Effect of different wavelengths of light on trap capture of the mold mite, Tyrophagus putrescentiae (Schrank) (Acari: Acaridae)

The mold mite, Tyrophagus putrescentiae (Schrank) (Acari: Acaridae), is a serious pest of dry-cured ham and other stored products. Methyl bromide, the most effective fumigant in managing this pest, is being banned due to its ozone-depleting ability, hence, other management methods should be investigated. Early detection of pests is useful in deciding if and when management is required. 

The black-painted standard KSU trap and the unpainted version of the trap, developed in our laboratory, were used to determine the effect of light on trap capture. Experiments were carried out in lit rooms using a standard black trap and an unpainted trap. Fewer mites were caught in the unpainted traps (P<0.01). Experiments were also conducted in dark rooms with paired standard traps in which one trap was equipped with a light-emitting diode, LED, generating light within narrow wavelength ranges, and the other trap had no LED. Mites oriented more positively to traps with violet and ultraviolet LEDs, by up to 3-fold more compared to unlit traps (P<0.001). When a blue LED was tested, there were similar numbers of mites in the lit and unlit traps, and tests of yellow, green and red LEDs consistently had more mites in the unlit traps (P<0.05). Also, in four-choice experiments where white, ultraviolet and yellow LEDs were compared with one unlit trap, more mites were caught in ultraviolet-equipped trap (P<0.05). Findings may help develop more sensitive traps to more accurately predict the population dynamics of the mite, hence, help in management decisions.