Why Pest and Weed Pressure Doesn’t Need to Bug You

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15 February 2022, San Carlos: As Spring approaches, it’s a time for new beginnings. A new crop is planted and a new season of optimism is sprung. But that also means you’ll be faced with the inevitability of pest pressure and weed pressure. It’s an unavoidable fact of farming that you’ll deal with both of these at some point. 

But having expectations that these issues arise means you can also think about how to factor crop protection into your operation. And planning ahead will help fight these pressures.

What fuels pest populations

There are a number of factors to consider but they are generally environmentally based. Some of these factors include:


  • Weather patterns during the summer and winter
  • Historic pressure
  • Temperature
  • Moisture

You’ll also need to consider what types of crop rotations are grown within regions as well as fungal pressures. As an example, corn earworm can infect multiple crops one year but you could see a soybean crop that works the next. This shows the network effect of crop rotations in a given area. 

Weed pressure is also something to consider. Weeds are a constant management target where fungal pressures are a little more targeted based on year and environment. 

Predicting Pests

Looking at this winter, you can consider the overall severity to some degree but generally it’s been a warmer winter.

There may be some positive downstream effects for overall test pressure but most growers use intuition to look for certain paths at certain times of the year.

That allows growers to know certain life cycles of insects on certain crops where you have a timeline of high alerts. 

But you can and should also use environmental data like weather, moisture and precipitation for predictive models of what crops may be at highest risk.

There are also observation networks where people are nothing where there’s a high prevalence of certain pathogens of where outbreaks are happening. 

Integrated Pest Management

The best way to deal with pests is an approach called Integrated Pest Management. It accounts for when an outbreak is occurring and what crop stage is going to be detrimental to overall yield impacts. 

By looking at the past, you can determine whether spraying chemicals had an effect and the impact of weather events.

Looking at the different types of crop protection products (whether it’s chemical or biological) will also help with pest management. 

A good Integrated Pest Management plan will factor in a number of strategies that consider:

  • Biological control
  • Cultural control
  • Chemical control
Biological control

Think of biological control as pitting pests against their own natural enemies such as parasites, predators, or pathogens to help control pests and the damage they cause. 

Cultural control 

Cultural control is a way of reducing where pests establish themselves, where they reproduce, and ultimately their survival. An example of cultural control would be changing your irrigation practices. 

Chemical control 

Using pesticides combined with other controls is an effective and long-term strategy. Choosing pesticides that cause minimal damage to people, other organisms and the environment is an integral part of any pest management system. 

Weed Pressure

It’s known that if you’re trying to grow a crop, weeds are also trying to grow. You know you’ll be managing weeds year over year. So how do you deal with weed pressure?

Growers understand there are certain times of the year to spray. If you have enough weeds, you’ll want to spray them and kill them immediately.

But there’s also a prophylactic approach where you know you’ll have bare ground where there’s no vegetation. 

About a month or two after you plant, you’ll have full canopy closure where the plants are big enough that the bare ground is no longer showing and it shades out the weeds.

The time in between planting the seed and canopy closure allows for different prophylactic spray options that keep weed seeds from germinating.

There are also residual herbicides that try to control weeds before they germinate. So you can take a multi-prong approach to weeds. 

There are resistance concerns to account for. There are certain weeds that have developed mutations to certain herbicides.

It’s good to understand what does and doesn’t always work but to try the multi-prong approach of trying prophylactic applications. 

Mistakes to avoid

Not paying attention to things like insects on fungal pathogens can sometimes be overlooked. It’s important to be scouting and evaluating your crop so that you don’t miss your timing window and catch yourself in an emergency situation where you have damage to your crop.

By scouting early, you’ll hopefully avoid having to perform life saving measures on crops. That’s a worst case scenario so it’s always good to be on top of things.

Variety selection is also important. Choosing the right seed with proper resistance to fungal pathogens is another good strategy that can be easily overlooked. 

Making the right chemistry decision is going to be effective and will help determine if you need to apply multiple active ingredients to get full control.

And while you want to get full control, you can certainly under apply which will ultimately impact yield. Paying attention to chemistry, chemistry mixes and overall rate will help you stay on top of things. 

Need advice?

​​Knowing a good agronomist is important to deal with unexpected issues that can arise during a growing season.

Reaching out to an agronomist at your local university or an independent or retail agronomist will help you better understand the disease life cycle and pest life cycle. As well, they’ll help you make the right decisions to manage your operation. 

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