Shoots diseases

The status of the control of swollen shoot diseases has been summarized recently (35). According to Posnette (AO) the diseases grouped under swollen shoot are... 

In some areas of West Africa, swollen shoot disease is under control by cutting out infected and suspected trees, the exclusion of areas of mass infection, and chemical control with systemic insecticides. In other areas of Africa, however, the disease continues to spread in spite of the control measures applied. Up to February 1954 (19) a total of 24,632,839 trees had been destroyed. The total number of trees in the Gold Coast alone is estimated at 400,000,000. 

Compound (V) is used as an insecticide and is marketed as a 50 per cent solution under the name of hanane, which also contains 5 per cent of O.M.P.A. Hanane properly placed at the roots of cocoa trees kills mealy-bugs in the crown of the tree without harming beneficial insects such as ants which effect pollination. Five hundred trees infested with mealy-bugs were treated 2 10 per cent of the trees, chosen at random, were cut down before treatment and after treatment, and the number of mealy-bugs counted under a binocular microscope. After 6 weeks only thirty-five mealy-bugs were present on the treated trees as opposed to 42,971 counted before treatment in the untreated portion, a reduction of 99-9 per cent. It is well known that several species of mealy-bug, especially Pseudococcus ujalensis, transmit strains of swollen shoot virus, which kill the cocoa tree in 2-4 years. Thus the spread of the disease can be effectively controlled by this systemic insecticide (see also p. 171). 

Annual losses of production due to disease and pest were estimated by Hale (20) in 1953 as follows capsid insects 70,000 tons, swollen shoot 50,000 tons, Phy-tophthora rot (black pod) 50,000 tons, witches broom and others 20,000 tons, and ants 10,000 tons. According to Wellman (51), cacao diseases are a threat to world production. 

Swollen Shoot. Losses due to swollen shoot, a virus disease discovered in 1937 in the Gold Coast and still restricted to West Africa, are staggering. 

Phytophthora Rot (Black Pod). Phytophthora rot is prevalent in most of the world s cacao-growing areas and causes losses comparable to those from swollen shoot. Since 1910 (U2) Bordeaux mixture has been used extensively for the control of this disease in several countries of the Western Hemisphere as well as in Africa. Yield increases due to this chemical control of the disease have been put at 200 to 300% in Costa Rica by Fowler (16). Results (UU) from a fungicidal experiment conducted by the Inter-American Cacao Center in Costa Rica showed an increase in production of approximately 50% when Bordeaux mixture was used. 

Keeping plants growing well is the best defense against pests and diseases. Potbound plants in overcrowded pots, watered erratically, will be more prone to pests such as red spider mite and aphids, especially in hot and dry locations such as a sheltered patio. Deal with any problem as it arises check plants regularly and pick off pests or diseased shoots or leaves as you notice them. Remove sickly and badly infested plants. 

Pick off or prune out any leaves or shoots that are diseased or badly infested with pests if a whole plant has succumbed, then take it out of the greenhouse and dispose of it, and check its neighbors carefully. Biological controls (see p.97) are ideal for controlling many common glasshouse pests. For more tips, see p.250. 

Remove damaged and diseased fruit shoots, and foliage. 

Shaping of trees, removing shoots that cross so that they do not chafe each other, creating entry points for disease. 

Canary Islands. Hot water extract of the fresh fruit juice is taken orally for cystitis and hot water extract of the fresh stem is used ophthalmically for conjunctivitis . Guatemala. Hot water extract of the dried leaf is taken orally for renal inflammation and as a diuretic . Hot water extract of the dried stalk is used externally for skin diseases and irritations, mouth lesions, stomatitis, dermatitis, and inflammations . Hawaii. Water extract of the shoot is taken orally for asthma . 

Araucaria cunninghamii Aitonex Sweet Na Yang Shan (shoot) Methyl communate, methyl isocupressate, methyl acetyl-isocupressate, labdadien, diacetate, methyl amentoflavone.57 Treat skin diseases. 

Powdery mildew attacks leaves, shoots, and bunches. It is evidenced by an ash gray to white powdery growth on both the upper and lower surfaces of the leaves. Moreover, the disease attacks the bunches with the same ash gray/white powder showing up on the berries and stalks. Other than crop losses, the most negative aspect is that the disease causes off flavors in wine production. 

Black rot, caused by Guignardia bidwellii (Ellis) Viala and Ravaz, is favored by warm humid weather. Rainfall is necessary for disease buildup and spread, eliminating occurrence in California. Black rot is characterized by brown circular lesions which may coalesce to destroy large areas of diseased leaves or girdle infected shoots. Fruit infection is particularly destructive and can result in complete crop loss. The fungus survives from one season to the next in mummified fruit. Infection periods can be identified based on the occurrence of rainfall and the relationship between temperature and leaf wetness duration. 

He did more than speculate. He hurried to Frankfort to study the treatment of disease with serums. He was one of those who watched Paul Ehrlich shoot injections of fluids into the blood stream of animals suffering from malignant diseases. Arrhenius marvelled at his dexterity and almost superhuman perseverance. He made a careful study of the work, and was the first to attempt to explain the chemistry of this serum therapy,... 

AM-Toxin. The pathogen Alternarla mall causes leaf spot disease of apple and produces necrotic spots on fruits, leaves, and shoots of susceptible cultivars. AM-toxIn [18], a host-specific toxin, and several related toxins are responsible for these symptoms and their structures have been elucidated and confirmed by total synthesis 1101-1031. 

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