5 Things Growers Should Consider Before Using Beneficials
December 20, 2024 Biological control is becoming an increasingly popular way to manage pests in controlled environment agriculture (CEA) across North America. If you’re a grower who wants to make the switch from pesticides to beneficial insects (beneficials), here are five things you should consider.
1. What You’re Growing
Rose Labbe
The type of beneficial you need depends on the crop you’re growing. In CEA, there are five key pest types you might encounter: aphids, spider mites, thrips, whiteflies, and fungus gnats. To find the right beneficial for your facility, it’s important to know which pests are attracted to your crops.
“Different crops can have different pest species. If you grow ornamental plants, for instance, you may consistently see certain thrips species that you don’t necessarily see on vegetable crops,” said Rose Labbe, research scientist at the Harrow RDC (AAFC), a greenhouse, CEA, and field crop research complex in Ontario. “So being able to accurately identify and recognize your pest species is very important. To this end, it can be really valuable to access one of the many online resources available for pest identification such as this simplified key for thrips ID, or reach out to IPM consultants or entomologists to first accurately identify your pest, then develop an biological control program that is appropriate for the crop type and pest species.”
2. Where You’re Growing
It’s important to consider the environmental conditions you’re growing in as well, as certain beneficials are sensitive to humidity and temperature. Knowing which types of beneficials will thrive in your environment is key to effectively reducing pest pressures. Use these charts from Kansas and Michigan State Universities, the Ontario Ministry of Food, Agriculture and Agribusiness (OMAFA), and the Entomological Society of America to match the right biocontrol to your crop.
“Location affects which organism you use,” said Labbe. “It might be very hot and humid for a grower in Florida, for instance, but not so much in Arizona. Knowing a little bit about [a beneficial’s] activity thresholds and optimal environments (relative humidity, temperature and lighting) are really valuable.”
The whitefly parasitic wasp works wonders for greenhouse whitefly control but is sensitive to temperatures below 64 degrees Fahrenheit. | Photo: AAFC
3. How Much Beneficials Cost
No matter how you tackle your pest problem, there will be costs associated with it. Beneficials aren’t inexpensive, but according to Matt Korpan, executive director of R&D at the Center of Horticultural Innovation, they’re worth the investment as long as you’re proactive about keeping your pests in check. Plus, there are several drawbacks to pesticides that you don’t typically encounter with beneficials.
“There’s no guarantee that chemicals will work,” said Korpan. “They might work, but their effectiveness is not 100%. Beneficials are known to tackle bugs from a few different angles. Either you spend money on chemicals and they don’t work, or you spend money on beneficials. So, you can end up spending the same amount of money on both, but I think it’s safer to use beneficials because you know they’re in [the greenhouse] doing the work.”
Western flower thrips is one of the most common thrip species in greenhouses across North America. | Photo: AAFC
4. When to Start Using Beneficials
It’s important to note that it takes time for beneficials to alleviate pest pressures. Their level of effectiveness depends on temperature, climate, and how soon you introduce them to your operation. According to Korpan, it’s better to implement beneficials sooner rather than later to avoid playing catch-up with pests.
“We like to start using beneficials about two months in advance of when you think you’ll see the pest,” said Korpan. “Their life cycle is about a month depending on temperature and climate. So, if you’re planting a conventional crop without lights, then you’ll plant in December or January and you’ll want to get your bugs established immediately. If you see an issue and you want to want to introduce beneficials at the same time, you only have a couple weeks where things can go one way or the other.”
5. Other IPM Strategies
Beneficials aren’t the only way to manage pests without using chemicals. Both Labbe and Korpan have tried different IPM methods that don’t require beneficials.
“We have recently worked on the sterile insect technique,” said Labbe. “It’s a really interesting strategy that involves the sterilization of males of a particular pest species, followed by their introduction to the greenhouse where you basically inundate the target pest population. So, if you want to eradicate a particular target, males will meet females but produce zero offspring. This strategy has been used in many locations around the world, but not so much in the greenhouse. But I think this is an up-and-coming strategy we could be using more of in greenhouses.”
While the sterile insect technique isn’t commonplace in CEA facilities just yet, there are simple IPM methods growers can start using right away. Labbe suggests trying insect screening, selective de-leafing, and mass trapping with long ribbon-like sticky traps. Korpan also recommends placing sticky cards in various parts of your facility so you can monitor how many pests enter your greenhouse from week to week.
“Sticky traps are always a good method,” said Korpan. “They’re fairly cost effective, but it takes a little bit of labor to put them in your greenhouse. When it’s hot and you’ve been going up and down rows all week long, looking at the same plants all the time, your attention is not as focused later in the week as it might have been on Monday morning. So, we started using trap eye, which is a sticky card with a camera that counts and identifies bugs on sticky cards.”
Finding the Right Way to Manage Your Pests
If you want to start using beneficials in your facility, it’s important to consider these five things before working with a biocontrol company. Have you used beneficials or an alternative IPM strategy in your operation? Tell us about your experience in the comments below.