scholarly journals Effects of Vegetation Strips, Fertilizer Levels and Varietal Resistance on the Integrated Management of Arthropod Biodiversity in a Tropical Rice Ecosystem

Insects ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 328 ◽  
Author(s):  
Horgan ◽  
Crisol Martínez ◽  
Stuart ◽  
Bernal ◽  
de Cima Martín ◽  
...  
Keyword(s):  
Mung Bean ◽  
Production Systems ◽  
Integrated Management ◽  
Interspecific Interactions ◽  
Nilaparvata Lugens ◽  
Varietal Resistance ◽  
Rice Varieties ◽  
Nitrogen Levels ◽  
Predatory Bugs ◽  
Arthropod Biodiversity

Integrated biodiversity management aims to conserve the beneficial species components of production ecosystems and reduce the impacts of pests. In 2011 and 2013, experiments were conducted at Los Baños, Laguna, Philippines, to compare arthropod communities in rice plots and on levees with and without vegetation strips. Vegetation strips included spontaneous weeds, sesame and okra (2011), or mung bean (2013). The plots were treated with one of three nitrogen levels and in one experiment were planted with planthopper-resistant (IR62) and susceptible (IR64) rice varieties. Parasitoids and predators of lepidopteran pests and of the ricebug, Leptocorisa oratorius, were more abundant in high-nitrogen rice plots where their prey/hosts also had highest densities. Planthoppers and leafhoppers were more abundant in low-nitrogen plots. Weedy and sesame/okra bunds provided habitat for a range of natural enemies including spiders, parasitoids and predatory bugs, but did not have higher pest numbers than cleared bunds. Higher abundances of the predator Cythorhinus lividipennis and higher parasitism of planthopper (Nilaparvata lugens) eggs by Anagrus sp. were associated with sesame/okra bunds in late season rice plots. Mung bean also provided habitat for key predators and parasitoids that spilled over to adjacent rice; however, mung bean was also associated with higher numbers of lepidopteran and grain-sucking pests in the adjacent rice, albeit without increased damage to the rice. For ricebug in particular, damage was probably reduced by higher parasitoid:pest ratios adjacent to the vegetation strips. Varietal resistance and mung bean strips had an additive effect in reducing abundance of the planthopper Sogatella furcifera and the leafhopper Nephotettix virescens. Reduced numbers of these latter pests close to vegetation strips were often compensated for by other plant-sucking bugs, thereby increasing the intensity of potentially stabilizing interspecific interactions such as competition. We highlight the benefits of diversifying rice landscapes and the need to optimize vegetation strips, e.g., by including lepidopteran trap-plants, for intensive rice production systems.

scholarly journals Cryptic Species Diversity of Rice Hopper Parasitoids in Southeast Asia

2017 ◽  
Author(s):  
Christina Sann ◽  
Franziska Wemheuer ◽  
Alexis Beaurepaire ◽  
Rolf Daniel ◽  
silvio Erler ◽  
...  
Keyword(s):  
Southeast Asia ◽  
Cryptic Species ◽  
Morphological Analysis ◽  
Production Systems ◽  
Nilaparvata Lugens ◽  
Egg Parasitoid ◽  
The Philippines ◽  
Morphological Identification ◽  
Rice Varieties ◽  
Dna Database

On-going intensification of rice production systems in Southeast Asia is causing devastating yield losses each year due to rice hoppers. Continuing development of immunity to resistant rice varieties and pesticide application further complicate this problem. Hence, there is a high demand for biological control agents. Egg parasitoid wasps are among the most important natural enemies of rice hoppers such as Nilaparvata lugens and Nephotettix spp. However, our knowledge on their diversity is still very limited due to their small size and the lack of available morphological information. Classifying these parasitoids is the first step to properly understand their role in the rice agroecosystem. We used traditional morphological identification as well as DNA sequencing of COI and 28S genes to investigate the diversity of four important hopper egg parasitoid genera in the Philippines. Parasitoids of the genera Anagrus spp., Oligosita spp., Gonatocerus spp. and Paracentrobia spp. were collected in eight study landscapes located in Luzon. We found discrepancies between the morphological and the molecular analysis. Morphological and molecular results were only valid for Paracentrobia spp. Anagrus spp. and Gonatocerus spp. showed more genetic diversity, than expected after the morphological analysis, indicating cryptic species. The sequences for Oligosita spp. revealed less variation than expected. This is the first study on molecular diversity of rice parasitoids in the Philippines. More research combining morphological, behavioural and genetic methods as well as the establishment of a comprehensive DNA database is urgently needed to assess the performance and suitability of these organisms as biocontrol agents.

Productivity of rice varieties under varied nitrogen levels

Green Farming ◽  
2020 ◽  
Vol 11 (4-5) ◽  
pp. 324
Author(s):  
E. ARUNA ◽  
A. PRATAP KUMAR REDDY ◽  
G. KARUNA SAGAR
Keyword(s):  
Rice Varieties ◽  
Nitrogen Levels

scholarly journals Detection of Yeast-like Symbionts in Brown Planthopper Reared on Different Resistant Rice Varieties Combining DGGE and Absolute Quantitative Real-Time PCR

Insects ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 85
Author(s):  
Chengling Lai ◽  
Yun Hou ◽  
Peiying Hao ◽  
Kun Pang ◽  
Xiaoping Yu
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Brown Planthopper ◽  
Nilaparvata Lugens ◽  
Quantitative Real Time Pcr ◽  
Nymphal Instar ◽  
Rice Varieties ◽  
Development Stages ◽  
The Third ◽  
Minimum Number

The brown planthopper (BPH), Nilaparvata lugens, is a serious pest of rice throughout Asia. Yeast-like symbionts (YLS) are endosymbionts closely linked with the development of BPH and the adapted mechanism of BPH virulence to resistant plants. In this study, we used semi-quantitative DGGE and absolute quantitative real-time PCR (qPCR) to quantify the number of the three YLS strains (Ascomycetes symbionts, Pichia-like symbionts, and Candida-like symbionts) that typically infect BPH in the nymphal stages and in newly emerged female adults. The quantities of each of the three YLS assessed increased in tandem with the developing nymphal instar stages, peaking at the fourth instar stage, and then declined significantly at the fifth instar stage. However, the amount of YLS present recovered sharply within the emerging adult females. Additionally, we estimated the quantities of YLS for up to eight generations after their inoculation onto resistant cultivars (Mudgo, ASD7, and RH) to reassociate the dynamics of YLS with the fitness of BPH. The minimum number of each YLS was detected in the second generation and gradually increased from the third generation with regard to resistant rice varieties. In addition, the Ascomycetes symbionts of YLS were found to be the most abundant of the three YLS strains tested for all of the development stages of BPH.

scholarly journals Ketahanan padi (Oryza sativa L.) varietas IPB 3S terhadap wereng batang cokelat (Nilaparvata lugens (Stål) (Hemiptera: Delphacidae)

2020 ◽  
Vol 17 (2) ◽  
pp. 97
Author(s):  
Andi Nurdaaniyah ◽  
Dadang Dadang ◽  
I Wayan Winasa
Keyword(s):  
Sex Ratio ◽  
Insect Pests ◽  
Oryza Sativa L ◽  
Feeding Activity ◽  
Brown Planthopper ◽  
Nilaparvata Lugens ◽  
Population Increase ◽  
Rice Varieties ◽  
High Loss ◽  
Rice Plants

<p>Brown planthopper (<em>Nilaparvata lugens</em> (Stål)) is one of the major rice insect pests that is known to cause high loss of rice production. One of the strategies to control this pest is by using resistant rice varieties. The aim of this research was to study the resistance of IPB 3S variety to BPH by measuring BPH fecundity, sex ratio, feeding activity as well as population increase compared to Ciherang variety against brown planthopper (<em>N. lugens</em>). Fecundity test used a pair of BPH adult infested on 21 days after planting (DAP) of rice plants. Eggs laid in rice stalks and the rest of eggs in the ovary were counted. In order to know the change of sex ratio, a pair of BPH adults was infested on 30 DAP rice plants and allowed to lay eggs. The calculation of sex ratio was conducted at adult stage of BPH by segregation between male and female adults. Feeding activity of BPH was evaluated using ninhydrin and analyzed qualitatively using spectrophotometer. Ten fourth instar nymphs of BPH was infested on 30 DAP old of rice seedlings. Honeydew secreted by BPH was collected to filter paper sprayed with ninhydrin. Population increased test was conducted by infesting five pairs of BPH adults on 35 DAP old rice plants. Observations was conducted on nymph and adult stages. Each test was replicated 10 times. In general, IPB 3S is slightly resistant to BPH, compared to Ciherang variety. The feeding activity of BPH is higher in Ciherang compared to IPB3S. However, the fecundity and population increased of BPH in Ciherang is similar to IPB3S.</p>

scholarly journals Tomato Breeding for Sustainable Crop Systems: High Levels of Zingiberene Providing Resistance to Multiple Arthropods

Horticulturae ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 34 ◽  
Author(s):  
João Ronaldo Freitas de Oliveira ◽  
Juliano Tadeu Vilela de Resende ◽  
Renato Barros de Lima Filho ◽  
Sergio Ruffo Roberto ◽  
Paulo Roberto da Silva ◽  
...  
Keyword(s):  
High Performance ◽  
Production Systems ◽  
Cropping Systems ◽  
Integrated Management ◽  
Interspecific Cross ◽  
Sources Of Resistance ◽  
Tomato Crop ◽  
Integrated Management System ◽  
Tomato Breeding ◽  
F2 Generation

In sustainable cropping systems, the management of herbivorous arthropods is a challenge for the high performance of the tomato crop. One way to reduce the damage caused by these pests is the use of resistant cultivars within a sustainable integrated management system. The host selection of Tetranychus urticae, Bemisia tabaci, and Tuta absoluta was evaluated, characterizing their preference among the tomato genotypes RVTZ2011-79-503-143, RVTZ2011-79-335-164, RVTZ2011-79-185-250 (high zingiberene content—HZC), and RVTZ2011-79-117-273 (low zingiberene content—LZC). Such genotypes were selected in the F2BC2 generation (the F2 generation of the 2th backcross towards Solanum lycopersicum after the inicial interspecific cross S. lycopersicum × S. habrochaites var. hirsutum), resulting from crossing Solanum habrochaites var. hirsutum PI-127826 (HZC and resistant to mites) and the commercial cv. Redenção (S. lycopersicum) (LZC and susceptible to mites). In choice and no-choice bioassays by T. urticae, and in choice bioassays by B. tabaci and T. absoluta, arthropods preferred to stay and oviposit in an LZC genotype. In contrast, genotypes with HZC showed repellency to pests and induced a non-preference for oviposition. The F2BC2 genotypes selected for HZC are considered sources of resistance genes to these pests for tomato breeding programs, and therefore have excellent potential for sustainable cropping systems. These results represent an advance in obtaining tomato genetic materials which can be used in sustainable production systems with less loss from pests.

scholarly journals Bacterial Symbionts of the Brown Planthopper, Nilaparvata lugens (Homoptera: Delphacidae)

2010 ◽  
Vol 76 (6) ◽  
pp. 1740-1745 ◽  
Author(s):  
Ming Tang ◽  
Lu Lv ◽  
Shengli Jing ◽  
Lili Zhu ◽  
Guangcun He
Keyword(s):  
Brown Planthopper ◽  
Nilaparvata Lugens ◽  
Rrna Gene ◽  
Rice Varieties ◽  
Ovipositor Sheath ◽  
Operational Taxonomic Units ◽  
Metaseiulus Occidentalis ◽  
High Virulence ◽  
Gene Libraries

ABSTRACT The brown planthopper (Nilaparvata lugens Stål), the most destructive pest of rice, has been identified, including biotypes with high virulence towards previously resistant rice varieties. There have also been many reports of a yeast-like symbiont of N. lugens, but little is known about the bacterial microbes. In this study, we examined the bacterial microbes in N. lugens and identified a total of 18 operational taxonomic units (OTUs) representing four phyla (Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes) by sequencing and analyzing 16S rRNA gene libraries obtained from three populations of N. lugens, which were maintained on the rice varieties TN1, Mudgo, and ASD7. Several of the OTUs were similar to previously reported secondary symbionts of other insects, including an endosymbiont of the psyllid Glycapsis brimblecombei, an Asaia sp. found in the mosquito Anopheles stephensi, and Wolbachia, found in the mite Metaseiulus occidentalis. However, the species and numbers of the detected OTUs differed substantially among the N. lugens populations. Further, in situ hybridization analysis using digoxigenin-labeled probes indicated that OTU 1 was located in hypogastrium tissues near the ovipositor and ovary in biotype 1 insects, while OTU 2 was located in the front of the ovipositor sheath in biotype 2 insects. In addition, masses of bacterium-like organisms were observed in the tubes of salivary sheaths in rice plant tissues that the insects had fed upon. The results provide indications of the diversity of the bacterial microbes harbored by the brown planthopper and of possible associations between specific bacterial microbes and biotypes of N. lugens.

Responses by the brown planthopper,Nilaparvata lugens, to conspecific density on resistant and susceptible rice varieties

2016 ◽  
Vol 158 (3) ◽  
pp. 284-294 ◽  
Author(s):  
Finbarr G. Horgan ◽  
Bhaskar S. Naik ◽  
Eko Hari Iswanto ◽  
Maria Liberty P. Almazan ◽  
Angelee Fame Ramal ◽  
...  
Keyword(s):  
Brown Planthopper ◽  
Nilaparvata Lugens ◽  
Rice Varieties ◽  
Conspecific Density

scholarly journals Recent Strategies for Detection and Improvement of Brown Planthopper Resistance Genes in Rice: A Review

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1202
Author(s):  
Bello Sani Haliru ◽  
Mohd Y. Rafii ◽  
Norida Mazlan ◽  
Shairul Izan Ramlee ◽  
Isma’ila Muhammad ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Large Scale ◽  
Insect Pest ◽  
Durable Resistance ◽  
Brown Planthopper ◽  
Gene Clusters ◽  
Nilaparvata Lugens ◽  
Scale Production ◽  
Rice Varieties ◽  
Resistant Genes

Brown planthopper (BPH; Nilaparvata lugens Stal) is considered the main rice insect pest in Asia. Several BPH-resistant varieties of rice have been bred previously and released for large-scale production in various rice-growing regions. However, the frequent surfacing of new BPH biotypes necessitates the evolution of new rice varieties that have a wide genetic base to overcome BPH attacks. Nowadays, with the introduction of molecular approaches in varietal development, it is possible to combine multiple genes from diverse sources into a single genetic background for durable resistance. At present, above 37 BPH-resistant genes/polygenes have been detected from wild species and indica varieties, which are situated on chromosomes 1, 3, 4, 6, 7, 8, 9, 10, 11 and 12. Five BPH gene clusters have been identified from chromosomes 3, 4, 6, and 12. In addition, eight BPH-resistant genes have been successfully cloned. It is hoped that many more resistance genes will be explored through screening of additional domesticated and undomesticated species in due course.

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