Friday, 24 May 2013

Pest management for home gardens

The May 2013 meeting of the Garden Club of PEI welcomed Stephanie Compton, who spoke about pest management in home gardens.


Stephanie lives in Savage Harbour.  She has worked at golf courses, at Vesey's Seeds, and with the provincial Department of Agriculture.  She is starting a small business which offers horticultural services, and her family has taken over the management of Island Gold Honey.
For more about Stephanie, click this link:
http://acornorganic.wordpress.com/2013/05/07/meet-acorns-fruit-and-berry-network-coordinator

She says dealing with pests is about management, not control, because we will never rid ourselves of all pests.  The most important tool is using organic mulch.  Mulch will control up to 78% of weeds.
Organic mulch can be composted bark mulch, straw, eel grass sea weed, all of which have no weed seeds.  Using wood chips or sawdust as mulch has one drawback:  as it decomposes, it uses up nitrogen that is needed by the growing plants.  Newspaper and cardboard also makes effective mulch.  Compost is a very good mulch that adds nutrients to the soil.
Inorganic mulch includes plastic, landscape fabric, and biodegradable film.  Organic mulches are preferable to inorganic mulch.
Image of Weed-Wand
The weed want sold by Vesey's Seeds is powered by a propane cannister.  It is a good organic way to control weeds on walkways.  Use caution, howver - you could start a fire.


Chemical weed control:  Iron is toxic in high doses. Iron is the active ingredient in products such as Weed b Gone.  It can be used as spot control for perennial weeds, but it will leave dead spots in your lawn.
Corn Gluten Meal, when spread on lawns or gardens, inhibits all seeds from germinating.  It does not affect plants that have already sprouted.  Do not spread corn gluten meal on a garden before your vegetable seeds have sprouted.  Buy it at Agri Co-op.  It is much cheaper than at a garden supply store.
Vinegar (ascetic acid) burns weeds.  It is effective on walkways.  It lowers the pH of the soil, and so it is necessary to apply lime to restore a balanced pH.  Use a spray bottle to apply it.

Disease control
Prevention is key.  Plant disease-resistant cultivars.  For example, Knock-Out roses are much more resistant to fungus diseases than regular hybrid varieties.
Boron will kill moss growing on lawns.  Spot spray a product called Solubor at the recommended application rate.
Clean garden practices will prevent many disease problems.  
Don't plant the same types of plants in the same spot year after year.
If you make your own compost, it must heat up to 60 degrees C in order to kill weed seeds and pathogens.
Dispose of infected material properly.  Do not put it in your own compost heap.  Double bag it and take it to the Energy for Waste facility.  Do not dump it in rural areas.  For example, tar spot on infected maple leaves will spread to new areas when leaves are dumped.
Late blight on tomatoes or potatoes:  double bag infected plants and leave in the sun to break down.
Black knot is a disease affecting wild cherry and choke cherries.  This is a disease that is hard to control.  Continuous pruning is the only method of control.  The affected branches should be pruned six inches from the affected area.  Burn the material or double bag it and take it to the Energy from Waste plant.

Chemical disease control
Image of Safer's Garden Sulphur Dust
Sulphur dust forms a barrier that prevents fungus spores from attaching to the plant.  Repeat application after a heavy rain.  Baking soda dissolved in water can be effective.  Apply every 7-10 days or after a rain.
Copper mixes have been used in the past.  They are not used as much anymore.  Use caution.  Copper is toxic to fish and plants.
Bordo or Bordeaux is copper sulphate and hydrated lime.  It causes a drying action that dessicates plants.  It  forms a protective film which is drying and toxic.  It is best to apply it using a hand pump sprayer.
Compost tea fights diseases when used as a spray on plant leaves.  To make it, put some active compost in a burlap sack and soak in water 4-5 days.

Pest insect management
Monitor plants and check for problems often.  Insects can be monitored using sticky traps, lures, bait, pitfall traps, a sweep net, and by observation.  If you catch an insect and you want to know what it is, take it to Agriculture Canada research station on University Avenue, and an entomologist will identify it for you.
A home-made insect trap:  cut a plastic pop bottle in half.  Pour wine, vinegar, or sugar water in the bottom.  Squeeze in a teaspoon of dish soap.  Insert the spout end into the bottom end.
Or take a pop can, fill it half-way with diatomaceous earth, and lay it on its side in the garden.  It will attract earwigs, which will have their outer skins cut by the sharp diatomaceous earth.  Buy this at Agro Co-op in a 45-pound bag, which is much cheaper than buying it in small amounts at a specialty store.
Lures
A plastic dish half-filled with beer will attract and drown slugs.
to attract fruit flies, put balsamic or white vinegar in a dish, cover with plastic wrap, and poke a few holes in the top.
a mixture of sugar water and yeast will attract mosquitoes.
Red bait will attract apple maggot fly.
Meat will attract wasps and flies.
Diatomaceous earth will kill all crawling insects that walk through it.  Put a 4-inch wide circle of diatomaceous earth around each hosta plant to protect it from slugs.  Coffee grounds may work.
A circle of copper pennies around plants will deter slugs. They get a shock from the copper.
A mosquito magnet or a UV light trap or a bug zapper may attract more bugs to the area than you already have.

Mating disruption
This is not commonly used by home gardeners.  To fight coddling moth in apples, growers put twist ties impregnated with mating hormones.  this confuses the moths, and they won't be able to find each other to be able to breed.

Physical barriers
  • Image of Diatomaceous Earth 
  • Diotomaceous earth (right) 
  • copper or tin foil, coffee grounds, lime sulphur, nets and screens, are very expensive to use in large amounts.  It is not viable for low-value crops, and very labour intensive to apply and maintain.  
Natural insect repellant:  lemons, garlic, cinnamon, lemon balm - cinnamon and lemon rind keeps cats out of children's sand boxes.  Plants evolved to have strong smells as a way to protect themselves from pests.  e.g. scented geranium.  

Poisons

Image of BTK Biological Insecticide
Bacillus thuringingus (Bt)- will kill caterpillars, mosquitoes, colorado potato beetle.  Need to apply the correct variety of Bt for the insect targeted.  Check the label.  

Pyrethrum or pyrethrin are neurotoxins which attack the nervous system of all insects.  They are not toxic to humans or dogs.  They break down when exposed to sunshine.  They can be toxic to fish, cats, and beneficial insects.  

Insecticidal soap must hit the insect directly and has no residual effect.  It dissolves the waxy cuticle of the insect's exoskeleton, dehydrating it.  The soap breaks the surface tension of water, clots the breathing tubes of the insect adults, larvae, and eggs.  Be sure to spray the undersides of leaves, where eggs are laid.  

Beneficial organisms
Ladybug larvae
Ground beetle
Beneficial organisms include earthworms, ladybugs (adults eat aphids), bees, spiders, butterflies, bats, hummingbirds, ground beetles, dragonflies, lacewings, assasin beetle.
Bees and butterflies are natural pollinators.  The other species are predators.
Ladybugs can be a problem for grape growers.  They land on the ripe grapes when being picked, and give  the resulting wine a bitter taste.

To encourage the growth of beneficial soil organisms, aim for soil pH of 6.5.  Add organic matter and compost and mulch to help good bugs thrive.


Mycorrhizae (soil fungus) has a symbiotic relationship with roots.  It attaches itself to roots, gets some sugar from the roots, and in return brings nutrients to the plants.

cranefly adult
Cranefly larvae eat grass roots, and overwinter on slopes.  They kill lawns in spring.  Solution:  resod the area or plant with white clover, which is not affected by crane fly.  Mix white clover into lawn seed.
cranefly larvae
Lawn seed usually has three kinds of seeds:  perennial ryegrass, fescue, and kentucky bluegrass.  White clover is more drounght tolerant than grass, attracts beneficial bees, and adds valuable nitrogen to the soil.
white clover

1 comment:

  1. anyone know where one can buy diatomacious earth in PEI in large quantities?....none at HH HD agri coop,

    ReplyDelete