Photos of stringy sinuous white growth in the fruit of the Papaya (pawpaw)
(Carica papaya L.)
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Photographs and discussion of the cause and edibility concerns of white sinuous or filamentous growth through the fruit or ovary of a papaya (Carica papaya) or "pawpaw" address these questions:
What are the white lines or striations inside of a papaya? Why is the papaya white inside the fruit? Papaya (pawpaw) diseases causing white growth in the fruit, and is the white stuff inside my papaya a disease and is the papaya safe to eat?
What is the probable cause and what may be the significance of the white growths throughout the fruit of this papaya? Is this a plant disease, a fungus, or a genetic anomaly? Is this papaya safe to eat?
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Papaya (Carica papaya L.) White Growth or "Disease" Photographs
[Click to enlarge any image]
Shown here are photographs of a white fibrous growth throughout the normally-edible portion of the fruit of a papaya plant.
We have asked for opinions from experts on the papaya plant to address the following six questions. Readers and papaya experts are invited to CONTACT US with comments or suggestions.
What is this white growth?
Is it fungal, is it a plant disease, or is it a genetic disorder or aberration?
...
Above we see fairly typical papaya seeds in the center of this fruit, and in our second photo we see rather obvious indication that the white fibrous growth that permeates the normally pure orange fruit of the papaya ovary wall is emanating from the white liner or lactifer (latex ducts) to which seeds are attached and from which they are formed.
I think this may be a growth caused by early germination of some of the seeds along the interior wall of the papaya - notice that a few of the seeds themselves are covered in white material.
What are the causes of this papaya "disease"?
Is this papaya safe to eat?
Are there external symptoms on a papaya fruit that might indicate the presence of this papaya disorder?
Is there something else we should ask about this papaya and its edibiltiy?
Other observations about this specific papaya shown above included a sticky surface on the fruit's exterior and a bit of (rather typical) mould growing at the fruit's base.
I could but did not bother to identify this fungus as it is entirely common on other papayas in the marketplace and from its location and compared with the internal growths we document above, I did not see an obvious connection between the fungus and the problem under discussion.
Typically I find species of Aspergillus sp. or sometimes Penicillium sp. in these white mould deposits and on occasion one finds one of the mildews present. For example
And under the microscope we see the fibrous growth and no obvious fungal material in the papaya flesh.
It is possible that these white growths inside of the papaya are related to a different, viviparous phenomenon that is itself caused by germinated or pre-germinated seeds inside the fruit, but to be clear,
usually such growths appear not throughout the flesh of the fruit (as in our photos above) buy rather as a large, hard white blob or growth inside the center of the fruit (not shown here).
Note: reviewing lists of diseases of papaya we did not find a description that included white streaks or striations within the fruit of the papaya itself.
The only papaya disease involving the term "streaks" was of "streaks of an oily appearance" along the main stem of papaya plants describe by Hine, Gonsalves and others,
in discussion of payaya ringspot disease a viral infection that does not appear related to the white streaks or striations shown on this page. (Hine 1965)
The first
symptoms are the appearance of oily streaks on the younger leaves and the
younger leaves show clearing along the veins that gives an appearance of
flecks.
These early symptoms are used to detect infected plants when rogueing
is used for managing the disease. - (Gonsalves 2010)
Thanks for your query regarding the flesh disorder of papaya which was forwarded to our pathology group in North Queensland, Australia.
The group has seen and is not aware of similar symptoms occurring in Australian produced fruit.
After looking at all the images we agree with Daniel that the disorder is not related to any disease.
It appears that something has affected the laticifers (latex ducts) or the vascular material resulting in an aberration of the tissue.
It is difficult to determine the actual cause without having knowledge of the growing conditions, variety, field and postharvest treatments, incidence and severity (eg. one fruit on one plant).
One way to determine if it is specifically the laticifers that are affected would be touch the surface of freshly cut fruit and feel if it is sticky. - Kathy Grice, Senior Experimentalist, Horticulture and Forestry Science, Department of Agriculture and Fisheries, Mareeba, Queensland Australia [by private email] 2016/06/22
List of Diseases of the Papaya Plant & Fruit
List of Common Diseases of Papaya
Ilustrations above and below: Hawaiian payaya infected with Phytophtora parasitica, a fungal disease, discussed by Hine et als in Diseases of Papaya, cited below. The first photo is of Phytophtora parasitica on papaya in the field and the second is a payaya infected with Phytophtora parasitica after having been inoculated in the lab.
[Click to enlarge any image]
We include these payaya fungal infection photos to help distinguish between the white streaky striations found in the papaya fruit discussed above on this page from common payaya diseases.
Various authors including Hine cite the predominant diseases infecting papaya (Carica payaya L.) to include the following conditions. These are discussed by the authors cited below, beginning with Hine (1965).
Non-Parasitic Diseases of Papayas
Over-watering or water-saturated soil exposure for 24-hours or more
Nutritional diseases such as nitrogen deficiency
Defective plants, females, lacking stamens, don't produce fruit
Parasitic Diseases of Papayas
Virus Diseases of Payaya
Papaya Mosaic
Papaya Ringspot
Fungus Diseases of Payaya
Anthracnose (Colletotrichum gleosporoides) - a fungal disease, anthracnose lesions appearing as black, brown, or tan spots on the surface of the papaya fruit. Also called charcoal spot on papaya.
Black rot of Papaya (Mycosphaerella caricae) - a fungal disease resuting in large sunken areas on the exterior of the fruit, typically caused by airborne fungi entering an wound on the fruit.
Black Spot (Asperisporium caricae) of Papaya - appearing over large areas of the papaya skin as small black dots or spots within a larger white area on the fruit.
Black Spot (Cercospora papayae) - appearing as many little black spots spread out over most of the skin of the papaya, not within a larger white area.
Dry Rot and Stem-end Rot
Internal Blight
Oomycetes (water molds) Phytophthora palmivora causing stem rot and whitening of the fruit followed by rot.
Phytophthora Blight - shown in the photo (Hines 1965)
Powdery Mildew (Oidium caricae-papayae) white growth on the leaves of the plant, possibly also appearing on the surface of the fruit. [Illustrated below]
...
Above and below: Oidium sp. is one of the most common appearances of the sub-group of molds in the mildew family.
Bacterial infection (Erwinia spp. or possibly Rickettsia spp.) of wounds or lesions on the papaya, possibly transmitted by aphids attacking the fruit.
Papaya ringspot virus (Potyvirus PRSV) appearing on the plant leaves and possibly showing up as small lumpy spots and dark green rings on the yellow-green surface of the papaya fruit.
Papaya Damage from Insect Pests
Papaya mealybugs (Paracoccus marginatus) produce a white cottony deposit on the leaves and fruit of the Papaya
Papaya Diseases of Unknown Cause
Freckles
Lumpy Fruit
Research References on Payaya Diseases
Illustration: a photograph of healthy flesh and seeds of a payaya - Plantvillage (2020) cited in detail below.
Abreu, Paolla, Tathiana FS Antunes, Anuar Magaña-Álvarez, Daisy Pérez-Brito, Raúl Tapia-Tussell, José A. Ventura, Antonio AR Fernandes, and Patricia Fernandes. A current overview of the PAPAYA MELEIRA VIRUS, an unusual plant virus [PDF] Viruses 7, no. 4 (2015): 1853-1870. Retrieved 2020/05/20 original source: https://biblioteca.incaper.es.gov.br/digital/bitstream/item/748/1/CurrentOverviewofthePapayameleiravirusVentura.pdf
Abstract excerpt:
Papaya meleira virus (PMeV) is the causal agent of papaya sticky disease, which is characterized by a spontaneous exudation of fluid and aqueous latex from the papaya fruit and leaves. T
The latex oxidizes after atmospheric exposure, resulting in a sticky feature on the fruit from which the name of the disease originates.
Note: This article offers an additional 71 research citations on diseases of papaya - Ed.
Andersen, M. T., J. Longmore, L. W. Liefting, G. A. Wood, P. W. Sutherland, D. L. Beck, and R. L. S. Forster. "Phormium yellow leaf phytoplasma is associated with strawberry lethal yellows disease in New Zealand." Plant Disease 82, no. 6 (1998): 606-609.
Ayoola, P. B., and A. Adeyeye. "Phytochemical and nutrient evaluation of Carica papaya (pawpaw) leaves." IJRRAS 5, no. 3 (2010): 325-328.
Chukwuka, K. S., I. O. Okonko, and A. A. Adekunle. "Microbial ecology of organisms causing pawpaw (Carica papaya L.) fruit decay in Oyo State, Nigeria." American-Eurasian Journal of Toxicological Sciences 2, no. 1 (2010): 43-50.
Crane, J. H. Papaya growing in the Florida home landscape. University of Florida IFAS Extension. https://edis.ifas.ufl.edu/pdffiles/MG/MG05400.pdf
Da Silva, JA Teixeira, Zinia Rashid, Duong Tan Nhut, Dharini Sivakumar, Abed Gera, Manoel Teixeira Souza Jr, and Paula F. Tennant. "Papaya (Carica papaya L.) biology and biotechnology." Tree and Forestry Science and Biotechnology 1, no. 1 (2007): 47-73.
Firrao, G., K. Gibb, and C. Streten. "Short taxonomic guide to the genus'Candidatus Phytoplasma'." Journal of Plant pathology (2005): 249-263.Maktar, N. H., S. Kamis, F. Z. Mohd Yusof, and N. H. Hussain. "Erwinia papayae causing papaya dieback in Malaysia." Plant Pathology 57, no. 4 (2008): 774-774.
Hine, R.B., O.V. Holtmann, R.D. Raabe, DISEASES of PAPAYA [PDF], University of Hawaii, Hawaii Agricultura Experiment Station, Bulletin 136 (JUly 1965), retrieved 2020/05/20 original source: https://www.ctahr.hawaii.edu/oc/freepubs/pdf/B-136.pdf
Gonsalves, Dennis, Savarni Tripathi, James B. Carr, and Jon Y. Suzuki. PAPAYA RINGSPOT VIRUS [PDF] The Plant Health Instructor 10 (2010): 1094. retrieved 2020/05/20 original source: http://sipco.ica.gov.co:8080/bitstream/123456789/17511/2/Gonsalves_etal_2010.pdf
Abstract excerpt: The term papaya ringspot (PRS) was first coined by Jensen in 1949 to describe
a papaya disease in Hawaii.
Previously described diseases such as papaya
mosaic (caused by Papaya mosaic virus) and watermelon mosaic (caused by
Watermelon mosaic virus1) were shown recently to be caused by Papaya
ringspot virus (PRSV).
The virus (PRSV) causes a major disease of papaya and
cucurbits and is found in all areas of the world where papaya and cucurbits are
cultivated.
Kumar, Vinod, PAPAYA DISEASES & ... CONTROL [PDF] Agropedia, retrieved 2020/05/20 original source: http://agropedia.iitk.ac.in/content/papaya-diseases-its-control
Macalood, J. S., H. J. Vicente, J. G. Gorospe, R. D. Boniao, and E. C. Roa. "Revisiting Carica papaya L. latex potentials may resolve agricultural infestation problems." International Journal of Scientific & Technology Research 3, no. 1 (2014): 95-8.
Abstract:
Infestation problems are among the top concerns of many farmers worldwide. The use of synthetic pesticides as one of the pest control
methods had been employed which caused many negative impacts both in the environment and human health.
Effectivity of synthetic pesticides is only
short-term which cannot compel for its undesirable impacts. Researches investigating plant potentials as an alternate pesticide for pest control were
suggested as a promising solution without sacrificing the environment and its components.
Carica papaya L. latex is known to contain a lot of
phytochemicals including papain, a cysteine proteinase thought to effectively involved in plant defense against herviborous insects, mollusc, fungi and
other farm pests.
Hence, this review summarizes the C. papaya L. latex potentials as pesticide, molluscicide and fungicide in order to pave the way for
an alternate pests control without damaging the components of the ecosystem and environment.
Maktar, N. H., S. Kamis, F. Z. Mohd Yusof, and N. H. Hussain. "Erwinia papayae causing papaya dieback in Malaysia." Plant Pathology 57, no. 4 (2008): 774-774.
Ortega, Monica Moralma Garces, "Effect of proteolytic enzyme and fiber of papaya fruit on human digestive health." PhD diss., University of Illinois at Urbana-Champaign, 2011.
Pernezny, Ken, R.E. Litz, SOME COMMON DISEASES of PAPAYA in FLORIDA [PDF] University of Florida IFAS Extension, retrieved 2020/05/20, original source: https://ufdcimages.uflib.ufl.edu/IR/00/00/28/59/00001/VH05000.pdf
Excerpt: Diseases are the most important limiting
production problems of papaya. Although the plant is
classified botanically as perennial, virus diseases
have reduced the effective crop life to 1-2 years.
This fact sheet describes the symptoms of
several important Florida papaya diseases and
recommendations for control.
Since few pesticides
are registered by the Environmental Protection
Agency for use on papaya, and the plant is prone to
damage by some chemical sprays, consult the
University of Florida extension service or the Plant
Disease Control Guide for current fungicide
recommendations.
Persley, Denis M., and Randy C. Ploetzz. "1 7 Diseases of Papaya." Diseases of Tropical Fruit Crops (2003): 373.
Website excerpt: PlantVillage is built on the premise that all knowledge that helps people grow food should be openly accessible to anyone on the planet. PlantVillage is a user moderated Q & A forum dedicated to the goal of helping people grow their own food. It is an open, freely available resource that helps you solve all your plant related questions.
Rampersad, Sephra N. "Molecular and phenotypic characterization of Colletotrichum species associated with anthracnose disease of papaya in Trinidad." Plant Disease 95, no. 10 (2011): 1244-1254.
Singh, S. K., P. K. Jha, and P. K. Ray. "Papaya diseases in Bihar: an overview." In II International Symposium on Papaya 851, pp. 481-486. 2008.
Streten, C., and K. S. Gibb. "Phytoplasma diseases in sub-tropical and tropical Australia." Australasian Plant Pathology 35, no. 2 (2006): 129-146.
Vawdrey, L. L., K. R. E. Grice, and D. Westerhuis. "Field and laboratory evaluations of fungicides for the control of brown spot (Corynespora cassiicola) and black spot (Asperisporium caricae) of papaya in far north Queensland, Australia." Australasian Plant Pathology 37, no. 6 (2008): 552-558.
Vawdrey, L. L., K. E. Grice, R. A. Peterson, and J. De Faveri. "The use of metalaxyl and potassium phosphonate, mounds, and organic and plastic mulches, for the management of Phytophthora root rot of papaya in far northern Queensland." Australasian Plant Pathology 33, no. 1 (2004): 103-107.
Vawdrey, L. L., K. E. Grice, and R. A. Peterson. "7.3 The Use of Mounds and Organic and Plastic Mulches for the Management of Phytophthora Root Rot of Papaya in Northern Queensland." [PDF] Diversity and Management of Phytophthora in Southeast Asia: 167. Retrieved 2016/07/04, original source https://core.ac.uk/download/files/153/6693118.pdf#page=166
Abstract:
Options for the control of root rot of papaya caused by Phytophthora palmivora were evaluated in a
field experiment in northerly parts of Queensland, Australia. In the experiment, growing papaya
on 0.75 m mounds reduced the incidence of root rot by 38.4% and significantly increased fruit yield.
Soil covers of 2 m wide plastic mulch and organic mulch, in combination with 0.75 m mounds,
further reduced plant losses by 20 and 10%, respectively.
Plastic mulch on flat ground was as
effective as the mounded treatments in reducing the incidence of root rot and increasing yield.
Zentmyer, G. A., Nishijima, W. T., Rohrbach, K. G. & Ohr, H. D. (eds) (1994). Compendium of Tropical Fruit Diseases. American Phytopathological Society Press
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Reader Comments, Questions & Answers About The Article Above
Below you will find questions and answers previously posted on this page at its page bottom reader comment box.
On 2020-05-20 - by (mod) - white veins in papaya not actual "plant disease"
Melissa
Gracias por el foto y su comentario.
I also live in Mexico and have opened a papaya to find the same white striations - though not often.
I don't think it's an insect nor a plant disease but rather a growth abnormality, because having reviewed quite a few articles on payapa "disease" I have not found a photo nor descriptions of quite what you and I are seeing in these Mexican papayas; I agree that the papaya taste was the same.
[Click to enlarge any image]
I just found the fruit so unappealing that I threw it out. I'm researching further to see if I can put a name to this symptom and will post that here.
As we wrote above,
It appears that something has affected the laticifers (latex ducts) or the vascular material resulting in an aberration of the tissue.
It is difficult to determine the actual cause without having knowledge of the growing conditions, variety, field and postharvest treatments, incidence and severity (eg. one fruit on one plant).
My request to a papaya expert in Austraila expressed that view, as you'll see in the article above.
On 2020-05-20 by Melissa Saravia
I live in Mexico and yesterday I opened a papaya that had this exact characteristic. [photo above]
I did not find the taste was different, I did not find any insects, thinking it could make those burrows.
On 2018-04-03 - by (mod) - white streaks in papaya ok to eat?
Thanks for asking, Bree.
In the papaya disease article above I quoted from experts who agreed that the white streaks are not associated with any disease.
They were, of course referring to plant disease. It’s reasonable to infer that if the streaky papaya is not suffering a plant disease it’s also not a health hazard.
I would prefer not to eat Papaya that has a lot of those white streaks because it's its texture not so nice as its sisters, but on researching I have not found any expert who claimed that there was any health hazard.
On 2018-04-03 - by (mod) - streaky papaya problem - ok to eat
Thanks for asking, Bree.
In the papaya disease article above I quoted from experts who agreed that the white streaks are not associated with any disease. They were, of course referring to plant disease. It’s reasonable to infer that if the streaky papaya is not suffering a plant disease it’s also not a health hazard.
On 2018-04-03 by Bree
Sorry, maybe I'm stupid or blind but I don't see where the answer is. Is a papaya with these white spots/streaks ok to eat?
I opened one today with these white spots. It smells good and seems normal besides the white spots. Just wondering if its safe to eat or if I should throw it away.
...
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Citations & References
In addition to any citations in the article above, a full list is available on request.
Adkins and Adkins Dictionary of Roman Religion discusses Robigus, the Roman god of crop protection and the legendary progenitor of wheat rust fungus.
Kansas State University, department of plant pathology, extension plant pathology web page on wheat rust fungus: see http://www.oznet.ksu.edu/path-ext/factSheets/Wheat/Wheat%20Leaf%20Rust.asp
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