Integration of monoterpenoids with low pressure simulating vacuum for control of diapausing Indian meal moth larvae and red flour beetle adults

Abstract

Monoterpenoids as well as low pressure simulating vacuum, when applied alone have been demonstrated to cause mortality of stored-product insect pests. The current report explored the possibility of integrating these two control methods in the management of stored-product insects. The insects used for this study were the adults of the red flour beetle, Tribolium castaneum, and diapausing larvae of the Indian meal moth, Plodia interpunctella. The monoterpenoids investigated were E-anethole, estragole, S-carvone, linalool, L-fenchone, geraniol, γ-terpinene and DL-camphor. Exposure of the insects to all the monoterpenoids alone, with the exception of camphor, at a concentration of 66.7μL/1L of volume required more than 24 h to generate 100% mortality at 28.0 ± 0.8°C and 70 ± 2.5 r.h. However, exposure of the insects to camphor alone generated 100% mortality with 3 h exposure in T. castaneum. Exposure of the insects to low pressure at 36.5 mm Hg generated 100% mortlity in beetles with 24 h exposure and in the diapausing P. interpunctella larvae with 48 h exposure. However, combination of the monoterpenoids with low pressure reduced exposure periods (3-24 h) required to generate 100% mortality in both diapausing larvae of P. interpunctella and the adult beetles of T. castaneum. In all cases T. castaneum showed signs of weakness faster than diapausing P. interpunctella larvae.

Keywords: Low pressure, DL-camphor, Estragole, γ-terpinene, Carvone