Every controlled environment crop presents a unique set of challenges. Biological tools are increasingly part of the solution. By Richard Jones Corporate Content Director, Meister Media Worldwide
Controlled environment was one of the first production systems to embrace biocontrol, but new tools and new crops mean there’s still a lot to learn about what’s happening with crop protection and plant health in the greenhouse.
We reached out to three experts who approach the topic from different perspectives:
The three of them met in an online discussion to share their view on the current use of biologicals in all of the major greenhouse crops, as well as where there’s opportunity for improvement. We tossed a question out to get the discussion started:
Q: Let’s talk about the current situation around the industry in terms of fully incorporating biological tools in controlled-environment production. What's happening out there? What's the state of biologicals in the greenhouse?
Michael Brownbridge: I think it varies by what crop you're talking about. In the case of crops like cannabis, for example, there really are only biological tools. I live in Canada, where cannabis is fully legal so one regulatory system covers the whole country — versus the U.S., where different states have different regulations around products. That being said, I don't think anywhere is allowing anything other than biopesticides and biological controls in cannabis.
On the vegetable side I think they've been using biological tools forever. They’re using integrated programs. That's not saying they don’t still use chemistry in some crops in some situations quite extensively, but certainly their first thought is probably on the biological mindset.
I think the biggest challenge is in ornamentals because of the huge variety of crops, the duration of the production period, different environments, etc.
Suzanne Wainwright-Evans: I would have to agree-ish. Cannabis in the States is very different than Canada and some states do allow registered pesticides for use in cannabis. Others don't. It’s very challenging to remember what we can use in each state.
I spend a fair amount of time with ornamentals too, and I agree that has some of the biggest challenges, partially because of climate. Especially working in warmer regions, growing zones 7, 8, 9, and even 10 because we deal with a lot of tropical pests that Canada or the northern U.S don't necessarily get. Much of the research on biocontrol was done in Europe and more temperate climates, and the focus has been on the major temperate pests. When we get these tropical pests moving in, trying to figure out how to manage it without disrupting your biocontrol program is extremely challenging. I see a lot of successes, but I think a lot has to do with the grower and their knowledge level.
John Sanderson: I agree with you both. As is being pointed out, we will always need pesticides —biopesticides and synthetics — at some point in crop production in controlled environments because you have unexpected pests.
But biocontrols usually are not fast. You've got a great biocontrol program going and then all of a sudden, you bring in some pests that you didn't expect — mealybugs or scale insects, things like that. Now, what do you do? Some kind of fast control strategy will be always necessary, but also sanitation and scouting and all of the standard pest management. Those are all still going to be needed. You can't just willy nilly throw biocontrol agents out into the greenhouse and say, “Go do your thing,” and expect everything will be fine.
Wainwright-Evans: What's been really interesting about working with cannabis, it has pushed my sanitation knowledge to go further. In ornamentals, there's always that opportunity for the grower to come in and do a clean-up spray. Cannabis growers don't have that option.
The sanitation for things with six and eight legs is really important. Taking what I’ve learned in cannabis over these last few years and applying it more into our ornamentals has allowed us to be more successful with our bios because we're starting with a lower pest population density. The biocontrol agents have a better chance. That has been extremely successful.
Brownbridge: If you want a silver lining to COVID for the greenhouse sector, it's that raised awareness around disease transfer — the absolute importance of sanitation. I know you didn't mention diseases but diseases are so easily undetected or latent but assumed to be okay, and then, boom, the whole crop falls over.
New thinking is managing your crop using every single tool you have available, good nutrition, sanitation, cultural, and biological, and if you have to — and if you can — chemistry at the end.
Sanderson: Michael, I would be interested to get your perspective on dipping incoming plant materials as a preventative with biorational products. I have seen in New York, what I think was some very successful poinsettia production when the cuttings were dipped when they first came in. After that they began a biocontrol program but that preventative dipping starts you with a very low population and that's something that the natural enemies can handle. But my question — the big concern about dipping is disease transmission.
Brownbridge: I think if you had to choose one thing that sets a great foundation for biocontrol strategy on incoming cuttings it would be dipping. The original work we did for easier control on poinsettia was with BotaniGard and insecticidal soap. It works like a charm in terms of knocking back that initial population.
You ask about the risks if you have a few infected cuttings in with healthy cuttings — whether that disease will be transmitted because essentially, you're putting them all in the same bath. We found until you got up to the point where the water would be turbid with bacteria, we saw no disease transfer to healthy cuttings.
With diseases there's always a risk, but it’s a question of where you place your risk. I think the risks of disease transfer with dipping are less than not dipping and risking pests just going totally off the charts.
Wainwright-Evans: I'm always wondering about contact pesticides, and if dipping cuttings removes some of the pesticide residue of the contact products. If you change your water regularly enough, especially the offshore cuttings, can you remove some of these older contact pesticides that have been creating problems with trying to use bios?
Brownbridge: That is great question. That was one of the reasons we included insecticidal soap in the original work we did on poinsettia because we know the cuttings were coming in loaded with all sorts of pesticides, not just insecticides, but also, you know acaricides, fungicides. It touches on a point you raised earlier, Suzanne, about how we don't know the side effects of anything that doesn't kill a biocontrol agent. If you take that a step further and we recognize that cuttings are coming in with multiple types of pesticide on them, any single one on its own may not be lethal, but if you add multiple sublethal exposures did you get a lethal concentration? These are huge unknowns.
But it's a good question and soap oil, I think, is probably one of the finest things you can use as a dip just in terms of the spectrum of pests it will eliminate. The pH value in soap helps degrade some of the active materials on the leaf surface, so I wouldn't doubt that it would help in that regard.
Wainwright-Evans: it really it takes a lot of effort to make biocontrol happen. You need the education from Extension, you need the research from the University, you need the biocontrol suppliers to have sales reps helping the growers.
Sanderson: Another challenge is the size of the operation. Here in New York, we have a whole bunch of little one-acre greenhouses. It's been a real challenge to extend biocontrol information to them, but that is what they have to rely on because the pest control company salespeople can't spend the time to visit all the time.
Wainwright-Evans: Sometimes we see failures and people think that biocontrol doesn't work, but I think it's because there needs to be such a higher educational level to get into biologicals. It gets a lot easier, but the first year is really tough. Especially with ornamentals where you go in and they have 50 different crops all with different pest complexes.
Oftentimes vegetables are giant monocrops in a pepper greenhouse or a cucumber greenhouse. Biocontrol has really excelled there. We've got set programs for cucumbers or tomatoes. There is no set ornamental program because they all are so variable.
Cannabis is becoming more like a vegetable because it generally is a monocrop, but again, we have the problem that every state has different rules on what spray products you can use. There are a lot of variables with the fragmentation of the cannabis industry right now, but when federal regulation does come and it's more streamlined cannabis is going to go more the way of the vegetables. We’ll have a massive “here's your program each week” monoculture kind of thing.
Brownbridge: I find the floriculture side will share information with each other. They're competitive but there's a lot of sharing of knowledge and information. Everybody's got the secret sauce in cannabis. They tend not to tell anybody what they’re doing, so everybody's had to relearn the same old lessons every single time. But I do see a level of sophistication starting to evolve and some cannabis operations doing a great job. Others, there's still a heck of a lot of learning to go on there. It'll happen, but it's just new.
Wainwright-Evans: There are so many new young growers now and we're starting at ground zero with them. With the greenhouses already doing biocontrol, a lot of the growers I’ve worked with for 30 years are getting ready to retire. And this new crew is coming in and we've got to work really hard to get them up to speed on the bios, the ID and how to do it. It takes a lot of time. You do not learn biocontrol overnight.
These young people really want to make biocontrol work and they're thinking outside of the box and trying new things. I'm really happy to be working with these young, ambitious IPM managers and growers.
Brownbridge: One thing we haven’t talked about is biostimulants and biofertilizers. I don't see a huge amount yet, but I do see a role for the biostimulants in that it improves plant health. When you improve plant health you reduce susceptibility to diseases and pests, and your biologicals are going to work better.
To me it's this is how we should be approaching things. It’s not, “What do we have to take care of a problem?” It's, “How do we prevent the problem occurring in the first place, or reduce the severity?” Then everything else starts to work much, much better.
Sanderson: I agree, Michael that's a hot area right now. There's a lot of fundamental research going on. I think it's going to be a while before we see anything in the greenhouse, but I think that's something industry is already very interested in.
