Ash Borer

More emerald ash borer resources:

Emerald Ash Borer Information Network
Emerald Ash Borer- Canadian Forest Service

Japanese Beetle

Japanese beetle, Popilla japonica



“The Japanese beetle is probably the most devastating pest of urban landscape plants in the eastern United States.” ~ M.F. Potter, D.A. Potter, and L.H. Townsend, Extension Entomologists, University of Kentucky College of Agriculture.

Japanese beetle (native to Japan) likely arrived in the United States in 1912 in a shipment of iris bulbs. It was first found on PEI in 2009 in a campground between Charlottetown and Cornwall. It now can be found in some areas of Charlottetown and is likely in other locations as well.

The adult Japanese beetle feeds on the foliage and fruit of more than 300 plant species, including elm, maple, grape vine, peach, apple, apricot, cherry, plum, roses, zinnia, corn, asparagus, soybean, blueberries, raspberries, blackberries and other plants. The odors from the damaged leaves of certain plants seem to attract the beetles that then, aggregate and feed as a group, starting at the top of the plant and working their way down, causing serious defoliation.

The larval stage of the Japanese beetle also causes damage. Adult beetles dig down 2—3 inches in the soil to lay their eggs. The eggs hatch and the larvae begin feeding on the roots of nearby plants. Adult beetles are attracted to moist areas, such as well watered turf or gardens, as their eggs and small larvae need adequate soil moisture to survive. The preferred food of larvae is turf/grass roots but they will feed on other vegetable and shrub roots as well. The feeding larvae reduce the plants ability to take up water, and can cause large brown patches to form anywhere turf is plentiful - your lawn, golf courses, parks or even a cemetery.

What can you do if you have the Japanese beetle?



There is no silver bullet... the Japanese beetle is not easy to control once you have it but you can do some things to minimize the damage it does and reduce its population numbers.

There are a few things to consider when managing Japanese beetle populations. It is important to recognize that both the adult beetle and the larvae (grubs) cause damage. Adults are capable of flying and will travel a considerable distance to feed on preferred host plants so controlling their population in your yard does not prevent re-infestation. Beetles attract beetles, so keeping the population low attracts fewer beetles to your yard.

Get rid of the beetles as soon as you see them in the spring. Controlling the beetle as soon as they emerge helps to keep the population down in your yard or the local area.

When replacing or adding new plants to your yard, select plants that the beetle tends to avoid (this does not mean that they will avoid them totally). Plants the beetles prefer are roses, grapes, lindens, Norway maple, Japanese maple, some flowering crab apples, fruit trees, horse chestnut and many others. Lists of preferred host plants and “resistant” plants can be found online.

Manually controlling a population in a small area by hand picking beetles or shaking the beetles off the plants into a bucket of soapy water, can be effective. Morning is a good time of day to do this as the beetles are sluggish because of the cooler temperatures. If you have quite a large population of beetles, a small hand held vacuum can be used to vacuum the beetles off your plants. Empty the vacuum into a bucket of soapy water to get rid of the beetles. Warning - the vacuum may only be good for vacuuming beetles after that!

Excluding the beetles with materials such as cheesecloth or fine netting can protect highly prized plants.

Neem oil products can deter adult beetle feeding for 3-4 days. Insecticidal soaps, extracts of garlic, hot pepper, orange peels and companion planting, according to the literature, seem to be ineffective.

There are some products that can be applied to the soil to deter the larvae but since the larvae prefer to feed on the roots of turf (but will feed on other plant roots as well) they can be anywhere making application of these soil applied products problematic.
Lily Leaf Beetle

What’s eating your lilies?

 

Lily Leaf Beetle, Lilioceris lilii


The lily leaf beetle is native to Europe and Asia.  It was first discovered in Canada in the early 1940's.  The lily leaf beetle voraciously eats lily plants and can totally strip a lily plant of its leaves and flowers.

Identification:


The eggs of the lily leaf beetle are small and reddish-orange.  They are laid in irregular lines of 3 to 12 eggs, on the underside of leaves.  The adult females will only lay eggs on true lilies and fritillary so when the eggs hatch the larvae have a ready source of food.  Each female adult can lay 200-300 eggs which hatch in about 8-10 days.

The larvae  are the most destructive stage of the lily leaf beetle life cycle.  The have a slug-like appearance and are  yellowish-white to orange in color with black head.  You will rarely see the larvae's true colors because they cover themselves with their feces to deter predators and protect themselves from the sun.

The larvae feed voraciously on the foliage for 16-24 days.  It is often difficult to spot them as they begin feeding on the underside of the leaves.  They can rapidly defoliate plants, eating the leaves, buds and flowers.  Mature larvae crawl down the plant and pupate in the soil.

The pupae are a fluorescent orange color inside a waterproof cocoon.  Their y pupation takes about 20–22 days.  When the adult emerges, it digs it’s way out of the soil and feeds on lilies until the fall.

The adult beetles are a bright scarlet red with a black head, antennae, legs and under parts.  They are less than 1/3” or 6-8 mm long.  If you squeeze them slightly they will squeak as a defense mechanism, hoping that you will drop them.  The adult beetles overwinter in the soil beneath their host plants.  The emerge in early spring (late April to early May) to forage and mate.  At this time they feed on young lily leaves.  The adults are strong fliers so can spread long distances.

Food Preference:


Lily leaf beetles love true lilies, Lilium sp. (true lilies: Turk’s cap, Tiger, Easter, Asiatic and Oriental lilies) and will also feed on Fritillary species.  They have been known to also feed on Solomon’s seal and Indian cucumber root.  They will lightly “taste” other plants (Bittersweet, potato, hollyhock, hosta sp.) but the most damage will occur on true lilies and their close relatives.  The lily leaf beetle does not feed on daylilies .

Management:


Knowing the life cycle of the lily leaf beetle, it's feeding habits and it's food preference will help you to detect it's presence.  Hand picking and destroying the adults, larvae and eggs helps to keep the population lower.  Take a stroll in your garden each evening and look for the lily leaf beetle and all it's life stages!

The adults will jump off the plants if even slightly disturbed.  Hold a soapy bucket of water under them to capture them in the water.

Organic products such as Neem oil can be applied to the plant and will stop the beetles and larvae from feeding.  The larvae are more susceptible to chemical applications than adult beetles.  The entire plant and both sides of leaves must be treated.  Use chemicals sparingly as they also kill beneficial insects such as lady beetles.

What can we do?


Don’t import plants from infested areas.
Control the lily leaf beetle in your own back yard.
Be aware of the impact pesticides can have on other insects and wildlife.
Viburnum leaf beetle

Check your Snowball Bush!



Viburnum Leaf Beetle, Pyrrhalta virburni



The viburnum leaf beetle is native to Europe.  It feeds on Viburnum species like you snowball bush and can totally defoliate your shrub!

Identification


It lays its eggs, starting in July.  The eggs overwinter and start to hatch in early to mid-May as the leaves of the shrubs start to emerge.  The eggs are laid in straight rows at the ends of new twigs.  They are covered by an egg cap which is dark brown and raised.

The larvae is the most destructive stage.  It is small (up to 10mm long) and ranges from blackish to greenish-yellow in color with a black head.  It is found mainly on the undersides of leaves feeding between the leaf veins.  It can totally skeletonize the leaves, preventing them from being able to carry out photosynthesis which produces the food the shrub needs to live.  This feeding takes place from from May to mid-June

In mid-June, the mature larvae crawl to ground and pupate in the soil.

The adult beetles are also destructive.  They emerge in late June and feed on the leaves causing irregular holes.  The beetles are are brown and about 4.5 - 6.5 mm long.

Food Preference


The viburnum leaf beetle and its larvae only feed on Viburnum species such as highbush cranberry (V. trifolium), wild raisin (V. cassinoides), hobblebush (V. lantanoides, V. alnifolium), snowball bush (V. opulus).

Management


The most effective control method is to prune off the infested twig tips where the egg caps are located. This is easiest to do after leaf drop as the egg caps are more visible.

Encouraging beneficial insects such as lady beetles, who feed on larvae may be helpful.

Research is being done on applying a sticky coating to the stems of the shrubs to prevent larvae reaching the soil to pupate

Why do we care?


The damage to the leaves of the shrub makes it very unsightly.
Continued defoliation affects the health of the your shrub.
Tar spot
Tar Spot is a fungal disease caused by Rhytisma spp.  Tar spot affects the leaves of maple species, especially Norway maples.

The tar spot fungi overwinter on infected leaf litter and produce spores in the spring that infect the new maple leaves.

In mid to late summer, black tar-like spots with yellow halos develop on the leaves.

Can it be controlled?



This leaf disease occurs so late in the season that it generally does not affect the health of the tree so spraying a fungicide is not usually necessary, nor is it feasible for mature trees due to their size.

Raking and disposing of the diseased leaves in the fall stops spores from developing in the spring. Realistically, there are many Norway maples, especially in urban areas, making it difficult to avoid this disease.