Effect of two chitinase inhibitor treated diets on the eastern subterranean termite, Reticulitermes flavipes (Kollar)

Baiting, with chitin synthase inhibitors, is a common termite control practice. However, chitinase inhibitors (chitin degradation) are yet to be explored in terms of termite control. The objective of this study was to evaluate the effects of pentoxifylline and psammaplin A (Family 18 chitinase inhibitors) treated diets (filter paper) on the eastern subterranean termite at the levels of food consumption (palatability of treated diet), concentration dependent mortality, and chitinase protein activity. Treated diets were assessed at two concentrations of pentoxifylline (25 and 50 µM) and psammaplin A (50 and 100 µg/ml). Termites were allowed to feed on the diet for a period of 14 days with response variables being evaluated at 3, 7, and 14 days. Acetone treated filter paper was used as a control diet. Pentoxifylline and psammaplin A were shown to not deter feeding by termites at either concentration. Both treatment diets caused significant mortality by 7 and 14 days when compared to the control treatment, however no significant concentration dependent differences were seen between the two concentrations tested in both chitinase inhibitor treatments. An in-gel SDS-PAGE chitinase activity assay showed reduced levels of chitinase isoform activity at 3, 7, and 14 days in response to both concentrations of each treatment tested. Specific chitinase isoforms were inhibited/active in response to each chitinase inhibitor treatment.