Indica Populations Research Articles

Evolution of multiple target-site resistance mechanisms in individual plants of glyphosate-resistant Eleusine indica from China.

Glyphosate has been used for weed control in South China in various situations for four decades, and most Eleusine indica populations are suspected to have evolved resistance to glyphosate. This research investigated underling target-site glyphosate resistance mechanisms in six field-collected, putative glyphosate-resistant (R) E. indica populations. The six R E. indica populations were confirmed to be low (1.8 to 2.6-fold) to moderately (5.6- to 8.4-fold) resistant to glyphosate relative to the susceptible (S) population. Sixty-seven glyphosate-surviving plants from the six R populations were used to examine target-site resistance mechanisms. Target-site 5-enolpyruvylshikimate3-phosphate synthase (EPSPS) overexpression (OE) (plus further induction by glyphosate treatment) and gene copy number variation (CNV) occurred in 94% R plants, and among them, 16% had the P106A mutation and 49% had the heterozygous double TIPS (T102I + P106S) mutation (plus P381L). In addition, a low number of R plants (6%) only had the homologous TIPS (plus P381L) mutation. The (CT)6 insertion mutation in the EPSPS 5†-UTR always associates with EPSPS OE and CNV. Progeny plants possessing EPSPS OE/CNV (and P106A) displayed low level (up to 4.5-fold) glyphosate resistance. In contrast, plants homozygous for the TIPS mutation displayed higher (25-fold) resistance to glyphosate and followed by plants heterozygous for this mutation plus EPSPS OE/CNV (12-fold). Target-site glyphosate resistance in E. indica populations from South China is common with prevalence of EPSPS OE/induction/CNV conferring low level resistance. Individual plants acquiring both the TIPS mutation and EPSPS OE/CNV are favored due to evolutionary advantages. The role of (CT)6 insertion mutation in EPSPS CNV is worth further investigation. © 2021 Society of Chemical Industry.

Decrease sensitivity of Eleusine indica treated with Paraquat and Glyphosate sub-lethal doses

Populations of Eleusine indica glyphosate-sensitive weed seeds taken from Polytechnic Negeri Medan Campus. This study aims to examine whether the use of sub-lethal doses of paraquat and glyphosate in three generations can cause a decrease in the sensitivity of the Eleusine indica population to each herbicide. This research was carried out at the Universitas Sumatera Utara Campus with a height of ± 25 m above sea level. This study used a paraquat herbicide under the recommended dosage of 200 g.a.i. ha−1 and glyphosate herbicide under the recommended dose 360 g.a.i. ha−1 with three replications. Data analysis using IBM SPSS Statistics 20 software.

Evolutionary Processes Involved in the Emergence and Expansion of an Atypical O. sativa Group in Madagascar

Understanding crops genetic diversity and the evolutionary processes that accompanied their worldwide spread is useful for designing effective breeding strategies. Madagascar Island was one of the last major Old World areas where human settlement brought the introduction of Oryza sativa. Early studies in the island had reported the presence of a rice group specific to Madagascar. Using 24 K SNP, we compared diversity patterns at the whole genome and at haplotype (30 SNP-long segments along the genome) levels, between 620 Malagasy and 1929 Asian rice accessions. The haplotype level analysis aimed at identifying local genotypic variations, relative to the whole genome level, using a group assignment method that relies on kernel density estimation in a Principal Component Analysis feature space. Migration bottleneck had resulted in 10–25% reduction of diversity among the Malagasy representatives of indica and japonica populations. Compared to their Asian counterpart, they showed slightly lower indica and japonica introgressions, suggesting the two populations had undergone less recombination when migration to the island occurred. The origins of the Malagasy indica and japonica groups were delineated to indica subpopulation from the Indian subcontinent and to tropical japonica from the Malay Archipelago, respectively. The Malagasy-specific group (Gm) had a rather high gene diversity and an original haplotype pattern: much lower share of indica haplotypes, and much higher share of Aus and japonica haplotypes than indica. Its emergence and expansion are most probably due to inter-group recombination facilitated by sympatry between indica-Aus admixes and “Bulu” type landraces of japonica in the central high plateaux of Madagascar, and to human selection for adaptation to the lowland rice cultivation. Pattern of rice genetic diversity was also tightly associated with the history of human settlement in the island. Emergence of the Gm group is associated with the latest arrivals of Austronesians, who founded the Merina kingdom in the high plateaux and developed lowland rice cultivation. As an intermediary form between Aus, indica and japonica, the three pillars of O. sativa domestication, Gm represents a very valuable genetic resource in breeding for adaptation to cold tolerance in tropical highlands. We proposed the name Rojo for this new rice group.

Efficacy of Amblyseius largoensis (Muma) as a biocontrol agent of the red palm mite Raoiella indica (Acari: Tenuipalpidae)

The red palm mite, Raoiella indica Hirst (Acari: Tenuipalpidae), is a severe pest of coconut (Cocos nucifera L.), banana (Musa sp.), and some ornamental palms. The predatory mite Amblyseius largoensis Muma (Acari: Phytoseiidae) has been reported in association with R. indica in several countries. Here, we assessed the interaction effect between prey density and population structure on predation and fecundity of this phytoseiid species. Specifically, we estimated the predation capacity of nymphs and females of A. largoensis based on their functional and numerical responses when fed on eggs, immature stages (deutonymphs or protonymphs), and females of R. indica. Nymphs and females of A. largoensis presented type II functional responses to R. indica, except for nymphs of the predator when consuming immature stages of the pest that exhibited a type III functional response. Nymphs and females of the predator showed a higher attack rate and shorter handling time when feeding on eggs of R. indica than on immatures and females. The highest oviposition rates of A. largoensis were observed when eggs and immatures of the pest were offered as prey. The results indicate that nymphs and females of A. largoensis may be effective in suppressing R. indica populations, mainly at lower prey densities.

Multiple Herbicide Resistance Evolution: The Case of Eleusine indica in Brazil.

The occurrence of multiple herbicide resistant weeds has increased considerably in glyphosate-resistant soybean fields in Brazil; however, the mechanisms governing this resistance have not been studied. In its study, the target-site and nontarget-site mechanisms were characterized in an Eleusine indica population (R-15) with multiple resistance to the acetyl-CoA carboxylase (ACCase) inhibitors, glyphosate, imazamox, and paraquat. Absorption and translocation rates of 14C-diclofop-methyl14C-imazamox and 14C-glyphosate of the R-15 population were similar to those of a susceptible (S-15) population; however, the R-15 population translocated ∼38% less 14C-paraquat to the rest of plant and roots than the S-15 population. Furthermore, the R-15 plants metabolized (by P450 cytochrome) 55% and 88% more diclofop-methyl (conjugate) and imazamox (imazamox-OH and conjugate), respectively, than the S-15 plants. In addition, the Pro-106-Ser mutation was found in the EPSPS gene of this population. This report describes the first characterization of the resistance mechanisms in a multiple herbicide resistant weed from Brazil.

Climate-based seasonal dynamics of the invasive red palm mite Raoiella indica.

Raoiella indica Hirst (Acari: Tenuipalpidae) is the most critical coconut and banana pest recently introduced in Brazil. Once the mite pests are introduced, it is essential to understand their dynamics in important crops under open-field climatic conditions to implement strategies for their management and determine the periods when species populations may increase in the field. Modelling tools have been used to determine the potential distribution of species and implications for the management of invasive species. Thus, our aim in this study was to determine the seasonal variation in R. indica and the influence of the monthly climate using CLIMEX modelling. We adjusted the CLIMEX model for R. indica based on distribution data, additional biological characteristics, and fluctuations in the R. indica population in a commercial coconut plantation. The model for the current climate shows a good match between the ecoclimatic index and the global distribution of R. indica. The model results demonstrate that most states of Brazil and several regions worldwide include areas with highly suitable climatic conditions for R. indica. We observed variations in the density of R. indica in commercial coconut crops, with the highest incidence occurring during the first months of the year. Our results showed different alterations in seasonal suitability for R. indica that may provide information for the implementation of methods for time management, such as strategies for sampling and control during periods with a high degree of suitability for R. indica. © 2020 Society of Chemical Industry.

Efeito letal de extratos de piperáceas ao ácaro-vermelho-das-palmeiras, Raoiella indica (Acari: Tenuipalpidae)

Desde a introdução do ácaro-vermelho-das-palmeiras, Raoiella indica, no Brasil, diversos métodos de controle têm sido estudados para supressão desta praga, a exemplo dos métodos de controle quarentenários, químicos, biológicos e com extratos vegetais. O presente estudo objetivou avaliar o potencial letal de extratos aquosos de folha de Piper aduncum, P. callosum, P. hostmannianum, P. marginatum e P. peltatum sobre R. indica. Foi avaliada a ação residual de contato dos extratos, aplicados por imersão, nas concentrações de 0, 5, 10, 15, 20, 25 e 30%, sendo a ação avaliada em três períodos de exposição, 24, 48 e 72 h. A partir dos dados de mortalidade nas diferentes concentrações e em cada período de exposição foram determinadas as mortalidades corrigidas e as concentrações letais (CL25% e CL50%) dos extratos das piperáceas para a população de R. indica. Apenas os extratos de P. aduncum, a 5% após 24 h de exposição, e P. callosum, nesta mesma concentração em todos os tempos de exposição, não apresentaram mortalidade corrigida diferente do controle. As CL25% variaram de 0,99 a 13,02%, 1,29 a 7,89% e 1,82 a 7,69%, respectivamente, para os períodos de exposição de 24, 48 e 72 h. Já as CL50%, respectivamente para os mesmos períodos, variaram de 2,27 a 21,29%, 2,33 a 13,26% e 2,84 a 10,94%. Os extratos aquosos de folha das cinco espécies de piperáceas apresentaram efeito toxicológico sobre a população de R. indica.

Genome-wide analysis of polymorphisms identified domestication-associated long low-diversity region carrying important rice grain size/weight quantitative trait loci.

Rice grain size and weight are major determinants of grain quality and yield and so have been under rigorous selection since domestication. However, the genetic basis for contrasting grain size/weight trait among Indian germplasms and their association with domestication-driven evolution is not well understood. In this study, two long (LGG) and two short grain (SGG) genotypes were resequenced. LGG (LGR and PB 1121) differentiated from SGG (Sonasal and Bindli) by 504439 single nucleotide polymorphisms (SNPs) and 78166 insertion-and-deletion polymorphisms. The LRK gene cluster was different and a truncation mutation in the LRK8 kinase domain was associated with LGG. Phylogeny with 3000 diverse rice accessions revealed that the four sequenced genotypes belonged to the japonica group and were at the edge of the clades indicating them to be the potential source of genetic diversity available in Indian rice germplasm. Six SNPs were significantly associated with grain size/weight and the top four of these could be validated in mapping a population, suggesting this study as a valuable resource for high-throughput genotyping. A contiguous long low-diversity region (LDR) of approximately 6Mb carrying a major grain weight quantitative trait loci (harbouring OsTOR gene) was identified on Chromosome 5. This LDR was identified as an evolutionary important site with significant positive selection and multiple selection sweeps, and showed association with many domestication-related traits, including grain size/weight. The aus population retained more allelic variations in the LDR than the japonica and indica populations, suggesting it to be one of the divergence loci. All the data and analyses can be accessed from the RiceSzWtBase database.

<p class="Body"><strong><em>Neoseiulus barkeri</em></strong><strong> Hughes (Acari: Phytoseiidae) as a potential control agent for <em>Raoiella indica</em> Hirst (Acari: Tenuipalpidae)</strong></p>

Raoiella indica Hirst (Acari: Tenuipalpidae) is a pest species that has expanded not only in geographical distribution but also in the number of host plants. Control measures are still being evaluated in recently invaded countries. In some countries and for some crops, spraying with botanical extracts has been used to reduce R. indica populations. Laboratory and field studies point to the predatory mite Amblyseius largoensis (Muma) (Acari: Phytoseiidae) as promising for combating R. indica. However, this predator has not yet been commercially available. Thus, the present study aimed to evaluate the potential of another predatory mite Neoseiulus barkeri Hughes, a commercially available generalist predator as a biological control agent of R. indica. The consumption and oviposition rate of N. barkeri were determined across the developmental stages of R. indica. The predation and oviposition capacity of N. barkeri and A. largoensis when fed R. indica eggs in the laboratory were compared. In the field, releases of the predator N. barkeri at densities of 900, 600 and 300 predators per plant were compared to spraying with botanical extracts such as cottonseed oil and azadirachtin to control R. indica. Our results suggested that N. barkeri is an effective predator to control R. indica. The consumption of N. barkeri was inversely related to the life stage of R. indica, and all developmental stages of R. indica enabled the reproduction of N. barkeri. The predation and oviposition of N. barkeri were higher than those of A. largoensis, and the releases of N. barkeri at densities of 900 and 600 predators/plant resulted in significant reductions in R. indica populations.

Genetic diversity and in silico evidence of target-site mutation in the EPSPS gene in endowing glyphosate resistance in Eleusine indica (L.) from Malaysia

Glyphosate-resistant populations of Eleusine indica are widespread in several states of Malaysia. A whole-plant bioassay confirmed that eight out of the 17 populations tested were resistant to glyphosate at double the recommended rate of 2.44 kg ha−1. Screening with allele-specific PCR (AS-PCR) revealed that resistant plants contained an EPSPS gene with either the homozygous S/S-106 or the heterozygous P/S-106 alleles. All susceptible plants contained only the homozygous P/P-106 allele. In addition, DNA sequences of the full-length EPSPS gene from one susceptible (SB) and four resistant (R2, R6, R8 and R11) populations revealed an amino acid substitution of T102I in all the resistant plants, while another substitution of P381L was only found in resistant populations R6 and R11. The significance of the P381L mutation was examined by Molecular Mechanics Poisson-Boltzmann Surface Area (MM-PBSA) and residue interaction network (RIN) analyses, which suggests the P381L mutation may contribute to resistance. Mutations at 102 and 106 occur widely in the EPSPS gene of glyphosate-resistant E. indica populations from Malaysia with the TIPS mutation. In addition, the P381L mutation could also contribute to resistance.

Cyhalofop-butyl and Glyphosate Multiple-Herbicide Resistance Evolved in an Eleusine indica Population Collected in Chinese Direct-Seeding Rice.

Eleusine indica is a typical xerophytic weed species with a cosmopolitan distribution. It is invasive and highly adaptable to diverse habitats and crops. Due to rice cropping-pattern changes, E indica has become one of the main dominant grass weeds infecting direct-seeding paddy fields. A Chinese E. indica population has evolved multiple-herbicide resistance to cyhalofop-butyl and glyphosate. In this study, the multiple-resistance profile of E. indica to these two different types of herbicides and their resistance mechanisms were investigated. Whole-plant dose-response assays indicated that the multiple-herbicide-resistant (MHR) population exhibited 10.8-fold resistance to cyhalofop-butyl and 3.1-fold resistance to glyphosate compared with the susceptible (S) population. ACCase sequencing revealed that the Asp-2078-Gly mutation was strongly associated with E. indica resistance to cyhalofop-butyl. The MHR plants accumulated less shikimic acid than S plants at 4, 6, and 8 days after glyphosate treatment. In addition, no amino acid substitution in the EPSPS gene was found in MHR plants. Further analysis revealed that the relative expression level of EPSPS in MHR plants was 6-10-fold higher than that in S plants following glyphosate treatment, indicating that EPSPS overexpression may contribute to the glyphosate resistance. Furthermore, the effectiveness of nine post-emergence herbicides against E. indica were evaluated, and one PPO inhibitor pyraclonil was identified as highly effective in controlling the S and MHR E. indica populations.

Glyphosate resistance of Eleusine indica populations from North Sumatra, Indonesia

Abstract. Tampubolon K, Purba E, Basyuni M, Hanafiah DS. 2019. Glyphosate resistance of Eleusine indica populations from North Sumatra, Indonesia. Biodiversitas 20: 1910-1916. Controlling of Eleusine indica populations in oil palm plantations using a similar mode of action of herbicide may cause resistant weed. Overall E. indica populations from oil palm plantations in North Sumatra, Indonesia have never been reported to be glyphosate-resistant. This research was aimed to determine the survival percentage and to classify the resistance of E. indica to glyphosate from oil palm plantations in 11 districts in North Sumatra Province. The research was conducted in the Weed Research Center Field Laboratory, Faculty of Agriculture, Universitas Sumatera Utara from October 2016 to August 2017. This research was arranged in a Randomized Block Design with the glyphosate-treatment using a recommended dose of two l ha-1 and three replications. The ESU0 population was collected in the soccer field of Politeknik Negeri Medan (Medan city) was used as a check, and has never been exposed to the herbicide. Parameters were analyzed using one-way ANOVA, and the means were compared using DMRT at a probability level of 5%. The results showed that 276 (65.56%) of 421 populations were classified as glyphosate-resistant, 88 populations (20.90%) were classified as glyphosate-resistant developing, and 57 populations (13.54%) were classified as glyphosate-susceptible. The highest range of dry weight of glyphosate-resistant E. indica populations were found in 5 districts including South Labuhanbatu District followed by the Serdang Bedagai, Simalungun, Asahan, and North Labuhanbatu Districts. The observed resistance level and dry weight range in the present study indicated the failure in controlling E. indica due to continued use of glyphosate and the potency of E. indica distribution into other oil palm estates due to its high biomass production capability.

Comparison of virulence, reproductive potential, and persistence among local Heterorhabditis indica populations for the control of Temnorhynchus baal (Reiche & Saulcy) (Coleoptera: Scarabaeidae) in Egypt

The scarab beetle, Temnorhynchus baal (Reiche & Saulcy) (Coleoptera: Scarabaeidae), becomes a key pest of strawberry, especially after increasing its cultivated area and economic importance in Egypt. Few entomopathogenic nematode (EPN) species/strains were tested against this pest, where only a foreign species had good effect comparable to the native populations tested previously. Thirty-eight indigenous Heterorhabditis indica populations were tested against the most damaging, third instar larvae of H. baal in two soil types, where strawberry cultivation prevails. The corrected mortality induced by indigenous H. indica population in T. baal larvae was (99.52 and 98.57%) for 15 populations in the sandy soil and 23 in loamy sand soil, respectively. Overall average of infective juveniles (IJs) per T. baal larva was about (41,000). The average of emerged nematode-IJs from the infected grubs for the 15 EPN populations in sandy soil, (46,960 IJs/grub), was significantly (P < 0.001) higher than that (36,502 IJs/grub) of 23 EPN populations in loamy sand soil. The insignificant difference was detected in the reproductive capacity among nematode populations in T. baal larvae in sandy or loamy sand soil. A highly significant difference was found among total IJ numbers collected 10, 18, 26, and 30 days post-inoculation in sandy or loamy sand soil. The persistence of the H. indica populations in the soil varied greatly. Obtained results suggest further use of at least ten populations of such indigenous nematodes under field conditions.

Intra-Plant Distribution and Population Fluctuation of Raoiella indica Hirst (Acari: Tenuipalpidae) on Coconuts in the State of Falcón, Venezuela

Knowledge of the ecology of the red palm mite, Raoiella indica Hirst, is still fragmentary in South America since it was only recently introduced from East Asia. Gathering intra-plant distribution and population fluctuation data could contribute to developing more efficient sampling methods for R. indica. Taking this into consideration, studies were carried out to determine spatial temporal distribution of R. indica in three commercial plantations in the state of Falcon, in Venezuela. Higher mite numbers were registered on middle and lower leaf portions collected from middle or lower plant strata, suggesting that sampling should be allocated to these canopy areas on coconut trees. The R. indica population showed to be negatively associated with rainfall. In 2010, population levels of R. indica were higher than in 2011 (maximum 7 mites/cm2); this was probably a function of lower rainfall values for that year. In 2011, the highest population levels were reached between April and July, coinciding with the lowest rainfall values over that year. Relating to this population spike, the Amblyseius largoensis population showed a numerical response in relation to R. indica density; this predator species does not appear to be exerting bio-control on the mite pest population.

Natural alleles of GLA for grain length and awn development were differently domesticated in rice subspecies japonica and indica.

SummaryRice (Oryza sativa L.) cultivars harbour morphological and physiological traits different from those of wild rice (O. rufipogon Griff.), but the molecular mechanisms underlying domestication remain controversial. Here, we show that awn and long grain traits in the near‐isogenic NIL‐GLA are separately controlled by variations within the GLA (Grain Length and Awn Development) gene, a new allele of GAD1/RAE2, which encodes one member of the EFPL (epidermal patterning factor‐like protein) family. Haplotype analyses and transgenic studies revealed that InDel1 (variation for grain length, VGL) in the promoter region of GLA (GLAVGL) increases grain length by promoting transcription of GLA. Absence of InDel3 (variation for awn formation, VA) in the coding region (CDS) of GLA (GLA va) results in short awn or no awn phenotypes. Analyses of minimum spanning trees and introgression regions demonstrated that An‐1, an important gene for awn formation, was preferentially domesticated and its mutation to an‐1 was followed by GLA and An‐2. Gene flow then occurred between the evolved japonica and indica populations. Quality analysis showed that GLA causes poor grain quality. During genetic improvement, awnlessness was selected in ssp. indica, whereas short–grained and awnless phenotypes with good quality were selected in japonica. Our findings facilitate an understanding of rice domestication and provide a favourable allele for rice breeding.

Sebaran Populasi dan Klasifikasi Resistensi Eleusine indica terhadap Glifosat pada Perkebunan Kelapa Sawit di Kabupaten Deli Serdang

&lt;p&gt;Eleusine indica populations on oil palm plantations in Deli Serdang Regency have not been reported to be resistant to glyphosate. This study was aimed to report distribution and resistance classification of E. indica population on oil palm plantations in Deli Serdang Regency. The research was conducted on Weed Research Center in Faculty of Agriculture, Universitas Sumatera Utara from October 2016 until August 2017. This research used Randomized Block Design with recommended dose at 720 g a.i.ha-1 of glyphosate and three replications. Population ESU0 (from Politeknik Negeri Medan Ball Field) as a comparison. Data on average survival, mortality, dry weight, resistance classification of E. indica were analyzeds using IBM SPSS Statistics 20 software. The results showed that there were 12 E. indica populations classified as glyphosate-resistant (56.52%), 7 glyphosate-resistant developing (30.43%), and 4 populations classified as glyphosate-susceptible (13.04%) with the recommended dose at 720 g a.i.ha-1 from oil palm plantations in Deli Serdang Regency.&lt;/p&gt;

Alterations in the 5' untranslated region of the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) gene influence EPSPS overexpression in glyphosate-resistant Eleusine indica.

The herbicide glyphosate inhibits the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Overexpression of the EPSPS gene is one of the molecular mechanisms conferring glyphosate resistance in weeds, but the transcriptional regulation of this gene is poorly understood. The EPSPS gene was found to be significantly up-regulated following glyphosate treatment in a glyphosate-resistant Eleusine indica population from southern China. To further investigate the regulation of EPSPS overexpression, the promoter of the EPSPS gene from this E. indica population was cloned and analyzed. Two upstream regulatory sequences, Epro-S (862 bp) and Epro-R (877 bp), of EPSPS were obtained from glyphosate-susceptible (S) and -resistant (R) E. indica plants, respectively, by high-efficiency thermal asymmetric interlaced polymerase chain reaction (HiTAIL-PCR). The Epro-S and Epro-R sequences were 99% homologous, except for two insertions (3 and12 bp) in the R sequence. The 12-base insertion in the Epro-R sequence was located in the 5' untranslated region (UTR) pyrimidine nucleotide-rich (Py-rich) stretch element. Promoter activity tests showed that the 12-base insertion resulted in significant enhancement of Epro-R promoter activity, whereas the 3-base insertion had little effect on Epro-R promoter activity. Alterations in the 5' UTR Py-rich stretch element of EPSPS are responsible for glyphosate-induced EPSPS overexpression. Thus, EPSPS transcriptional regulation confers glyphosate resistance in this E. indica population. © 2018 Society of Chemical Industry.

SCREENING SINGLE RESISTANCE OF Eleusine indica ON OIL PALM PLANTATION IN PADANG LAWAS AND TAPANULI SELATAN REGENCY INDONESIA

Abstract: Eleusine indica population from several estates in Padang Lawas and Tapanuli Selatan Regency, Sumatera Utara Indonesia has never been reported to be resistant to glyphosate herbicide. This study aims at distribution mapping and resistance classification of Eleusine indica glyphosate-resistant populations from several estates in Padang Lawas and Tapanuli Selatan Regency, Sumatera Utara. This research was conducted at Weed Research Center of the Faculty of Agriculture, Universitas Sumatera Utara from October 2016 to August 2017. This research used glyphosate at the recommended rate of 720 g ai ha-1 and three replications. Population ESU0 (from Politeknik Negeri Medan Ball Field) as a comparison. Data analysis using t-test at the level of 5% with IBM SPSS Statistics 20 software. The results showed 22 populations in Padang Lawas Regency have 8 populations classified as glyphosate-resistant (36.36%), 8 populations classified as developed-resistant (36.36%), and 6 populations classified as glyphosate-susceptible (27.27%). While from 6 populations in Tapanuli Selatan Regency have 5 populations classified as glyphosate-resistant (83.33%), 1 populations classified as developed-resistant (16.67%), and 0 populations classified as glyphosate-susceptible (0%). Keywords: glyphosate, goosegrass, oil palm plantation, resistance.

Efecto del vermicompost sobre el desarrollo de Raoiella indica Hirst (Acari: Tenuipalpidae) en dos cultivares de Musa

Después de ser introducida en el Caribe, Raoiella indica Hirst (Acari: Tenuipalpidae) ha representado una amenaza para la producción de musáceas, por lo que se requiere desarrollar estrategias para el manejo sustentable de las plagas. En este estudio se evaluó la variación poblacional de R. indica por efecto de la adición de 15 y 30 % de vermicompost en el sustrato de siembra de dos cultivares de Musa (Hartón y Manzano) bajo condiciones de umbráculo. Plantas de cada cultivar de entre 1 y 2 años de edad fueron sembradas en bolsas de polietileno conteniendo arena, mantillo y cascarilla de arroz (1:1:1) como sustrato. Una hoja por planta fue infestada artificialmente con 20 hembras y 10 machos de R. indica y fue evaluado el crecimiento poblacional cada semana. Adicionalmente se determinó el contenido de fenoles totales en hojas de cada cultivar. Aunque la densidad poblacional de R. indica fue menor en plantas tratadas con NPK, estas no mostraron diferencias significativas con vermicompost al 30 % en plantas de ‘Manzano’ o 15 % en ‘Hartón’. Las diferencias en el contenido de fenoles totales dentro de cada cultivar fueron detectadas debido al tratamiento de fertilización 96 h después de la infestación con ácaros. Los resultados sugieren que existen mecanismos de resistencia en las variedades de Musa, lo cual podría ser considerado al momento de establecer estrategias de manejo de la plaga en condiciones del trópico

Integrated Pest Management of melon borer, Diaphania indica (Lepidoptera: Pyralidae) in bittergourd

Field trials were conducted to evaluate the efficiency of different IPM treatments ( Trichogramma chilonis, Dolichogenidea stantoni, Nomuraea rileyi, Beauveria bassiana, Metarhizium anisopliae and Bacillus thuringiensis subspecies kurstaki ) for the management melon borer, Diaphania indica in bittergourd. Among the different treatments evaluated, T7 ( Bacillus thuringiensis / Dipel) and T3 (T. chilonis + D. stantoni) were more effective; T2 (D. stantoni) , T4 (N. rileyi) and T5 (B. bassiana) also gave good control over the D. indica population when compared to other treatments and control.