Assessing the Potential Infection of Tagosodes orizicolus (Hemiptera: Delphacidae) by Rice Hoja Blanca Virus in Texas.

Abstract

Tagosodes orizicolus (Muir) is the most important pest of rice in Latin America. Besides causing direct damage called hopperburn from feeding on and ovipositing in rice leaves, this insect pest also transmits rice hoja blanca virus (RHBV, Family Phenuiviridae, Genus Tenuivirus) in a persistent-propagative manner. This pathosystem can cause up to 100% yield loss in Latin American rice fields. T. orizicolus and RHBV symptoms were detected in Louisiana, Mississippi, and Florida rice fields in the 1950s, 1960s, and 1980s. However, neither has been detected in the United States since. Two outbreaks of T. orizicolus on ratoon rice occurred in the fall of 2015 and 2018 in counties southwest and south of Houston, TX. Insects were collected from ratoon rice fields by sweep net methods. Insects from the 2015 and 2018 outbreaks were tested individually and in pools of 10, respectively, for RHBV infection and the cytochrome oxidase 1 (CO1) gene from Delphacidae. No insects were positive for RHBV, however, all samples yielded amplicons for the CO1 gene. Furthermore, the CO1 gene from five 2015 individuals was sequenced and found to have a 100% identity to the Fer26_Argentina and 99.81% identity to the DEL074 Venezuela isolates of T. orizicolus. Five new sequences from 2015 individuals have now been deposited in GenBank. It is imperative to stay up to date on the potential invasion and establishment of this exotic pest of rice in Texas and other rice-growing regions of the United States through continued monitoring and research.