The arrival of warm weather means more insects will be out, some of whom will turn out to be garden pests. Homemade traps can be used to identify pests and monitor their activities, and sometimes traps are so effective that they provide a respectable level of control. Here are four homemade traps for garden pests to help you monitor insect life in your garden and warn you when pests are active.
Pit Traps for Slugs and Earwigs
Leaf-eating slugs like to go out at night for a bit of beer, the most popular bait for slug traps. Shallow containers filled with an inch of beer are placed among lettuce, strawberries, or other plants with slug issues, and the slugs come for a drink and then fall in and drown. You also can use sugar water with a light sprinkling of yeast instead of beer, or a thin slurry of flour, yeast and sugar. Slugs are attracted by the fermentation gases, preferring the traps over your plants.
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Earwigs are easy to trap in oil pit traps set out at night
The bane of container gardeners, earwigs hide under pots during the day and come out at night to chew ragged holes in plants. Shallow containers baited with vegetable oil and a spritz of soy sauce are remarkably effective earwig traps when placed among container plants at night.
Sticky Traps for Tiny Insects
Small insects including aphids, flies, flea beetles, and whiteflies can be caught with sticky traps, which can be made from cards, cups or other objects coated with a sticky substance. Tangle Trap is great because it’s weatherproof, but you will snare plenty of little victims with petroleum jelly or any thick syrup as a sticky coating for your homemade traps.
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A yellow sticky trap used to monitor onion root maggot flies
It is important to think strategically. In my garden, I have a problem with onion root maggots, the larvae of a fast-moving little fly that’s active in late spring. Yellow sticky traps placed among my garlic let me know if it’s looking like a good year or a bad one. If I catch more than a few flies in early May, the plants get covered with horticultural fleece.
A wide variety of insects are attracted to the colour yellow, including flies and flea beetles, but some aphids prefer spring green, and thrips are drawn to the colour blue. You can paint homemade sticky traps the colour you want before applying a sticky coating. Also install any hanging hooks or hardware in your trap before you get out the sticky stuff.
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Most insects are attracted to yellow, but sticky traps for thrips should be blue
Yellow Pan Traps for Aphids
If you have ever left a yellow bucket filled with water sitting in your garden, you have probably seen a yellow pan trap in action. Insects are attracted by the colour yellow, but end up stuck in the water. Adding a few drops of liquid soap to the water in a pan trap helps insects drown faster by hampering their ability to swim.
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This homemade trap for cucumber beetles (a pest in North American gardens) has a grid to exclude bees
Very shallow containers such as yellow frisbees are fine for catching aphids and other small insects, but deeper vessels that hold more than two inches of water are better for nabbing larger creatures. One of the problems with open pan traps is that they may also capture bees and other beneficial insects. To prevent these types of unwanted casualties, you can make jug or bottle traps with entry holes tailored to the size of the pest insect you want to trap.
What if you put out a trap and catch nothing? This is good! Wait a week or two and monitor again, and continue to watch your plants for signs of serious trouble. Some trapping here, some hand picking there, and you may just have an easy season.
