Pesticide resistance: A creeping problem in crop protection

February 27, 2020

NextGen Update – international connection

We reported back in August that the Crawford Fund’s NextGen program has had a boost with additional funding from ACIAR to carry out some activities in addition to our student awards (currently open) ), conference scholarships and volunteering opportunities, which are all still very active. These additional activities have been receiving lots of support and encouragement.

“We are finding that existing Australian stakeholders promoting agriculture to high school and university students have responded very positively to the opportunity of having the Fund provide a focus on international agriculture,” said Cathy Reade, the Fund’s Director of Outreach who is managing the NextGen work.

Cathy reports that in the project’s first six months, a broad number of partners have been found and engaged, nine NextGen events had been organised around the country, seven external blogs and opinion pieces have been produced, a set of videos have focused on volunteering opportunities with the Fund, our social media channels have been getting lots of NextGen interest, and Instagram guidelines have been developed and are now being piloted when we have trainers and awardees overseas. We are also working on developing some food security curriculum materials for high school teachers and hope to be further highlighting career pathways at upcoming ag shows and career days.

More recently, approaches have been made to some institutions making international efforts to encourage the ‘NextGen’ including to the Borlaug Training Foundation and YPARD, who are going to make use of some of our Australian blogs to their audiences.

The Fund was pleased to learn of the NextGen Plant Science Network which supports next generation plant scientists through training, professional development and mentorship. In support of these efforts, the Fund is happy to present the blog by one of the Network’s ambassadors on pesticide resistance and how it can be avoided – an issue as important in Australia as it is in the developing world.

Pesticide resistance: A creeping problem in crop protection

A farmer spraying pesticide on cabbage plants.

By John Julius Manuben, NextGen Plant Science Network

“By their very nature, chemical controls are self-defeating, for they have been devised and applied without taking into account the complex biological systems against which they have been blindly hurled.”
Rachel Carson, Silent Spring

Rachel Carson was an American marine biologist, author, and conservationist who has given the world a new perspective on the use of pesticides through her book Silent Spring, published in 1962. Rachel discussed in her book the results of improper and careless use of chemicals to control pests in crops, which resulted in the fast development of pests that are resistant to pesticides.

What is pesticide resistance and why is it important?

Pesticide resistance is the decrease in the susceptibility of pests to pesticides. It can be observed when there is a failure of the pesticide to control the pest using the given-approved recommended rate.

To illustrate, a farmer plants tomatoes the whole year round, using pesticide to control the different insect pests like aphids, cutworms, and beetles. When a pesticide is applied to the crop, a tiny number of the pest population, say 1 in 1 million, may withstand the exposure from the pesticide due to carrying a resistant gene. When the surviving pests reproduce, some of its offspring may inherit the resistant gene, which is then resistant to the pesticide. This produces a population of pests which are not affected by the pesticide. If the farmer continues to use the same pesticide repeatedly for a long period of time, the population of the resistant organisms will increase until the entire population of the pest is resistant to the pesticide.

The practice of using the pesticides with the same active ingredient and pesticides with the same mode of action constantly could result in faster development of pesticide resistance which leads to decreasing effectiveness to control the insect pests. Ultimately, the uncontrolled pests result to losses in yield which translates to a large reduction in the farmer’s income and livelihood.

Illustrating the development of pesticide resistance.

What needs to be done to combat resistance?

The best way to avoid the development of resistance is by following Integrated Resistance Management (IRM). This is an assimilated approach where resistance management programs are incorporated in Integrated Pest Management (IPM). IRM involves the three basic components: monitoring of the pest, focusing on guidelines when management is needed, and integrating control strategies.

Monitoring Pests: This is an important practice and supports the adage, “know your enemies”. Farmers should be aware of the pest population in the fields as well as its possible natural enemies.

Focusing on guidelines when management is needed: After assessing the pest population, the farmer should decide if using pesticide is necessary or not. It is crucial to consult local advisors about the pesticide/s or biocontrol agents to be used.

Integrating control strategies: First, use only registered pesticides for the control of specific pests. Make sure to follow the label recommendations regarding its rate of usage, frequency, interval, and timing of application. Second, spray equipment should be properly calibrated and checked on a regular basis. Third, alternate the use of different pesticide classes. It is important to know the mode of action (MoA) grouping which will be the basis on what pesticide to use for rotation to avoid using the same MoA consecutively. Lastly, destroy crop residues that can be the source of food and possible pest alternate hosts.

To learn more about resistance and pesticide mode of action grouping for insecticides, you can visit the Insecticide Resistance Action Committee (IRAC) website.

About the author

John Julius Manuben is a chemist and an MS Agricultural Chemistry student under the Pesticide Management Division, National Crop Protection Center at the University of the Philippines Los Baños. He is currently working on pesticide residue analysis using chromatographic and rapid detection tools with emphasis on food safety. He is also an Ambassador for the NextGen Plant Science Network, a global community of early career professionals and students in plant science, supported by CropLife International.