- Fields with poor drainage often experience water molds, which make it difficult to establish a stand. “If a field has a problem with water molds, you can manage it by waiting to plant until the soil is dry and the forecast says it will stay that way long enough to get the crop up,” Ferrie says. “This can work if the forecast is accurate and you have time to wait. But using treated seed to manage the water molds probably is a better solution. Treatment might not pay every single year, but because of the frequency of the problem, it will pay over the long term.”
- If nematodes are present, they’ll be there for multiple crop years, whether the field is planted in corn or soybeans. Nematodes might increase the chance of sudden death syndrome in soybeans. “If the field has nematodes and you haven’t been able to manage the problem with variety selection, it should receive a preventive nematicide,” Ferrie says. “Here’s where it pays for the pest boss to be involved with the rest of the operation: If the farm has a multi-hybrid planter, they might be able to put the same variety in each seed tank, treat one tank of seed with a nematicide and plant the treated seed in the problem areas.”
- Other pests that, once established in a field, are likely to stick around for years include true grubs, wireworms and insect-resistant corn rootworms. “In fields with insect resistance to a trait or insecticide, the pest boss must implement a multi-prong approach, changing both traits and insecticides,” Ferrie says. “Once he starts changing them, he must be aware of reactions between the insecticides and herbicides he is using.”
- Once present, white mold remains in a field, although it shows up only when cool, wet conditions occur during the plants’ flowering period. Treatments include variety selection and planned fungicide applications.
- If frogeye leaf spot develops resistance to a fungicide in a field of soybeans that becomes a long-term problem. Solutions include variety selection and changing to a fungicide with a different mode of action.
- When herbicide-resistant weeds are present in a field, that’s a perennial weakness the pest boss must deal with every season.
- Some perennial threats are inherent with certain cultural practices. In fields where no-till, strip-till and cover crops are used, the pest boss can expect rodents such as voles and ground squirrels, every season. “Today, many farms use more than one system,” Ferrie notes. “They might adopt a system to manage the weakness in a certain field, such as no-till or strip-till on a field of highly erodible land. Pest management gets more complicated when different systems are in use.”
Preventive Versus Reactive TreatmentsKnowing his fields might allow a pest boss to replace a preventive treatment with a reactive one, which is required only if a pest shows up in threshold numbers.
“With insects, some growers have moved away from planting traited seed, a preventive measure, to control corn borers,” says Farm Journal Field Agronomist Ken Ferrie. “As a result, they might see more borer pressure in their fields. But whether or not they do will depend on the insect survival rate and the environmental conditions.” The previous year’s scouting reports will alert the pest boss to fields that might face a borer problem. To decide if treatment is needed, he or she will track heat units, monitor the borer population with insect pheromone and light traps and have the pest control team prepared to scout at the appropriate time. If they discover threshold levels of borers, the pest boss can control them with an insecticide. “In contrast,” Ferrie says, “there’s no reactive treatment available for corn rootworm larvae [unlike the adult beetles, which can be controlled with an insecticide]. So in fields where rootworms are likely to be a problem, the pest boss will make a preventive application of an insecticide.”