Is bacteria a viable alternative to pesticides?

Sep 23, 2018

With many now choosing to eat organic and concern growing regarding how pesticides are adversely affecting pollinators, alternative solutions would most likely be welcomed with open arms. However, with news that bacteria could replace pesticides, would this be so welcome? Even if consumers and producers endorsed the idea, is it even a credible option?

Utilising microbes as a form of biopesticide isn't actually such a new concept:

'Organic farmers have long used bacteria called* Bacillus thuringiensis *as a pesticide, and the gene for its insect-killing toxin is genetically engineered into most corn and cotton grown in the US' 1

However, with increasing concerns regarding the environmental impact of synthetic chemicals and the advancements in technology / microbiology, biopesticides are hitting the headlines again. As well as receiving more publicity, microbial pest control and other biopesticides are receiving bigger chunks of the market share:

'The biopesticides market grew 24% from 2014 to 2016 globally to over $1.8 billion' 2

Not only is the biopesticide market share growing rapidly but biopesticide growth rates are expected to surpass sythentics by the mid century:
'Growth of biopesticides is projected to outpace that of chemical pesticides, with compounded annual growth rates of more than 15% [7]. It is expected that biopesticides will equalize with synthetics, in terms of market size, between the late 2040s and the early 2050s' 3

So, what are the benefits of adopting the use of biopesticides? As explained in 'Microorganisms in Biological Pest Control — A Review (Bacterial Toxin Application and Effect of Environmental Factors)', the author notes that:

'They have efficiency and safety for humans and other nontarget organisms. They leave less or no residue in food. They are ecologically safe, so that other natural enemies are free of their threatening, leading to preservation of other natural enemies, and increased biodiversity in managed ecosystem.' 4

This all sounds good, but who is developing biopesticide technology and how does it work?

Agricultural Technology startups such as Indigo (with a microbiologist co-founder) are at the forefront of this revolution in agricultural pest control
Indigo Agriculture and other startups in the industry are developing (among other things):

  • Pest control using microbes
  • Nitrogen producing plants using microbes
  • Products that reduce stress in plants and increase survival (such as when in drought conditions) using microbes 5

Plants that thrive in difficult conditions are collected and the microbiomes of these plants are analysed using genetic sequencing. Once a pattern emerges of which microbes are more frequently present in the plants that are more successful and healthier, these microbes are used in further testing to assess if they can help plants survive stressful conditions. 6

Indigo in particular hope to use these experiments and develop the technology to rely on microbes and reduce the need for chemical pesticides, fertilisers and GM seeds.

Indigo's trials and products have proven successful. Their first product Indigo Cotton™  was launched in Spring 2016. 7 Later in the same year, Indigo Ag launched their second product Indigo Wheat™ (both products being seeds coated with microbes). 8

As reported by Bloomberg:

'microbe coatings have boosted cotton yields by an average of 14 percent in full-scale commercial trials in Texas and wheat yields by as much as 15 percent in Kansas' 9

This is not the only way in which bacteria is being used as a non synthetic form of pest control. Researchers from the Werner Siemens Chair of Synthetic Biotechnology at TU Munich have developed an insect repellent that is biodegradable and not harmful ecologically. Their focus has been on creating a solution that aggravates pests but is not poisonous and therefore does not harm pollinators. 10

Inspired by a molecule that the tobacco plant naturally produces to protect itself from pests and utilising biotechnology, the team isolated the tobacco plant genome that forms the pest resistant molecule. The sections of the genome that were isolated were then built into the genome of bacteria, specifically coli bacteria. Once fed with wheat bran, the bacteria produced the active ingredients needed. These ingredients were separated using centrifugal separation chromatography and this resulted in a spray that could be tested. The results suggest that the spray is biodegradable and non toxic to insects, a repellant in contrast to the poisonous synthetic pesticides currently available. 11

As mentioned above, it's not only pesticides that researchers are trying to replace with bacteria. Nitrogen fertilisers are inefficient and harmful for the environment as eloquently explained here by Dr. Pham Thi Thu Huong, from the Field Crop Research Institute:
'Rice, like other crops relies on getting its essential nutrients from nitrogen fertilizer, but over 50% of the fertilizer used either evaporates, or washes away....It forms nitrous oxide which is 300 times more harmful than carbon dioxide as a greenhouse gas.' 12

This is why in Vietnam, Dr. Pham Thi Thu Hong and other researchers are trialling the use of nitrogen fixing bacteria (sourced from sugarcane sap) to help solve this problem. In similar ways to the methods mentioned above, the team are accomplishing this by treating some seedlings with the bacteria whilst leaving others to grow without and comparing the rates of growth. 13

The bacteria coating aids the plant in absorbing nitrogen from the atmosphere making it no longer reliant on the fertiliser. As nitrogen fertiliser has caused pollution of waterways which has led to the occurence of marine deadzones, it is just as important to find alternatives to this destructive agricultural component. 14

So what does the future look like for agricultural pest control?

Driven by consumer demand for cleaner alternatives to toxic chemicals, big agriculture (Monsanto, Bayer, Dupont)is already investing heavily in microbial biopesticides. In addition to this, several agricultural startups are providing innovative solutions that are yielding impressive results. This all points to a bright future for agricultural microbial products.

References:
1 https://www.wired.com/2016/03/good-riddance-chemicals-microbes-farmings-hot-new-pesticides/
2 https://www.hortweek.com/global-biopesticides-market-grew-24-two-years/plant-health/article/1458625
3 Damalas, Christos A. and Koutroubas Spyridon D. 2018. Current Status and Recent Developments in Biopesticide Use www.mdpi.com/2077-0472/8/1/13/pdf
4 Usta, C. 2013. Microorganisms in Biological Pest Control — A Review (Bacterial Toxin Application and Effect of Environmental Factors) https://www.intechopen.com/books/current-progress-in-biological-research/microorganisms-in-biological-pest-control-a-review-bacterial-toxin-application-and-effect-of-environ
5, 6, 9 https://www.bloomberg.com/news/articles/2018-04-16/indigo-s-scientists-are-replacing-pesticides-with-bacteria
7 https://harvardmagazine.com/2018/03/sustainable-agriculture-and-food-security
8 https://www.indigoag.com/pages/news/press-release-indigo-wheat
10, 11 https://www.hortweek.com/biodegradable-crop-protection-product-research-paper-published/plant-health/article/1484478
12, 13, 14 https://www.bbc.co.uk/news/business-44357673

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