Substrata for Rearing the Japanese Beetle in the Laboratory

In tests with peat, vermiculite, and sand, used alone or in mixtures containing 3 proportions of sassafras sandy loam soil, the mixtures containing more than 33% of a humus-type soil (peat) were generally more favorable for development of immatures of Popillia japonica Newman (Coleoptera: Scarabaeidae) than were mixtures containing 33% or more of a mineral-type soil (vermiculite or sand). When Michigan peat was mixed with sand at ratios ranging from 0:100 to 100:0 (wt/wt), the minimum proportion of organic matter necessary for the development of 3rd-stage larvae was found to be less than 10%.