B. J. Williams

Louisiana State University, Baton Rouge, LA, United States

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Publications (3)2.91 Total impact

  • K V Tindall, M J Stout, B J Williams
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    ABSTRACT: The impact of a herbicide-tolerant rice, Oryza sativa L., variety was assessed for its resistance to rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), and its place in current integrated pest management (IPM) programs. Greenhouse experiments were conducted to evaluate the resistance of a glufosinate-tolerant rice variety and its glufosinate-susceptible parent line Bengal to the rice water weevil in the presence and absence of glufosinate applications. The LC50 dose-response and behavioral effects of glufosinate on adult rice water weevils also were studied. Field studies investigated the impacts of glufosinate-tolerant rice on rice water weevil management in the presence and absence of glufosinate under early and delayed flood conditions. Greenhouse studies demonstrated that in the absence of glufosinate, oviposition was 30% higher on the glufosinate-tolerant rice line than on Bengal rice or on glufosinate-tolerant line treated with recommended rates of commercially formulated glufosinate. Applications of glufosinate to glufosinate-tolerant rice resulted in a 20% reduction in rice water weevil larval densities compared with nontreated glufosinate-tolerant rice. The LC50 of glufosinate against adult rice water weevil was nearly 2 times the concentration recommended for application to glufosinate-tolerant rice. There was no difference in the amount of leaf area consumed by adult rice water weevils on glufosinate-treated and nontreated foliage. The absence of direct toxicity of glufosinate to rice water weevil at recommended glufosinate use rates and lack of behavioral effects suggest that the reduction in rice water weevil densities observed after glufosinate applications resulted from herbicide-induced plant resistance. Field experiments showed that neither rice variety nor herbicide use affected larval densities; however, delaying flood and applying insecticide effectively reduced numbers of rice water weevil larvae.
    Journal of Economic Entomology 01/2005; 97(6):1935-42. · 1.60 Impact Factor
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    ABSTRACT: Field experiments were conducted in 2002 and 2003 to investigate weed density, its relationship to rice stink bug (Oebalus pugnax, F.) populations, and damage to rice caused by stink bugs. Graminaceous weeds examined were barnyardgrass, Echinochloa crus-galli Beauv., Amazon sprangletop, Leptochloa panicoides (Presl.) Hitchc., broadleaf signalgrass, Brachiaria platyphylla Nash., and large crabgrass, Digitaria sanguinalis, (L.). Rice seed weight, percent filled seed, percent pecky rice, milling quality, and yield were measured. Data showed that 13–23 weeds/1 m2 was associated with an increase of one rice stink bug per plot. Weeds served as hosts of rice stink bugs prior to panicle emergence of rice; consequently, rice stink bugs infested rice early in the grain filling process and reduced the percentage of filled seeds. One hundred weeds/1 m2 caused a 1% increase in pecky rice, and for every 1% pecky rice, milling quality was reduced by 0.5%. Plots not treated with insecticide had significantly more non-filled seeds, pecky rice, and broken kernels than treated plots. Neither weeds nor insects at the densities observed in this test appeared to effect seed weight. Rice stink bug damage did not significantly contribute to yield losses greater than weeds in the absence of rice stink bugs. Rice stink bugs had more of an affect on the quality of rice rather than the yield. Results reported here suggest that late season weed control may be important in terms of indirect losses in grain quality associated with increased populations of rice stink bug.
    Crop Protection. 01/2005; 24(11):991-998.
  • K. V. Tindall, M. J. Stout, B. J. Williams
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    ABSTRACT: Both the rice water weevil, Lissorhoptrus oryzophilus Kuschel, and rice stink bug, Oebalus pugnax (F.), are important pests of rice, Oryza sativa L., in the United States. The host ranges of both insects primarily consist of monocotyledonous plants. Previous research has shown that the rice water weevil prefers barnyardgrass, Echinochloa crus-galli Beauv., over rice for feeding and oviposition. Barnyardgrass is also a preferred host for rice stink bug. Thus, presence of barnyardgrass in rice fields may alter populations of one or both insects. Field experiments were conducted to determine how the presence of a preferred host influences rice water weevil and rice stink bug populations on rice. Mixed plots of barnyardgrass and rice were cultivated such that either rice was surrounded by barnyardgrass or barnyardgrass was surrounded by rice. Insects were collected from rice portions of mixed plots and compared with numbers collected from whole plots of rice in the same location. Presence of barnyardgrass had little impact on rice water weevil densities on rice. In contrast, presence of barnyardgrass influenced rice stink bug populations on rice. Rice stink bugs were found on barnyardgrass in mixed plots before panicle emergence of rice. After panicle emergence of rice, results varied from 2001 and 2002. In 2001 and 2003, rice stink bugs were up to 9 times more abundant on rice in mixed plots of barnyardgrass and rice compared with whole plots of rice. Rice stink bugs were up to 4 times greater on rice in whole plots of rice than in mixed plots in 2002. Differences are likely a result of the developmental stage of barnyardgrass relative to rice. Data suggest the presence and developmental stage of barnyardgrass can influence the severity and timing of rice stink bug infestations.
    Environmental Entomology 05/2004; 33(3):720-726. · 1.31 Impact Factor