It’s a mystery! Why are some apple trees declining in Eastern New York? - PROJECT FILLED

Worksite Location
Cornell Hudson Valley Research Laboratory (Highland, NY)
Project Dates
May 30 - August 18
Faculty Sponsor
Dr. Kerik Cox, Plant Pathology Section of Integrated Plant Science
Field Mentors/Supervisors
Daniel Donahue Extension Associate – Area Tree Fruit Specialist Eastern New York Commercial Horticulture Program Cornell Cooperative Extension Cornell Hudson Valley Research Laboratory
Project Summary and Intended Outcomes

Starting with the 2014 season, a team of Cornell research and extension staff have been active in an ARDP funded research project looking at the role of the Black Stem Borer (BSB) Xylosandrus germanus and its associated fungi in the apple decline phenomenon in WNY (Dr. Cox), as well as documenting the presence and impact of BSB in Hudson Valley (HV) apple orchards (Mr. Donahue). During the course of this project, BSB was found to be distributed widely in HV orchards and was playing an active role in the decline phenomenon. However, observations made throughout the Hudson Valley, and a detailed study in a Columbia County orchard over the last two years, indicate that BSB, Dogwood Borer (DB), and the wood decay fungus Schizophyllum commune (SC) are more likely secondary contributors, not the primary causal agents of tree decline. Other than leaf chlorosis, no other symptoms appear to be consistently associated with the stages of decline, and pest species were rarely observed attacking healthy trees. Two classes of symptom progression have been observed; 1. An increase in the severity of leaf chlorosis over an extended period of time, and 2. The rapid decline and death of the tree mid-summer, over a period of weeks. The bottom line is that we don’t know what is causing the initial decline from healthy (category 0) to slightly chlorotic (category 1). In addition to BSB, DB, and SC, pomologists are also concerned about latent virus infections, chronic herbicide injury, nutritional deficiencies, rootstock/scion incompatibilities, and drought stress as potential factors in the decline. The objective of the proposed internship project is to develop a database of orchard survey data that will document cases of apple tree decline and record the presence and extent of suspected causal agents, for use in identifying unique factors, or the interactions, which are initiating apple tree decline.

Roles and Responsibilities

The intern will assist in fine-tuning the orchard survey and identifying target orchards in ENY counties from Saratoga, south to Orange. Following the completion of appropriate training, the intern will be responsible for contacting targeted growers, collecting data on tree health, decline distribution, rootstock, variety/strain, planting date, planting density, training system, nursery of origin, irrigation status, history of herbicide use, BSB infestation, DB infestation, and presence of fungal cankers. The intern will be responsible to enter the data in a database, work under the supervision of Mr. Donahue and Dr. Cox to analyze the data for correlations to decline symptoms. If additional grant funding becomes available to cover lab analysis expenses, the project will be expanded and the intern will assist in the collection of soil and apple tissue samples as required to improve the utility of the data collected.

Qualifications and Previous Coursework

Biology, chemistry, horticulture, familiarity with computers running Microsoft Windows, strong interest in problem-solving, good communication skills. Reliable transportation required, business use of a personal vehicle will be reimbursed for mileage

Benefits and Skills

The intern will learn about apple tree decline, the biology of BSB and other wood decay fungi, and other sources of abiotic tree decline in commercial apple orchards. The intern will also come of an understanding of apple production in NY, integrated pest management, and orchard surveys.