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Everyone should know that using cosmetic pesticides is banned in all three North Shore municipalities.
Using these pesticides, besides being in contravention of the law, could put you and your family’s health at risk. It seems a no-brainer to avoid unnecessary products like these which increase our risk of developing illness.
Right now one of my favourite native flowers, Camassia quamash, is in bloom – I will leave it to you to research and enjoy it on your own. The City of North Vancouver is using it in some traffic calming bump-outs, so it’s easy to spot around town with its tall blue spiky flowers.
But the more urgent topic on my mind isn’t related to native flowers I admire; right now I’m focused on pests that can do damage to plants. Take, for example, cottony camellia scale, or Pulvinaria floccifera and black sooty mould (a collective term for several different fungi), which are a team of pests that work together to target your camellias and hollies. I have even seen cottony scale on magnolias.
You might first notice a black substance on your camellia leaves, but the source of the problem is under the leaves.
Pulvinaria floccifera are living underneath and are just now emerging from their cottony sacs to start their damaging life cycle. The cottony sac contains thousands of eggs ready to hatch. Early spring is a good time to start control measures. Various articles outline oils and soaps to treat the pest, but I have found results from spraying the leaves with a sharp spray of water (flat setting on the nozzle) and washing off the pests just as effective as applying substances, and somehow more rewarding to see the shrub immediately free of the black coating and many, hopefully most, of the pests.
From these scales emerge the nymphs, and these little critters are mobile. Another spraying, about two to three weeks after the first, will tackle the mobile nymphs, and by the time they have been washed to the ground they will not be in any shape to return to the plant. Spray again in a couple more weeks, and the shrubs should be in pretty good shape for the summer. A fall spraying might be a good idea to catch any females ready to overwinter on the leaves.
So where does the sooty mould come in? The nymphs of Pulvinaria floccifera are sap suckers, and black sooty mould is a fungus that feeds off the honeydew. Sooty moulds do not attack the plant directly but reduce plant vigor by preventing photosynthesis – and they look unsightly. Not a good situation for a plant already stressed by parasites sucking on their leaves. Washing camellias is a good activity for both hot sunny days and cold rainy days wearing full rain gear. It’s truly an all-weather task!
Heather Schamehorn is a certified residential landscape designer, educator, sustainability advocate and acupressure therapist. Contact via perennialpleasures.ca.