Shiitake pest

In case you didn't know or haven't eaten it yet Shiitake (Lentinula edodes) is an edible mushroom native to East Asia. It is a feature of many Asian cuisines. It is also considered a medicinal mushroom in some forms of traditional medicine.

Mainly in Asian countries, shiitake is generally cultivated in greenhouses under controlled conditions. Recently, in many shiitake nurseries of Korea, farmers have experienced a serious loss of crops and have even had to abandon mushroom farming due to severely damaged cultures. Mycophagous maggots had caused serious damage by preventing formation of the mushrooms fruiting body. However, they couldn't be identified due to their lack of morphological characteristics in larvae and female adults. As a consequence, farmers and entomologists are unable to determine what species are the primary cause of the shiitake damage which in turn means that there are no adequate ways to fight this pest. Members of the two fly families Cecidomyiidae and Sciaridae are believed to be the main vermin species but their identity remains uncertain as only a few males could be identified using genital morophology.

Life stages of Camptomyia migdes (A-D)
and the mushroom culture(E)

A group of Korean researchers has now conducted a study using DNA Barcoding to test if the method can help to identify the maggots and female flies. Their results suggest that five dipteran species collected from shiitake farms were present among the collected samples, which is consistent with some morphological identifications of male specimens. The two main species they found were Camptomyia heterobia and Camptomyia corticalis. Interestingly last year another group from Korea had tested a variety of plant essential oils for the potential to serve as larvicides. The organism they used to test the oils was the gall midge Camptomyia corticalis. Nice coincidence (if it is one). I guess it is time the two groups get together and discuss potential applications of both their findings.