Developing a Pesticide Resistance Management regime utilizing soluble silicon fertilizer

Commodities

• Additional Plants: ornamentals

Practices

• Pest Management: integrated pest management

PROBLEM & RESEARCH: Growers understand that the sole use
of chemicals to control insect pests is not a sustainable
long-term solution (Seal et al., 2013), and creates high
selective pressure for pest resistance. Hawaii Floriculture and
Nursery (HFN) industries’ reliance on chemical management stems
from the wide range of invasive pests they encounter due to the
diverse crops grown by this industry.

Silicon-medicated plant resistance to herbivorous insects has
been well documented over the past two decades. This project will
expand upon research by Bloese et. al. 2023 (In Review) that
found significant benefits of Si to reduce various invasive
invertebrates and fungal pathogens in nursery crops.

This project will conduct applied research through on-farm trials
to quantify reduction in pest and disease densities, yield
differentials, and changes in plant physiology among four Si
augmented pesticide regimes across four species of ornamental
crops. Research results will inform a resistance management
strategy which will reduce growers’ reliance on chemical
controls, reduce the high selective pressure for resistance, and
improve overall sustainability of the industry.

SIGNIFICANCE & OUTCOMES: Hawai’i’s potted plants and cut flowers
represent approximately 45% (almost $35 million) of a $77.6
million HFN industry in 2017 (HDOA Annual Summary, 2018).
Additionally, HFN industries have a rich cultural and
environmental significance. They produce flowers and foliage for
lei and hula, as well as many native plants. Minimizing pesticide
use for this industry will: (a) protect the biosecurity of native
plants, (b) increase industry profitability, (c) increase the
health and safety of farm systems and workers, and (d) reduce the
selective pressure for resistance by invasive pests.

EDUCATION & DISSEMINATION OF RESULTS: Outreach and education
objectives will incorporate research results in the development
of a Si enhanced pesticide resistance management program and
updated Best Management Practices (BMPs). The active
participation of stakeholders in the project enhances ease of
dissemination of project results through Field Days, extension
publications, webinars, conferences and peer-reviewed
publications. These modes of communication will ensure that the
project findings reach and benefit a broad audience, including
growers, researchers, industry stakeholders, and policymakers. A
series of questionnaires and surveys will evaluate the long-term
adoption of BMPs by growers.

Logic Model for Silicon-Enhanced Pest
Management.

This logic model illustrates the flow from resources and actions
to the anticipated results and eventual broader impacts of the
research and education project.

RESEARCH PLAN

Objective 1: Conduct five multi-island on-farm trials to
evaluate the efficacy of four Si-augmented pesticide regimes
across key ornamental crops in Hawaii. Efficacy of the four
pesticide + Si-augmented treatment groups will be determined
through the following sub-objectives. (Specific treatment
levels are detailed in Research Plan section of the
Narrative). 

Subobjective 1(a): Determine yield differential and flower
quality among Si treatment groups.

Subobjective 1(b): Quantify pest composition and prevalence among
Si treatment groups.

Subobjective 1 (c): Quantify disease composition and prevalence
among Si treatment groups.

Objective 2: Assess changes in plant physiology to better
understand mechanisms of plant protection by Si to maximize
resource efficiency and optimize application. This will be
achieved through the following subobjectives. 

Subobjective 2(a): Measure canopy size, stalk number or root mass
to quantify gross plant growth across Si treatment groups.

Subobjective 2(b): Quantify Si, nutrient, and chlorophyll content
in plant tissue among Si treatment groups. 

Subobjective 2(c): Image leaf surfaces and tissue sections among
treatments and crops to quantify stomata and trichome number and
document organ size and structure, respectively, to evaluate
possible morphological markers for physiological effects of
Si.  

Objective 3. Conduct cost-benefit analyses to assess the
economic viability of using Si as an amendment in pesticide
management regimes.

EDUCATION PLAN

Our Education Plan is three-fold.

Objective 1: Develop Best Management Practices (BMPs) for
pesticide resistance management in nursery crops that are
practical, effective, and adopted by stakeholders.

Objective 2: Promote long-term sustainability of BMP
adoption through active learning and student-centered education
outreach activities.

Objective 3: Reassess adoptability of BMPs by addressing
concerns and misconceptions related to BMPs, providing
information to mitigate perceived risks, as well as develop
strategies for scaling up BMP adoption through
grower-extension-researcher collaborations.