Pests/Diseases Archives | Russell Nursery

Do You Need to Worry about Winter Moth?

Oct 10|in Pests/Diseases /by Kathryn Verlinden

By Faye

Winter moth (Operophtera brumata) originated in Europe and came to BC in the 1970s. The larvae, smooth green ‘inchworms’ about ¾” long, hatch in spring and can cause serious damage to emerging leaves if not controlled; after three years of infestation, the tree can become so weakened that dieback and possible mortality can occur.

Their favourite hosts include oak, apple, crabapple, ash, birch, maple, and other broadleaf trees. Damage from the winter moth has been extensive this year, with blueberries and roses also falling prey to their voracious appetites.

The following excerpt from Linda Gilkeson’s website explains the most effective means of control, and the time is right now to get this done.

Tree Bands: If winter moth caterpillars ate holes in your tree leaves early last spring (apples and other fruit, oaks, other deciduous trees), then mid-October is good timing to put up sticky tree bands to intercept the females before they lay eggs. The female moths can’t fly so when they emerge from their cocoons at the base of trees they have to walk up the trunk to lay eggs out on the branches. Spread insect glues – ‘Tanglefoot’, ‘Tangletrap’ (‘Tree Guard Tape’ is a ready to use – double-sided sticky tape) available at garden centres on a foot-wide band around tree trunks. The band can be anything that is easy to wrap around the trunk: plastic food wrap, waterproof package tape, or other waterproof material that can be spread with glue. If the tree has deep crevices in the bark, wrap a layer of cotton batting around the tree first, pushing it into the cracks to block moths from crawling under the sticky band. Don’t put the glue directly on bark—it will damage young bark and will also keep on catching insects—mainly beneficial ones–during the growing season (and also kid’s hair, dog’s tails, shirt sleeves, etc.). The moths lay eggs from late October to January so you can remove the tree bands in February.

There is a more extensive section on Winter Moth in Linda’s book Natural Insect, Weed and Disease Control. She mentions removing and replacing the bands when they become full of trapped moths, and making sure that each trunk of a multi-trunked tree is banded. On a lighter note, she advises placing the bands high enough to avoid the aforementioned small children’s hair or dogs’ tails!
Some further options mentioned are:

*** Spray dormant oil between December and February, which smothers the eggs. This must be done before buds begin to swell.

***Spray BTK (Bacillus thuringiensis kurstaki) in the spring, when caterpillars are small and actively feeding, but make sure to get the spray into new buds and rolled leaves.

***More of a prevention than a cure, planting to attract beneficial insects, beetles, ants and birds which will eat the cocoons left on the ground. (planting chart p. 108 in the book)

As always, we thank Linda Gilkeson, PhD entomologist for her help and advice regarding these pesky varmints!

Start Now To Foil Next Season’s Pests

Nov 26|in Maintenance, Pests/Diseases, Winter /by Kathryn Verlinden

There is much we can do between now and spring to eliminate or lessen the damage from insects and disease.

We in southern BC are very fortunate to have food-growing expert, author and entymologist Linda Gilkeson, PhD in our midst. She has generously provided the information for this article.(www.lindgilkeson.ca)

TO DO NOW:

1. 1. Mulch, mulch, mulch! A clean and tidy garden does not provide habitat for the good guys. Leave the leaves in garden beds as a haven for ground beetles, rove beetles, and bumble bees. The largest mortality for winter moths is actually from ground beetles attacking the cocoons while they are still in the soil.
  2. Rabbit Damage
    
    Very important if you have rabbits around: protect the lower 2-3 feet of trunk on young trees with chicken wire or other tree guards. Bunnies can kill a whole orchard in a winter by ringing the bark.
  3. Put out safe slug bait containing iron. Slugs are very active in a warm wet winter.
  4. Rake up, remove and destroy all leaves from your roses if they had black spot this year. Do not compost. Rose hygiene is the best defense.
  5. Don’t allow potatoes to keep growing in the garden, that’s where late (tomato) blight can overwinter.
  6. Climbing cutworms are still active on leafy greens. Evening inspection, just after dark with a flashlight, will expose the critters. Pick off and destroy.
  7. People around Victoria should already have sticky tree bands up on their fruit trees and boulevard trees, especially Garry oak, birch, poplar, maple, willow and other broadleaf trees. If not done already, it is still worth doing asap.
  8. Pear Leaf Mite
    
    If you do it right now, you can still spray lime sulphur on your pear trees for pear leaf blister mite, which cannot be reached by dormant sprays in winter. Also useful for peach leaf curl.

*** Please note, only do the lime sulphur treatment if you had problems with these diseases last year. There is no benefit at all treating trees that have not been infected.

*** Stay tuned, we’ll write again in early February with an update on what to do while the trees are dormant.

Biological Warfare: Treatment for Root Weevils

Jan 17|in Pests/Diseases /by Kathryn Verlinden

vine weevil bite

vine-weevil-xbites Do you have any leaves that look like the ones in these pictures? This kind of damage is produced by adult root weevils. Root weevil larvae overwinter in the soil and can do serious damage to root systems. Rhodos, Camellias, Laurels, Bergenia, Heuchera, Primula and a host of other plants are all susceptible to weevil damage.

Stratiolaelaps: Treatment for Vine Weevils

Applied Bionomics is a local company that is a world leader in the development and production of biological pest controls and they have been testing Stratiolaelaps scimitus (formerly Hypoaspis miles) with impressive results. Stratiolaelaps are microscopic organisms that seek out and destroy root weevil larvae, thus disrupting the cycle so there are fewer adults feeding during the growing season. It takes a year or so for the results to show, but in test areas the weevils have all but disappeared, as evidenced by the healthy foliage on plants that were previously badly eaten. It also appears to be effective against cutworms and other grub producing species as well as flower thrips.

Stratiolaelaps can be applied at any time of year and needs to be used just once as it will establish in the garden once introduced. It comes mixed with sawdust and all you have to do is shake a tablespoon or so around plants that show signs of weevil damage. For a small garden or one with only a few affected plants there is a half litre bag and for a larger garden there is a 1 litre bag. Give us a call and we will order you some in for you, usually for pickup on Thursday or Friday.

Protecting Your Winter Vegetable Garden

Nov 18|in Edible Gardening, Maintenance, Pests/Diseases, Winter /by Kathryn Verlinden

Most of the vegetables suitable for the winter garden are perfectly hardy, but minor protective measures will ensure a greater harvest, better quality leaves, and cleaner produce. I’ve grown kale, leeks, chard and purple sprouting broccoli in a raised bed with no protection over the winter other than leaves covering the soil.

The soil needs more protection than the plants, ironically. If we have a mild, wet winter, constant rain will leech nutrients away, compact the soil, and enable weeds to take hold. If we have a cold winter with freezing and thawing, the soil needs an insulating buffer, because if it freezes, water can’t be absorbed by the plants, and the freeze/thaw cycle causes heaving of the soil with subsequent damage to the fine root hairs.

Kale mulched for winter

The best soil mulch is a 4-6” layer of autumn leaves, which insulates, protects and feeds the soil as it’s broken down first by worms, and later by microbes. The breaking down process takes place faster if the leaves are chopped up first, but even if left whole, they will work. In really cold weather, a further mulch of fluffy conifer branches or larger leaves may be used to cover the plants entirely. The shoulders of root veggies will benefit from a covering when the temperature plummets.

Covering with a plastic sheet is very effective in cold and rain; it raises the temperature while also protecting from drying winds. A covering such as this needn’t be attached to a frame, it can just be draped over the bed and held down with rocks. Some people make a support with pipe hoops, or a tunnel of wire mesh which keeps the plastic from weighing down the plants if rain or snow accumulates on top. On warmer days, you can leave the plastic sheet on to trap the warmth, or remove it for ventilation.

What about a greenhouse? This of course is the ultimate protection, and crops grown in an unheated greenhouse will have unblemished leaves, no slug damage, and the warmth of sunny days brings on spurts of growth unseen outside. Just remember to water occasionally, and in a very cold snap, a blanket or tarp will keep the plants warmer. On sunny days you may have to open the doors to moderate the wide swings of temperature from day to night, and to provide ventilation.

What about slugs? Slugs don’t go south for winter, but continue to share our harvests, unfortunately. Safers Slug bait is safe for pets and other animals, and is worth using sparingly all season long in a mild winter.

Climbing cutworms can do serious damage in the early spring; their presence looks like slug attacks, but there will be no slime trail. They come out at night to eat, so either go out with a flashlight, or check for the characteristic C-shaped, ugly-looking caterpillar curled up in the leaf litter. Their pupae look like mahogany bullets, something to eliminate whenever you see them.

So enjoy your winter garden, and with these few precautions your harvest will be bountiful and rich.

At the risk of sounding like a broken record, I will remind you all of Linda Gilkeson’s fine book Year Round Harvest: Winter Gardening on the Coast, available via her website.

Tending Your Winter Vegetables In October

Oct 18|in Edible Gardening, Maintenance, Pests/Diseases /by Kathryn Verlinden

Mid October has finally brought the first rains of the season, as we say goodbye to the lovely, long late summer. Has there ever been a fall as gorgeous as this one?

The extended fall has unfortunately enabled those evil white cabbage moths to produce yet another generation of their voracious offspring. Even today, I found several of the green hairless caterpillars munching on the leaves of my Lacinato Kale. Oddly enough, the Red Russian Kale seems unscathed.

Kale leaf with aphids

I was away for 10 days!

Aphids as well have had another chance in this warmth. Their veggie of choice appears to be the Purple Kale. If it’s not possible to blast them off with the hose, a good squishing does the job.

Kale leaf with aphids

Keep inspecting both sides of the young leaves; while insects aren’t generally a problem for winter gardening, the young plants in a warm fall will fall prey to these very hungry munchers if you aren’t vigilant.

At this time of year, there is no point adding compost or granular organic fertilizer, as the microorganisms that convert these organics into usable food for the plants are dormant. It’s a better idea to feed frequently with liquid organics, alternating weekly with fish and seaweed dilutions while the plants are still small.

The whole point is to get your winter vegetables off to a good strong start before the cold weather really sets in; ideally they should be almost full size by Halloween. Don’t worry if yours are smaller than this, they’ll just produce a little later in the spring

Any of the taller winter vegetables, such as Purple Sprouting Broccoli or Brussels Sprouts will benefit from staking; these are quite top heavy and subject to wind lash.

Gather up fall leaves and mulch the veggies well, covering the soil with about 4” of loosely piled organic matter. When the storms of November toss piles of seaweed onto the beach, I like to bring some of this nutrient-laden bounty home, and add to the leaf mulch on my vegetable beds.

By the way, next time you are at the nursery, stop by our working greenhouse by the driveway, and see the staff veggie garden all tucked in for the winter, and enjoy seeing it mature over the coming months. Swiss Chard, Kale, Spinach, Green Onions, Mache and Purple Sprouting Broccoli—what a feast!