Sampling methods to detect and estimate populations of Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae) infesting dry-cured hams

Authors: AMOAH, BARBARA - Kansas State University; HAGSTRUM, DAVID - Kansas State University; SUBRAMANYAM, BHADRIRAJU - Kansas State University; Campbell, James - Jim; SCHILLING, M. WES - Mississippi State University; PHILLIPS, THOMAS - Kansas State University

Submitted to: Journal of Stored Products Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/18/2017
Publication Date: 9/1/2017
Publication URL: https://handle.nal.usda.gov/10113/5814434
Citation: Amoah, B., Hagstrum, D., Subramanyam, B., Campbell, J.F., Schilling, M., Phillips, T.W. 2017. Sampling methods to detect and estimate populations of Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae) infesting dry-cured hams. Journal of Stored Products Research. 73:98-108. https://doi.org/10.1016/j.jspr.2017.07.004.
DOI: https://doi.org/10.1016/j.jspr.2017.07.004

Interpretive Summary: The ham mite, Tyrophagus putrescentiae, is an economically important pest of dry-cured ham, and historically was managed in ham aging rooms using methyl bromide fumigation. However, with the phase out of methyl bromide use there is a need for more effective integrated pest management programs, and a fundamental component of these programs is proper sampling techniques to determine pest abundance. Because there is no documented information on how to determine ham mite density, sampling techniques were compared and sampling plans were developed for the ham mite. The number of mites captured in traps increased as mite density increased, indicating a strong positive correlation. Trap capture also varied with trap location. In evaluating sampling protocols for mites on hams it was determined that mites preferred the proximal to the distal side of the ham. There were varying degrees of correlation between capture of mites in traps and other sampling techniques such as mite counts from the storage rack, vacuum sampling of the floor, and sampling mites on hams, with correlations between absolute mite counts and trap capture or ham sampling both being moderately strong and significant. Using this information two sampling plans for mites on hams were developed. These sampling plans can facilitate the development and evaluation of cost-effective integrated pest management alternatives to methyl bromide for the dry cured ham industry.

Technical Abstract: Spatial and temporal dynamics of pest populations is an important aspect of effective pest management. However, absolute sampling of some pest populations such as the ham mite, Tyrophagus putrescentiae (Schrank) (Sarcoptiformes: Acaridae), a serious pest of dry-cured ham, can be difficult. Sampling techniques were compared and sampling plans were developed for the ham mite. In one experiment, food-baited trap number was maintained at four and mite density varied from 500 to 10,000 individuals in environmentally-controlled 18 m2 rooms. The number of mites captured in traps increased as mite density increased, indicating a strong positive correlation. Experiments conducted in simulated ham aging rooms suggested that mites preferred the proximal to the distal side of the ham. Trap capture also varied with trap location. There were varying degrees of correlations between trap capture and the sampling techniques such as mite counts from the storage rack, vacuum sampling of the floor, and ham sampling used to count mites. Correlations between absolute mite counts and trap capture or ham sampling were both moderately strong and significant. Two sampling plans were developed for the mite and it was determined that an economic threshold close to 1 mite/sample unit on the ham can be estimated with 21 or 40 ham samples at precision levels of 0.35 and 0.25 respectively, or with 10 ham samples when classifying the mite’s infestation level as above or below to an action threshold of 0.43. These sampling plans for T. putrescentiae can facilitate the development and evaluation of cost-effective integrated pest management alternatives to methyl bromide.