If I walked up to a hive the same way I walked into a greenhouse when I was an IPM specialist for an ornamental horticulture company, I’d be expecting to have to look a lot harder for bugs. I’d walk between the rows of plants—or frames of bees—finding, identifying and noting down any insects, diseases and observations. I’d shake plants—or bees in a jar—to see what was hiding inside and scan everything for damage patterns. I’d leave with notes and numbers and maybe Ziploc’d plant samples to examine under the microscope later.
Detective work done, one step of IPM done.
Integrated Pest Management (IPM) is a pest control approach that involves a variety of strategies and aims to supress pest levels in an economically and environmentally sound and sustainable way. It’s a science, and although it was developed with plants in mind, an IPM program can be tailored for any biological system. Like my favourite striped and winged livestock.
While scouting an outdoor lavender crop I paused to photograph a minute pirate bug (Orius) scouting the leaves for a thrips. A hoverfly zipped past my face and I watched it helicopter around the flowers. Suddenly the place was alive, and I noticed half a dozen different types of good insects doing my job for me, scouting the plants and eating the bad guys. It was thrilling—live proof that my tailored IPM program was working.
As a plant IPM specialist, my job was to keep the insect and disease populations below the damage threshold, which is very low for ornamentals. My mission, however, was to minimize pesticides applied and to cultivate an ecosystem in the greenhouse or outdoor fields that would balance out the pest existents with good things.
I included the natural world and surrounding environment as much as possible, using phenological indicators and encouraging naturally occurring insects to get involved in my schemes. To see nature moving in and the plants buzzing with good guys got me buzzing with excitement.
IPM is not a one size fits all thing: it’s an idea with several concrete steps and strategies. Every crop, growing system and climate can require a different approach. No company—or even greenhouse—will be exactly the same as another. IPM is not a rule: it’s customizable, dynamic, rewarding and always challenging.
IPM was designed with 6 steps. All the steps are woven together and sometimes I felt like a leaf hopper, constantly bouncing back and forth between steps.
Planning and Prevention
I planned year round, but did most of my research and big-picture year planning in the winter. The company I worked for had multiple locations, greenhouses and outdoor spaces, totalling over 100 acres of ornamental plants. I broke the plan down into crops and weeks, and finally pests for each crop. With a lot of research (and a lot of hot chocolate to keep my fingers warm), I made a very detailed plan. Inevitably nature would throw an aphid wrench in the middle, but for a short time I’d be smug as a bug and itching to start the season.
Prevention strategies such as applying beneficial fungi and optimizing plant health were constant. In propagation, before Gaultheria seeds germinated or Cupressus cuttings sprouted roots I applied handfuls of a good mite with a fancy name (Stratiolaelaps scimitus) to the soil weekly, regardless of fungus gnat counts. Orius for thrips control was in the plan and applied before I even saw any thrips, as feeding scars on the deep pink flowers was not acceptable or reversible.
If there was one key to a successful IPM program (there isn’t), it would be good monitoring, aka scouting. Without good monitoring there is nothing to make IPM decisions about. Many agricultural companies hire several scouts which report to an agronomist who plans with the producer. Being both the boots-on-ground and in-office, I scouted the details while paying attention to big picture things such as the environment, changes week to week, noting suspect areas, and I was immersed in the plants (sometimes literally, to the amusement of my coworkers).
A huge part of this step was and is records! Numbers, charts, observations, comparisons, photos. When I started my job, it was invaluable to have years of scouting data to sift through and learn from, and from month to month and year to year it was essential to have that information on hand. Not only was it helpful to identify issues, but to determine whether or not they were at action threshold and if the treatment worked.
In the IPM hierarchy, ID would be the foundation and it is tied really closely to monitoring/scouting. Being able to identify the good and bad insects in the crop, recognize damage symptoms and diagnose diseases (often later with a microscope) is KEY. There are approximately 3500 species of pest insects in North America—too many to memorize—so I took photos or samples and identified anything I didn’t recognize later.
When monitoring and ID and analysis of economics and injury levels determined action was necessary, the fun really began. There are multiple strategies in IPM, and a good programs is often a combination or sequence of the following.
Biological Control: There are many biological options to choose from—introducing and encouraging beneficial insects, predatory insects, fungi, nematodes…
To develop an effective biological control program, I had to know my plant, pest insect and biological inside and out: plant damage, lifecycle, preferred temperatures and beyond. The two need to match up perfectly to achieve control. For example, black vine weevils love hydrangea leaves and will chew ugly D-shaped notches everywhere. They are active on cloudy days or at night and will fall from the leaves, playing dead, when they detect a scout’s shadow or are disturbed. These habits, combined with the bulky, leafy hydrangea plants make the adults very hard to find and control. Two species of nematode will infect black vine weevil grubs, but one needs soil temperatures above 14oC, and the other is effective at 5oC but doesn’t like the heat. Working with this, the 5oC’s were applied early in the spring to control any overwintered and early grubs, preventing spring weevil hatch, and the 14oC’s were applied as soon as it was warm enough to control new grubs over the rest of the season.
Cultural Control: Often, an insect pest or disease is a problem because of some bigger underlying issue compromising plant health and defense, such as suboptimal growing conditions. Cultural control could be adjusting the soil pH, irrigation schedule, fertilizer and such things.
Genetic Control: some people list this with cultural control, but I like to keep it separate because it isn’t something you can change after the fact (like temperature for example). Genetic control often includes disease resistant varieties.
Physical Control: This is often a great place to start. Physical barriers like greenhouse window screens to keep out flying insect pests, removing diseased plants or plant parts and picking off the handful of caterpillars noticed on a scouting round are all examples.
Chemical Control: As hard as you work to NOT spray, sometimes it can’t be helped. Before a chemical was applied, there are lots of questions to ask. What chemicals will specifically target the pest insect or disease with the least impact to the beneficial insects naturally occurring or introduced? What is the mode of action and active ingredient? What is the best time of day/weather to apply? Chemicals can be a part of an effective, environmentally and economically sound IPM program if they are used with caution and only when necessary.
Once decisions have been made, it’s action time. This could look like releasing packages of live Aphidius to turn an explosion of aphids into golden mummies that would hatch more Aphidius. Or going through and cutting out all the diseased branches. Or adjusting the irrigation water pH, improving airflow or drenching a beneficial fungi.
Ordering, releasing, and watching the beneficial insects at work was one of the best parts of my IPM experience. Whether it was a posse of lacewings chowing down aphids, a gang of Orius chasing thrips, finding brown nematode-infested black vine weevil larvae or noticing reduced spider mite damage after an application of a beneficial mite, it was all worth the hours of research. Many of the other control methods would be discussed with the growers—the real plant specialists— who would make the cultural decisions and apply the chemicals.
Being both the scout and specialist allowed me to simultaneously monitor and evaluate the efficacy of the strategies implemented. It’s an important step for making sure the treatments worked or the beneficial bugs were doing their job and if not, it was back to the control decisions step. Often, the season was a flip flop between steps and control strategies.
I’m not a beekeeping or home garden IPM specialist, but the concepts I used while working as an ornamental horticulture IPM specialist are transferable to any agricultural or biological system. Scouting, record keeping and prevention are as essential in beekeeping as in ornamental horticulture.
Because protecting an insect – even though I attempted to protect good insects (including bees!) in my job— is a different game than protecting plants, IPM in beekeeping is a whole new experience.
We can optimize colony health in multiple ways (cultural control), keep our equipment clean and use drone brood removal tactics (physical control), and keep locally raised and resistant bees (genetic control). Most of the solid strategies we—the bee “growers”—can use for the many issues honeybees can face are cultural and chemical options.
My beloved biological control option is currently not available for beekeeping. My favourite part of being a plant IPM specialist was using insects, fungi or mites to battle pest insects and diseases and seeing an ecosystem emerging, resulting in healthier plants and people. So here I am, patiently waiting for research on varroa pathogenic fungi to be finalized.
If you’d like to read more on IPM and my horticulture journey, check out my portfolio at http://sylviadekker.com/portfolio/ where I have links to multiple articles published in GrowerTalks Magazine. I share beekeeping and mountain adventures on Instagram @syl.dekker and would love to see and hear from you there!