Performing Department
Ecology & Evolutionary Biology
Non Technical Summary
I will test the hypothesis that different belowground herbivores induce specific plant responses in strawberry, and test the impact of these responses on native and introduced entomopathogenic organisms. This study's goals are to provide strawberry (Fragaria spp.) growers with new tools for: a) improved monitoring of cryptic root- feeding pests, b) increased efficacy of insect parasitic nematodes as a biological control tactic c) employing information on plant traits to study the functional role of diverse root characteristics associated with belowground environment. This work will contribute to future belowground pest management programs in strawberry and other agroecosystems. Living amongst a complex ecological foodweb, roots are often heavily attacked by herbivores and pathogens, yet there are significant gaps in our knowledge of belowground environments both from an agronomic and ecological perspective. Understanding complex belowground interactions could provide a model for monitoring soil disturbances while optimizing ecological scenarios to favor biological control. Traditionally, such interactions are studied one-by-one, and there is a need for a multidisciplinary approach to study such relationships. This study will evaluate belowground induced plant signals, the occurrence and life history characteristics of natural belowground populations, and the impact on the control of root pests. With techniques based on quantitative real-time PCR I will evaluate how herbivore induced plant chemistry alters the community dynamics of surrounding soil biota. This study will also determine if plants infested with Strawberry Root weevils, Black vine Weevil, and Rough strawberry weevil secrete recruitment chemicals attractive to entomopathogenic nematodes.
Animal Health Component
50%
Research Effort Categories
Basic
50%
Applied
50%
Developmental
(N/A)
Goals / Objectives
A.Training-through-research: During the project, new techniques, methodologies and basic and applied knowledge will be garnered towards an interdisciplinary approach: Molecular Biology: design of species-specific primers and probes, real time qPCR, sequencing methods of specific areas of the genomes of nematodes, fungi and bacteria for selecting areas with high variability as a way to characterize underground food webs. Volatile Collection: coordination and development of novel in situ volatile sampling surveys in both field and laboratory conditions for improving the sampling and resolution of root responses to herbivory. Integration of various techniques of volatile collection including but not limited to SPME and Dynamic flow-through trapping systems. B. Scientific skills: Workshops, courses, & conferences: I will attend and participate in the Annual California Nematology Workshop. I will also attend the International C. elegans Meeting, an opportunity to learn advanced techniques in the study and genetics of nematodes. The most important function of such conferences is to provide a forum for presenting cutting-edge research. It will also be important for me to continue to present at meetings such as the International Society of Chemical Ecology, Entomological Society of America, and Ecological Society of America. C. Outreach and mentoring: During my proposed research I will closely align myself with the Cornell Office of Minority Programs. Ecology and Entomology are particularly interesting as scientific disciplines, in that few students of non-western European dissent (not only traditionally underrepresented groups) go on to graduate studies. I want to assist in any activities which serve as a platform for minority students to exchange scientific knowledge and experiences, learn about the process of applying to graduate school and conducting graduate research, and present their findings to peers and faculty. Being a minority student and financially disadvantaged myself, I recognize the advantages of such opportunities. I was a member of the McNair Scholar program, a TRIO program funded by the Department of Education, designed to prepare undergraduate students for doctoral studies. I plan to facilitate such interactions by supporting students as undergraduate research assistants and participating in Cornell's Biology Scholars Program, consisting of students who come from economic, gender, geographic, ethnic, or cultural groups historically underrepresented in the fields of biology.
Project Methods
1st Step: Evaluation of strawberry induced responses to damage treatments under laboratory conditions: i. non-damaged controls, ii. damage by root herbivory, iii. damage by foliar herbivory, iv. application of hormonal elicitors. 2nd Step: Measure the specific consequences of plant herbivore interactions on organisms in the rhyzosphere using quantitative PCR under field conditions: introduction of weevil larvae from three Otiorhynchus spp. in order to evaluate specificity of elicitation and specificity of effect. 3rd Step: Evaluate efficacy of biological control in agroecosystem that have been demonstrated to affect nematode and fungal components of the food-web: application of synthetic/and or isolated components of plants' induced defences associated with aboveground and belowground herbivory in order to manage multitrophic interactions and their impacts on pest mortality. Describing and identifying the key dynamics and components of these plant interactions will allow for the application of these inferences and tools in a larger manipulative field experiment. There is no data on how weevil herbivory under varying soil conditions influences biological control, nor its associated consequences on surround soil fauna. To examine the importance of soil type and irrigation, I will allow each herbivore species (Strawberry root weevil, Black vine Weevil, and Rough strawberry weevil) to feed on the roots of strawberry plants in a constructed mesocosm. Each mesocosm will consist of a semi-porous (which nematode can penetrate) 75-L tree bag that will be placed in a strawberry field. The mesocosms will be filled with an either a 1:1, 2:1, or 1:2 volume (52 L) of a mixture of local loamy soil to sand. Four seedlings per mesocosm. There will be 10 mescosm replicates for each weevil species and non-weevil control in each soil type. This design will be replicated with either high, moderate, and low irrigation. This design allows for natural populations of microfauna to enter or leave the rhizosphere, while the root herbivores will be confined to each bag. This experiment will involve (4 herbivore treatments 3 irrigation levels X 3 soil compositions) X 10 replicates = 360 plantings. By quantifying soil moisture, volatile induction, nematode, bacteria, fungi, and induced plant defenses, we can evaluate the contribution of each factor to plant susceptibility, ultimately identifying dynamics key to increasing weevil mortality and plant performance. Experiments will be conducted in greenhouses or in the field. In all cases, individually growing plants will be considered the unit of replication and I intend to have a minimum of 10 replicate plants per treatment in all experiments. For each of the steps outlined above, I envision repeating each experiment at least twice. Statistical analyses will be conducted using Analysis of Variance, correlations, and some more sophisticated multivariate techniques. In particular, I anticipate using MANOVA as well as structural equation modeling (path analysis) to study the linkages between plant traits, the changes under different conditions, and the ultimate impact on the pest community.