The white-spotted flower chafer, Protaetia brevitarsis (Coleoptera: Scarabaeidae), is traditionally considered to be an important source of medicinal properties of suppression of cancer and prevention of liver-related diseases. Recently, it was listed as a temporal food ingredient by the Korean Ministry of Food and Drug Safety. To use this insect species without endangering wild populations and produce better quality insects, a mass rearing technique and the suitable rearing conditions are needed. The present study was carried out to determine whether different diets and temperatures can affect the larval weight of this beetle. The larval weight change of third instar larvae was tracked for 14 weeks with different combination of three rearing temperatures – 25, 27.5, and 30℃ - and two feed ingredients – soybean cake and rice bran. Among three temperatures, 27.5℃ was the best temperature condition for rearing this beetle. Among four combinations of two feed ingredients, the addition of soybean cake made significant weight increasement for third instar larvae. These results showed that adding soybean cake at 27.5℃ was the best rearing condition for larval weight gain. This rearing condition can be considered in terms of producing better insects and maximizing producers’ benefits.

Since we reported a viral disease extremely fatal to A. dichotoma, had landed on Korea in 2015, we have investigated this disease nationwide and it was turned out the viral disease has spread in the majority of the larva-rearing farms all over the country. The transmission of this disease is most severe when the larvae are harvested and stored for overwintering. During this period, even a few virus-infected larvae can easily transmit the virus and about two hundreds of larvae stored in a container can be killed. In a peroral infection experiment, 80% of infected larvae were killed but survived larvae became adults fully functional physiologically. These survived beetles were confirmed as live virus carrier. Also, about 75% of larvae hatched from the eggs laid by the infected beetles were infected and killed by the virus. This vertical transmission is due to the feeding and secretion activity of the infected parents.