Final part of commercial rat control series: Rat Control Practices in Agriculture

David Bennett David Bennett | October 3, 2018 | Agriculture, Environmental impact, Farming, Fenn Trap, Instructional, Integrated Pest Management, Mk 4 Fenn Trap, Mk6 Fenn Trap, Mole Traps, National Pest Management Association, NPMA, Pest Control, Pesticide, PestWorld2018, Public Health, Rat Infestation, Rat poisen, Rat Traps, Rats, Wildlife removal

As you can imagine, controlling rodent pests on farms is quite a challenging endeavor.  One problem is that rodents eat selectively, so a farmer might not notice a lot of crop loss in many different places.  However, if acreage is examined carefully, trouble spots can be found, and then damage to crops collectively calculated.  Victor Pest Control gives some alarming statistics as to how much damage rodents do to crops:

“In California, for instance, agriculture is an economic cornerstone of the state, which distributes much of its products throughout the rest of the nation. Growing $39 billion in annual crops, California leads the nation’s agricultural sector. The state is the lone supplier of everything from almonds and walnuts to figs, olives, and artichokes. Additionally, California is a leading supplier of avocados, tomatoes, grapes, and various other fruits and vegetables. 

However, the state has long had a problem with crop destruction caused by pests, including squirrels and even blackbirds. Combating this problem has been a costly process for growers, but they’ve managed to reduce infestations with the employment of pesticides, fences, and traps.

In 2009, a study was conducted by the California Department of Food and Agriculture—in partnership with the National Wildlife Research Center—on the annual effects of rodents on 22 agricultural commodities across 10 counties throughout the state. The study produced the following findings:

  • $168 million to $504 million in estimated loss of revenue
  • 2,100 to 6,300 jobs lost

In Monterey County, California, crop damage caused by rodent infestation was responsible for between $44 million and $128 million in annual revenue loss, as well as 515 to 1,514 jobs.”

As you can see, ecologically sound rodent control practices can help control the losses of crops (and profits) to farmers, but help keep down food prices for the general population.


The second issue with pest control is the weather.  When rain regularly comes, rodents multiply—there is plenty to eat and drink. When drought comes, rodents multiply less for survival.  When the rains come around again, rodents make up for lost time and as has been seen by the mouse plague in Australia, overpopulates.  Rodent species differences, and ecological differences in crops require different multipronged approaches to rodent control.

Rodent Control in Tropical Crop Agriculture

 For instance, rodent control for tropical agriculture such as in Florida and California must deal with alternating dry and wet seasons, when rodent reproduction can vary wildly.  The approaches as described by a study done by Fall and Fiedler on the USDA website called “Rodent Control in Practice (2015) are: sustained baiting method, which was developed in the 1970’s is a continuous, low level input which is monitored and replaced as bait consumption increases during the crop season, and pulsed baiting method, which promotes the application of second generation anticoagulants at intervals, which is designed to reduce labor and the amount of bait used, chemical repellents, disruption through natural means or human intervention, encouraging predators, putting up barriers or fences, including non-lethal electric barriers, and trapping, which, according to the USDA, has been particularly effective in deepwater rice growing operations.  Finally, habitat manipulation can be effective in reducing rodent populations.   Another interesting method is simply tolerating crop damage:

“In any rodent damage control effort there are three basic strategies to choose from: tolerance of the damage, management of the damage, or eradication of rodents. Tolerance is practised by both farmers and government officials. It is usually selected because of apathy, a lack of awareness of crop damage, unfamiliarity with other options, or because of religious, social or legal taboos against harming animals. Tolerance may be useful when control requires more effort and cost than simply accepting crop losses. Permanent or temporary eradication of rodents from crop areas is generally not practical or ecologically sound.”

With this in mind, tropical agriculture in other countries is beginning to experiment with artificial intelligence.

Artifical Intelligence Experimentation Being Done in Spain

Spain is famous for its olive trees, and thus has an olive industry that makes Spain number one in the world for olive oil production, and their export turnover exceeded 2 billion euros (2,324,298,000.00 USD).    According to South EU Summit, most of Spain’s olive production is centered around its southern coast near Andalucía. Right now, artificial intelligence is being used to study how the olive’s biggest enemy, the fruit fly, might be controlled, but this could also in future be extended to rodent control:

“The Andalusian Phytosanitary Alert and Information Network (RAIF) is a project of the Ministry of Agriculture, Fisheries and Rural Development financed by the European Agricultural Fund for Rural Development (EAFRD), which provides updated information on the phytosanitary status of the main crops of Andalusia.

The network relies on the work and collaboration of about 700 field technicians, mainly from the production sector itself, as well as 4,621 control stations distributed in different crop areas, with which they exchange the information and data they collect.”  

Meanwhile, back in North America….

Big Data is already being used in US agriculture, and we discussed in an earlier article how

collaborative practices amongst farmers and in urban areas in reporting pest infestations in conjunction with a multipronged pest control strategy utilizing traps, rodenticides and GIS are helping US and Canadian farmers control rodents. Crop rotation is a disruption method that disrupts the life cycle of many pests and is good for maintaining good topsoil. 

Cisse W. Sprague in her article “Advances in IPM Rodent Control in Agriculture,”   discusses how IPM (Integrated Pest Management) help protect crops in storage, and while crops are in the field. Eliminating excess weeds in-crop, garbage, piles of junk, burning fields after harvest to kill or displace rodents, which is used regularly in sugar cane. Poison baiting is used in conjunction with these other methods when rodents present a major threat to crops.  The article asses the pros and cons of poison baiting:

“There are three main classes of rodenticide poisons in use today. The oldest are the acute poisons which include compounds such as arsenic, strychnine, zinc phosphide, sodium monofluoroacetate, and others. Of these, zinc phosphide is the safest and the only one still allowed for use in many developed countries. Traditionally, acute poisons have been available for purchase in technical active form either legally or otherwise by end-users to mix with various food materials and make up their own baits. Besides potentially inviting opportunity for accidental poisoning, these baits are often not particularly effective. Acute poisons share a common problem in that they act very quickly and rodents will become ill shortly after eating the bait. They then associate this illness with the bait and will not eat it again. This effect is known as bait shyness and occurs with all acute poisons. If the rodent did not eat enough to kill it in the first feeding, it will not eat the bait again and not die. Because of bait shyness, an acute bait should not be used at less than 60 day intervals and even in the best circumstances 100% control will not result in the field. Due to the bait-shyness effect and the often relatively poor quality of “home-made” formulations, control results are often quite poor with acute home-made baits. In the United States today, zinc phosphide is the only rodenticide allowed for in-crop baiting due to its lack of crop residue problems and lack of secondary hazard effects (predator animals eating dead rodents and also dying from the poison). A sophisticated, ready-to-use pelleted formulation of zinc phosphide has been developed in the US which is highly palatable (attractive) to rodents, relatively safe to use, and water-resistant for baiting in crops such as sugar cane. Such formulations are still quite economical to use and are aerially broadcast over large land areas. Due to the bait-shyness effect however, it is generally impossible to achieve 100% control with an acute bait.”

Anticoagulants are also used, but while avoiding the bait shyness problem, present a resistance problem in consequent generations of rats so become less effective over time.

Trapping Is Underrated, and an Excellent Strategy for Farmers According to the University of Florida

The University of Florida Agricultural Extension, on the other hand, advocates trapping as an underrated, effective, ecological strategy for rodent management on the farm. In their article “Controlling Rats and Mice Around the Farm,” they point out that rats and mice don’t really have a large range of movement, and thus, respond well to trapping:

“Since rodents have a small home range, rats travel no more than 100 feet and mice less than 30 feet from their nesting site, trapping is an effective, quick and economical method of control. Trapping is often underrated, especially where only a few rodents are present. Common snap traps, glue boards, and live traps can be used to supplement baiting programs, or in situations where baits may pose a hazard. Traps should be placed along walls, near holes, or at right angles along beams, rafters, or other travel ways. Traps may be baited with a variety of food items such as whole nuts, peanut butter, or small pieces of meat.” We advocate using the same food source at location they are currently eating, effective particularly with rats, making them less circumspect. 

The University of Massachusetts at Amherst Center for Agriculture, Food and the Environment also encourages the use of traps as well as keeping barns clean, garbage picked up, and no access to potential food supplies which means good crop storage practices:

“Snap or box traps are useful in eliminating rodents. Rats are more distrustful of anything new in their environment and it may take 4-5 days before they are used to the traps. Live traps are good to use near runways used by mice and rats.”

The University of Florida Agricultural Extension promotes IPM using both traps and baits, recommending although it disagrees with the previous article in that it discourages the use of zinc phosphide which although it offers little risk of poisoning beneficial predators, is not appropriate for use around children, pets or livestock. 

We concur with both universities regarding implementing traps as part of your IPM, and we really want to become part of your farm operation’s Integrated Pest Management program. We have a wide variety of traps for all your needs, including squirrel, mole, rat and mice infestations, and we are here to consult with you whether you are just starting to put together or manage your current Integrated Pest Management strategies.  Tell your neighbors about us.

Visit us at  PestWorld 2018 meeting on October 23rd – 26th in Orlando, Booth # 733, Chat with us about your challenges


Tags: Agriculture, artificial intelligence, California Department of Food and Agriculture, Environmental impact, Farming, Fenn Trap, Instructional, Integrated Pest Management, Mk 4 Fenn Trap, MK6 Fenn Trap, Mole traps, National Pest Management Association, National Wildlife Research Center, NPMA, Pest Control, Pesticide, PestWorld2018, Public Health, Rat infestation, Rat poisen, Rat Traps, Rats, Tropical Crop Agriculture, USDA, Wildlife removal

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