Can nanotechnology combat soybean pests?

  • By Sean Clougherty, Managing Editor – Delmarva Farmer

    Thursday, November 2, 2017
    Dr. Naveen Kumar - horticulturalist / Extension specialist

    Nanotechnology, using particles about a billionth of a meter in size, has helped improve products from clothing to golf balls to sunscreen. At the University of Maryland Eastern Shore, a researcher is investigating how it can be used in soybean production.  

    The Maryland Soybean Board this spring approved $26,500 in funding for research using nanotechnology to help control some common soybean pests.

    Led by Dr. Naveen Kumar, assistant professor of horticulture at UMES, the project's objective is to evaluate nano-clay, nano-zinc oxide, nano-sulfur on common soybean pests at the plant's critical growth stages in greenhouse conditions as well as in field conditions with potted soybean plants. 

    Kumar calls the research “green technology” since clay and zinc compounds are naturally occurring minerals and have potential to decrease pesticide use and to be used in U.S. Department of Agriculture organic growing systems. 

    The research was one of 18 projects approved for funding by the Maryland Soybean Board, which administers soybean checkoff funds for research, marketing and education programs in the state. 

    Brian Johnson, a Somerset County farmer and chairman of the board's research committee, said the nanotechnology project was much different than many of the proposals it receives but could lead to better soybean growth if shown to be effective. 

    “You've got to be willing to try something new to increase efficiency,” Johnson said. “We're always looking to decrease chemical use … especially if it decreases costs.” 

    Through in vitro experiments with petri dishes coated with nano-particles, and another using single soybean leaves, Kumar evaluated the nanoparticles in controlling soybean looper and beet armyworm larvae. 

    In the coated petri dishes, more than 80 percent mortality was observed within five hours of treatment in all larval stages of soybean looper; 100 percent was achieved within 24 hours of treatments. 

    Similar observations were recorded for armyworm larval stages, but 100 percent mortality was achieved after 48 hours of treatments. 

    Kumar said larval populations in all the stages of development showed common characteristic signs of mortality. These observations indicate nanoparticles mediated rupture of the insect's larval cuticle, which led to desiccation and death. 

    “All the treatments were effective in control of soybean looper and beet armyworm larval populations using these in vitro conditions,” according to a progress report Kumar submitted to the soybean board. 

    Using research cages in a second in vitro experiment, adult cucumber beetles and Japanese beetles were released on nano-zinc oxide-treated soybean leaves and untreated leaves. 

    Kumar said one hypothesis tested was whether insects ingesting nanoparticles with leaf material would die. 

    In cages featuring treated and untreated leaves, Kumar said the insects preferred the untreated leaves. Without untreated leaves, both insects fed on the treated leaves with no insect mortality, which Kumar said suggests nano-zinc oxide can be used as a repellent to prevent Japanese and cucumber beetle infestation. 

    There also is a possibility, however, these insects may attack alternate hosts, Kumar noted. The lack of mortality could signify the application rate was too low. Rates too high could also impact production. 

    Using potted soybean plants set outdoors on the UMES farm in July, Kumar applied nanoparticles periodically though their growth stages and continued until maturity. 

    Kumar is collaborating with Dr. Sudipta Seal, a University of Central Florida professor, on using their nano-clay formulation. Other universities also are studying nanotechnology in fertilizer, testing its effectiveness in reducing application rates and its capacity for slow release. 

     If funded for a second year, Kumar said he plans to repeat the experiments in greenhouse and field conditions.  


    Editor's note: This article was originally published by The Delmarva Farmer and is reproduced here with the newspaper's permission.