Bug Patrol
An effective integrated pest management strategy brings out the detective, researcher and reporter in us all.
An effective integrated pest management strategy brings out the detective, researcher and reporter in us all.
When it comes to ways to control insect pests on your farm, there’s good news, and there’s bad news. First, the bad news: “There is no ‘one size fits all’ integrated pest management solution,” says Ethan Stoetzer, communications specialist for the Integrated Pest Management Program at Iowa State University. “As much as those of us involved in crop protection would love to standardize pest management solutions, we are aware of the fact that everyone’s farm, economics and long-term goals are different.”
Now, the good news: “It’s because of the lack of standardization that makes integrated pest management something worth adopting,” Stoetzer says. “Because everyone’s inputs and outputs are different, they each will have a plan that’s tailored to them and only to them. This gives farmers both the challenge and the freedom to govern their farms as they wish.”
For this article, we’ll focus on the good news; that is, integrated pest management — IPM — is your solution for controlling insects on your farm, no matter the size, scale or crop. (Incidentally, IPM is relevant for controlling weeds and diseases, too, but we’ll save that for another article.)
Identify Your Pests
With hundreds of types of insects on your farm at any given time, identifying the pests that have the potential to cause problems — or that are currently causing problems — is a tricky first step in your IPM strategy.
“A robust IPM program starts with good knowledge of the crop,” says Nicole Sanchez, assistant professor of horticulture at Oregon State University. “Growers need awareness of the most likely pest problems they will encounter and to be able to anticipate them. What environmental conditions make that problem likely? When and how often should a grower expect to encounter this issue?”
In other words, farmers have to be smarter than insects, which is more difficult than it sounds.
If you already have insects present, swift identification is vital to getting ahead of them. Ayanava Majumdar, an extension professor in the department of entomology and plant pathology at Auburn University and the Alabama Sustainable Agriculture Research and Education coordinator, advises to look at the symptoms and note them. “You have a phone with a camera,” he says. “Take good pictures, and share them with your extension agent. Google is there, but Google doesn’t give you context. You still need a person to talk to.”
Your county extension agent and local Natural Resources Conservation Service officer are great resources for identifying insect pest issues.
MONITOR YOUR PESTS
No matter how prepared you think you are for bug battles, your crops will still attract insects, and these insects will come and go as the season progresses.
“Through scouting [for insects], we can measure the rate of damage and make notes for next year,” Stoetzer says. “Crop scouting is the backbone of IPM, as it gets you into the fields to make a prognosis and be more thoughtful about your management solutions.”
Scouting will also help you determine if you simply have insect pests or an actual pest problem.
Scouting can take several forms:
• Casual monitoring. While you’re working in your garden, be observant and note the insects you see.
• Specific monitoring: Make it a point to examine your crops on a regular basis.
“Growers should try different times of day and different patterns through the field, closely inspecting any plants that look different and checking undersides of leaves,” Sanchez says. “Some insects are closely matched in color to the leaves they are feeding on, so good observation is important.”
• Use sticky wing traps. This is Majumdar’s go-to monitoring system. The traps have different pheromones designed to attract certain pests. These aren’t meant to reduce the pest populations, rather to help you notice which insects are emerging.
• Use degree-day models. Sanchez suggests degree-day modeling websites, such as USPest.org, to help predict when certain pests might be arriving in your garden. This free resource from the Oregon IPM Center is a weather- and climate-driven support website with more than 140 pest and crop models across the U.S. Enter your ZIP code, select the model you want to look at — tomato leaf miner, for example — and you’ll see the expected first spring egg lay, peak spring egg lay, first generation adult emergence and more.
“Monitoring will help farmers learn how insect life cycles and behaviors change,” Majumdar says.
It won’t take long before monitoring helps you become an accurate pest predictor.
MANAGE YOUR PESTS
IPM is part management, part prevention. The four main categories of IPM techniques — cultural, biological, physical and chemical — are meant to work together for a well-rounded management plan.
Selecting IPM techniques takes thought. “Anything you do in the ecosystem is going to have an effect somewhere,” Majumdar says.
So as you put together an IPM plan for your crops, consider how they interact with each other and the bigger picture.
While this is not an exhaustive list, here are several techniques from each management category that might fit in to your IPM strategy.
CULTURAL
Cultural techniques involve changing the pests’ environment, such as:
• Trap crops. If Japanese beetles are all about your green beans, plant soybeans and zinnias to distract them, suggests Ryan Adams, extension associate with the Center for IPM at North Carolina State University. By planting alternative crops to attract insect pests, you draw them away from your main crop.
• Companion planting. “A companion planting would consist of a plant that deters [for example] aphids and might be planted near, or even interspersed with, the cash crop,” Sanchez says. “An alternative companion-plant option would be to plant flowers that encourage predatory insects,” such as the zinnias mentioned previously.
• Crop rotation. Crop rotation comes up often in discussion about farm health. IPM is yet another area where crop rotation is important.
“Insects are able to overwinter in various fields, potentially putting a future crop at risk of insect infestation,” Stoetzer says. “The best way to get rid of an insect is to remove its food supply.”
Rather than plant cabbage season after season, plant something not in the mustard family in its place next year. “By substituting cabbage with sweet corn, for example, for perhaps two growing seasons, you can greatly reduce this pest pressure,” Stoetzer says.
• Change the planting date. For some crops, choosing a later planting date means that food isn’t available to the insect at the time of feeding, which could reduce pest numbers. By planting later, you can also expose the crop to the pests at a time in which the plant is able to tolerate more damage without affecting yield.
PHYSICAL
Physical IPM techniques involve the actual physical removal or destruction of a pest, including:
• Hand-picking. “There is nothing that defines IPM more, in my opinion, than hand-picking as many pests as possible directly off the crop,” Adams says. “An example would be removing a tomato hornworm from a tomato plant.”
Time-consuming? Yes. Effective? Yes, particularly if the insects are large — think Colorado potato beetle or larger. Hand-picking is more difficult when you’re dealing with something as small as aphids.
• Whole plant removal. This works well if you have small insect pests, like aphids, or if it seems just a few plants are infested.
“If just a few aphids are present, removal of the affected plant part or hand removal (both physical controls) might be sufficient,” Sanchez says. “If the population has built up on a single plant but not surrounding ones, removal of the entire plant might be effective.”
• Sanitation. Sanitation involves removing the affected plant and also destroying it.
“Spotted wing drosophila provides an excellent example,” Sanchez says. “Part of a management strategy for this insect includes removing and destroying infested fruit from the plant. This removes the larvae, which feed inside ripening fruit where insecticides cannot be applied. If the fruit is removed but not destroyed, nothing stops the larvae from developing and becoming an adult, capable of continuing the cycle.
“Moving infested fruit to row ends or the corner of the field is not sufficient. The emerging adult flies do, after all, have wings.”
• Row cover. Used primarily for season extension, row cover also serves as a physical barrier for insects. Majumdar uses a special row cover for pest exclusion — thinner and more delicate than temperature-boosting row covers — early in the season.
For example, to keep squash bugs away from zucchini plants, you’d cover the seedlings when transplanted and keep them covered until they need pollination, when flowers bloom. At this time, plants are larger and strong enough to ward off some pest pressure on their own, and the squash bugs may have moved on without a ready food source.
BIOLOGICAL
Pitting nature against nature is essentially behind biological IPM techniques, for example:
• Predatory insects. Lacewings, ladybugs and spiders are common predatory insects found in the garden. Welcome these good bugs by having the right habitat for them to thrive. You can also purchase predatory insects to release in your garden when the time is right.
• Resistant varieties. Specific crop varieties have been bred to be more resistant to insects. For example, you might consider butternut squash, which Adams points out is resistant to squash vine borer. These varieties still need to be suitable for your soil and growing conditions.
For conventional commodity-crop producers, seeds genetically engineered to be resistant to insect pests are an option.
CHEMICAL
As it sounds, chemical IPM techniques involve using chemicals, organic and not.
“Generally, chemical controls are considered a last resort once other management strategies have been exhausted. But I will stress that chemical management is a necessary and integral part of a successful IPM program,” Adams says.
Sometimes you didn’t get ahead of the insect pest and may be forced to consider spraying or otherwise losing your crop.
“Rotation of two different active ingredients is a helpful strategy if an infestation has gotten to this point,” Sanchez says. This reduces the likelihood an insect population will become resistant to any ingredient.
No matter if you’re using substances approved by the National Organic Program or chemical pesticides, read the label and consider how your spray will impact other insect populations.
EVALUATE YOUR EFFORTS
With a full IPM strategy in place, the only thing left to do is evaluate your efforts. Revisiting monitoring efforts mentioned previously, evaluation takes a similar path. Instead of looking for pest emergence, you’re looking for remaining pest populations.
Sanchez suggests reviewing your efforts at least annually, but before doing that, she urges you to keep notes and records: “It’s helpful to remember that many IPM strategies are long-term, with several years before results are understood.”
Here, again, your extension and NRCS folks can be great partners in evaluating your IPM efforts.
Managing insect pests is a long road, and the way forward is constantly changing as weather and the crops you grow also change. “IPM isn’t a destination. You don’t all of a sudden reach IPM,” Stoetzer says.
With a good IPM plan, you’ll be on your way in the right direction.