First record of occurrence of Dervishiya cadambae on grapevine, Vitis vinifera, along with its morphological and molecular identification and pathogenicity evaluation potential of Metarhizium brunneum as its biocontrol agent

Increasing demand for grapes (Vitis vinifera L.) worldwide makes it a high-value crop and also an important, valuable export commodity for India. In February 2016, a vineyard from Maharashtra, India was identified with entirely new insect damage symptoms from those observed earlier. After, further inspection, a new type of wood borer was noticed which was later identified as Dervishiya cadambae (Moore) (Lepidoptera Cossidae). D. cadambae is known as a major pest of Tectona grandis L.f. plantations in Kerala, Karnataka and Tamil Nadu states of India and causes extensive damage to the timber. Surveys were conducted in affected vineyards to assess the extent of infestation from 2016 to 2018. In 20 infested vineyards located in Sangli and Nashik districts of Maharashtra, 12-72% of grapevines were found to have active infestations. Young larvae fed under the bark and later instars bored inside and made galleries. D. cadambae caused extensive damage to the sapwood and heartwood of grapevine stem and reduced both vitality and productivity of the vines. Deoxyribonucleic acid (DNA) barcode for this new pest of grapevines was also provided. The DNA barcode grouped D. cadambae in the clade of Cossidae samples supported with a bootstrap value of 85% in phylogenetic analysis. To our knowledge, this is the first record of D. cadambae occurrence on V. vinifera. A green muscardine fungus was isolated from the field infected larvae of D. cadambae. The pathogenicity test confirmed Koch's postulates. The fungus was identified as Metarhizium brunneum (Petch), which proved to be an efficient antagonist of this pest in laboratory bioassays.