Growers who practice Integrated Pest Management (IPM) can positively impact their crop production and their bottom line.
Integrated strategies offer the strongest protection for potato growers, who need a complete plan for combating every element that threatens their crop. Managing obvious threats like insects, nematodes, diseases, and weeds are often at the forefront of IPM tactics, but taking steps to monitor water management and crop rotation are also important in keeping potatoes healthy and in maximizing yield and quality. Additional components like knowing field history and developing a successful treatment plan help to fortify a successful IPM plan.
As growers work at managing everything—timing and mixing modes or sites of action in chemical applications, selecting healthy seed stock, scouting for weeds and live pests, and even identifying weather events that can have potentially devastating results—they take the power of new technology and put it to work with age-old growing practices. It’s the careful orchestration of each of these things that makes Integrated Pest Management a success. Growers should consider the following best practices for a successful IPM program:
Best Practices for an Effective IPM Program for Potatoes
1. Develop a pest management plan that combats resistance
Prevention is key with potato crops, as many growers know. Plan for the worst, and hope for the best. To do this, collect data from previous years to develop an educated plan for insecticide, herbicide, nematicide and fungicide usage. That data should include:
Part of the plan should employ different modes of action as one way to combat resistance.
“The idea is you’re hitting different generations of the different insects with different modes of action,” says Erik Wenninger, associate professor of entomology for the University of Idaho in Kimberly, Idaho. “When you hit multiple generations with the same mode of action, that increases the likelihood of resistance developing.”
He recommends clustering modes of action. “If you do six sprays per season, do the first and second spray using one mode of action, then for sprays three and four, use another mode of action.”
2. Seed stock
Don’t just rely on your own samples of seed from each field. Get a North American Certified Seed Potato Plant Health Certificate for your seed lot, Gudmestad says.
This is especially critical as new strains of disease appear. “The emergence of Potato Virus Y, which causes tuber necrotic ringspot disease (TNRD) in susceptible varieties, and the emergence of blackleg Dickeya, both serious seedborne diseases, are very important reasons why you need to get a copy of the North American Certified Seed Potato Health Certificate (NACSPHC) for each lot of potato seed you buy,” warns Cornell University’s Cooperative Extension Vegetable Program website.
It’s essential to know where your seed is coming from. If you’ve not used a particular seed supplier before, visit the farm and visually inspect the seed potatoes and the general sanitation conditions of the operation, Gudmestad recommends. It’s critical to be sure you’re starting with the healthiest seed, as many diseases can be traced back to seed pieces.
Hire professionals to scout for insects, diseases, weeds and nematodes. Scouts in the field should set traps and look for aphids, Colorado potato beetle, wireworm, psyllids and other pests and closely examine plants for key diseases like Verticillium wilt, early blight, late blight, black spot, black dot, and white mold.
First, focus on field history. Know the history of your fields and document what previous crops were planted; this helps determine which nutrients might be present (or lacking) in the soil and which diseases, pests and weeds were present.
“When it comes to your own fields, all growers should sample their fields to know what the fertility is—to plan for the crop based on residual nutrients in the soil,” Gudmestad says. Growers also must note any pests or diseases found in ANY crop planted in that field (not just potatoes). This helps accurately determine what pre-planting soil treatment may be necessary.
4. Crop rotation
Crop rotation is widely used already, but growers may implement a shorter rotation than would be optimal.
“Growers might grow potatoes (in one field) and come back three years later and plant potatoes again when it might be better to come back five or seven years later,” Wenninger says. “Yields can suffer a bit without proper rotation.”
Log previous crops in current fields (and adjacent fields, if possible) to help determine what pests and diseases might be present and to develop a crop rotation plan. Whether you own or rent your land, document and consult planting data back several years (up to a decade) to determine crop history.
Rotating potatoes with other crops, like sugar beets for example, can provide an added benefit. By exposing them to fungicides in the soil that wouldn’t be used on potatoes, they’re exposed to a different mode of action that can combat diseases and weeds while helping to prevent resistance, says plant pathologist Jeff Miller, president and CEO of Miller Research, a firm that conducts scientific research for the improvement of crop production.
5. Water management
Analyze water management strategies; too much water (even just in isolated spots) encourages weed growth and can promote a variety of diseases. Carefully controlling moisture can make the difference between a low-disease/low-pest crop and one that requires additional chemical treatments.
“Growers need to use the ‘checkbook’ method—write down the amount of water you use, figure evapotranspiration rates, and be sure the irrigation can meet that demand without overdoing it,” Gudmestad advises. Factor in predicted precipitation before watering, too. Other helpful factors include:
6. Post-harvest data
Gather post-harvest data to create next year’s IPM plan. Use data from previous years that includes:
This provides powerful insight into crop success. Use this data to target insect-, disease- and weed-prone areas with specialized treatments instead of treating the entire field, where possible.
A Look Ahead: What’s on the Horizon
IPM is a melting pot of strategies and statistics. As growers go about their everyday duties of scouting for pests and diseases, they should also watch for new strategies that are on the forefront. Advances in the field that are ones to watch include biotechnology, using a flexible schedule for treatment application, and row spacing.
Boise, Idaho-based J.R. Simplot Co. has pioneered gene manipulation in the Innate Generation 2 tuber, which is bred for late blight resistance. The Innate Generation 2 potato currently offers a single gene for late blight resistance, but genes can be stacked, so the next generation will have more than one gene for resistance, making it more durable, Gudmestad says.
Flexible Schedule for Treatment
As we move forward, growers will be challenged to reduce the amount of chemicals on their crops because of environmental protection issues and public perception, Taysom notes. It’s about working smarter, not harder, to combat resistance. Targeted treatments based on regional climatic conditions, coupled with fine-tuning treatments via different modes of action will be key.
Any non-chemical method to balance integrated pest management is worth a look. Some Idaho growers are experimenting with decreasing the space between rows from 34-36 inches to 32 inches, Taysom says. Narrower rows allow for quicker row closure, which helps control weeds in the fields. Large-scale trials of this are not yet happening.