Recipient Organization
SEPRO CORPORATION
11550 NORTH MERIDIAN STREET, SUITE 600
CARMEL,IN 46032
Performing Department
(N/A)
Non Technical Summary
Multiple exotic, invasive aquatic weeds have been introduced into the United States in the last century with major negative impacts including reduced floodwater control, disruptions to navigation, recreation, irrigation and water intake systems, and degradation of wildlife habitat. Introduced into the US in the late 1950s, the most problematic aquatic weed in the United States is currently hydrilla (Hydrilla verticillata). There is a shortage of effective, environmentally appropriate options for management of hydrilla. The use of an inundative, plant-specific pathogen for selective weed control with minimal water quality concerns would be a highly desirable approach for hydrilla management. Mycoleptodiscus terrestris (Mt) is an aquatic weed pathogen first examined for use as an inundative bioherbicide for submersed weed biocontrol in the 1970s. Initial efforts at development and commercialization were not successful due in part to lack of pathogen stability. A recent
cooperative research effort between the US Department of Agriculture, the US Army Engineer Research and Development Center, and SePRO Corporation developed new fermentation methods that produce more stable Mt materials. However, a bioherbicidal formulation of these new materials with sufficient virulence for full commercial development has not been identified. The overall goal of Phase I research is focused on determining the feasibility of an effective bioherbicidal formulation of Mt pathogen for commercialization for hydrilla control with potential translation to other target submersed weeds. The specific objectives of this research program are: 1. Test the feasibility of various combinations of Mt pathogen with formulating agents for improved bioherbicide efficacy on hydrilla. 2. Quantify changes in several physiological responses of hydrilla in early stages of Mt infection to determine which response best correlates with bioherbicide treatment efficacy. 3. Evaluate best
physiological indicator in expanded formulation screening to improve bioassay efficiency for research and future quality assurance purposes. In Phase II, necessary studies would be performed to meet standards for potential Section 3 biopesticide registration with the US Environmental Protection Agency. Ultimately, successful Phase I and II research would form the basis for the successful commercial introduction of a much-needed aquatic bioherbicide, a technology with a unique fit for a highly environmentally-sensitive market.
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Goals / Objectives
The specific objectives of this research program are: 1. Test the feasibility of various combinations of Mt pathogen with formulating agents for improved bioherbicide efficacy on hydrilla. 2. Quantify changes in several physiological responses of hydrilla in early stages of Mt infection to determine which response best correlates with bioherbicide treatment efficacy. 3. Evaluate best physiological indicator in expanded formulation screening to improve bioassay efficiency for research and future quality assurance purposes.
Project Methods
Objective 1: Test the feasibility of various combinations of Mt pathogen with binding agents, density modifiers, dispersants, and other adjuvents for improved bioherbicide efficacy on hydrilla under mesocosm conditions. New formulated bioherbicidal tests materials will be produced by USDA-ARS-NCAUR in Peoria, IL and subjected to bioassay analysis. Bioassays will be conducted in 12-liter, clear acrylic cylinders to grow hydrilla and treat with bioherbicide test formulations. Hydrilla aboveground biomass will be harvested 10-14 days after treatments. Objective 2: Quantify changes in net photosynthesis, chlorophyll content, and non-specific ion leakage from cell membranes of hydrilla tissue in early stages of infection under preliminary microcosm bioassay conditions to determine best correlate(s) with bioherbicide treatment efficacy at mesocosm scale. Physiological responses of treated hydrilla during early stage infection, if quantifiable and consistent, could be very
useful data for future research efforts. To address this question, microcosm studies will be run in parallel with mesocosm bioassay efficacy evaluations. Three physiological parameters will be examined: net photosynthesis, non-specific ion leakage, and tissue chlorophyll content. Hydrilla stem sections will be grown in culture media in small flasks and grown in Percival growth chambers. At intervals post-treatment, net photosynthesis will be evaluated through short incubations of treated tissue in BOD bottles using a dissolved oxygen meter. Total chlorophyll per gram hydrilla tissue used for net photosynthesis measurements will be measured using a DMSO extraction. Tubes with hydrilla tissue will be agitated on a shaker table for an additional 16-24 hours, and the conductivity of tube water will be measured using a Fisher Scientific Model 09-326-2 conductivity meter. Objective 3: Evaluate best physiological indicator from Objective 2 under expanded microcosm trials in conjunction with
remaining mesocosm studies to improve bioassay efficiency for research and future quality assurance purposes. During the first three monthly cycles of SBIR Phase I studies, all results of initial microcosm studies of physiological responses of treated hydrilla to Mt infection will be correlated to biomass reductions measured in concurrent aquarium mesocosm evaluations. Regression models or similar comparative statistical techniques will be utilized to determine which physiological indicator under microcosm testing is best correlated to final mesocosm efficacy on hydrilla. If results of the different approaches are well correlated, evaluation efforts for the final months of the project will be altered to focus more energy on microcosm-scale studies with higher replication. Alternatively, well-correlated physiological parameters may be monitored on plants in mesocosm-scale testing to generate an alternate form of quantitative evaluation data that would shorten study cycles and greatly
improve efficiency of such trials.