Status of Pineapple mealybug wilt-associated virus across major pineapple growing localities in Mauritius

​

Arty Gungoosingh Bunwaree¹,

​

​

Fazal Maudarbaccus¹

​

&

​

Wulf Menzel²

​

¹Plant Pathology Division, Food and Agricultural Research and Extension Institute (FAREI), Réduit, Mauritius

² Plant Virus Department, Leibniz Institute DSMZ – German Collection of Microorganisms and Cell Cultures, Inhoffenstraße 7 B, Braunschweig 38124, Germany

UOM RW 2021

​

​

• Occurrence of PMWaV

Disorder 1^st observed in Mauritius in 2011 at Les Mariannes/Ilot regions during routine disease surveillance by FAREI Plant Pathology Division

• Pineapple crop of major economic importance in Mauritius – local consumption, tourist industry and export
• In 2018:
• production of 10 300t over 439 ha
• out of which 1736t fresh fruits exported
• 3M USD

• Visible symptoms observed during 2011 surveillance:

Unusual reddening in pineapple leaves; plant drying/wilting, reduction in pineapple fruit size

• Yield loss: 10 to 30%

• Islandwide survey across pineapple growing areas in 2011/2012 revealed the disease to be present in 41.7% sites monitored, with an overall mean disease incidence of 7.2%, as shown in Table 1 below. Disease present on pineapple varieties Queen Victoria, Bourgault and Honey but NOT on wild pineapple

• Symptomatic samples despatched to DSMZ lab in Germany revealed presence of Pineapple mealybug wilt associated virus -1(PMWaV1) and Pineapple mealybug wilt associated virus-2 (PMWaV2) from the Closteroviridae family by RT-PCR

​

• Mauritian virus strains (PMWaV-1, GenBank Accession No. MZ787952) and (PMWaV-2, MZ787957) showed high degree of nucleotide (nt) sequence identity, namely 96.6% and 99.5% to the corresponding PMWaV-1 and PMWaV-2 reference sequences (NC_010178 and NC_043105) respectively.

• Brief info on the virus

First reported on pine apple in Hawaii in 1933.

Susceptible hosts species found among members of Bromeliaceae

• Geographical distribution:

Present in major pineapple growing countries e.g. Hawaii, Cuba, Australia, Kenya and even Reunion;

• Transmission: By mealybugs (e.g Dysmicoccus sp) and/or infected suckers

In Reunion island PMWaV considered as a highly destructive disease for the crop on variety “Queen Victoria” and a potential major threat to their pineapple export industry

“Extract from Agronews-Edition Reunion-Mayotte-August 2021”

• Sensitization campaign on PMWaV management strategies started in 2011 with Extension Officers and pineapple growers

1. Eliminate old, infected plantations
2. Control of vectors (mealy bugs)
3. Careful selection of suckers prior to plantation
4. Hot water treatment of suckers

- up to 2hrs at 50 ^oC

5. Follow GAP

Decline in PMWaV incidence ≤ 10% observed over the years…

• PMWaV under control until…. 2020 Post COVID-19 confinement,

when disease incidences flared up in certain regions as indicated in Table 2 below

• Disease symptoms observed at 74.1% site surveyed and an overall mean disease incidence of 23.6% recorded

• No disease symptoms observed in a shadehouse planted with pineapple vitroplantlets

• PMWaV-1 and -2 once more detected from symptomatic leaf samples tested by RT-PCR in November 2020 at the DSMZ laboratory, Germany

• Flare up of PMWaV symptoms in 2020 attributed to a drastic decline in the demand for fruits from hotels & a reduction in volume of fruits exported growers no longer considered disease management practices as a priority rise in insect vectors populations & disease symptoms.

Only 239t fresh pineapple fruits exported in 2020 14% volume exported in 2018

​

• An improvement in plant and fruit quality noted over the months following the COVID 19 de-confinement in 2021
• Essential for all growers to maintain good cultural practices at field level and to encourage the mass production of indexed in vitro pineapple plantlets in order to ensure a supply of clean planting material at all times

• Conclusion

Disease surveillance is an important tool in the detection of new and emerging diseases at field level and to equally monitor the status on existing ones

​

​

• Acknowledgements
• The Management of FAREI
• Principal Research Scientist and colleagues at Plant Pathology Division, FAREI
• Extension Staff FAREI and Pineapple growers visited during routine surveys
• Dr Wulf Menzel and team at DSMZ lab, Germany
• Organising Committee of UOM RW 2021

THANK YOU !!!

My Bio Data

• Name: Dr (Mrs) Arty Gungoosingh Bunwaree
• Address: Plant Pathology Division, FAREI, Réduit
• Email: agbunwaree@yahoo.fr
• Tel: +230 465 1011
• Brief: Joined FAREI as Research Scientist/Senior Research Scientist in 1998. Over 20 years of experience in Plant Pathology. From 2005 to 2007 was the Senior Agricultural Officer (Officer in Charge) at the Agricultural Services in Rodrigues. From 2010 to 2013, I was the Principal Investigator on two Mauritius Research Council (MRC) funded research projects on plant phytoplasmas affecting vegetable crops. From 2014 to 2015 worked as Policy Officer (Crop Production/Crop Protection) at the African Union Commission in Addis Ababa, Ethiopia, and from 2016 to 2019, was the National Project Coordinator of two FAO Technical Cooperation Programs (TCPs), one on Organic Farming and the second one on Plant Health and Food Safety. Have a keen interest in plant virology, emerging plant pathogens and their management.