Se realizaron estudios en campos de arroz, Oryza sativa L., con riego en parcelas del sistema de riego río Guárico y en la Estación Experimental del Instituto Nacional de Investigaciones Agrícolas del estado Guárico (INIA-Guárico) entre los años 2003 y 2006. El objetivo fue determinar las plantas hospederas en el cultivo de arroz para la chinche vaneadora del arroz, Oebalus insularis Stal. (Heteroptera: Pentatomidae) en Calabozo estado Guárico. Once gramíneas fueron identificadas como hospederos alternos. Studies, between 2003 - 2006 years, were conducted at irrigated growing areas of rice located Oryza sativa L. at river Guárico irrigation system and Guárico Experimental Station, of the National Agricultural Research Institute of Guárico State (INIA-Guárico) between 2003 and 2006. The objective was: Determine host plant in the cultivation of rice for the rice bug vaneadora, Oebalus insularis (Heteroptera: Pentatomidae). Eleven Gramineae plants were identifed as alternate hosts.
STINKBUGS, POPULATION dynamics, RICE, PEST control, and PADDY fields
The rice stem stink bug, Tibraca limbativentris Stål (Hemiptera: Pentatomidae), is one of the most harmful insects for Brazilian rice fields. Aiming to define the most appropriate time and place for pest management measures in commercial paddy fields, we adjusted regression models (Poisson, Zero Inflated Poisson, reparametrized Zero Inflated Poisson, Negative Binomial and Zero Inflated Negative Binomial) for modeling the population variation of T. limbativentris along the phenological cycle of the flooded rice cultivation. We hypothesize that the rice stem stink bug population's size is influenced by the rice cycle (time) and geographical positions within the crop. It was possible to predict the occurrence of the rice stem stink bug in the commercial flooded rice crop. The population of the rice stem stink bug increased significantly with the time or phenological evolution of rice. Our results indicated that the start of T. limbativentris monitoring should occur up to 45 d After Plant Emergence (DAE), from the regions along the edges of the rice paddies, which are the points of entry and higher concentration of the insect. In addition, 45 and 60 DAE were considered the crucial times for T. limbativentris control decision making in flooded rice paddies. [ABSTRACT FROM AUTHOR]
NILAPARVATA lugens, RICE, INSECT pests, SINGLE nucleotide polymorphisms, FOOD crops, and IDENTIFICATION
Rice is the most important staple food crop, and it feeds more than half of the world population. Brown planthopper (BPH) is a major insect pest of rice that causes 20–80% yield loss through direct and indirect damage. The identification and use of BPH resistance genes can efficiently manage BPH. A molecular marker-based genetic analysis of BPH resistance was carried out using 101 BC1F5 mapping population derived from a cross between a BPH-resistant indica variety Khazar and an elite BPH-susceptible line Huang–Huan–Zhan. The genetic analysis indicated the existence of Mendelian segregation for BPH resistance. A total of 702 high-quality polymorphic single nucleotide polymorphism (SNP) markers, genotypic data, and precisely estimated BPH scores were used for molecular mapping, which resulted in the identification of the BPH38(t) locus on the long arm of chromosome 1 between SNP markers 693,369 and id 10,112,165 of 496.2 kb in size with LOD of 20.53 and phenotypic variation explained of 35.91%. A total of 71 candidate genes were predicted in the detected locus. Among these candidate genes, LOC_Os01g37260 was found to belong to the FBXL class of F-box protein possessing the LRR domain, which is reported to be involved in biotic stress resistance. Furthermore, background analysis and phenotypic selection resulted in the identification of introgression lines (ILs) possessing at least 90% recurrent parent genome recovery and showing superior performance for several agro-morphological traits. The BPH resistance locus and ILs identified in the present study will be useful in marker-assisted BPH resistance breeding programs. [ABSTRACT FROM AUTHOR]
Plant Journal. Jan2010, Vol. 61 Issue 1, p46-57. 12p. 2 Color Photographs, 1 Black and White Photograph, 1 Chart, 4 Graphs.
LYASES, PLANTHOPPERS, RICE, GENES, and XANTHOMONAS
A pre-infestation of the white-backed planthopper (WBPH), Sogatella furcifera Horváth, conferred resistance to bacterial blight caused by Xanthomonas oryzae pv. oryzae ( Xoo) in rice ( Oryza sativa L.) under both laboratory and field conditions. The infestation of another planthopper species, the brown planthopper (BPH) Nilaparvata lugens Stål, did not significantly reduce the incidence of bacterial blight symptoms. A large-scale screening using a rice DNA microarray and quantitative RT-PCR revealed that WBPH infestation caused the upregulation of more defence-related genes than did BPH infestation. Hydroperoxide lyase 2 ( OsHPL2), an enzyme for producing C6 volatiles, was upregulated by WBPH infestation, but not by BPH infestation. One C6 volatile, ( E)-2-hexenal, accumulated in rice after WBPH infestation, but not after BPH infestation. A direct application of ( E)-2-hexenal to a liquid culture of Xoo inhibited the growth of the bacterium. Furthermore, a vapour treatment of rice plants with ( E)-2-hexenal induced resistance to bacterial blight. OsHPL2-overexpressing transgenic rice plants exhibited increased resistance to bacterial blight. Based on these data, we conclude that OsHPL2 and its derived ( E)-2-hexenal play some role in WBPH-induced resistance in rice. [ABSTRACT FROM AUTHOR]
Heinrichs, E. A., Sy, A. A., Akator, S. K., and Oyediran, I.
International Journal of Pest Management. Oct-Dec1997, Vol. 43 Issue 4, p291-297. 7p.
PLANTING and RICE
Monthly plantings of the rice variety Bouake 189 were made under lowland irrigated conditions, to obtain information on the phenological and seasonal occurrence of pests and diseases on the West African Rice Development Association (WARDA) research farm near Bouake, Cote d'Ivoire. Regular sampling of insect pests and observations on rice yellow mottle virus (RYMV) disease infection throughout the year provided information on the occurrence of RYMV and potential insect vectors. RYMV incidence and grain yields varied depending on planting date, and for a given planting date, varied from one year to another. There was no evidence that RYMV incidence increases in successive seasons under continuous cropping. There was no significant correlation between RYMV incidence and either rainfall or wind speed. Leaf feeding damage by the beetle vector of RYMV, Trichispa sericea Guerin-Meneville (Coleoptera: Chrysomelidae), and percentage RYMV infected plants were severe in the July and August plantings in 1993, but whereas T. sericea was not observed thereafter, RYMV spread continued. The white leafhoppers Cofana spectra (Distant) and C. unimaculata (Signoret) (Hemiptera: Cicadellidae), the green leafhoppers Nephotettix spp. (Hemiptera: Cicadellidae), the spittle bug Locris rubra F. (Hemiptera: Cercopidae), the diopsids Diopsis longicornis Macquart and D. apicalis Dalman (Diptera: Diopsidae), and the grasshopper Oxy hyla Stal (Orthoptera: Acridadae) were the most abundant of the insect pests and had distinct population peaks within a year. However, population abundances were not correlated with RYMV incidence. The variability of RYMV in time and space and the potential role of weeds as alternative hosts for RYMV are discussed. [ABSTRACT FROM AUTHOR]