Effect of Planting Date on <I>Lissorhoptrus oryzophilus</I> (Coleoptera: Curculionidae) Density–Yield Relationship on Rice in Southeastern Texas

Abstract

Results of planting date and insecticide efficacy experiments targeting Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae) on rice, Oryza sativa L., in southeastern Texas between 2002 and 2007 were used to determine density-yield relationships as a function of planting date. Soil core samples were collected on two dates during main crop development to estimate immature L. oryzophilus populations followed by main and ratoon crop harvests. Analysis of covariance (ANCOVA) revealed that planting date did not affect the density-main crop yield relationship during most years and that these relationships varied substantially among years. For ratoon crop yield, an effect of main crop L. oryzophilus immature infestation was detected during some years, but the real effect of these populations on ratoon crop yield remains unclear. Using estimates of yield reduction per L. oryzophilus immature, economic injury levels were calculated. Main crop yields from treated plots and first soil core sample L. oryzophilus immature populations from untreated plots were significantly higher in plots planted at recommended dates than in plots planted earlier or later. This suggests that the presence of high populations of reproductive L. oryzophilus coincides with the period when rice fields planted at optimum dates are flooded. Results from this study reinforce the importance of managing L. oryzophilus populations when planting rice at recommended dates in southeastern Texas.

Effect of Depth of Flooding on the Rice Water Weevil,Lissorhoptrus oryzophilus, and Yield of Rice

“…Given the modest reduction in weevil numbers associated with shallow flooding and the non-significant increase in yield, it is clear that a shallow flood would not be a substitute for chemical control, but it may serve as a valuable component of an integrated pest management system. Other cultural practices that could be used in conjunction with a shallow flood include: avoiding planting at low seeding rates (Thompson and Quisenberry 1995; Stout et al 2009), delaying the permanent flood to allow plants to develop a robust root system and become more tolerant to L. oryzophilus injury (Stout et al 2002a), selecting a planting date appropriate to the area (Thompson et al 1994; Espino et al 2009; Stout et al 2011), and choosing a variety that is more tolerant to weevil injury (N'Guessan et al 1994; Rice et al 1999; Stout et al 2001; Bernhardt and Richards 2003; Tindall et al 2004). A shallow flood is more likely to be beneficial in areas that have historically low infestation levels.…”

“…Early planting dates in Louisiana appear to allow plants to escape severe weevil infestations sometimes and to tolerate damaging populations of L. oryzophilus better than at later planting dates (Thompson et al 1994; Stout et al 2011). However, Espino et al (2009) suggested that producers in Texas must choose between planting dates that will produce higher yields or planting dates that produce low L. oryzophilus populations. There is evidence of differences in the tolerance of some rice varieties and lines to L. oryzophilus feeding (N'Guessan et al 1994; Stout et al 2001; Bernhardt and Richards 2003).…”

Impacts of Seeding Rate on Interactions Between Rice and Rice Water Weevils

“…Given the modest reduction in weevil numbers associated with shallow flooding and the non-significant increase in yield, it is clear that a shallow flood would not be a substitute for chemical control, but it may serve as a valuable component of an integrated pest management system. Other cultural practices that could be used in conjunction with a shallow flood include: avoiding planting at low seeding rates (Thompson and Quisenberry 1995;Stout et al 2009), delaying the permanent flood to allow plants to develop a robust root system and become more tolerant to L. oryzophilus injury (Stout et al 2002a), selecting a planting date appropriate to the area Espino et al 2009;Stout et al 2011), and choosing a variety that is more tolerant to weevil injury Rice et al 1999;Stout et al 2001;Bernhardt and Richards 2003;Tindall et al 2004). A shallow flood is more likely to be beneficial in areas that have historically low infestation levels.…”

“…Early planting dates in Louisiana appear to allow plants to escape severe weevil infestations sometimes and to tolerate damaging populations of L. oryzophilus better than at later planting dates Stout et al 2011). However, Espino et al (2009) suggested that producers in Texas must choose between planting dates that will produce higher yields or planting dates that produce low L. oryzophilus populations. There is evidence of differences in the tolerance of some rice varie- Table 1.…”

Analysis of junction site between T-DNA and plant genome in Lissorhoptrus oryzophilus resistance GM rice

“…벼물바구미 성충은 벼 잎의 엽육을 갉아먹어 어린 묘에 피해를 주고, 유충은 뿌 리로 이동하여 뿌리의 내부조직을 가해하여 초장과 뿌리 의 감소, 생육지연 등의 피해로 벼 수확량의 20% 이상을 감소시킨다고 알려져 있다 (Shang et al 2004;zou et al 2004;Saito et al 2005). 벼물바구미 방제는 대부분 유기살충제를 사용하고 있 으나, 살충제의 유해성과 비 목표인 무척추동물에 부정 적인 영향을 미치게 되는 문제점으로 인해 새로운 방제 전략으로 빠른 시기의 이앙, 이앙 후 논 전면에 수면처리 등의 방법이 이용되고 있고 (Stout et al 2002;Espino et al 2009;Stout et al 2011), 최근에는 효과적인 방제를 위한 생명공학기술을 이용한 저항성 작물 개발 연구가 이루어 지고 있다.…”