Examining the biofumigation and innate potential of ground papaya seeds to induce host plant resistance against soil-borne pathogens in Hawaii

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Commodities

• Fruits: papaya
• Vegetables: cucurbits, greens (leafy), greens (lettuces), onions

Practices

• Education and Training: demonstration, extension, on-farm/ranch research
• Pest Management: biofumigation, biological control
• Production Systems: agroecosystems
• Soil Management: soil analysis, soil microbiology, soil quality/health
• Sustainable Communities: local and regional food systems, sustainability measures

Plant pathogens pose a serious threat to food security, and growers in Hawaii are especially challenged by pest pressure all year round. Rising cost of agriculture production inputs is calling food producers in Hawaii to adopt sustainable pest management tactics using local resources. Papaya seeds are considered as an agricultural waste in Hawaii. This project aims to evaluate the use of ground papaya seed (PGS) to suppress plant-parasitic nematodes and soil-borne fungi, as the hydrolysis of PGS produces a biofumigant, benzyl isothiocyanate (BITC), which is suppressive to many soil-borne pathogens. The novelty of this project is to explore the innate immune response of treated crops to the microbiome associated with PGS treatment. Specific objectives are to 1) examine if PGS can induce systemic resistance (ISR) of crops against broad spectrum of pests and pathogens by examining expression of ISR genes and related phytohormones, 2) evaluate the efficacy of using PGS on kai choi, onion, and zucchini seedlings through seedling media amendment to protect these seedlings at transplanting, 3) examine the adequate frequency of post-plant foliar spray vs soil drenching of transplants in fields naturally infested with Fusarium spp. or Meloidogyne incognita. We will work with three commercial farmers in Hawaii challenged by the above-mentioned pathogens, while collaborating with extension agents to disseminate research findings with vegetable crop producers in Hawaii through workshops and online extension newsletters or publications. We expect successful adoption of this local farms’ waste-based biofumigation approach to help Hawaii farmers to combat a year-round pathogen infestation problem.

Research objectives:

Objective 1: Examine if PGS can induce systemic resistance (ISR) of crops against broad spectrum of pests and pathogens by examining expression of ISR genes.

Objective 2: Evaluate the efficacy of using PGS crude extract on kai choi, onion, and zucchini seedlings through drenching of seedling media.

Objective 3:  Examine the adequate frequency of post-plant foliar spray vs soil drenching of transplants in fields naturally infested with Fusarium spp. or Meloidogyne incognita.