2 February 2023

US potatoes survive pests thanks to lobster shell


Ground lobster shells can feed communities of beneficial microbes, creating a line of defense against soil pests. Researchers from University of Maine researchers offer a potential circular solution to safeguard the state’s major crop. Which would also avoid tons of waste

by Matteo Cavallito


Researchers at the University of Maine believe they can use of lobster shells to naturally counter pathogens plaguing potato fields according to a press release. The investigation, which is still ongoing, aims to offer a solution that can link “two cornerstones of Maine’s food system and enhance the state’s circular economy.”

Potatoes are the leading agricultural commodity in the northeastern U.S. state, with sales topping $215 million in 2021. But diseases have always posed a serious threat with most affected crops recording mortality rates as high as 50 percent. The researchers’ hypothesis is that different concentrations of cooked, dried and ground lobster shells can prevent potato disease in combination with several factors: soil microbial communities, overall crop yield and plant traits.

Microbes love lobster

The focus of scientists’ interest is chitin, a substance that makes up 75 percent of lobster exoskeleton and is also contained in fungal and bacterial pathogens. According to Katie Ashley, one of the researchers involved, adding the shells to the soil could stimulate the growth of certain beneficial microorganisms that specialize in breaking down the chitin. These microbes, which are already found in the soil, could turn into a line of defense against pests.

The idea is based on the results of some previous experiences. “Chitin from other types of shellfish is already part of integrated pest management programs on farms in South Korea, Japan and California,” says the statement.

The first greenhouse trial, conducted on 90 plants on the University of Maine campus this fall, provided positive indications. Preliminary results, in fact, “indicate that the amendment also benefits aboveground plant growth by an average of 200%.” Further field trials are planned in the coming months.

Are microorganisms better than pesticides?

The research follows other initiatives designed to harness the ability of microbes in promoting soil balance and productivity. “Soil microorganisms are the key to improve soil quality and can be measured as an indicator of soil health,” says Jianjun Hao, a professor at the University of Maine and director of the laboratory involved in the research.

Moreover, “These beneficial microorganisms are highly driven by soil amendments such as crops, plant residues, animal manures and, in this case, lobster shell meal.”

The success of the proposed technique would also provide growers with a viable alternative to the use of chemicals. “Reducing the reliance on pesticides for disease management in favor of enhancing microbial soil ecology could benefit both agriculture and the environment,” Ashley says.

A circular solution

Finally, one of the most interesting points of the research lies in the circularity of the assumed solution. The use of lobster shells would make it possible to exploit a resource too often wasted by the local fishing industry. In 2021, according to data from the Maine Department of Marine Resources quoted by the University of Maine, fishermen in the state caught about 45 thousand tons of lobsters.

Nearly half of these were processed before being placed on the market largely leading to the disposal of the shells (which account for a quarter of each lobster’s weight) in landfills. Opening a new market for this by-product, the researchers explain, would reduce the waste stream while offering significant benefits for soil.