An invasive insect pest of rice, the rice Delphacid (Tagosodes orizicolus Muir), has been detected in Louisiana. No adverse impacts on rice have been observed in Louisiana as yet, but the detection is certainly a concern. The rice delphacid is native to Central America where it is a major pest of rice. Historically, the pest was sporadically detected in the US including the last detection in Louisiana in 1964, but it was not thought to be permanently established here. That changed in 2015 when the Delphacid was found in Texas. The pest has become a consistent pest of rice in Texas since that year and often requires insecticidal control to prevent yield losses. Further, last year the highly damaging Hoja Blanca (white leaf) disease that is transmitted by the rice delphacid was detected for the first time in the US in Texas. Because of the delphacid’s high populations in east Texas, it’s eventual expansion into southwest Louisiana was expected. However, the location of the detection this year came as a surprise.

Figure 1. Rice delphacid adult (left) and nymph (right). Photos by J. Villegas

Specimens were first detected in July by field crops entomologist, Dr. James Villegas, in a rice field near Newellton in Tensas Parish (Fig. 1). Species confirmation was provided by Dr. Stephen Baca, Director of LSU’s Louisiana State Arthropod Museum, through specimen examination and genetic analysis. The cause of this long-distance spread is unknown. Subsequent surveys detected additional infestations in western Calcasieu Parish, but its distribution in the State remains largely unknown. However, it has not been observed at the Rice Research Station in Crowley. This suggests that the population is not continuous from southwest to northeast Louisiana and that the NE LA population may have been an isolated introduction. The pest has now spread to multiple Parishes in NE and Central Louisiana as well as southern Arkansas. On-going survey efforts aim to determine where the delphacid is occurring in rice in the state. Producers in infested Parishes should exercise caution to avoid additional spread. Rice straw or hay should not be moved out of these Parishes.

Figure 2. A rice field with hopper burn in Texas. Photo by M.O. Way.

Currently, damaging infestations have been detected in only a few fields in Louisiana, but the situation is changing rapidly. The pest routinely reaches high populations in Texas and producers there are struggling to manage widespread outbreaks. High numbers of the rice delphacid cause large patches of dead and shriveled rice called “hopper burn” (Fig. 2). Infestations are most prevalent in late-season and second crop rice. Producers or consultants who think they have detected the rice delphacid in other Parishes should take photos or collect specimens to report the finding to LSU AgCenter extension agents. More information on rice delphacid biology and management can be found on the LSU AgCenter website.