Screening and evaluation for varietal resistance against the invasive rice delphacid (Tagosodes orizicolus Muir) in greenhouse studies

Since its detection in 2015, the invasive rice delphacid (Tagosodes orizicolus), poses a growing threat to rice production in Texas. T. orizicolus feeds on the phloem of rice plants leading to yellowing and in cases of heavy infestation, hopperburn, a condition marked by patches of dried plants as result of intense feeding. Yield losses from direct feeding can range from 30 to 40%. Moreover, this species is the vector of Rice hoja blanca virus (RHBV), which can cause yield losses up to 75% when present. Given that Texas rice varieties have not historically been selected for resistance to T. orizicolus, a broader management strategy is needed. This study aims to assess T. orizicolus adult preference for oviposition (choice experiment) on nine commercial varieties grown in Texas under greenhouse conditions at the Beaumont Research Center. Each treatment will include five replicates (cages) containing one pot of each variety (two plants per pot). Cages will be infested once with 18 pairs (male and female) of adult rice delphacids. After five days, individual pots will be caged to exclude adults. Nymph emergence (first instar) will be counted and removed every three days until none remain. This study will be conducted with 3-, 5- and 8-weeks old plants. Data will be analyzed using repeated measures ANOVA (SAS) to determine significant differences in first instar densities among varieties in choice tests. This study will provide insights into varietal resistance and support IPM efforts to protect rice yields from this invasive pest.