If you are a fan of The Office, you would surely be familiar with the proverb “The enemy of my enemy is my friend.” Who can forget a smirking Dwight Schrute using this logic to plot against a colleague in an iconic scene from the hit comedy TV series? Perhaps the most historic illustration of this proverb was during World War II, when two notorious adversaries— the United States and the Soviet Union— joined hands to fight their common enemy, Nazi Germany. Well, you may be surprised to know that forming unlikely partnerships to tackle a shared enemy is not just a clever strategy in politics and high school gossip gangs. For farmers, forming alliances with crop pests’ natural predators could be a game-changing strategy to save their crops from these troublesome bugs.
Insect herbivores are one of the peskiest perils in agriculture. These pests are always lurking around, waiting for the right time to steal a meal from plant leaves, fruits, and roots. Whether they feed by chewing plant parts, sucking sap, or boring tunnels in fruits, they wreak havoc on crops. Unlike us fortunate animals who can simply swat away hungry mosquitoes encircling our bodies, plants don’t have the luxury of movement to shoo away insect pests. Being rooted in the same place for their entire lives, they can be severely damaged or killed by such hungry attackers, leading to devastating crop losses in agriculture. Traditionally, farmers have heavily relied on pesticides to manage these infestations. However, amidst the growing concern over their environmental and health safety and the development of pesticide resistance, researchers are exploring another solution: teaming up with the insects’ natural enemies to kill these pests and protect the plants.
Forging friendships with fungi
Entomopathogenic fungi— fungi that infect insects— are a fascinating group of microorganisms that regulate insect populations in natural ecosystems. Some common examples that can attack a variety of insects are species of Beauveria and Metarhizium. These fungi are specialized to derive nutrients for growth by attacking and killing insects. Since they do not infect plants, they have gained significant interest as allies to crop growers looking to eliminate insect pests. When entomopathogenic fungi’s spores land on an insect’s body, they germinate into hyphae that penetrate the insect’s tough chitinous exterior using cuticle-degrading enzymes. The battle for life between the two commences; the hyphae bore their way into the internal body cavity and rapidly propagate there. The insect’s immune system tries to attack the fungal cells while the fungus counter-defends with toxins, immunity suppressors, and specialized metabolites that go unrecognized by the insect’s immune system. The battle continues until the pathogen ultimately kills the insect. Soon after, the hyphae grow outwards from the body cavity and over the cadaver’s exterior, where they sporulate and can spread to other insects (Figure 1). Many entomopathogenic fungi can infect insects throughout their life from eggs to adults. This is particularly advantageous as they can be used in fields to effectively control pest populations at all different developmental stages.
Studies are underway on how we can sustainably leverage these fungal allies to mitigate insect pests and protect crops. Some species of Beauveria and Metarhizium already show promise. However, a major practical obstacle when spraying fungal spores on crops is that the spores require moisture and high humidity to germinate and spread. In field conditions, this is often difficult to achieve because spore-containing formulations lose water and dry out in the hot environmental conditions. To solve this problem and create a friendlier environment for spore germination, scientists recently designed a formulation that can meet the fungus’s moisture needs even in low-humidity environments. The research group developed a superabsorbent paste-type formulation containing cellulose and xanthan gum among other ingredients. This paste was highly efficient in absorbing and retaining water, keeping fungal spores sufficiently moist for high sporulation even under 40% relative humidity. Although a few previous attempts were made to design such water-retaining formulations, these relied on synthetic non-biodegradable polymers. In comparison, this novel cellulose-xanthan-based formulation’s biodegradability is a highly advantageous feature.
Teaming up with the enemy’s enemy is a promising approach for mitigating pests and protecting our crop plants while minimizing toxic environmental impacts. This strategy has also garnered interest in solving other insect-related problems, including the control of human disease vectors such as mosquitos. As researchers continue to explore ways to harness the power of biocontrol, here’s hoping for a near future where our fruits and vegetables aren’t soaked in layers of pesticides!
Dr. Gauri Binayak
Ph.D., Dept. of Biology, Indian Institute of Science Education and Research (IISER), Pune
About the author: My curiosity about the world led me to the world of science for higher education. During my Ph.D., I realized that the research we do remains understood only by a small community. To the general public, science remains a mysterious realm inhabited by strange white coat-wearing species who mix fumy chemicals and speak in complicated language. I have become deeply interested in bridging this gap through content creation.
1 Comment
Nice article Gauri It’s fascinating how the concept of “the enemy of my enemy is my friend” applies not just to interpersonal dynamics but also to ecological systems and agriculture. The idea of harnessing natural predators or pathogens of crop pests as allies in pest management is a promising avenue for sustainable agriculture. Entomopathogenic fungi, in particular, offer a compelling solution due to their ability to target specific pests without harming plants or other organisms.
The challenges associated with using these fungi in agricultural settings, such as maintaining optimal humidity for spore germination, highlight the importance of ongoing research and innovation. The development of formulations like the cellulose-xanthan-based paste represents a significant step forward in making biocontrol methods more practical and effective.
Furthermore, the potential applications of this strategy extend beyond crop protection to areas like controlling disease vectors, which could have significant implications for public health.
Overall, the idea of forming alliances with nature’s own pest control agents represents a promising direction for reducing reliance on chemical pesticides and promoting more sustainable agricultural practices.