Presence of carbaryl in the smoke of treated lodgepole and ponderosa pine bark

Lodgepole and ponderosa pine trees were treated with a 2% carbaryl solution at recreational areas near Fort Collins, CO, in June 2010 as a prophylactic bole spray against the mountain pine beetle. Bark samples from treated and untreated trees were collected one day following application and at 4-month intervals for one year. The residual amount of carbaryl was determined, and bark samples were burned to examine the smoke for the active ingredient. Smoke recovered from spiked bark samples showed a very high correlation between the treated rate and the concentration recovered from the smoke. Residual carbaryl on the bark was relatively stable throughout the study and carbaryl was detected in the smoke throughout the duration of the test.