BACTERIAL LEAF BLIGHT, RICE – MADAGASCAR: FIRST REPORT’

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BACTERIAL LEAF BLIGHT, RICE – MADAGASCAR: FIRST REPORT’

Tuesday, 02 January 2024 12:26:34

Grahame Jackson posted a new submission ‘

Submission

BACTERIAL LEAF BLIGHT, RICE – MADAGASCAR: FIRST REPORT

ProMED
http://www.promedmail.org

Source: European Plant Protection Organisation (EPPO) Reporting Service 11/2023/253 [summ. Mod.DHA, edited]
https://gd.eppo.int/reporting/article-7735

Bacterial leaf blight of rice caused by _Xanthomonas oryzae_ pv. _oryzae_ (EPPO A1 List) was considered to be absent from Madagascar, as shown by regular monitoring for rice diseases carried out since the 1980s. In December 2019, symptoms resembling those of bacterial leaf blight were observed in 2 rice (_Oryza sativa_) fields in the Central Highlands of Madagascar. Affected plants showed yellow to greyish, water-soaked lesions starting from the leaf tip and progressing along the central vein or leaf margin. At a later stage, leaves became completely desiccated and sometimes had droplets of yellow exudate at the leaf margin.

Symptomatic leaf samples were collected from both fields. Laboratory analysis (morphological, PCR, pathogenicity tests) confirmed the presence of _X. oryzae_ pv. _oryzae_. Further surveys from 2020 to 2022 confirmed the presence of the bacterium in Madagascar and a sharp increase in disease incidence.

Communicated by:
ProMED

[Bacterial leaf blight (BLB) of rice caused by _Xanthomonas oryzae_ pv. _oryzae_ (Xoo) causes yellowing and drying of leaves, as well as wilting of seedlings. Blight lesions caused by severe strains elongate over the entire length of the flag leaf, giving a striped appearance. Severe strains may also affect panicles. Mild strains cause only small leaf lesions and may not lead to any detectable yield loss. Various saprophytic fungi may invade the lesions, contributing to the damage. Field patches infested with bacterial blight have a whitish, ragged appearance. In Asia, for example, millions of hectares of rice paddies are severely affected by Xoo every year, with reported yield losses of up to 60%.

BLB is favoured by rain, high levels of fertilizer, high humidity, standing pools of water and warm temperatures. The bacterium is short-lived in soil and suspected to be seed borne but also to be short-lived in seeds. Grassy weeds, infected plant material (such as rice stubble or ratoons) and contaminated irrigation systems are thought to be primary pathogen reservoirs. The disease spreads by windblown rain and mechanical means (for example when transplanting seedlings or by high insect activity).

Disease management usually includes phytosanitation (control of weed and volunteer rice reservoir hosts, removal of contaminated materials), cultural measures (optimal plant spacing and fertilisers) and use of resistant crop varieties. Control of insect populations by insecticides may help reduce the unspecific spread of bacteria via their scratching and sucking wounds. Antibacterial sprays containing antibiotics are rarely used because they often provide little benefit; furthermore, agricultural application of antibiotics is strictly regulated in most countries. The related _X. oryzae_ pv. _oryzicola_ causes bacterial leaf streak of rice.

More recently, another bacterial leaf blight of rice caused by _Pantoea ananatis_ has also been identified (see links below).

Pictures
BLB symptoms on rice leaves:
http://agropedia.iitk.ac.in/sites/default/files/uas%20raichur/diseases%20of%20paddy/blb00.jpg and
http://www.knowledgebank.irri.org/images/stories/bacterial-leaf-blight-4.JPG
BLB affected rice plants:
http://www.invasive.org/images/768×512/0162037.jpg
Droplets of Xoo exudate on leaf:
http://www.invasive.org/images/768×512/0162038.jpg

Links
Source publication:
https://doi.org/10.1094/PDIS-03-23-0411-PDN
BLB of rice, disease & pathogen information:
http://www.knowledgebank.irri.org/decision-tools/rice-doctor/rice-doctor-fact-sheets/item/bacterial-blight,
https://gd.eppo.int/taxon/XANTOR (with distribution map),
https://doi.org/10.1079/cabicompendium.56956,
http://www.apsnet.org/publications/PlantDisease/BackIssues/Documents/1993Articles/PlantDisease77n01_5.pdf and via
http://www.oisat.org/pests/diseases/bacterial/bacterial_leaf_blight.html
_X. oryzae_ pv. _oryzae_ taxonomy:
http://www.uniprot.org/taxonomy/64187
_P. ananatis_ leaf blight of rice:
https://doi.org/10.1094/PDIS-08-22-2014-PDN and
https://doi.org/10.1007/s42161-023-01514-x
EPPO A1 quarantine list:
https://www.eppo.int/ACTIVITIES/plant_quarantine/A1_list
– Mod.DHA


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POTATO SPINDLE TUBER VIROID – RUSSIA: (AMUR)

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POTATO SPINDLE TUBER VIROID – RUSSIA: (AMUR)

Monday, 01 January 2024 19:49:00

Grahame Jackson posted a new submission ‘POTATO SPINDLE TUBER VIROID – RUSSIA: (AMUR)’

Submission

POTATO SPINDLE TUBER VIROID – RUSSIA: (AMUR)

ProMed 
http://www.promedmail.org

ProMED-mail is a program of the
Source: Port Amur [in Russian, machine trans., summ. Mod.DHA, edited]
https://portamur.ru/news/detail/v-priamure-vyiyavili-novyiy-dlya-regiona-kartofelnyiy-patogen//

In the Amur region, potato spindle tuber viroid has been detected, as reported by Rosselkhoznadzor [Federal Service for Veterinary and Phytosanitary Surveillance]. Samples of potato tubers were sent for laboratory analysis which revealed the viroid. This “quarantine object” was discovered in the Amur region for the 1st time.

A “quarantine phytosanitary regime” was introduced in the area of 1st detection (Belogorsky district) and a “quarantine phytosanitary zone” with a total area of 275 hectares [680 acres] was established. Also, certain measures are prescribed to individual farmers who own infected potato fields.

Communicated by:
ProMED

[_Potato spindle tuber viroid_ (PSTVd; type member of genus _Pospiviroid_) is an important pathogen of solanaceous crops. Yield losses can be up to 65% in potato and up to 50% in tomato. Symptoms in potato may include spindly shoots; stunting of plants; severely distorted tubers (spindles); and delayed sprouting. In tomato, symptoms include leaf chlorosis and distortion; shortening of internodes; stunting of plants; and absence of flowers. Capsicum plants often display only mild symptoms. Solanaceous ornamentals and weeds are often symptomless and may serve as pathogen reservoirs for crop infections. All varieties of tomato and potato appear to be susceptible, but mild strains causing latent infections in some host cultivars exist.

PSTVd is transmitted by true seed in potato and tomato at a rate of up to 100%, depending on the host cultivar. Tomato seed is considered an international quarantine risk (ProMED post 20140122.2222560). Spread occurs also via infected plants or vegetative plant parts, pollen, mechanical means and plant-to-plant contact. PSTVd is exceptionally stable and can persist in dried sap or plant residue for considerable times. Due to the multiple potential transmission routes and the large number of host species, both epidemiology and control of PSTVd are complicated.

In Russia, PSTVd is widespread and poses problems for seed potato production (ProMED posts 20101020.3801, 20190606.6506616). A reduction in yield and quality of seed potatoes had been observed in the country since the 1980s. As PSTVd was identified to be the main cause, the pathogen has been made a national quarantine organism and is being monitored nationwide (see links below).

Pictures
PSTVd symptoms on potato:
https://www.agric.wa.gov.au/sites/gateway/files/PSTVd%20on%20Atlantic.JPG and
http://www.dpi.nsw.gov.au/__data/assets/image/0003/583842/above-ground-symptoms-of-infected-potato.jpg (compared to healthy)
PSTVd symptoms on tomato:
http://www.forestryimages.org/images/768×512/0162082.jpg and
https://www.agric.wa.gov.au/sites/gateway/files/PSTVd%20on%20Rutgers.JPG (compared to healthy)
Photo galleries of PSTVd symptoms on potato and tomato:
http://www.forestryimages.org/browse/subimages.cfm?SUB=11936 and
https://gd.eppo.int/taxon/PSTVD0/photos
Symptoms of pospiviroids on different hosts:
https://www.ipmimages.org/search/action.cfm?q=pospiviroid

Links
Information on PSTVd:
https://gd.eppo.int/taxon/PSTVD0,
https://doi.org/10.1079/cabicompendium.43659,
https://www.agric.wa.gov.au/potatoes/potato-spindle-tuber-viroid and via
http://www.apsnet.org/publications/apsnetfeatures/Pages/Viroids.aspx
Seed transmission of PSTVd (and some other viroids):
https://doi.org/10.1007/s10658-016-0868-z
Detection methods and quarantine risk analysis of pospiviroids:
https://doi.org/10.2903/j.efsa.2011.2330 and
https://gd.eppo.int/download/standard/258/pm9-013-1-en.pdf
PSTVd in Russia:
https://gd.eppo.int/reporting/article-616 and
https://doi.org/10.1094/PDIS-93-7-0752
PSTVd taxonomy via:
https://ictv.global/taxonomy
– Mod.DHA


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Fall armyworm, Spodoptera frugiperda (J.E. Smith) Damage on Rice in the Philippines

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ISSN: 2338-1345 e ISSN 2808-8948 – Vol. 11 (2) 37-46 https://ojs.bakrie.ac.id/index.php/APJSAFE/about
37

Asia Pacific Journal of Sustainable Agriculture Food and Energy (APJSAFE)

Fall armyworm, Spodoptera frugiperda (J.E. Smith) Damage on Rice in the Philippines

Evelyn M. Valdez1, Genaro S. Rillon1, Ravindra C. Joshi1,4*, Kennedy B. dela Cruz1, Dindo King M. Donayre1, Edwin C. Martin1, Femia R. Sandoval1, Eduardo Jimmy P. Quilang1, Minda Flor Aquino2, Maria Katrina Pascual2, Jose Mariano, Jr.2, Evergilio Aquino3,
Muhammad Faheem4 and Sivapragasam Annamalai4

1Philippine Rice Research Institute, Maligaya, Science City of Muñoz, 3119 Nueva Ecija, Philippines
2Department of Agriculture-Regional Crop Protection Center II, Ilagan City, 3300 Isabela, Philippines
3 Department of Agriculture-Regional Crop Protection Center III, PhilRice Compound, Maligaya, Science City of Muñoz, 3119 Nueva Ecija, Philippines 4 Centre for Agriculture and Biosciences International – South East Asia, Serdang, Selangor, Malaysia
*Corresponding author: rc.joshi@mail.philrice.gov.ph

Received: 3 Oct 2023 | Revised: 13 Nov 2023 | Accepted: 28 Nov 2023

Fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) is a global invasive pest of corn, and is also common on sorghum, rice and millets, and is reported to be a larval host of 353 cultivated and uncultivated plants. FAW, a native to the tropical and subtropical regions of north, Central, and South America, continues to rapidly spread to Africa and Asia since 2016, threatening food security worldwide. In the Philippines, its first damage on corn was reported in June 2019 in Piat, Cagayan, while that on rice was in May 2021 in Gonzaga, Cagayan, and subsequently to other municipalities in Region 2. Unlike corn, however, little is known about FAW damage and host preference for rice in the Philippines. Rice, a key food security crop for the Philippines and in Asia, is amongst the key host of the FAW elsewhere (e.g., USA). The injury that the FAW will inflict in the rice plant should be known and assessed to quantify the potential yield losses, and predict when an intervention is necessary to avoid incurring potential yield losses. With this background, we conducted FAW monitoring and damage assessment in the areas reported to have FAW occurrence starting May 2021. During 2021 and 2022 assessment periods, monitoring was conducted during the months of May, June, and July. However, starting January 2023, the monitoring and damage assessments were conducted monthly with the exception for May and June wherein it was done weekly since these months coincided with the seedling stage of the rice in a majority of rice-growing areas in the Philippines and where FAW attack was reported during the previous years. FAW larval population and damage were assessed in rice seedbeds. The number of FAW larvae were counted and visual damage was estimated in a 1 m2 with three replicates.

Keywords : Fall armyworm, Rice, Damage, seedbeds, invasive species, Spodoptera frugiperda, Philipines
FAW-infested areas in the Philippines

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New Record of the Egg-larval Parasitoid, Chelonus formosanus Sonan of Fall Armyworm, Spodoptera frugiperda (J.E. Smith) in the Philippines

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New Record of the Egg-larval Parasitoid, Chelonus formosanus Sonan of Fall Armyworm, Spodoptera frugiperda (J.E. Smith) in the Philippines

JPT: JJurnal Proteksi Tanaman ( Journal of Plant Protection) p-ISSN : 25802580-0600604, e-ISSN: 2621-3141 Accredited: Sinta Publisher: Universitas Andalas, Website: http ;// jpt.faperta.un and. ac .id/index.p hp/jpt Vol. 7 No. 2 (2 023): 103 – 114

New Record of the Egg-larval Parasitoid, Chelonus formosanus Sonan of Fall Armyworm, Spodoptera frugiperda (J.E. Smith) in the Philippines

Orlando Adona Calcetas Calcetas1) , Ravindra Chandra Joshi 2)*2)*, Ankita Gupta Gupta3) , Avinjikkattu Parambil RanjithRanjith4) , Mary Ann Madrid Madrid5) , Joash Fameronag Fameronag5)

  1. Department of Agriculture, Regional Field Office-IVA-CALABARZON, Regional Crop Protection Center, Marawoy, Lipa City, Batangas, Philippines.2)Philippine Rice Research Institute, Maligaya, Science City Muñoz, Nueva Ecija, Philippines3)ICAR-National Bureau of Agricultural Insect Resources, P.B. No. 2491, H.A. Farm Post, Bellary Road, Hebbal, Bengaluru, Karnataka, India. 4)Insect Biosystematics and Conservation Laboratory, Ashoka Trust for Research in Ecology and the Environment, Bengaluru, Karnataka, India.5)Batangas State University University- The National Engineering University, Pablo Borbon Campus, 12 RizalAvenue, Poblacion, Batangas City, Batangas, Philippines.*E-mail: rcjoshi4@gmail.com

Abstract

The egg-larval parasitoid on fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae) have not reported in the Philippines. This paper summarizes the global biological information on two species of Chelonus and their role in the regulation of FAW. The FAW egg masses and larvae were collected in the corn plantations inside the Lipa Agricultural Research Station, Marawoy, Lipa City, Batangas. The collected egg masses and larvae were reared at the Entomology Laboratory of the Department of Agriculture-Regional Crop Protection Center IVA. The larvae of FAW were observed for the emergence of parasitoids. Two cocoons of the parasitoid from the rearing cages were obtained for species determination. Three adults from the emerged parasitoids, each male and female, were initially preserved and labeled. Color images of habitus and other morphological characters of the parasitoid were taken using a DSLR camera attached to an Olympus SZ61-60 microscope. This research found two species that emerged from FAW: Chelonus formosanus and the new record of C. semihyalinus. We also highlight the need for more research in the Philippines on exploring the diversity of indigenous natural enemies, the development of mass-rearing techniques, and their utilization to manage fall armyworms.

Keywords: Chelonus semihyalinus, corn, natural enemy, rice, parasitoid

Received: 02 October 2023 1st Revised: 15 November 2023 Accepted: 02 December 2023 Published: 15 December 2023

For more information contact: rcjoshi4@gmail.com

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Zea mays genotype influences microbial and viral rhizobiome community structure

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Zea mays genotype influences microbial and viral rhizobiome community structure

Friday, 08 December 2023 08:03:07

Grahame Jackson posted a new submission ‘Zea mays genotype influences microbial and viral rhizobiome community structure’

Submission

Zea mays genotype influences microbial and viral rhizobiome community structure

Nature

ISME Communications volume 3, Article number: 129 (2023)  

ABSTRACT
Plant genotype is recognized to contribute to variations in microbial community structure in the rhizosphere, soil adherent to roots. However, the extent to which the viral community varies has remained poorly understood and has the potential to contribute to variation in soil microbial communities. Here we cultivated replicates of two Zea mays genotypes, parviglumis and B73, in a greenhouse and harvested the rhizobiome (rhizoplane and rhizosphere) to identify the abundance of cells and viruses as well as rhizobiome microbial and viral community using 16S rRNA gene amplicon sequencing and genome resolved metagenomics. Our results demonstrated that viruses exceeded microbial abundance in the rhizobiome of parviglumis and B73 with a significant variation in both the microbial and viral community between the two genotypes. Of the viral contigs identified only 4.5% (n = 7) of total viral contigs were shared between the two genotypes, demonstrating that plants even at the level of genotype can significantly alter the surrounding soil viral community. An auxiliary metabolic gene associated with glycoside hydrolase (GH5) degradation was identified in one viral metagenome-assembled genome (vOTU) identified in the B73 rhizobiome infecting Propionibacteriaceae (Actinobacteriota) further demonstrating the viral contribution in metabolic potential for carbohydrate degradation and carbon cycling in the rhizosphere. This variation demonstrates the potential of plant genotype to contribute to microbial and viral heterogeneity in soil systems and harbors genes capable of contributing to carbon cycling in the rhizosphere.

Read on: https://www.nature.com/articles/s43705-023-00335-4


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