title: Efficacy of Rice Insecticide Seed Treatments at Selected Nitrogen Rates for Control of the Rice Water Weevil (Coleoptera: Curculionidae).
abstract: Seed-applied insecticides are the standard control method used in the United States to minimize rice water weevil (Lissorhoptrus oryzophilus Kuschel) injury to rice (Oryza sativa L.) roots, and often results in greater yields than rice that receives no seed-applied insecticide. Yield increases from seed-applied insecticides often occur even when insect pressure is low and should not cause yield loss. The research objective was to evaluate the effect of urea-nitrogen rate and seed-applied insecticide on number of rice water weevil larvae, nitrogen uptake, and rice grain yield. Six trials were conducted at the Pine Tree Research Station (PTRS) and the Rice Research Extension Center (RREC) to examine the response of rice plants receiving different insecticide-seed treatments and urea-nitrogen rate combinations. Insecticide-seed treatments included label rates of clothianidin, thiamethoxam, and a no-insecticide (fungicide only) control, in combination with season-total nitrogen rates of 0, 50, 100, 150, and 200 kg urea-nitrogen/ha. Rice seed that was treated with clothianidin or thiamethoxam generally had equal numbers of rice water weevil larvae, which were significantly fewer compared with rice that received no insecticide with an equivalent urea-nitrogen rate. Nitrogen uptake at panicle differentiation was not affected by insecticide-seed treatments at four of six sites and usually increased positively and linearly as urea-nitrogen rate increased. As urea-nitrogen rate increased, grain yield increased either linearly or nonlinearly. Averaged across urea-nitrogen rates, both insecticide seed treatments had similar yields that were 4 to 7% greater than the grain yields of rice that received no insecticide at four of the five harvested sites.
authors.affiliation: Valent FMD Specialist, Formerly: University of Arkansas Department of Entomology M.S. Graduate Student, 1404 Brierwood St.Cleveland, MS 38732. malever89@gmail.com.
authors.forename: Mallory
authors.initials: M
authors.lastname: Everett
authors.affiliation: University of Arkansas, Extension Entomologist, P.O. Box 357, 2001 Hwy 70 East, Lonoke, AR 72086.
authors.forename: Gus
authors.initials: G
authors.lastname: Lorenz
authors.affiliation: Professor & Director of Soil Testing, University of Arkansas Division of Agriculture, 1366 West Altheimer Drive, Fayetteville, AR 72704.
authors.forename: Nathan
authors.initials: N
authors.lastname: Slaton
authors.affiliation: Rice Extension Agronomist, University of Arkansas, Rice Research & Extension Center, 2900 Hwy 130 E. Stuttgart, Ar 72110.
authors.forename: Jarrod
authors.initials: J
authors.lastname: Hardke
mesh_terms: D000818:Animals; D005308:Fertilizers / Q000032:analysis; D006146:Guanidines; D007300:Insect Control; D007306:Insecticides; D007814:Larva / Q000254:growth & development; D000073943:Neonicotinoids; D009574:Nitro Compounds; D009584:Nitrogen / Q000008:administration & dosage / Q000378:metabolism; D012275:Oryza / Q000254:growth & development* / Q000378:metabolism; D010078:Oxazines; D012639:Seeds; D000077922:Thiamethoxam; D013844:Thiazoles; D014508:Urea / Q000008:administration & dosage; D048889:Weevils
chemical_list: D005308:Fertilizers; D006146:Guanidines; D007306:Insecticides; D000073943:Neonicotinoids; D009574:Nitro Compounds; D010078:Oxazines; D013844:Thiazoles; C480342:clothianidin; D000077922:Thiamethoxam; D014508:Urea; D009584:Nitrogen
keywords: insecticide seed treatment; rice; water; weevil, nitrogen