will using pesticides help?

The very first step in dealing with a sick plant is to find out why the plant is sick. Many plant problems are the result of how they are tended or because of growing conditions. Spraying pesticides will not help some sick plants and may actually cause additional problems.

Pesticides are for specific pests on specific plants. Some plants are sensitive to some pesticides. If you apply a proper pesticide for a pest but the plant is sensitive to the chemical, you can severely damage the plant — this causes more damage than would have been caused by the pest itself.

Insecticides have no effect on fungi and fungicides don't kill insects. Know what the problem is and use the correct solution for the problem.

Beneficial "good" insects that eat or kill pests such as aphids, caterpillars or slugs (and therefore naturally keep these pests under control) are often more sensitive to pesticides than the pests themselves.

Different pests have different life cycles and different tolerances to insecticides. You have to apply a pesticide when the pest is in a vulnerable life stage and while it is still present at the spray site.

Pesticide treatments could be a waste of time and money and could be hazardous to the ecological balance in your yard if the proper amount and timing of the spray is not followed for a given pest. Follow the label carefully!

Some pesticides, especially fungicides, are only preventive. Plants won't heal the damage from mildew or other damage already present, but if the spray is timed properly it may prevent new infestations.

identifying pests

There are many resources to help you know what is making your plant sick. If you need to identify a pest, first obtain a specimen of the pest/problem.

You can also take the sample to a master gardener clinic, a local nursery or a commercial pest control business.

Alternatives to spraying

Knowing the plant and meeting its cultural needs helps prevent many plant problems. A healthy plant can survive attacks by insects and diseases frequently with no spraying or intervention on the part of the homeowner.

Consider that a certain amount of damage from insects or disease is normal and that there are natural forces working against the pest. The plant can usually sustain a fair amount of damage before its health is adversely affected. A small amount of damage may be more of an aesthetic issue than one of the health of the plant. If damage is slight, the affected leaves could be hand picked or just left alone. Being able to tolerate a few holes in leaves or other small amounts of damage could be looked upon as your contribution to the natural balance in your yard.

Look for less toxic ways of controlling infestations, including:

• Hand-picking or pruning out infested leaves or branches

• Trapping pests

• Spraying insects off with the water from a hose

• Changing watering or fertilizing practices to discourage pests, and

• Select pest-resistant varieties of plants when adding to your garden.

Your responsibilities when using pesticides

You are liable for any damage your spray causes to neighbouring property. This can be caused by wind drift or when pesticides are carried off your property by water runoff. You are also negligent if you do not use the pesticide labeled for a specific pest on a specific plant at the specified rate of application listed on the label.

Any use not specified on the label is a violation of federal and provincial laws.

Make sure that the pesticide label specifies the plant you are spraying (such as rhododendron) And site (leaves, soil, garbage can). Do not let the spray come into contact with food crops (fruits, vegetables, herbs, berries, etc.) unless it is labeled for those crops and the instructions are followed regarding when the crops can be safely harvested.

Do not let the spray drift onto neighbouring properties unless you have consulted with the owners in advance. Toys, barbecues, picnic tables, etc. Should be moved indoors or covered. Make sure children and pets are safely inside and follow label instructions carefully concerning when they can safely be allowed back into the sprayed area.

Don't spray on windy days or allow insecticides to drift onto blooming plants or weeds where bees might encounter it. Bees can carry the toxins back to the hive and kill off the entire hive.

Slug bait can be attractive to dogs and can make pets sick if eaten directly or accidentally (as when preening themselves after having rolled in the bait in the garden). Slug bait is also toxic to birds and other wildlife. Birds feeding on treated areas may be killed. when purchasing slug and snail bait select those containing iron (or ferric) phosphate. This is a naturally occurring mineral and is much less toxic to pets and wildlife than baits containing metaldehyde. It is best to put the slug bait under a board or in a trap. A simple trap can be made by cutting windows in the side of an empty margarine or cottage cheese carton. Put the bait (beer works well) in the bottom of the carton and snap on the lid. Place the trap where slugs have been a problem. The bait will stay dry and effective for a long time but will be safely away from children and pets.

Don't over-apply pesticides. Many of the pesticides are easily carried by runoff water into ground water, streams, ponds, lakes, wetlands, and coastal areas where birds, fish and other wildlife can be killed.

Don't dispose of unused chemicals in sewers or dump them down the drain. Sewage treatment does not filter out pesticides and the chemicals eventually make it into the ocean. Take unused, old or unwanted chemicals to a hazardous household waste pickup point for disposal. The consumer product stewardship program operates several collection depots across bc. There is no charge when dropping off leftover products at these depots. For the depot nearest you call:

1-800-505-0139

Before you spray

• Do you know what insect / disease you are spraying for?

• Are both the plant or situation and the pest/disease you are spraying for listed on the label of the pesticide you have chosen?

• Is the level of damage great enough to warrant treatment or pesticide application or will the problem take care of itself naturally?

• Is the pest present and in a stage that will be killed by the pesticide at the time you are planning to spray?

Prepared by dr. Grant a. Bracher, p.ag.

Acknowledgements

This fact sheet is largely reproduced verbatim from:

Haldeman, ann. 1990. Before you spray read this. Community horticulture fact sheet #95 pesticide cautions, washington state university, cooperative extension — king county. Cooperating agencies: washington state university, us department of agriculture and king county.

we greatly thank washington state university cooperative extension — king county for their permission to use this material.