When most people hear the word “pest” they might think of something that is bothersome, or a nuisance. But for farmers around the world, the word evokes something much more alarming.
Given that 40 percent of global crops are lost to agricultural pests each year, and that those losses could double without modern crop protection tools, it’s worth taking the time to learn more about the challenges modern farmers face.
Regardless of where they are grown, all crops face threats from insects, weeds, and diseases. As a result, crop protection is a global necessity, requiring a variety of tools and practices. Making things even more complicated is the fact that a plant or insect that is harmless in one region could wreak havoc in another. Conversely, what works in one region could be ineffective elsewhere.
These are among the reasons why farmers spend so much time thinking about, planning for, and acting on crop protection needs. As with any problem-solving endeavor, the best chance for finding a solution starts with identifying the problem.
Let’s take a closer look at five of the agricultural world’s most dangerous, damaging, and costly insects, weeds, and diseases.
Perhaps the most devastating species of rootworm in North America, its larvae have wreaked havoc on Corn Belt farms for the past two decades. According to the USDA, it causes roughly $1 billion in damage annually.
Farmers use a combination of methods to control rootworm populations. Crop rotation helps prevent the species from reproducing year over year. Genetically modified Bt corn targets rootworm larvae as they feed on crops without affecting beneficial insects and other organisms. Advanced breeding methods have also been used to develop corn that can defend itself against these agricultural pests in a very precise manner, by preventing the expression of certain genes necessary for rootworm survival and reproduction.
Cassava is among the most important African tuber crops, providing nutrition to roughly 700 million people in the eastern and central regions of the continent. Whitefly is estimated to cause around $2 billion in damage annually.
Whitefly is known for evolving resistance to pesticides1 very rapidly. As a consequence, this quick adaptation makes using these products much more challenging. Current strategies involve advanced breeding and genomics, with the goal of developing cassava that is resistant to the diseases spread by whitefly. Another promising approach, especially for diversified smallholder farmers, is intercropping. This practice of planting other crops in close proximity helps reduce pest pressures on any one crop by attracting predator pests, creates shade to block weeds from sunlight, and provides other benefits like improved yield potential. However, intercropping is difficult to scale as operations grow.
Palmer amaranth has emerged in recent years as a growing threat to cotton and soybean crops. Known for its ability to rapidly colonize fields, its stalks can be up to 10 feet tall and grow strong enough to impede or even damage mechanized harvesters. Some cotton growers in the Southeastern U.S. have witnessed entire fields taken over by pigweed, which aggressively competes with the crops for sunlight, nutrients, and water, rendering harvest impossible. In many regions, it has even developed resistance to certain herbicides, adding to the challenge of controlling it.
Though every set of circumstances is unique, a general pattern has emerged for effective control of pigweed. It involves crop rotation, early detection strategies, the use of pre-emergence (before the seeds have broken the soil surface) herbicides, regular scouting of fields, and using multiple types of herbicides if topical application becomes necessary. In recent years, the planting of cover crops has shown promise in preventing weeds from emerging.
Considered the most damaging brinjal pest in South and East Asia, the fruit and shoot borer has the potential to render entire crops unfit for human consumption. These harmful insects have a habit of infiltrating the most tender and desirable part of the fruit. In regions where brinjal is a staple crop, this can be catastrophic.
Until recently, a patchwork of methods was used to prevent crop losses. These include crop rotation, the disposal of the previous season’s crop stubble, the use of pest-free seedlings, vigorous scouting, and the removal of infested shoots by hand or machinery. Then in 2015, Bt brinjal was introduced to Bangladesh, where it has since been used successfully. This genetically modified version of brinjal produces a protein that targets fruit and shoot borers in their larval stage, preventing crop damage.
First discovered in China in 1943, HLB can be translated as “yellow dragon disease” in Chinese. Within three years of its 2005 arrival in Florida, HLB had traveled to nearly every citrus growing region in the state. Its impact on the orange industry has intensified in recent years, causing $4 billion in damage along the way.
There is currently no effective way to heal the affected plants. To prevent its spread, infected groves are often destroyed. However, the USDA continues to provide millions in research grants to various universities in search of a solution. If successful, creating an effective and scalable method of control will provide relief and growth across the citrus industry.
For the world’s farmers, crop protection is serious business, requiring considerable time and resources. The pests featured here are just a sampling of the many insects, weeds, and diseases that regularly make farmers’ jobs harder. As a global industry, modern agriculture is dedicated to finding solutions to help farmers address these challenges. Whether it’s the next generation of precision technologies and chemistry, conservation practices, or other areas of innovation—crop protection will remain a top priority for years to come.
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