Otiorhynchus sulcatus Family: Curculionidae
Life cycle: Generations per year: one in the Pacific Northwest
Description & Life Cycle: This weevil overwinters in the soil as immature larvae. In early spring, when the larvae have reached their mature sixth instar stage at 0.4 – 0.6 inches (10 – 15 mm) long, they enter the pupating stage. They are white and have the rough outline of the adult weevil. This last roughly 10 days after which the adults emerge. This is usually from late May through June. Adult weevils require 3 – 4 weeks of active foliage feeding before they start laying eggs. As many as 500 eggs are laid in the soil around the base of host plants over a 2 – 3 week period. The legless white larvae with a brown head will hatch in 10 – 14 days and begin feeding on the plant roots. In the fall, when the temperatures start to decrease, the larvae will move deeper into the soil where they will overwinter.
Special Notes: Native to Europe, this weevil species was discovered and identified in Connecticut in 1910. Since that date, it has become widespread throughout North America.
It is interesting to note that only female adult weevils are produced in North America. They reproduce parthenogenically. Adults feed on host plant leaves during the night leaving a multitude of half-round notches along the edges of the leaves. In a particularly high weevil populated area of the garden, this can look quite unsightly on your targeted evergreen plants.
Remedial Action: There are some insect killing nematodes available which will control root weevils in their immature, larval stage. These are applied as a soil drench and best used when the soil temperatures are 12 °C (55 °F) or higher in late summer and early fall. Soil must be very wet at time of application and never in direct sunlight. The UV rays will quickly kill the beneficial nematodes.
Unfortunately, there is not much data on the effectiveness of this treatment.
Posted on May 17, 2022
Scaphinotus angusticollis Family: Carabidaea
Common name: narrow-collared snail-eating beetle;
Food: snails; slugs; earthworms; spiders; insects; berries
Life cycle phases:
Eggs are laid under debris in May through June. After hatching, larvae actively feed on slug and snail eggs, as well as earthworms and other insects. Larvae overwinter in soil. Pupation occurs when soil warms up in spring. Adults appear in June and are active through into September, largely at night.
Posted on August 12, 2020
|Harpaphe haydeniana Family: Xystodesmidae
Common name: cyanide millipede; almond-scented millipede; yellow-spotted millipede
Food: leaf litter; conifer needles
Adult size: 1.5 – 2 in (4-5 cm) long
Description & Life Cycle: Adult cyanide millipedes are quite distinct with their black colouring and bright yellow patches along both sides. The body consists of about 20 segments with males having 30 pairs of legs and females having 31 pairs.
Millipedes are oviparous (egg-laying) and mating begins in spring. Cyanide millipede females will lay anywhere from 30 to 300 eggs in a season, typically underneath a rotten tree or log. The young hatch into an immobile dupoid in three weeks or more. The dupoid then molts into a pale-coloured instar stage. Each subsequent instar molt produces another segment which is slightly darker until it reaches maturity and is fully black with its yellow patches on the side. Adults live for 2 to 3 years.
Special Notes: Harpaphe haydeniana is native to the Pacific Northwest from southeast Alaska to California and west as far as the Sierra Nevada Mountains. The adult millipedes play an important part in maintaining the health of the forest ecosystem by breaking down the leaf litter and releasing nutrients for other organisms through their digestive system. The immature millipedes feed on humus.
This millipede has few predators due to its ability to exude hydrogen cyanide through its exoskeleton. This secretion is relatively harmless to humans, although it may cause some skin irritation so be forewarned. If possible, wash affected area immediately with soap and water. A more extreme reaction will occur if any secretion should get into the eyes. Seek medical aid if this occurs. Small-sized pets…cats and dogs…may exhibit stronger reactions to the hydrogen cyanide if it should get into their eyes. Rinse with water immediately, if possible, and seek veterinary aid.
Remedial Actions: This insect is highly beneficial to the health of the forest ecosystem so no remedial action is needed. In fact, they should be respected and left to do the work they are meant to do. Unfortunately, in just one week, we have seen two Harpaphe haydeniana which had been stepped on and killed in our local forest.
Posted on July 15, 2020
|Whitefly Family: Aleyrodidae
Host plant(s): multiple species
Adult size: varies by species, but generally –
Description & Life Cycle: Whiteflies are not true flies. They are more closely related to aphids, mealybugs and scale. This puts them in the order of Hemiptera rather than in the order Diptera with the true flies. The name “whitefly” comes from the white wax covering on the wings and body of the adults.
Females lay 200 to 400 eggs in groups of 30 to 40. Eggs hatch in about a week into flattened nymphs with tiny legs. These crawlers, as they are called, will wander around the plant before settling in one spot and inserting their mouth part into the plant to start feeding on its sap. This crawler stays in one place through the next three instar stages…growing larger and losing its tiny legs as it grows larger. At the end of the 4th instar stage, the nymph enters the pupa stage, although technically it does not go through a true complete metamorphosis. Adults emerge to mate and live about a month.
Some adult whitefly species have distinctive markings on their wings but many have no markings. In the nymph stage, colour can be black with a white fringe, transparent yellow or white depending on species.
Whiteflies typically overwinter on plant debris and in branch crevices…although I could not find any mention in which life cycle stage this occurs.
Special Notes: There are over 1500 species of whitefly, most of which will feed on only one or a few species of plants. All whitefly species are sap-sucking feeders and a few are responsible for transporting viruses from plant to plant. They are difficult to identify in their specific species designation but are easily recognizable by the cloud of white which will erupt when an infested plant is disturbed. Another indication of a whitefly problem is sticky patches on the upper side of leaves caused by the honeydew excretions from whiteflies feeding in the undersides of leaves higher up on the plant. Another clue can be black sooty mold on the upper side of leaves which develops on the honeydew. While this looks unsightly, it rarely does any serious harm to the plant.
Remedial Actions: Whiteflies have many natural enemies in the garden including ladybugs, lacewings, spiders and predator bees as long as you do not use chemical sprays. These sprays are also harmful to beneficial insects.
Another solution is to use yellow sticky traps…although these will catch beneficial insects as well as the pests.
Best remedy of all is to provide appropriate water and nutrients to your plants to guard against pest infestation. Healthy plants are much, much better at thwarting pests from attacking them than those plants which are struggling because they are underfed or underwatered.
Posted on February 26, 2020
|Stephanitis takeyai Family: Tingidae
Common name: pieris lacebug; andromeda lacebug
Adult size:0.08 – 0.2 inch (2.0 – 5.0 mm)
Now found in areas of the Comox Valley but not in our garden, as yet
Life cycle: possibly as many as five generations per year, depending on region
Description & life cycle details: Eggs…inserted into, or alongside, the mid-rib on the underside of the leaves and covered by a dark-coloured, varnish-like secretion…overwinter on the underside of pieris leaves. Hatching begins sometime in late April or early May, depending on temperature in your region. Egg hatching can extend over a period of roughly one month.
Emerging nymphs are relatively clear in colour…beginning to darken within a few days. Initially, the young nymphs will remain clustered together but start spreading out into new feeding territories after the second or third moult. They go through 5 instars, or growth stages…the whole growing and moulting process taking roughly about one month. By the time the nymphs reach the 4th instar, they have darkened to brown-black in colour and have grown spines on their bodies. At 5th instar, nymphs are half the size of an adult lace bug.
Adults are up to 0.2 of an inch (5.0 mm) long. Bodies are slightly flattened and black in colour. Clear wings, conspicuous because of the black, lace-like veining and prominent black X-shaped marking, lay flat along the body. Females lay five to seven eggs per day…as many as 300 in their lifespan. There are multiple generations per year, depending on the temperatures and length of the growing season in your region. (Research conducted by the entomolgy department at Pennsylvania State University revealed two to three generations of Stephanitis takeyai occur in that state. The University of Connecticut claims four to five generations are produced every year in their state. No reference found for number of generations in BC.)
Special Notes: Native to Japan, this pest was accidentally introduced into the United States around 1945…according to the University of Connecticut. And yet, reports from England claim the pieris lace bug was not discovered in that country until 1998 when it was spotted in a garden near Windsor. In truth, it is definitely on the move.
Both nymphs and adult lace bugs feed on the underside of Pieris spp. leaves…piercing the epidermis layer and sucking up the plant sap. Early clues this pest may be present are the yellowing and mottled appearance on the upper side of the leaves. This mottling and discolouration impacts on the photosynthesis process…reducing overall plant vigour and causing premature leaf drop.
Of special note, the Entymological Society of Washington reported their discovery of two new host plants for Stephanitis takeyai. This pest was found on Lindera benzoin (spicebush) and Sassafras albidum (sassafras) in parts of D.C. in 1977.
Remedial Action: During winter months, check underside of pieris leaves for a line of varnish-like substance along the midrib. This is an indication there are hibernating eggs. Treat with horticultural oil at this stage. Keep an eye on shrubs in late April through into May for any signs of hatching light-coloured nymphs. If spotted, and while they are still in a cluster, spray leaves with either horticultural oil or an insecticidal soap. Best results are treating the nymphs while their body is still soft. It will begin to harden by the third moult or so. Repeat spraying in ten to fourteen days to catch newly hatching nymphs…and continue to monitor the shrub for any further pest activity.
Posted on January 31, 2015; updated on November 26, 2018