A Superhero without a Cape: Using the Cover Crop Sunn Hemp to Feed the Soil, Suppress Nematodes and Smother Weeds

Project Overview

Project Type: Professional + Producer
Funds awarded in 2005: $7,716.00
Projected End Date: 12/31/2006
Region: Western
State: Hawaii
Principal Investigator:
Hooks Cerruti
University of Hawaii

Annual Reports


  • Agronomic: corn
  • Fruits: melons
  • Vegetables: eggplant
  • Additional Plants: herbs


  • Crop Production: cover crops, double cropping, multiple cropping, organic fertilizers, strip tillage
  • Education and Training: demonstration, extension, on-farm/ranch research
  • Farm Business Management: whole farm planning
  • Pest Management: biological control, cultural control, integrated pest management, mulches - living, mulching - vegetative
  • Production Systems: agroecosystems, integrated crop and livestock systems
  • Soil Management: green manures, organic matter, soil quality/health
  • Sustainable Communities: sustainability measures


    Even though cover crops rarely provide direct cash returns,
    they're rapidly proving their worth as off-season crops for
    helping to control insect pests, plant pathogens and weeds.
    They also reduce soil erosion, improve soil structure and
    nutrients and increase soil organic matter. This project is
    intended to demonstrate
    the value of sunn hemp as a cover crop in cucumbers. Field
    trials of sunn hemp helped determine its impact on soil and its
    effectiveness at helping to manage nematodes, insects and


    The main cash crop of the farmer producer is cucumber. However, he was suffering a significant loss in marketable yields in this crop due to plant-parasitic nematodes. Additionally, the farmer producer had discontinued growing bitter melon a high value
    crop because of continued crop failure. Subsequently, prior to initiation of this project it was determined that plant -parasitic nematodes were responsible for crop failure. The main goal of this project was to teach him and his laborers how to improve the economic viability of their farm by using the cover crop, sunn hemp as part of an integrated pest management system. Our main goals were to demonstrate how sunn hemp could be incorporated into his current production practices to concurrently improve soil health and
    nutrient level, and help suppress weed and nematode pests.

    Project objectives:

    1. Determine the impact of sunn hemp on soil and plant nutrient status.
    2. Determine the effect of sunn hemp on key nematode, weed, and insect pest populations.
    3. Quantify the impact of sunn hemp on vegetable productivity and marketable yields.
    4. Encourage Hawaiian growers to produce their own sunn hemp seedsource.
    5. Deliver an integrated, sustainable, and economically viable cover crop system to growers and educators.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.