Pest and Pest Control Topic #6

What is a Pest? From the point of view of a farmer or forester, a pest is any organism that causes plants to die or produce less From the point of view of a farmer or forester, a pest is any organism that causes plants to die or produce less Obviously, some of these organisms wouldn’t see themselves as pests – ex. Ants are part of the natural system and just want to eat wood – not necessarily bother foresters and trees! Obviously, some of these organisms wouldn’t see themselves as pests – ex. Ants are part of the natural system and just want to eat wood – not necessarily bother foresters and trees!

Pest Problem Pests that cause most damage are: Pests that cause most damage are: Insects – usually eat some part of the plant Insects – usually eat some part of the plant Fungi & Bacteria – can cause infections, destroying part or all of the plant Fungi & Bacteria – can cause infections, destroying part or all of the plant Weeds – are thieves and steal moisture, nutrients, space or light from the plant Weeds – are thieves and steal moisture, nutrients, space or light from the plant

Dandelion – Super Pest Why are dandelions so successful? Why are dandelions so successful? Powerful roots – long taproot that anchors it well Powerful roots – long taproot that anchors it well Broad leaves – shade out other plants Broad leaves – shade out other plants Super seeds – can produce flowers and seeds all summer long – and hundreds of spreading seeds Super seeds – can produce flowers and seeds all summer long – and hundreds of spreading seeds Adaptable – grow well in all kinds of soil Adaptable – grow well in all kinds of soil Chemical weapons – release chemical agents to slow down the growth of grass and other plants Chemical weapons – release chemical agents to slow down the growth of grass and other plants

Canola and its Pests Here are some of Canola’s worst pests: Here are some of Canola’s worst pests: Canada Thistle – steals nutrients and water Canada Thistle – steals nutrients and water Wild Oats – same as above Wild Oats – same as above Blackleg Fungus – infecting seed pods and cutting the flow of water through roots Blackleg Fungus – infecting seed pods and cutting the flow of water through roots Sclerotina – infecting leaves and causing damage Sclerotina – infecting leaves and causing damage Fusarium Fingus – attacks stems Fusarium Fingus – attacks stems Bertha Army Worm – eating everything in sight! Bertha Army Worm – eating everything in sight! Lygus Bugs – sucking the juice out of buds, flowers, seeds Lygus Bugs – sucking the juice out of buds, flowers, seeds

Introduced Species Many of the worst weeds and insect pests are organisms that were introduced from other countries Many of the worst weeds and insect pests are organisms that were introduced from other countries Many of the weeds that cause crop loss were accidentally introduced from Europe: ex. Quack grass, thistles, chickweed Many of the weeds that cause crop loss were accidentally introduced from Europe: ex. Quack grass, thistles, chickweed Dandelions were brought from Europe on purpose as a salad vegetable, but the natural controls for dandelions did not come with them! Dandelions were brought from Europe on purpose as a salad vegetable, but the natural controls for dandelions did not come with them!

Controlling Pests There have been many methods used to control pests There have been many methods used to control pests Large pests can be chased or scared away Large pests can be chased or scared away Smaller pests can be picked off plants by hand Smaller pests can be picked off plants by hand Farmers used to rotate crops each year to control weeds and diseases Farmers used to rotate crops each year to control weeds and diseases Regular summer fallow also helped control weeds and crop diseases but led to soil erosion Regular summer fallow also helped control weeds and crop diseases but led to soil erosion

Chemical Controls When first introduced, chemical controls were effective and relatively inexpensive When first introduced, chemical controls were effective and relatively inexpensive Herbicides, insecticides and fungicides controlled weeds, insects and fungus Herbicides, insecticides and fungicides controlled weeds, insects and fungus The chemicals were simple to use, gave impressive results and WERE considered to be safe The chemicals were simple to use, gave impressive results and WERE considered to be safe It took many decades for humans to figure out they weren’t as great as first thought It took many decades for humans to figure out they weren’t as great as first thought

Problems with Chemicals Pollutants such as chemicals in pesticides can accumulate through the food chain – bioaccumulation Pollutants such as chemicals in pesticides can accumulate through the food chain – bioaccumulation Some chemicals wash off the plant and leave residues in the soil and water – they can remain in the environment and remain poisonous Some chemicals wash off the plant and leave residues in the soil and water – they can remain in the environment and remain poisonous Chemicals can also harm organisms that are not the target of the chemicals and can actually worsen the pest problem Chemicals can also harm organisms that are not the target of the chemicals and can actually worsen the pest problem With increased chemical use, some species have become resistant so new and more dangerous chemicals must be used With increased chemical use, some species have become resistant so new and more dangerous chemicals must be used

Organic Food Organic food is food that has been grown without the use of chemical fertilizers and chemical pesticides Organic food is food that has been grown without the use of chemical fertilizers and chemical pesticides Organic food growers use manure and compost to add nutrients to the soil Organic food growers use manure and compost to add nutrients to the soil They fight weeds and other pests using a combination of methods such as tilling, crop rotation, mulching, companion planting and removing insects by hand or biological control They fight weeds and other pests using a combination of methods such as tilling, crop rotation, mulching, companion planting and removing insects by hand or biological control