Leaf spot

A.ltemaria spp. tobacco brown spot leaf spot of brassicas... 

Other materials based on EDA have also been suggested as fungicides. The most important of the imida2oline type (162) is 2-heptadecyl-2-imida2oline (163), prepared from EDA and stearic acid [57-11-4]. It is used as the acetate salt for control of apple scab and cherry leaf spot. A 2 1 EDA—copper sulfate complex has been suggested for control of aquatic fungi (164). 

Mineral Bicarbonate (K and NA) Kaligreen Powdery mildew, black spot, leaf spot Grapes, strawberries Fungicide... 

Blackcurrants Currant leaf spot Pseudopeziza ribis Bordeaux mixture, copper ammonium carbonate... 

Samac, D.A., Willert, A.M., McBride, M.J. and Kinkel, L.L. (2003). Effects of antibiotic-producing Streptomyces on nodulation and leaf spot in alfalfa , Applied and Soil... 

Subbaiah, C.C., P. Manikandan, and Y. Joshi. 1986. Yellow leaf spot of cashew a case of molybdenum deficiency. Plant Soil 94 35 42. 

Dusfr and Spray Control of Target Leaf Spots... 

Practically all the coffee planted commercially comes from seed, except in the rather limited Robusta-growing region of Java where grafted plants are used. Coffee seeds are planted in seedbeds and are treated in about the same way all over the tropics. The mature and apparently healthy fruits are selected and the seeds are pressed out, washed and dried in the shade, and planted rather soon, because coffee seed viability is lost within a comparatively short while. Handled in this manner, the chances are lessened that coffee diseases will be carried by seeds. However, it has been proved experimentally that infected plants can be produced from seeds contaminated with both the coffee Colletotrichum and the coffee Cercospora from either field material or artificial inoculation. This contamination is probably not uncommon in plantation practice and thus far it is not of extreme importance. The Hemileia rust is probably not carried on the seed (93). The American leaf spot is not carried on seed (97). 

Iron toxicity is a syndrome of disorders associated with large concentrations of Fe + in the soil solution. It is only found in flooded soils. A wide range of concentrations produce the symptoms, from 1000 to only 10mgL in soils with poor nutrient status—especially of P or K—or with respiration inhibitors such as H2S. There are large differences in tolerance between rice varieties. The effects include internal damage of tissues due to excessive uptake of Fe + impaired nutrient uptake, especially of P, K, Ca and Mg and increased diseases associated with imbalanced nutrition, such as brown leaf spot (caused by Helminthospo-rium oryzae), sheath blight (caused by Rhizoctonia solani) and blast (caused by Pyricularia oryzae). 

A little tolerance is also to be advised. Plants are part of the natural world, and are inevitably going to be less than perfect a leaf spot here or a nibbled leaf there is not going to be life-threatening. The A-Z of Plant Problems (seepp.320-342) contains more detailed advice on specific problems affecting woody plants the entries on aphids, black spot, powdery and downy mildew, and rose rust are particularly applicable to roses. 

Bacterial leaf spot causes small, angular black spots on leaves. Leaves may turn yellow and drop early. Spray lime-sulfur every 10-21 days until leaf drop if weather is wet or humid, or if the spots are spreading. 

Clear up fallen leaves in fall, especially if currant leaf spot has caused early leaf-fall. 

Symptoms Small to large black spots on the leaves eventually merge into large irregular patches. Affects both leaf surfaces. Edges of leaf spots may turn yellow. Leaves fall prematurely. Bushes become weak in severe cases. 

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