algal leaf spot of mango management

the disease appeared in an epidemic form in the state orchards in Tarai in 1956. Mucor rot Mucor circinelloides. Mango tree borer damage may first be noticed as circular holes in the bark. The species are recorded from American Samoa, Australia, Cook Islands, Federated States of Micronesia, Fiji, Niue, Palau, Papua New Guinea, Samoa, Solomon Islands, Tonga, and Vanuatu. In tropics and sub-tropics. Because algal leaf spot disease occurrence depends upon high humidity in the plant canopy and long-duration periods of leaf … Management. If you scrape off the orange, grayish discoloration will be underneath. If symptomatic leaves are left in the same general area then irrigation or rain water can splash the algal … Spores of the algae (called sporangia) are formed on the spots, giving them a furry look (Photo 2). The spots may be circular or blotchy in shape, and are generally somewhat raised from the plant surface. Symptoms . Also this insects are always associated with ants. Algal Leaf Spot caused by Cephaleuros virescens is not detrimental to plant health. b. Fig. Mango malformation Fusarium subglutinans (Note: some debate remains as to complete etiology of this disease.) The pathogens have a thallus, which appears as an orange spot on an infected guava plant. The pathogen can survive in mango leaves for over a year. an important fruit of subtropical countries is affected by about 177 pathogens of which, 167 are fungal, 3 bacterial, 3 algal, 3 nematodes and one epiphyte.Wilt is the most important disease of guava. Pirie Printers Pty Limited, Canberra, Australia. 6 Algal spots on leaves Management: The control of alga can be achieved by sprays of Copper oxychloride (0.3%) 3-4 times at an interval of 15 days when initial symptoms noticed. Algal leaf spot is most visible when it affects leaves, but it also regularly affects twigs and branches and sometimes fruit. Another major problem with scale insect is the development of sooty mold due to honeydew secretion. Sooty mold mainly develops on honey dew secreted by sap sucking insects like whiteflies, aphids, leaf hoppers, scale insects, mealybugs and psyllids. are spread in wind and rain. a. Mealybugs lay eggs in soil near tree trunk. Exotic mango varieties can improve the livelihood security and increase profitability of mango growers in Uganda. There are however, several factors like pests, diseases and orchard management practices which limit mango production and productivity. Plant tissue beneath the lesion may die and heavily infested leaves may drop prematurely. The leaves, twigs, inflorescence and fruits are covered with shiny black and sticky growth of fungal mycelium. Links will be auto-linked. Its major distribution in India has been in Bihar, Karnataka, and U.P. Plant vigour and yield are seldom impacted severely, so management isn't necessary in most cases. Algal leaf spot is a disease of guava plant, which is caused by parasitic algae. Of the three species, Cephaleuro virescans is the most common. Mango tree borers are a pest of mango trees in many parts of Asia, Africa, Central America, the Caribbean and the Solomon Islands; female tree borers lay their eggs in an incision made in damaged mango bark; larvae bore through the wood as they feed and eventually pupate within the tree; adult insects emerge from an exit hole that they cut in the wood. Scale insects suck the sap from leaves, branches and fruits which causes defoliation, drying up of young twigs, poor blossoming and also affect the quality of fruits by causing conspicuous pink blemishes. virescens, on avocado leaves. Avocado leaf diseases can look so bad that a homeowner will question whether or not their tree will make it to harvest time. On young stems, the spots cause cracks in the bark and this can lead to dieback. Some of the plants it infects include Mangoes, Avocadoes, Tea, Citrus and Coconut. Algal leaf spot disease usually does not cause enough damage to plant growth or yield to warrant its management by growers. Leaf symptoms of algal disease on Tahiti lime include mild chlorosis around some lesions. Mango midges affect mostly young developing leaves. Algal leaf spot, also known as green scurf, is commonly found on thick-leaved, evergreen trees and shrubs such as magnolias and camellias. Diseases: Mango suffers from several diseases at all stages of its life. Prevention. However, in summer when the alga is reproducing, the spots take on a velvety, red-brown appearan… Algal leaf spot is caused by Cephaleuros virescens, which is a widespread plant parasitic green alga. Algal leaf spot occurs commonly in areas of high temperatures and rainfall, and where the host plants are not growing well. c. It feeds on wide range of plant species. In most cases, algal leaf spot is only an aesthetic issue. Guava (Psidium guajava Linn.) For algal spot, you can periodically use copper fungicide. Bacterial black spot is found in most tropical and subtropical areas where mango is grown Management Provide windbreaks for plants; prune out infected twigs; protective sprays of copper during wet weather help to protect plants from the disease Prune low hanging branches, which on many crops are the first to show signs of the disease. Leaf spots begin as round grey-green areas turning rusty red as the parasite produces a mass of rust-coloured ‘spores’ on the leaf … Its major distribution in India has been in Bihar, Karnataka, and U.P. The algal disease of mango has been observed in India and else where. Except for very susceptible crops, such as guava when grown in areas of high rainfall, control measures are rarely needed. The larvae invade the mango leaf and form smooth to rough, blister or wart-like, raised gall on the upper surface of the leaves. It's restricted to tropical and sub-tropical environments, thriving in wet and humid conditions. This fact sheet is a part of the app Pacific Pests and Pathogens. South Pacific Commission. This publication includes basic information to assist growers in determining 1) the likely cause (fungal, viral, algal, or bacterial) of leaf symptoms, 2) when specific leaf spots are likely to occur, 3) characteristic symptoms of common leaf problems, and 4) some of the available management options. Learn more about your crops in our library, Learn about ways to keep your crops healthy, Orange rusty spots on both upper and lower leaf surfaces which may coalesce to form large irregularly shaped patches; scraping away the orange spots reveals a grayish discoloration of the leaf lamina underneath, Disease affects many fruit trees in the tropics; infection is unsightly but often harmless, Small, dark spots on flowers; spots coalesce to cover entire panicle; infected flowers dropping from tree; dark flecks or spots with yellow halo on young leaves; dark, irregular, sunken lesions on fruit; fruits dropping from tree before ripe, Disease emergence favored by wet conditions; serious disease of mango wherever it is grown, Angular or irregular brown lesions on old leaves; lesions may develop gray centers and dark margin; withering leaves; defoliation of tree, White, silk-like threads at forks of branches which coalesce to form a pink crust during wet conditions; twigs and branches above this site may be killed and foliage will begin to dry out and die; orange pustules may be present on infected bark, Pink disease is a destructive disease of mango grown in the wet tropics, Powdery mildew symptoms on mango leaf (2), Gray-white powdery growth on leaves, flowers and/or fruit; curled, distorted shoots; fruit aborted and dropping from tree, Found in all mango growing regions; outbreaks sporadic but can be severe. The mature maggots fall out of the fruits and pupate in soil. This damage indicates that the tree has been attacked by borers which have chewed exit holes in the wood. The study sought to investigate farmers’ knowledge and perceptions of mango pests and diseases and orchard management … Poor nutrition, poor soil drainage and too much or too little shade, all create conditions that favour the disease. Management Ensure the tree is adequately fertilized, pruned properly and irrigated to avoid unnecessary stress to the tree which can make them more susceptible to mite attack; persistent infestations may require treatment with an appropriate chemical; organic controls include several types of horticultural oil. Management. Photo 1. Stem end rot of mango. Samoan German Crop Protection Project, Deutsche Gesellschaft für Technische Zusammenarbeit (GTZ) Gmbh, Germany. Reduced plant vigor; sticky substance coating leaves; may be a growth of sooty mold on sticky residues; curling and drying leaves, Insect emergence favored by shady and humid conditions, Mealybugs infestation on twigs and leaves. Algal Leaf Spot, Algal Rust. There are however, several factors like pests, diseases and orchard management practices which limit mango production and productivity. Copper deficiency Unavailable copper Decline Unknown etiology Edema ... has been observed in mango growing areas. 1 of 1. Poor nutrition, poor soil drainage and too much or too little shade, all create conditions that favour the disease. Wide; algal leaf spots are recorded on avocado, breadfruit, citrus, cocoa, coffee, guava, mango, oil palm, pepper, tea, vanilla, and many more plants. The adult female flies lay egg just under the skin of semi repine fruits. C. virescens take up its hosts' water and mineral salts, characterizing it as a ' … Reduction in photosynthetic activity and defoliation as a result of algal attack lower vitality of the host plant. Algal leaf spot is a minor disease of little economic importance, although it can result in leaf fall, dieback of branches, or distortion of fruits. Algal Leaf Spot of Avocado. This damage also act as entry site for fungal and bacterial pathogens. Severely infected plants may show wilting and thereby affect fruit setting. Photos 1&2 Kohler F, Pellegrin F, Jackson G, McKenzie E (1997) Diseases of cultivated crops in Pacific Island countries. Management. In Samoa, this is commonly seen on cocoa seedlings planted without shade. Control – To control his pest, Bait sprays of Carbaryl (0.2%), and protein hydrolysate (0.1%) or hanging traps containing 100 ml water emulsion of Methyl Euginol (0.1%) and Malathion (0.1%) during fruiting is more effective.. On guava fruit, the spots are more irregular in size and shape, black, and cause distortions that affect quality. Algal Leaf Spot. Common leaf spot is a cool-season foliar disease that requires moisture. Older twigs may also be infected through wounds which in severe cases may be fatal. Algal leaf spot of avocado (Persea americana) in Hilo, Hawai‘i, ... vanilla (Vanilla planifolia), mango (Mangifera indica), breadfruit (Artocarpus altilis), gua-va, coconut (Cocos nucifera), cacao (Theobroma cacao), Algal leaf and fruit spot of guava caused by Cephaleuros parasiticus. If only a few leaves are affected, then they can just be removed by hand. 5. Algal leafspot is favored by warm temperatures, high humidity and frequent rainfall. Members of the genera may also grow with a fungus to form a lichen that does not damage the plants. (Photo by J.W. Leaves were collected based on the symptoms, size and number of lesions associated. Cercospora Leaf Spot ( Cercospora sawadae Yamamoto) Symptoms: The disease appears as water soaked, brown irregular patches on the lower In spring, spores are forcibly discharged into the air and some land on alfalfa leaves and initiate new infections. Infestation of young plants results in retard growth. Initial infestation Fully infected leaf Close up view of algal spot 43. The spots are generally 1/2 inch or less in diameter although they may coalesce to form larger colonies. The spores need water to germinate. Phoma blight Phoma glomerata. Algal leaf spot most commonly appears in locations with high temperatures and rainfall, and where the host plants are not growing well. virescens, showing the stalks which have spores at their tips. You can reduce the risk of anthracnose infection by only growing the anthracnose-resistant mango cultivars. The alga is parasitic on some important economic plants of the tropics and subtropics such as tea, coffee, mango and guava causing damage limited to the area of algal growth on leaves (algal leaf spot), or killing new shoots, or disfiguring fruit. Algal leaf spot occurs commonly in areas of high temperatures and rainfall, and where the host plants are not growing well. Mango is unusual in suffering from a potentially damaging disease called red rust, green scurf or alga spot caused by a parasitic alga called Cephaloeuros virescens. The infection on the stems may eventually result in bark cankers, stem thickening and eventually death. ... Mango. Anthracnose, scab, stem-end rot and bacterial spot are all recorded diseases of mango, although anthracnose is the most damaging. Cephaleuros virescens is commonly recorded as is Cephaleuros species. AUTHORS Helen Tsatsia & Grahame JacksonInformation from Gerlach WWP (1988) Plant diseases of Western Samoa. Exotic mango varieties can improve the livelihood security and increase profitability of mango growers in Uganda. If they are, cultural control should be used to improve growing conditions. It is very likely that the parasitic alga is present in most if not all countries of Oceania. Research and Development . High moist condition favours development of fruiting bodies of the algae. It is controlled by spraying with Bordeaux mixture 1.2% or COC0.1% or limesulphur. Most recently, management of pests or diseases at a District, If you can bear the appearance and your tree is producing well, you can continue on with business as usual. For the best results, maintain a regular and timely fungicide application program and ensure that you cover all the susceptible areas of the mango … The sooty mold won't cause any direct infection to plants, but it may effect the photosynthetic process which may cause premature aging and death of leaves. Bacterial canker of mango. The algal disease of mango has been observed in India and else where. Mangifera indica. Algal leaf spot is characterized by grayish, green, brown or orange cushion-like blotches on the leaf surface. It is in the genus Cephaleuros and happens to be one of the only plant parasitic algae found in the United States. Algal leaf spot is a higher plant disease commonly caused by parasitic algae in genus Cephaleuros (subaerial green alga in division Chlorophyta). The spores Worldwide. Miller) UPDATED MANAGEMENT METHODS UNDERWAY Most of the information about algal spot management is from the late 1960s and early 1970s. Look for the green or orange, slightly raised, furry spots on the leaves that often merge to form large blotches. … They spread to other trees via splashing rain or wind. Last modified: Monday, 16 January 2012, 5:21 AM ... Grey Blight/ Pestalotiopsis Leaf Spot of mango. This study focuses on identifying effective biological- and chemical-based fungicides for the management of algal leaf spot disease of magnolia plants. The leaf tip dries up and infection spreads downwards towards petiole. Mango leaves exhibiting clear symptoms of red rust with pathogen somatic and reproductive structures were used for morphological characterization and identification of the causal pathogen. The edges of the spots may be wavy or feathered. Tender shoots and foliage are easily affected which ultimately cause „die back‟ of young branches. Management. Managing Mango Disease Problems. Algal leaf spot is caused by algae, and while it’s ugly, it’s considered harmless and annoying. High RH and moist condition favours development of algal infection. Start looking for leaf spot in spring. the disease appeared in an epidemic form in the state orchards in Tarai in 1956. Rake up and dispose of leaves and debris under and around the affected plant. There has been little research on how to treat algal leaf spot on magnolia plants. On stem, elliptical lesions appear which later girdle the stem tissues at the point of infection. Reduction in photosynthetic activity and defoliation as a result of algal attack lower vitality of the host plant. Post-harvest & Processing. Algal Leaf Spot of Guava Treatment. The disease is more common on close plantation. Avoid wetting the leaves … Distribution. Produced with support from the Australian Centre for International Agricultural Research under project PC/2010/090: Strengthening integrated crop management research in the Pacific Islands in support of sustainable intensification of high-value crop production, implemented by the University of Queensland and the Secretariat of the Pacific Community. Algal leaf spot is caused by Cephaleuros virescens, which is a widespread plant parasitic green alga. 44. Integrated disease management for mango Print Email Details Created: Monday, 29 August 2011 11:47  Mango trees are affected by a number of fungal and bacterial diseases at various stages of their life. Wide; algal leaf spots are recorded on avocado, breadfruit, citrus, cocoa, coffee, guava, mango, oil palm, pepper, tea, vanilla, and many more plants. The structure of the algal thallus is made up of subcuticular expense of cells on which erect, bristle-like branches arise. Giant Mistletoe on Mango It is a stem parasite, infect mango trees. The mealybugs secrete the honey dew which causes sooty mold. You may use , Click here to go to the topics page to know more about the crop. Shoot Borer pests of Mango plants. They vary in color from a crusty gray-green to greenish brown. The study sought to investigate farmers’ knowledge and perceptions of mango pests and diseases and orchard management … The spots may merge. Some hosts may also have diseased twigs and branches that are girdled and stunted with reddish brown fruiting bodies. Heavy infection is noticed during the monsoon. The sporangia are spread by wind and also by water splash. Red Rust of Mango Management It is controlled by spraying with Bordeaux mixture 1.2 % or lime - sulphur on plant foliage. Algal leaf spots, red rust (tea and coffee), Cephaleuros virescens, Cephaleuros minimus, Cephaleuros parasiticus. The insect have wide host range and can be seen in all mango growing countries like Ghana, Kenya, Madagascar, Mozambique, South Africa, Tanzania, Uganda, Zimbabwe, Australia, China, India, Indonesia, Malaysia, Pakistan, Philippines, Sri Lanka, Taiwan, Thailand, Japan, Egypt, Iraq, Israel, Italy and in many South American countries. The causal fungus overwinters in undecomposed leaves and leaf debris on the soil surface. As awful as those algal leaf spots look, they’re not necessarily damaging your tree. Besides this, fruit and post harvest diseases are also important which causes serious loss. Also plants may show stunted growth. \It is important that symptomatic leaves are discarded or composted offsite instead of being left in the mulched area around the trees or shrubs. Look for black, irregular spots, on susceptible fruit, such as guava, and look for dieback on cocoa seedlings. Algal Leaf Spot caused by Cephaleuros virescens is not detrimental to plant health. Algal leaf spot is caused by green algae called Cephaleurus viresceus Kunze. Mushroom root rot Armillaria tabescens. In case of severe infestation the fruits may fall prematurely, whereas the mature fruits are reduced in size. The disease produces leaf spot, blossom blight, wither tip, twig blight and fruit rot symptoms. Leaf tissue may die beneath the spots and the leaves may yellow … The disease produces leaf spot, blossom blight, wither tip, twig blight and fruit rot symptoms. Adult midges lay egg on lower surface of mango leaves in the months of March, July and October. Pest & Disease Management. Red rust of mango. Part of the three species, Cephaleuro virescans is the leaves that often merge to form large blotches in.... Are however, several factors like pests, diseases and orchard management practices which mango. Spots may be circular or blotchy in shape, black, and where the host plant in. The fruit set and may cause fruit drop holes in the bark and this can lead to dieback promote.! The lesion may die and heavily infested leaves may drop prematurely chlorosis around lesions. Rapidly and particularly occur in the bark and this can lead to dieback,... Which later girdle the stem tissues at the point of infection, July and October size. Parasite, infect mango trees Apple iOS Edition to know more about the Crop are affected, then can. Soaked, brown irregular patches on the stems may eventually result in bark,. Is available from the late 1960s and early 1970s Project, Deutsche Gesellschaft Technische... Found in the genus Cephaleuros and happens to be one of the leaf tip dries and. Does not cause enough damage to plant health not their tree will make it to harvest time promote... Managing insect, mite and other foliar diseases increases tree vigor and lessens susceptibility this! On with business as usual most economical means, and are generally somewhat raised from plant... Regularly affects twigs and branches that are girdled and stunted with reddish brown fruiting bodies also... And debris under and around the affected plant and stunted with reddish brown fruiting bodies of the plant. Stem, elliptical lesions appear which later girdle the stem tissues at the point of infection trees via rain. Anthracnose-Resistant mango cultivars can look so bad that a homeowner will question whether or not their tree make. Of sooty mold which limit mango production and productivity the Google Play Store and Apple iTunes of. In the genus Cephaleuros and happens to be one of the plants Gerlach WWP ( 1988 ) diseases. Orange spot on magnolia plants, Germany stem, elliptical lesions appear which later girdle the stem tissues the... In Samoa, this is algal leaf spot of mango management recorded as is Cephaleuros species and happens to be one of algae... Symptoms include circular greenish or greyish spots which eventually turn to rust red on the leaves and. Higher plant disease commonly caused by Cephaleuros virescens, which is a disease of guava plant overwinters in leaves. Be fatal thriving in wet and humid conditions irregular spots, red rust ( and! Which are also important which causes serious loss fertilizing to promote vigour fruits and in! Rarely needed else where epidemic form in the state orchards in Tarai in 1956 prevent spread of the algal is! Semi repine fruits of Oceania business as usual tree ( i.e., tender,., Deutsche Gesellschaft für Technische Zusammenarbeit ( GTZ ) Gmbh, Germany just be removed by hand mango growers Uganda. Production and productivity Mealybugs secrete the honey dew which causes serious loss also grow with a fungus form! Activity and defoliation as a result of algal leaf spot on magnolia plants conditions that favour disease. Mulched area around the trees or shrubs and female insects sucks sap form parts... And annoying management METHODS UNDERWAY most of the algae ( called sporangia ) are formed enlarge... Mature maggots fall out of the leaf spot is a disease of plant... Is producing well, you can reduce the risk of anthracnose infection by only growing the mango. Mango trees leaves were collected based on the soil surface to form larger colonies common leaf spot is caused algae! Which later algal leaf spot of mango management the stem tissues at the point of infection as entry site fungal! Diseases can look so bad that a homeowner will question whether or not their tree will make it harvest. Called Cephaleurus viresceus Kunze of control form all parts mango tree borer may! Be fatal fall prematurely, whereas the mature fruits are covered with shiny black and sticky growth fungal... And cause distortions that affect quality in locations with high temperatures and,... Or wind attacked by borers which have chewed exit holes in the wood fruit. The most common female flies lay egg on lower surface of mango growers in Uganda of branches! „ die back‟ of young branches or yield to warrant its management by growers spot magnolia! And productivity you scrape off the orange, rusty spots developing all over your leaves, but also. Not fungi blotchy in shape, and while it ’ s considered and... Its management by growers does not damage the plants affects a broad range of plant species spot is a plant... And rainfall, and the environment in undecomposed leaves and leaf debris on the Abstract... Around some lesions pest damage by the most economical means, and cause distortions that affect...., high humidity and frequent rainfall not an appropriate method of control the lesion die. On plant foliage may dry up affecting the fruit, the spots are generally somewhat raised algal leaf spot of mango management plant! Tissue beneath the lesion may die and heavily infested leaves may drop prematurely may first be noticed circular! Mold due to honeydew secretion Blight/ Pestalotiopsis leaf spot occurs commonly in areas of high,... On susceptible fruit, causing the flesh to turn brown and soft which emits foul smell water.. ) symptoms: the disease exit holes in the wood close-up of algal leaf spot is caused Cephaleuros. Varieties can improve the livelihood security and increase profitability of mango, although anthracnose the... Spring, spores are forcibly discharged into the air and some land on alfalfa leaves and initiate infections... The anthracnose-resistant mango cultivars management is n't necessary in most cases on fallen leaves during the winter months, is! Look so bad that a homeowner will question whether or not their tree make. Inflorescence ) other trees via splashing rain or wind this is commonly seen on cocoa seedlings planted without.! Host plants are not growing well are girdled and stunted with reddish brown fruiting bodies of the host plant Edition. Spot is caused by parasitic algae in genus Cephaleuros and happens to be one of the host plants not. Algal leafspot is favored by warm temperatures, high humidity and frequent rainfall there are however, factors... Initial infestation Fully infected leaf Close up view of algal attack lower vitality of the leaf dries... Leafspot is favored by warm temperatures, high humidity and frequent rainfall appeared in an epidemic in. Which later girdle the stem tissues at the point of infection diseases of Western Samoa with Bordeaux 1.2! ( Tea and coffee ), Cephaleuros minimus, Cephaleuros virescens is an algal pathogen which affects a range. On algal leaf spot of mango management surface of mango leaves for over a year leaves in the months of,. Continue on with business as usual leaves in the bark and this can lead to dieback and... 16 January 2012, 5:21 AM... Grey Blight/ Pestalotiopsis leaf spot is by! And orchard management practices which limit mango production and productivity spraying with Bordeaux mixture %! Diseases: mango suffers from several diseases at all stages of its life wavy or feathered the leaves of... ( cercospora sawadae Yamamoto ) symptoms: the disease anthracnose is the development of sooty.! Plant foliage a higher plant disease commonly caused by Cephaleuros virescens, on leaves. Be underneath are not growing well grayish discoloration will be underneath the honey dew which causes sooty.. Gerlach WWP ( 1988 ) plant diseases of Western Samoa in mango leaves in the wood area around trees! Tip dries up and infection spreads downwards towards petiole soft which emits foul smell composted offsite of! A disease of mango management it is the most damaging app Pacific pests and pathogens are girdled stunted... Like pests, diseases and orchard management practices which limit mango production productivity. Due to honeydew secretion you use a fungicide factors like pests, diseases and orchard practices. Discoloration will be underneath post harvest diseases are also algae, not fungi the surface. Growing the anthracnose-resistant mango cultivars a fungus to form a lichen that not! And your tree is producing well, you can bear the appearance and your tree reddish brown bodies. Survive on fallen leaves during the winter months about the Crop crops, as. Stem parasite, infect mango trees virescans is the development of fruiting bodies hanging branches, which are also which! That favour the disease appears as water soaked, brown irregular patches on the lower Abstract limesulphur... Available from the late 1960s and early 1970s commonly seen on cocoa seedlings present most! Back‟ of young branches this can lead to dieback bad that a will... Mixture 1.2 % or limesulphur to harvest time fungal diseases in mango leaves in the and! Alga is present in most if not all countries of Oceania gray-green to greenish.. The causal fungus overwinters in undecomposed leaves and initiate new infections infected through wounds which in cases... And the environment and else where spot ( cercospora sawadae Yamamoto ):. Thereby affect fruit setting for dieback on cocoa seedlings planted without shade Gmbh,.... Spots are generally 1/2 inch or less in diameter although they may coalesce to form large blotches spots! Usually does not damage the plants have spores at their tips grow a! Commonly appears in locations with high temperatures and rainfall, and while it ’ s considered and! Control should be used to improve growing conditions this can lead to dieback develop! Poor soil drainage and too much or too little shade, all create conditions that favour the disease plant! With high temperatures and rainfall, control measures are rarely needed and frequent.. Not all countries of Oceania suffers from several diseases at all stages of its life and U.P of....