Scouting for Insects: Save Money, Time and Your Sanity in the Greenhouse and Garden

Let’s face it, greenhouses provide the perfect environment for breeding pest insects.  But unfortunately, by the time we see pest related damage on plants, the infestation may be well on the way to careening out of control. 

One way to save money, time and ultimately your sanity in the greenhouse – or garden is to use simple and affordable sticky traps to trap and monitor for pest insects. 

Using sticky traps will help you grow better in several ways.  Use them to:

• Identify specific insect and mite problems - before plant damage occurs.
• Locate where the problems are occurring.
• Observe changes in the severity of infestation - this information will help you make the decision of whether to intervene or not.
• When interventions are necessary, having the pest identity will help you treat exactly the problem you have. Ultimately this will save you money and time spent on unnecessary purchases.
• Use the trapped insects to identify the phase of the pests life cycle that you are confronting.

How do sticky traps work?

Sticky traps can either use a pheromone attractant, a smell attractant or a color attractant.  The color attractants attract an assortment of pest insects while the pheromone and smell attractants attract specific insects.  Today, we’re looking at the sticky traps that use color as an attractant and they are excellent for trapping:

• Aphids
• Fungus gnats
• Leafminer flies
• Shore flies
• Thrips
• Whiteflies
• Plus many others

The color of the sticky trap attracts pest insects, once the insects land on the trap they struggle and become trapped by the sticky adhesive.   Use a loupe or hand lens at least 5X magnification to take a close look at what gets trapped.  Any magnification above 5x should allow you to identify the pest(s) on the trap.  I use a 30X loupe and I can see excellent detail of the microscopic world.  One of the great side benefits trapping the pest on the sticky board – when you don’t recognize what is on the trap, place the trap in a plastic bag and take it to your local county extension office or to a fellow grower for help with identification.

For traps to provide you with the most complete information, divide the greenhouse into logical units.  Set traps throughout and around the perimeter.  Make sure to place traps near openings and ventilation systems – these are likely spots for pests to enter the greenhouse.  Setting some traps just outside any openings will help with very early detection.

We recommend using 3 to 4 of the 3”x5” traps for every 1,000 square feet.  Place some near doors, vents and in plant species and varieties that are highly susceptible to pest insects.

Monitor the traps daily and keep a record of what you find.  You can use this data to identify the pest, determine the level of infestation, progress of the life cycle.  All of this data is helpful to determining when and if you need to intervene.  Change out the traps when the sticky substance is covered with insects, dust, or grime.

On a personal note, the traps are sticky to us as well.  If you get any of the sticky substance on your hands, simply remove it using either a waterless hand cleaner or a little vegetable oil.