How do Farmers and Agronomists Determine Which Pests Need to be Managed?

Jul 08, 2020

Have you ever looked for insects? Insects are ubiquitous in our environment. For farmers, many types of insects live in their fields. Some are beneficial like pollinators and predators. Others, though, can be called pests because they cause serious crop loss. The July 7th Sustainable, Secure Food Blog explores how farmers and agronomists use integrated pest management to control insects.

According to blogger Lesley Lubenow, “integrated pest management gives clear guidelines to when it is appropriate to spray pesticides. Each guideline details the growth period(s) during which crops are most susceptible to damage. This helps growers know when to keep a keen eye out for problems. The guidelines also help with identification of the pest. Finally, they help to determine what size pest population will damage yields. This helps farmers determine when to treat the pest problem.”

There are several techniques farmers and agronomists use to manage pests with integrated pest management techniques:

Measuring the level of crop damage. In the case of canola, if flea beetles cause 15% leaf damage, then farmers are advised to use a pesticide. Below that, they don’t need to treat.
Some pests are only occasional visitors and their damage is less than the cost of the treatment. Blister beetles migrate to faba bean fields for only a few days, they move on. Depending on how much of the field is affected, no treatment may be needed.
Some pests cause damage at only certain life cycles. As hungry catepillars grow into pupas, they can eat a lot of leaves. Cutworm is one such pest.

Click here to see more...

Video: Spring 2026 weather outlook for Wisconsin; What an early-arriving El Niño could mean

Northeast Wisconsin is a small corner of the world, but our weather is still affected by what happens across the globe.

That includes in the equatorial Pacific, where changes between El Niño and La Niña play a role in the weather here -- and boy, have there been some abrupt changes as of late.

El Niño and La Niña are the two phases of what is collectively known as the El Niño Southern Oscillation, or ENSO for short. These are the swings back and forth from unusually warm to unusually cold sea surface temperatures in the Pacific Ocean along the equator.

Since this past September, we have been in a weak La Niña, which means water temperatures near the Eastern Pacific equator have been cooler than usual. That's where we're at right now.

Even last fall, the long-term outlook suggested a return to neutral conditions by spring and potentially El Niño conditions by summer.

But there are some signs this may be happening faster than usual, which could accelerate the onset of El Niño.

Over the last few weeks, unusually strong bursts of westerly winds farther west in the Pacific -- where sea surface temperatures are warmer than average -- have been observed. There is a chance that this could accelerate the warming of those eastern Pacific waters and potentially push us into El Niño sooner than usual.

If we do enter El Nino by spring -- which we'll define as the period of March, April and May -- there are some long-term correlations with our weather here in Northeast Wisconsin.

Looking at a map of anomalously warm weather, most of the upper Great Lakes doesn't show a strong correlation, but in general, the northern tiers of the United States do tend to lean to that direction.

The stronger correlation is with precipitation. El Niño conditions in spring have historically come with a higher risk of very dry weather over that time frame, so this will definitely be a transition we'll have to watch closely as we move out of winter.