Pest Control

Elm Spanworm

The elm spanworm is a member of the Geometridae family (looper) of the order Lepidoptera (moths and butterflies). This insect was mainly responsible for the total defoliation of thousands of deciduous trees in St. John's during the summer of 2002 and caused great concern as to the fate of those trees. The insects common name is misleading, for it is a general feeder on a wide range of deciduous trees, such as maples, lindens, chestnut, beech, oaks and elms.

There are approximately 150 species of spanworms, inchworms or loopers which have been collected on the island of Newfoundland. It is important to bear this in mind when determining the appropriate course of action to take as many species look the same, but their life cycles are entirely different. Therefore, the first step is the correct identification of the insect because what works for one type does not necessarily work for all of them.

Description and Life Cycle

Larvae are slate gray to brownish black in colour with a rust- colored head and usually grow to about 50 mm long before they pupate. The adults are snow white moths. Over wintering eggs hatch in early spring when the tree buds break, usually in late May to early June depending on the weather. The larvae feed for four to six weeks and then pupate in net-like cocoons on the host tree. Six to 10 days later, the adult moths emerge, mate and deposit their egg clusters on the underside of twigs where they overwinter. There is only one generation per year.

Damage

Damage from the elm spanworm is cause by the larva. As soon as the eggs hatch, larvae begin to feed on the underside of the leaves. Larvae will eat all the leaf material between the veins of the leaves and are capable of completely defoliating a tree in a relatively short period of time.

Trees should be monitored from May to early June for signs of elm spanworm eggs and larva. If found in its early stages, there are various control options available. Often, if elm spanworm is left unchecked and not detected until moths are seen, then treatment options are not effective.

Control

Two important egg parasites appear in great numbers when moths are abundant. Other natural enemies are also important in keeping infestations in check. Chemical controls may be needed to protect high value trees but is usually limited to smaller trees. It is practically impossible to reach insects in mature trees due to the height and congested crowns. Defoliating insects don't normally cause any long-term damage to the host tree, unless the tree is in poor health prior to infestation or suffers from repeated years of defoliation.

Strategy 1 (Long-Term Solution)

Unlike flower gardens, trees and shrubs are often neglected. They suffer from nutrient deficiency, insect infestations and diseases. Trees and shrubs are lasting investments for your property and the environment. They, therefore, deserve all the care we can give them. Think of preventive health care for trees as an investment in natural beauty that pays big dividends. Remember, that curing a problem once it develops is much more difficult, annoying, time consuming and costly than preventing one.

The most critical step in promoting tree health is providing a tree with suitable space and environment to ensure healthy development. It's about getting the right tree for the right space. An effective tree maintenance program should include four major practices: inspection, mulching, fertilizing and pruning.

Strategy 2

Dormant oil spray is quite effective against the eggs when sprayed at the correct time. Thoroughly wet the trunk and crown prior to bud break. At this time, it is easier to get the spray solution into the tree because there is less congestion. However, once the leaves start to appear it is too late to spray because the dormant oil could damage the new leaves.

Strategy 3

Spray with Bacillus Thuringiensis (BTk). BTk is a naturally occurring spore-forming bacterium that causes a fatal disease in spanworms. Commercial formulations of the bacterium, under several trade names, are available from garden stores and have proved effective in the control of spanworms. The best results are obtained if spray is applied when all eggs have hatched and larvae are still small.

Strategy 4

Banding trees in the early spring with a registered systemic insecticide such as cygon will offer some protection to younger trees during the period of larval feeding. Systemic insecticide must be applied in early spring so it can travel throughout the tree prior to larvae feeding.

Strategy 5

Insecticide Sprays - Most common insecticides, including insecticidal soap, are effective against young spanworms. Best results are obtained if the spray is applied after all the eggs have hatched and the larvae are still small. Please remember that most insecticides are non-selective, which means that they kill all insects, not just the 'bad ones'.

Recommended Treatment

The recommended treatment is to spray the entire tree (from trunk to tip) with dormant oil prior to bud break. Dormant oil is a domestic product available at any of the local garden centres and can be applied by the homeowner.

Giant Hogweed

Giant Hogweed (Heracleum mantegazzianum) is an invasive plant species that can cause health issues in humans, and is dangerous to the plant ecosystem. It is native to the Caucasus region of Eurasia and was likely introduced to North America as an ornamental garden plant. It is usually found along road beds, streambeds and forest edges. Hogweed can reach a height of approximately 4.5 metres (15 feet). It has hollow stems with dark reddish-purple splotches and coarse white hair. The leaves can grow up to 1.5 metres (5 feet) wide and have hairs on the underside. The plant also produces flattened oval shaped fruit and white flowers. Giant Hogweed resembles cow parsnip, Queen Anne's Lace (wild carrot) and Angelica, but is much larger.

Giant Hogweed has a clear watery sap on the stems and leaves that burns the skin when exposed to sunlight. The initial burning red rash progresses to form blisters, resembling a burn.

If you come in contact with Giant Hogweed:

• Avoid touching your eyes or wiping the sap on other parts of your body or clothes
• Wash affected areas immediately
• Keep the affected area out of the sun
• Seek medical advice

If it is possible that your pet has had contact with the sap from Giant Hogweed, it is important not to touch your pet with bare hands. The sap will likely not affect your pet, but there is potential that you could get the sap transferred to your skin via your pet's fur. Using protective gloves, immediately wash your pet with soap and water and seek medical attention if you feel you have been exposed. Seek the advice of a veterinarian if you have concerns about your pet.

If you suspect you have found Giant Hogweed in a park, playground or open space do not touch the plant and contact the City: Access St. John's at 311 or (709) 754-CITY (2489).

If you find Giant Hogweed on your own property, it is strongly recommended that you contact a landscape professional to identify and remove the plants. The City does not remove plants from private property.

Insects

The City of St. John's may perform pest control on parks, playgrounds, sport facilities, waterways, trails and public rights-of-way as deemed necessary to combat infestation of stinging insects, elm spanworm, etc. We do not offer this service on private property.

Norway Rat

If you have rats it doesn't mean your property is dirty, it means there is shelter and an open food source for them. Rats are attracted to small spaces because they feel protected in them. If a space is small enough for rodents to access, but not for their predators such as cats and dogs, rats will make a home there. Rats can make homes in anything that provides shelter including sheds and garages, wood or rock piles, under enclosed patios and stairwells, and in unwanted items such as old water tanks, appliances, building materials and tires.

Rat Prevention

Give them nothing to eat:

• Do not store garbage outside; place it at the curb no earlier than 6 a.m. on your garbage collection day.
• Remove bird feeders or attach catch basins so bird feed does not fall on the ground.
• Do not store pet food, bird feed and lawn seed outside.
• Pet owners should feed dogs and cats only what they will eat and then remove the food and any spillage.
• Compost properly - do not add fish or meat to backyard compost bins.
• Refrain from feeding birds and limit the use of bird feeders:
  • Feeding birds by throwing feed on the ground attracts rodents and is not permitted. Any food or other waste on the ground of a residential property should be removed and disposed of immediately.

  • The City’s Residential Property Standards By-Law states that a resident may feed songbirds only on their own property with the use of a bird feeder.

  • Bird feeders must be kept free of wet or spoiled food and cleaned and disinfected regularly. Up to two feeders are permitted except on residential lots that are larger than 465 square meters, in which case one additional bird feeder is allowed. 

Give them nowhere to live:

• Tall grass, weeds and vegetation next to buildings and fences should be removed.
• Lumber, rocks, garbage, building materials, and other unwanted or unused materials should be removed.
• Do not enclose the base of patios and raised stairwells, not even with lattice.
• Construct concrete floors and foundations of high quality materials.
• If building a patio or shed on a grade, bury sheet metal 30 cm (12 inches) below the grade and skirting
• In the case of patios and sheds built on grade, use sheet metal buried 30 cm (12 inches) below grade to skirt the structure.
• Items that must be stored outside should be at least 46 cm (18 inches) off the ground and 30 cm (12 inches) from walls and fences.
• Make it impossible for rats to get into any structure; use screens in drains and tightly seal where utilities enter buildings and install a metal kicking plate or heavy weather stripping beneath doors, including garage doors.
• Norway rats can be deterred from climbing vertical pipes by applying a 30 cm (12 inch) band of glossy paint around the pipe or conduit.

Eradication

As the Norway rat has such an enormous reproductive capacity, controlling the spread of this species means eradication, followed by year-round inspections to ensure the problem is corrected.

In a community-wide rodent control program, poisoning rats is an essential part of the plan. Timing of the poisoning effort is of utmost importance. Rat poisoning methods are applied most effectively before sanitation and cleaning programs are begun to prevent out migration of rats to other areas. Also early in the spring where burrows are easily recognized and prior to initial breeding of mature rats.

Forms of eradication include:

• traps
• glue boards
• rodenticides
• fumigation
• ultra-sonic devices

Whichever method of eradication is used, it is best conducted by a professional Pest Control Operator. Look for 'Pest Control Services' in the Yellow Pages or online.

Precautions and legal implications

• All rodenticides are potentially dangerous enough to cause death to animals other than rodents, so be sure to place them where they are inaccessible to children, pets, livestock and wildlife.
• Read and follow the rodenticide label instructions.
• Dispose of dead rats immediately and avoid handling rats with bare hands.
• When baiting outdoors, put all bait deep into burrows or in covered rodent bait stations. If placed directly into burrows, baits must be contained in their original packets unopened. This will prevent spoilage caused by moisture and insects, as well as making it recognizable as a poison.
• The burrow should then be covered to prevent access by children or non-target animals.
• When baits are placed indoors, use covered bait stations where possible. It is legal to use open bait trays indoors only when they are protected under equipment, furniture or some other fixed structure which limits access to humans or animals.

Note: We strongly advise against baiting indoors as there is always a chance of rodents dying in the walls and creating a foul odour.

Also, no matter what form of eradication method is used, it has to be placed where the rat will come into contact with it, i.e. adjacent to a wall, behind objects.

To obtain information on provincial legislation as it relates to rodenticides contact:

Department of Environment & Lands

Pollution Prevention Division

Pesticides Control Section

Phone: (709) 729-3395

Community Control Program

There is no government organized rodent control program in St. John's, or in the province of Newfoundland and Labrador. The responsibility for rat control lies with the owner and/or the occupant of the land, dwelling or business.

If you suspect there is a rodent problem on City owned land, contact Access St. John's at 311 or (709) 576-CITY (2489) to arrange for an inspection.

Understanding the Norway Rat

The Norway rat (Rattus norvegicus), also known as the sewer rat, harbour rat, wharf rat or common rat, is the only species occurring in Newfoundland. It is not native to North America, but is believed to have been introduced by early settlers when their rat infested ships first visited our eastern shores. The Norway rat quickly spread and became a serious pest.

Wild rats are recognized as the most destructive vertebrate animal in the world, both in terms of economic losses they cause and their effects on human health.

Knowledge of the biology, physical abilities and behaviour of the rat can help you in establishing a successful control program.

The adult Norway rat weighs an average of 450 g (1 lb). Body length various from 190 to 255 mm (7.6 to 10 inches). The tail is round, almost hairless and shorter than the body, averaging approximately 180 mm (7 inches) in length. The life-span of a wild Norway rat may extend from nine to 14 months.

In general, Norway rats have large litters of eight to 12 young. Under ideal conditions Norway rats can produce six to seven litters in a single year. Born in a nest about 21 to 23 days after conception, young rats are naked and their eyes are closed. Females may mate again within a day or so of littering.

At about three months of age the young are reproductively mature. The females come into 'heat' every four to five days and remain receptive to males for a day or two.

Rats have an excellent sense of balance and, like a cat, a falling rat always lands on its feet. A Norway rat can drop as much as 15 meters (50 feet) without being killed or seriously injured.

Norway rats are good swimmers. They are able to swim up through floor drains and toilet bowl traps. They may swim as far as 0.8 km (½ mi), dive through water plumbing traps, and travel in sewer lines, even against substantial water currents.

The Norway rat can climb quite well when necessary. When rat proofing a structure, it would be wise to consider that rats can:

• Climb both horizontal and vertical wires
• Climb the inside of vertical pipes that are 4 to 10 cm (1.5 - 4 inches) in diameter
• Climb the outside of vertical pipes that are up to 7.5 cm (3 inches) in diameter
• Climb brick or other rough exterior walls which offer footholds

Rats are omnivorous, meaning they eat nearly any type of food although each colony or group of rats has its own preferences. The Norway rat is an avid consumer of garbage. Rats are a nocturnal animal which means they are most active at night.

Rats can be very aggressive with other rats, especially when they become numerous. Dominant males exclude other males from the burrow which may be occupied by several females. This is one major cause of rat migration. Again, migration will occur when all suitable habitat is occupied or if available food is not sufficient to sustain the present population.

Rats will often avoid strange objects, and other changes in their environment for three or more days. The rat will recognize a trap or poison bait only as a new object to be avoided; something which may be hazardous. A change in location of a familiar object may cause avoidance, or a noticeable drop in feeding. In environments where strange objects appear regularly, such as at dumps or in busy warehouses, rats may show little evidence of shyness.

Rodents

There is no government organized rodent control program in St. John's or in the province of Newfoundland and Labrador. The responsibility for rodent control lies with the owner and/or the occupant of the land, dwelling or business.

If you suspect there is a rodent problem on City owned land, contact Access St. John's at 311 or (709) 576-CITY (2489) to arrange for an inspection.

We do not provide this service or advice on private property. If you are experiencing a problem with rodents on your own private property, please call a private pest control company.

Tar Spot

Tar spot is a fungus that affects the leaves of trees. As the name implies, the fungus causes raised black spots on leaves that resemble drops of tar. It is one of the most common tree pests found in an urban setting and is most often seen on maple trees.

Life cycle & development

Tar spot first appears on the leaves between late May to early June. They first appear as small pale-yellow spots on the leaves. Throughout the summer more yellow spots will emerge on the leaves. By late summer, typically August, the spots will have grown (up to 19mm across) and turn a deep brown or black in color. The mature black tar spot is the fruiting structure of the fungus and will live on the leaves overwinter.

Control or Management?

The good news is that tar spot is not fatal by itself and rarely detrimental to a trees health. A heavy infestation will cause early leaf drop and give a tree an unsightly look. The best management of tar spot is to remove the infected leaves as they fall from the tree. If they are left onsite or mulched, the spores will be released and reinfect your tree.