Diseases 123
to prevent damping off of seedlings. Pick up, remove and destroy fallen fruits, espe-
cially those with diseased symptoms. Intercrop papaya with non-susceptible host
plants and avoid successive crops in the same field (Ko 1982). Seedbeds in nurseries
should be fumigated by formaldehyde (10.0 mL/L water) prior to planting and avoid
mechanical injury during cultivation practices (Nelson 2008).
10.11.2 Chemical Control
In high-rainfall and humid areas, preventive sprays of mancozeb and copper oxy-
chloride @ 2.5 g/L water should be used at about every 2 week interval. Once
Phytophthora blight appears in a field, the disease can become a major concern
due to its ability to spread among plants and destroy fruits rapidly during windy,
rainy periods. In that case, curative, systemic metalaxyl fungicides (Ridomil MZ) @
2.0 g/L water would be very effective (Nishijima 1999). Under high-rainfall condi-
tions, high-volume sprays are required at 2 week intervals. Under drier conditions,
low-volume sprays at 4 week intervals are adequate to protect the exposed fruit sur-
faces. The use of a surfactant is important to ensure good distribution and adherence
of the fungicide spray.
10.12 Freckles..................................................................................
Papayas are frequently blemished by a condition called ‘freckles’ of unknown origin
and mysterious hard lumps of varying sizes and forms may be found in ripe fruits.
No freckles were detected on young fruit; the skin area got affected and freckle
diameter (FD) increased during the last phase of fruit growth as the fruit approached
maturity. More freckles were seen on the exposed side of the fruit away from the
stem (Eloisa et al. 1994). These spots are apparently associated with stomata. Star
spots (greyish-white, star-shaped superficial markings) appear on immature fruits
after exposure to cold winter winds. As the fruit matures, these spots may vary from
pinpoint to >5.0 cm in size with a reticulate pattern. Frequently, a large irregular-
shaped, water-soaked, or greasy spot area may surround several smaller dark spots.
The spots are essentially brown in color on the green or maturing fruit. In the larger
spots, the central portion may take on a greyish cast (Hine et al. 1965). Freckles are
more prevalent on the exposed surface of the fruit as it hangs on the tree. In Uttar
Pradesh, an alga, Cephaleuros mycoidea, often disfigures the fruit surface. Repeated
isolations have failed to consistently yield an organism of a possible parasitic nature.