What We Do to Prevent Pests

Ultimately, in the horticultural industry, you’re going to face bugs in your greenhouse. But, there are practices you can put in place to prevent pests and to be much better prepared to handle bugs when they do come. 

Five Main Categories of How We Prevent Bugs

• Scouting 
• Cleaning/Sanitizing
• Predator Bugs
• Fogging
• Strategic Spraying

Scouting

Scouting is the most important step you can take to prevent bugs from entering your greenhouse and causing havoc. Scouting is the act of searching for and identifying pests on crops.

Create a plan to scout your crops thoroughly to determine if you have any pests on your plants. If you do have pests, identify them, and then you can take steps to control them.

Utilize a hand lens or microscope in your scouting program to better see pests on plants, especially microscopic pests such as mites. Make meticulous records of any pests you find, where you found them, on what plants, what the date is, etc. By keeping these records, you can determine whether or not your methods to reduce pests have been successful or if you need to make any improvements.

Lastly, the more scouting you do, the more you will pick up on signs that pests may be present. For example, if you see spotting on leaves (i.e., tiny little dots grouped together), it may be a sign of mite damage. 

Cleaning/Sanitizing

Cleaning and sanitizing your greenhouse is incredibly important. Pests thrive in messy environments where they can hide and go unnoticed for long periods of time. Keep your greenhouse clean by consistently throwing out any trash, putting things away in an organized manner, sweeping floors, or spraying with a water hose often to remove any soil on the ground where pests like fungus gnats love to make their home. 

Sanitizing is another crucial step in this process. Sanitize your plastics, especially if you are reusing them, to ensure that no pests are harboring in crevices or underneath trays. Sanitize your tables and floors as well. The same concept applies here. Pests love to hide in areas that aren’t often reached with a spray, so wash your tables in between use. 

All of this may sound like extra work, but the additional steps go a long way in preventing bugs. 

Predator Bugs

Predator bugs are a great method to keep pest populations low. Use a large variety of predator bugs in your IPM program because different predators eat or parasitize different pests. Read up on the best mix of predators to use in your specific environment, but here are a few examples of predators we have used: 

• Predators for Mites
  • Amblyseius swirskii
  • Phytoseiulus persimilis
• Predators for Mealybugs
  • Green lacewings
  • Ladybugs
  • Cryptolaemus montrouzieri
• Predators for Aphids
  • Aphidius colemani
  • Aphidius ervi
• Predators for Whiteflies
• • Encarsia formosa
  • Eretmocerus eremicus

Fogging

Fogging is another good method to add to your IPM program to help prevent pests. A fogger is a piece of equipment that turns a specific volume of liquid into a mist or fog via a high rate of pressure.

There are handheld foggers and stationary ones. We use a stationary fogger. The biggest pro of foggers is that they can fill the entire space of your greenhouse, so the fog should hit all the hard-to-reach places in your greenhouse that a spray hose can’t reach, assuming it is completely sealed.

The downsides are that if you only need to spray one or two species of plants, then it doesn’t make sense to fog an entire greenhouse. And not all pesticides can be used as a fog, so read up on your pesticide labels to ensure they are usable for fogging. 

Strategic Spraying to Prevent Pests

Spraying pesticides should be your last resort. That does not mean never to spray. Having to spray your crops from time to time is as inevitable as pests being in your crops. But, if you strategically utilize spraying, it will go a long way toward suppressing pests.

So, how do I know when to spray and when not to? You should spray when you have done all the other preventative measures above, and you still have pests in your plants.

Be sure to scout well so you know exactly what pests you’re dealing with, and then you can choose the best pesticide for your needs.

Don’t forget many pests develop resistances against pesticides, so make sure you’re rotating the pesticides you use in your IPM program. 

A Few Final Notes

Pests on your crops are inevitable, but putting these methods into place will truly help with prevention and suppression.

If you do use predator bugs, don’t forget that most pesticides that you fog or spray will harm or kill the predators and the pests. So think carefully about your timing and approach.

Lastly, scouting will be your best friend when it comes to preventing pests. Use a hand lens or microscope in your scouting routine!