- Publisher: Greenhouse Grower, Meister Media
- Published: May 2014
A journey just over the United States’ border led Cascade Cuts of Bellingham, Wash., to begin using biocontrols.
The road to the company’s biocontrol use began in 1983. Owner Alison Kutz began visiting with her Canadian neighbors and found common ground with progressive Dutch growers. At this point in time, there were few people thinking about how to implement these tools into greenhouse production, she says.
“Dutch Canadians brought a lot of expertise,” Kutz says. “[Biocontrol] use largely started in Denmark and Holland, and they saw how it might work in vegetable production but not necessarily horticulture. So, early on there were producers just over the border. Specifically, Eric Voogt from Westcan Greenhouses had such a great attitude about working biocontrols into ornamental horticulture. I was impressed with his plant quality and started taking notes. We started thinking about how it could fit into our operation. My initial interest was getting natural controls into the herb production. It helped boost our confidence to have a network and support group of growers to lean on.”
Her experience with biocontrol use eventually led Kutz to found Sound Horticulture to educate growers about the ecological benefits of using biocontrols and provide solutions for pest control.
In a Q & A with Greenhouse Grower, Kutz explains the challenges and opportunities brought about with biocontrol implementation.
GG: In what types of greenhouse structures are you using biocontrols?
Kutz: At Cascade Cuts, our structures are a combination of wide varieties such as French Canadian Harnois. It has a retractable roof and full drop side walls that are computerized. We also have AgraTech greenhouses. All of the houses using biocontrols have a nighttime temperature of 50°F and above.
Around the country, I assist growers in large and small operations, as well as in a variety of conservatories, hydroponic rooftop operations and educational institutions. Biocontrols are now being employed in almost every conceivable environment. However, what we use in individual situations varies greatly.
GG: Who are your suppliers for biocontrols?
Kutz: Sound Horticulture distributes beneficial insects from at least eight different sources, across North America, and our beneficial nematodes come from Europe.
GG: What are your application methods? Sachets or any equipment?
Kutz: We often start with two main predator mites. The basis of a most biocontrol programs—a good organic program starts with Stratiolaelaps scimitus mite (formally known as Hypoaspis mites). We use Ss or Strat mites anywhere from propagation onward, as it feeds voraciously on the larvae of fungus gnats, as well as thrips and other soil dwelling stages of insect life cycles.
The second part of this tag-team of beneficial mites is the Amblyseius cucumeris mite, which is highly effective in the plant canopy feeding on western flower thrips (WFT). The WFT that might manage to evade the A. cucumeris then drop to the soil, only to be devoured by the Stratiolaelaps mites, which are lying in wait. These two beneficial mites play exceptionally well together and form the basis of many biocontrol programs. These predators are generally broadcast freely out of 1-liter containers. Occasionally, sachets might be called for in hanging basket production.
GG: Are there any government regulations that have prevented you from importing certain biocontrols?
Kutz: You can imagine that the USDA and the Animal and Plant Health Inspection Service (APHIS), the biological protection organization to the US government, regularly makes sure biocontrol agents are not inadvertently spread around the globe where they don’t belong. After the events of 9/11, there was a concern that there could be bioterrorism. APHIS was just one of the many organizations that received increased scrutiny. Of course, at the same time, uninvited pests continue to enter the country daily.
GG: What pests are you controlling with biocontrols? Which aren’t well controlled with biocontrols?
Kutz: We have had success with fungus gnats, shore fly, western flower thrips, aphids, whitefly, TSSM (two spotted spider mite), broad mite, cyclamen mite, mealy bug and more.
A lot of it is our approach; for all of us as good growers, are we equipped to be proactive enough with applications? Can we monitor closely and watch the trends from year to year? Can we learn from each other and fine tune these programs as we go along? These considerations, plus patience and good communication skills within a growing team, help immensely. These are the growers that will be successful with their biocontrol efforts. For many growers, a huge challenge is that of the quality of incoming plugs. It can be challenging if something comes in with whitefly, thrips or aphids.
Almost every common greenhouse pest these days we can handle with biological controls, if we are proactive enough and anticipate ahead of time what we might expect. However, realistically there may be times when it does not make sense to handle certain pest pressures biologically. Every situation is unique to some degree.
Increasingly, there are some occasional challenges with pests when there is no commercially available sourcing for the needed biocontrol. This problem will likely continue with the increase of exotic pests continuing to stake out new territory in northern climates.
For instance, there’s a parasitic wasp for greenhouse thrips. It is from Brazil and can handle this pest. The USDA gave special permits in 1980s for growers in Florida and California to do studies and release these parasitic wasps for this variety of thrips. They found wasps did well for those four years, but there is absolutely no commercial availability at this point in 2014.
There is the chicken/egg question that we deal with when we have the movement of pests like never before – the vectoring around the globe moving into a variety of different settings. Supply and demand dictates whether these pests can be produced commercially. Also ,how the USDA feels about it. It’s a broad issue with many important considerations.
GG: Are there special considerations when dealing with flowering potted vs. bedding plants when it comes to biocontrols?
Kutz: Certainly between vegetable production and bedding there are many differences, as you can imagine. There is a higher degree of tolerance for foliar damage in vegetable production as long as there is no damage to the fruiting portion of the crop.
In ornamental floriculture, we have next to zero tolerance for any pests. For example, if a grower has been growing African daisies and also has a greenhouse full of bedding plants, there is lots of pollen available as a food resource for a pest like WFT. These innocuous pests can increase their numbers rapidly over the spring and summer months. The grower has to be proactive and on the ball, with monitoring, watching trends and populations, and anticipating the increase of pest populations. Cleaning out between crops is always the goal but difficult at times. Good culture and sanitation and clearing out plant material that shouldn’t be in the greenhouse can be very helpful to reduce the excess pollen load because thrips will continue to feed on any pollen available.
In many instances growers find, for example, that Amblyseius cucumeris plus the Stratiolaelaps mite are very satisfactory for thrips control. A. cucumeris is an aggressive thrips predator that, when combined with the Stratiolaelaps mite makes a fantastic tool to tackle WFT. We use one application of Stratiolaelaps mites only. They will act as scavengers, mining through the top few centimeters of potting soil searching for thrips pupae. These two predator mites work well together because the A. cucumeris stays in the canopy and devours young thrips as they hatch on the underside of the foliage. If any thrips manage to evade the A. cucumeris, they will drop off the foliage and into the soil. Those elusive stragglers will then be handled by the soil-dwelling Strat mite.
Climate, time of year, relative humidity, crop mix and pollen load all influence WFT pressure and our most appropriate response. For instance, often we might find that beneficial nematodes are more appropriate as a primary tool for both WFT and fungus gnats. For instance, high summer humidity in the East and South may make nematodes more effective in the canopy than in the Pacific Northwest climate. There are reasons why different strategies that work for one operation may not be as effective in another. We see this over and over when talking to practitioners around the country. It boils back to understanding your pest, environmental conditions and the natural behaviors of your “hired hands.”