Monitoring and collecting environmental conditions during controlled environment agriculture production can assist growers in making the best use of integrated pest management strategies.
While maintaining the proper temperature and humidity is important to ensure the optimum growing conditions for controlled environment agriculture, these environmental factors become even more important when using biological controls.
“There are some pests that might be safer in hot climates because a predator of the pests might suffer from this type of climate,” said Yeshurun Plesser, Latin America and North America director at BioBee, a producer of biological controls. “If you consider an extreme environment, for example under an extremely low humidity, a pest may survive and a predator may not.
“The environmental conditions may be good for plants, but they may not be good for a predator. The environment could decrease the efficacy of the predator by as much as 15 percent. In most cases, if the pests can thrive under the environmental conditions, the biological controls can thrive as well.
“Under extreme conditions such as low temperatures, in most instances the pests are going to be very slow and the predator might work, but it will also be very slow. This would also be the case with extreme relative humidity conditions. The ideal environmental conditions for plants may not be the ideal environmental conditions for a biocontrol agent, but it still can do its job.”
Plesser said in most cases, there really isn’t much difference in using biological controls based on the time of the year.
“There are times when shorter day lengths may cause a biological control to go into diapause,” he said. “Most biologicals are not affected by day length. If the right temperature and humidity are maintained in the greenhouse, in most cases the biologicals will be effective.
“As long as pests are active in the greenhouse, the predators will function. If the outside temperature is cold, there may be fewer pests entering the greenhouse. But once the pests are in the greenhouse, it’s not going to really matter what the temperature is outside, but what the temperature is inside the greenhouse. Once the pests are in the greenhouse, the biologicals will be active.”
Maintaining the proper temperature, humidity
Plesser said temperature is the most important environmental factor related to the activity of biologicals.
“The optimum temperature for biologicals is going to vary by species,” he said. “There are temperatures where the biologicals’ activity will be very slow and they will not reproduce. There is a maximum temperature where they will not survive.
“The microclimate within the plant canopy may not be the same as the climate in the greenhouse. Even if the temperature in the greenhouse is 40ºC (104ºF), which might be detrimental to biologicals, because of the lower temperature and humidity around the foliage, the biologicals may survive.”
Plesser said a temperature range between 50ºF and 90ºF is good for most biologicals.
“Below 50ºF is not optimum for biologicals to be active,” he said. “Most of them will die above 95ºF, but they may be able to find a microclimate within the plant foliage that enables them to survive.
“Like temperature, the relative humidity is very species specific. Most are susceptible to low humidity. Between 75-95 percent relative humidity, most of them will do fine.”
Plesser said as long as growers maintain the proper environment for the production of their crops, the biological controls should be active.
“BioBee can also adapt the biologicals for the crops and climate that growers are using,” he said. “Growers should keep the climate favorable to the production of crops. The biological controls should be secondary to the crop because in most cases biologicals can be adapted to the crop and climate.
“I’m not sure changing the climate to allow biologicals to be more effective will be cost effective for most growers. The climate should be adjusted for the needs of the plants not the biologicals. If the cost to change the humidity or temperature is very little and it improves the activity of the biologicals so that they offer better pest control, then a grower may consider making those changes.”
Optimizing IPM strategies
Joanna Madej, head of product marketing and strategy at 30MHz, said there are three objectives in pest management:
- The identification of developing pest pressures.
- Ensuring the correct timing and conditions for the use of biopesticides or predators.
- Understanding the context within which previous issues developed in order to learn from and prevent future problems.
30MHz is an agri-technology provider that offers smart sensing solutions for growers to easily deploy wireless sensors that capture the metrics most crucial to their operations.
“The 30MHz agri-data platform provides a quick and precise feedback loop, enabling growers to verify and tailor their approach to crops providing key insights for all three of these objectives,” Madej said. “This combination of real-time and historical context on crops and their needs is proving crucial to the optimization of integrated pest management strategies. 30MHz’s wireless sensors enable growers to collect accurate, consistent and granular crop data from difficult to reach locations, and capture metrics that were previously impossible to measure. Developed with input from growers, our pointed microclimate sensor can capture the plant temperature of individual crops, ambient temperature and relative humidity.”
Madej said the collection of crop-level data is especially important when using biological controls.
“In the case of one of our customers, insights on microclimate helped optimize a strategy to fight thrips,” she said. “Thrips had caused over 30 percent in losses. Through real-time monitoring, the grower discovered that relative humidity should never fall below 63 percent to reduce hatch rates. The grower developed a new strategy with a new predator. Given the number of interrelated factors determining IPM performance, precise and accurate data captured in real time offers great potential for the optimization of pest management.”
Madej said the data captured by the pointed microclimate sensor enabled another customer to increase precision while fighting spider mites.
“After installing sensors in a problem area, this customer discovered that conditions were not optimum for Phytoseiulus above 25ºC (77ºF) and below 70 percent relative humidity,” she said. “Armed with insights, the customer implemented a series of alerts to increase application when conditions were reducing Phytoseiulus effectiveness.”
This article is property of Hort Americas and was written by David Kuack, a freelance technical writer in Fort Worth, TX.