Editing Papaya (section)

== Ecology ==
{{See also|List of papaya diseases}}
[[File:Papaya and birds.jpg|thumb|upright=1.4|Various birds eating papayas]]

=== Viruses ===
[[Papaya ringspot virus]] is a well-known virus within plants in Florida.<ref name="morton" /> The first signs of the virus are yellowing and vein-clearing of younger leaves and mottling yellow leaves. Infected leaves may obtain blisters, roughen, or narrow, with blades sticking upwards from the middle of the leaves. The petioles and stems may develop dark green greasy streaks and, in time, become shorter. The ringspots are circular, C-shaped markings that are a darker green than the fruit. In the later stages of the virus, the markings may become gray and crusty. Viral infections impact growth and reduce the fruit's quality. One of the biggest effects that viral infections have on papaya is taste. As of 2010, the only way to protect papaya from this virus is [[Genetically modified food|genetic modification]].<ref name="papaya ringspot">{{cite web |author1=Gonsalves, D. |author2=Tripathi, S. |author3=Carr, J.B. |author4=Suzuki, J.Y. |year=2010 |title=Papaya ringspot virus |url=https://www.ars.usda.gov/research/publications/publication/?seqNo115=231839}}</ref>

The [[papaya mosaic virus]] destroys the plant until only a small tuft of leaves is left. The virus affects both the leaves of the plant and the fruit. Leaves show thin, irregular, dark-green lines around the borders and clear areas around the veins. The more severely affected leaves are irregular and linear in shape. The virus can infect the fruit at any stage of its maturity. Fruits as young as two weeks old have been spotted with dark-green ringspots about 1 inch (25&nbsp;mm) in diameter. Rings on the fruit are most likely seen on either the stem end or the blossom end. In the early stages of the ringspots, the rings tend to be many closed circles, but as the disease develops, the rings increase in diameter consisting of one large ring. The difference between the ringspot and the mosaic viruses is the ripe fruit in the ringspot has a mottling of colors, and the mosaic does not.<ref name="papaya mosaic">{{cite web |last1=Hine |first1=B.R. |last2=Holtsmann |first2=O.V. |last3=Raabe |first3=R.D. |date=July 1965 |title=Disease of papaya in Hawaii |url=http://www.ctahr.hawaii.edu/oc/freepubs/pdf/B-136.pdf}}</ref>

=== Fungi and oomycetes ===
The fungus [[anthracnose]] attacks papaya, especially mature fruits. The disease starts small with very few signs, such as water-soaked spots on ripening fruits. The spots become sunken, turn brown or black, and may get bigger. In some of the older spots, the fungus may produce pink spores. The fruit ends up being soft and having an off flavor because the fungus grows into the fruit.<ref name="test">{{cite web |last1=Mossler |first1=M. A. |last2=Crane |first2=J. |date=2008 |title=Florida crop/pest management profile: papaya |url=http://edis.ifas.ufl.edu/pdffiles/PI/PI05300.pdf |archive-url=https://web.archive.org/web/20170630121711/http://edis.ifas.ufl.edu/pdffiles/PI/PI05300.pdf |archive-date=30 June 2017 |publisher=University of Florida}}</ref>

The fungus [[powdery mildew]] occurs as a superficial white presence on the leaf's surface, which is easily recognized. Tiny, light yellow spots begin on the lower surfaces of the leaf as the disease starts to make its way. The spots enlarge, and white powdery growth appears on the leaves. The infection usually appears at the upper leaf surface as white fungal growth. Powdery mildew is not as severe as other diseases.<ref name="powdery mildew">{{cite web |author1=Cunningham, B. |author2=Nelson, S. |date=June 2012 |title=Powdery mildew of papaya in Hawaii |url=http://www.ctahr.hawaii.edu/oc/freepubs/pdf/PD-90.pdf}}</ref>

The fungus-like oomycete ''[[Phytophthora]]'' causes damping-off, [[root rot]], stem rot, stem girdling, and fruit rot. Damping-off happens in young plants by wilting and death. The spots on established plants start as white, water-soaked lesions at the fruit and branch scars. These spots enlarge and eventually cause death. The disease's most dangerous feature is the fruit's infection, which may be toxic to consumers.<ref name="test" /> The roots can also be severely and rapidly infected, causing the plant to brown and wilt away, collapsing within days.

=== Pests ===

The [[papaya fruit fly]] lays its eggs inside of the fruit, possibly up to 100 or more eggs.<ref name="morton" /> The eggs usually hatch within 12 days when they begin to feed on seeds and interior parts of the fruit. When the [[larva]]e mature, usually 16 days after being hatched, they eat their way out of the fruit, drop to the ground, and [[pupa]]te in the soil to emerge within one to two weeks later as mature flies. The infected papaya turns yellow and drops to the ground after the papaya fruit fly infestation.<ref name="test" />

The [[two-spotted spider mite]] is a 0.5-mm-long brown or orange-red or a green, greenish-yellow translucent oval pest. They all have needle-like piercing-sucking mouthparts and feed by piercing the plant tissue with their mouthparts, usually on the underside of the plant. The spider mites spin fine threads of webbing on the host plant, and when they remove the sap, the mesophyll tissue collapses, and a small chlorotic spot forms at the feeding sites. The leaves of the papaya fruit turn yellow, gray, or bronze. If the spider mites are not controlled, they can cause the death of the fruit.<ref name="test" />

The papaya whitefly lays yellow, oval eggs that appear dusted on the undersides of the leaves. They eat papaya leaves, therefore damaging the fruit. There, the eggs developed into flies in three stages called instars. The first instar has well-developed legs and is the only mobile immature life stage. The crawlers insert their mouthparts in the lower surfaces of the leaf when they find it suitable and usually do not move again in this stage. The next instars are flattened, oval, and scale-like. In the final stage, the pupal whiteflies are more convex, with large, conspicuously red eyes.<ref name="test" />

Papayas are one of the most common hosts for fruit flies like [[Anastrepha suspensa|''A. suspensa'']], which lay their eggs in overripe or spoiled papayas. The larvae of these flies then consume the fruit to gain nutrients until they can proceed into the pupal stage. This parasitism has led to extensive economic costs for nations in Central America.<ref>{{Cite journal |last1=Sivinski |first1=J.M. |last2=Calkins |first2=C. O. |last3=Baranowski |first3=R. |last4=Harris |first4=D. |last5=Brambila |first5=J. |last6=Diaz |first6=J. |last7=Burns |first7=R.E. |last8=Holler |first8=T. |last9=Dodson |first9=G. |date=April 1996 |title=Suppression of a Caribbean Fruit Fly (Anastrepha suspensa(Loew) Diptera: Tephritidae) Population through Augmented Releases of the ParasitoidDiachasmimorpha longicaudata(Ashmead) (Hymenoptera: Braconidae) |journal=Biological Control |volume=6 |issue=2 |pages=177–185 |doi=10.1006/bcon.1996.0022 |bibcode=1996BiolC...6..177S |issn=1049-9644}}</ref>