Banana fruit freckle

Banana freckle is a serious threat to the banana industry. Banana freckle is a disease of banana leaves and fruit. The disease decreases plant health and productivity, and affects fruit quality and appearance. Blemished fruit may not be marketable.

Freckle disease of banana is common in Southeast and East Asia, especially on Musa clones in the Cavendish and Plantain subgroups.

Banana freckle is a plant disease caused by the fungus Phyllosticta cavendishii. It is also can caused by the fungus Guignardia musae.

Spores of the fungus are spread short distances in wind and rain. The fungus is spread over large distances with the movement of infected fruit, leaves and suckers used for planting. It can also be spread by contaminated fruit shipments.

The disease was first reported from Hawaii in 1917 and a few years later in the Philippines.

What are the symptoms of banana freckle?
• ‘Sandpapery feeling’ spots, predominantly on leaves and fruit.
• Spots can be very small to large (1–4 mm) and dark brown to black in color.
• The spots can run together to form streaks.
• Severe infection results in yellowing of the leaf, which can wither and die.

Sandpapery feeling is the most characteristic symptom of freckle. This is caused by the fungal spore structures protruding through the surface of the leaf tissue or fruit peel. If there are large numbers of spots, the leaves turn yellow and die early. Blackspots develop on green fruit and fruit stalks. They may completely cover the fruit by the time of harvest.
Banana fruit freckle

Topical Race 4 disease

Fusarium tropical race 4 (TR4) is the common name of the fungal strain that causes Fusarium wilt (aka Panama disease) in Cavendish cultivars and a wide range of other cultivars. Fusarium tropical race 4 also referred to as Panama disease. Panama disease tropical race 4 (TR4) is caused by the fungus fusarium odoratissimum. Panama TR4 has spread rapidly in Laos, Vietnam, Taiwan, Malaysia, Borneo, Indonesia, mainland China, Philippines, Jordan, Mozambique, Pakistan, Lebanon, Oman and India.

It has been estimated that 80 per cent of global production is under threat from Tropical Race 4. The term TR4 was coined to distinguish the strains that readily cause disease in Cavendish cultivars from the ones that need the presence of predisposing factors, such as low temperatures, to cause disease.

While the fungus is not harmful to humans, it has the potential to eventually wipe out Cavendish bananas, according to experts. Millions of people around the world rely on bananas and plantains as a staple food and as a cash crop.

The pathogen attacks the roots of the banana causing the Banana Fusarium Wilt disease by clogging its vascular system. Symptoms are more obvious at particular times of the year and crop stage. As bunch growth requires additional nutrients and water, this may promote appearance of symptoms. For example, plants may look healthy until bunches emerge, then suddenly start to show leaf yellowing and wilt.

The fungus spreads through infected plant materials and contaminated soil particles attached to items such as farm tools, shoes, clothes, animals and vehicles. Irrigation and drainage water also play a critical role in its spread.

There are 4 races of Panama disease:
*Race 1 attacks Lady Finger, Sugar and Ducasse, but not Cavendish bananas.
*Race 2 attacks cooking bananas like Bluggoe and Blue Java bananas.
*Race 3 attacks only Heliconia species, not bananas.
*Race 4 attacks nearly all varieties of bananas, including the main commercial variety, Cavendish.
Topical Race 4 disease

Banana leaf spot

The name of banana leaf spot is from that of the valley on Fiji where the disease first attracted serious attention. It is widespread but has not been reported from the producing areas of the Canary Islands, Egypt and Israel.

There are three main fungal that cause banana leaf spot: Mycosphaerella musicola, M. fijiensis and M. eumusae.

M.musicola was the first foliar to be identified as a major problem. Its spread from the Southeast Asian/Pacific region, where it was established by 1920s, to North and South America in the 1930s, resulted in widespread disruption to the export trade.

M. musicola produces spermatia in spermogonia, ascospores in perithecia, and conidia of the Cercospora type in sporodochia. Sporodochia appear while the spots are still light yellow, but successive crops of abundant conidia are produced by the same sporodochia only during the browns spot stage of the disease.

Symptoms are first seen as a yellowish green speck (1 mm long) on the leaves; this becomes a streak (3-4 x1 mm) which broadens and lengthens. The streak turns brown or rusty and has an ill-defined margin.
Banana leaf spot

Banana Disease: Malayan leaf Spot

Banana Disease: Malayan leaf Spot
This is usually a minor disease in Fiji, Tonga, Western Samoa and the highlands of peninsular Malaysia and Papua New Guinea. Severe development occurs in areas of Fiji with > 1 m of annual rainfall where temperatures are below 24 degree C, and on some local cultivars in Papua New Guinea.

Symptoms are varies in the different locations. In Fiji, lesions on the upper leaf surface are diamond shape, light grey, 2 - 4 x 3 – 5.5 mm, and have 0.5 mm wide black borders. Profuse growth of the causal fungus, Haplobasidion muscle, occurs on the leaf undersurface.

In Malaysia, lesions have dark purple borders, are pale grey on the upper and pale brown on the lower surface, and are either ellipsoid (2 – 4 x 3 – 12 mm) or round (2 – 5 mm in diameter). Lesions are similar in Papua New Guinea, and large patches of confluent necrosis can develop. Symptoms develop as early as the second or third leaf on local ‘Mala’.

Single to six conidiophores of H.musae are produced at the ends of hyphae that arise through the epidermis on the leaf’s lower surface. They are straight or flexuous, pale brown, one to four celled and 50 – 110 x 4 – um. They terminate in a subglobose cell. Conidia are spherical, brown, verrucose, 4 – 6 um in diameter, and borne singly or in chains of two to five.

Although control measures usually are not needed, maneb was effective. Spray oil enhanced disease development.
Banana Disease: Malayan leaf Spot