The panicle rice mite, Steneotarsonemus spinki Smiley, a re-discovered pest of rice in the United States

The panicle rice mite (PRM), Steneotarsonemus spinki Smiley, was reported in 2007 in the United States in greenhouses and/or field cultures of rice (Oriza sativa L.) in the states of Arkansas, Louisiana, New York, and Texas. PRM had not been reported in rice culture in the United States since the original type specimen was collected in Louisiana in association with a delphacid insect in the 1960s. PRM is the most important and destructive mite pest attacking the rice crop world-wide. It has been recognized as a pest of rice throughout the rice-growing regions of Asia since the 1970s. Historical reports of rice crop damage dating back to the 1930s also have been speculatively attributed to the PRM in India. In the late 1990s PRM was reported in Cuba, and quickly spread throughout the Caribbean and Central America. Rice crop losses of up to 90% in the Caribbean have been attributed to the PRM since first reported. The PRM attacks rice plants by feeding on the inside of the leaf sheath and developing grains. Damage associated with PRM infestations in rice include plant sterility, partial panicle infertility, and grain malformation. However, it is difficult to characterize the damage caused solely by the PRM because the mite is commonly reported interacting with several rice plant pathogens including Sarocladium oryzae (Sawada) and Burkholderia glumae (Kurita and Tabei). This presentation re-examines the taxonomic ranking of the PRM and includes a key to the U.S. species of Steneotarsonemus, its current distribution, damage to rice plants, its association with plant pathogens, host plant records, life history, survival under extreme temperature conditions, and current management strategies. We hope to stimulate research on the biology and management of the PRM in the United States.