Detection of Thaumatotibia (Cryptophlebia) leucotreta Granulovirus DNA in water samples in an insect rearing facility

A novel technique for the detection of baculovirus from insect cadavers, water and environmental samples in a Thaumatotibia (Cryptophlebia) leucotreta (false codling moth) mass rearing facility has been developed. Diseased insect larvae, water samples and sampling swabs from various sites in the facility were subjected to virus concentration using mixed-ester filters and/or directly subjected toDNAextraction using the QIAamp Ultrasens Virus kit (Qiagen). The use of non-charged mixed ester filters under vacuum allows for the rapid processing of large volumes of water. Extracted DNA was utilised directly in PCR to amplify the baculovirus core gene polh/granulin. Sequence analysis confirmed the presence of Cryptophlebia leucotreta granulovirus. Employing this technique, Cryptophlebia leucotreta granulovirus (CrleGV)was detected in 15.4%of the water samples; 75%of the environmental swabs and 42.9%of the larvae despite measures to control baculovirus contamination in the facility. No baculovirus contamination was detected in food samples. This rapid and reproducible technique will facilitate rapid diagnosis of baculovirus infection in mass-rearing facilities and other water samples.