The Challenges of Pest Control: Farming in a frost-free, urban environment (San Diego County)

As many San Diego homeowners know, pests like the whiteflies on this hybiscus are one of the downsides of our beautiful, mild climate

When most people think of San Diego, California, they think of the beach or Legoland or other tourist attractions.  It turns out that in addition to being a major urban and tourist center, San Diego is a major agricultural player.

In this 30 minute podcast ( ) I speak with Eric Larsen, the Executive Director of the San Diego Farm Bureau.  We talk about all sorts of interesting features of our farm economy (I also live in this county).  There are several points that come up concerning pest management and crop protection:

  • The fact that San Diego has very mild winters actually makes farming (and gardening) more difficult because the pest populations are not set back the way they are in harsher climates


  • A great many of the pests that SD farmers battle are introduced species, and unfortunately in many cases that introduction happened because urbanites and suburbanites bring in prohibited plant materials that carry the exotic pests.  They don’t do this on purpose, but there are reasons that this is an illegal practice


  • All farmers have to deal with pests – this includes conventional and organic farmers here in San Diego as in any region.  Some of our greenhouse producers are effectively able to prevent pests from ever getting to their crops, but only with careful management and exclusion strategies

This is the first podcast in a series that I will be working on for the CropLife Foundation



Do Farmers Really Drench, Douse or Slather Their Crops With Pesticides?

In many articles critical of modern agriculture, the narratives about pesticides tend to use terms like slathered, doused and drenched. These words conger alarming images and foster consumer fears about the role of pesticides in the food supply. Professionals actually involved in the control of pests on farms know that these are extremely misleading impressions of how farmers manage their crops. It is useful to make some visual comparisons to provide perspective.

A good example of what it means to “slather” (

Slather is a term we use to describe the process of applying a heavy dose of sunscreen. Putting 1/2 ounce of sunscreen on just your face (57 square inches) would amount to 0.009 ounces/square inch. If an acre of a farmed crop were slathered to that same degree, that dosage would be more than 54,000 ounces/acre. Most crop protection products are applied in the range of 3 – 64 oz. per acre. That means that the sunscreen slather image is exaggerated by a factor of 850 to 18,000 times as much as in reality. The use of the term slather is inappropriate and inaccurate when describing the use of pesticides in agriculture. Petroleum distillates (essentially mineral oils) are organic-approved pesticides and are applied at rates up to 1792 oz. per acre. Even that wouldn’t qualify as slathered in comparison to the sunscreen.

Most of what is in a farm sprayer is water in which the pesticide is diluted

One reason people perceive high pesticide use rates are the images of the spraying process. Most pesticides are delivered in a water spray. The actual amount of pesticide involved might range from a few ounces to a few pounds per acre, but it is diluted by a much higher volume of water. To get good spray coverage of something like an orchard crop, it might be necessary to use 100 to 400 gallons of water per acre. To be clear, that spray is almost all water. For something like an herbicide application to a row crop, the spray volume might be only five gallons of water per acre, again delivering a few ounces to maybe two quarts (64 oz.) of actual pesticide. How does a farmer’s use of five to 400 gallons per acre of water compare to the emotive terms drenched or doused?

What “drenched” really looks like

If you get caught in a sudden thunderstorm you might say you got drenched.”If you were not in the rain too long that drenching might represent five one-hundredths’ of an inch of rain. On an acre that amount of rain would represent 1,358 gallons – far more than even the largest volume used for a crop protection spray.

Cereal that has been truly “drenched”

When you put milk on your breakfast cereal (say ¼ cup to a bowl that is six inches across) you might say you drenched it. If that kind of volume were put on an acre of land, it would represent 3,465 gallons – eight to 700 times more than the water volumes in agriculture. Again, drenched is a seriously misleading way to describe what farmers do when they spray.

Are race winner being doused with Champagne

There is a tradition of dousing a winning race car driver with Champagne. That seems like a waste of good Champagne, but let’s assume only half of the bottle actually goes on the winner’s head. To apply that sort of volume to a farmed acre would represent 16,148 gallons. At this point, it is clear that pesticide application done by farmers is a far cry from a dousing.


Farmers don’t have any incentive to spray more crop protection agent than they need .  Why?  The products are expensive and it is one of the many time consuming processes they must undertake in taking care of their crops.


So when you hear or read about farmers slathering, drenching, or dousing their fields, remember that these emotive terms and mental images are at best, misleading and frequently, manipulative.