Leaf rust

United States Department of Agriculture. Office of Pest Management National Plant Disease Recovery System. "Recovery Plan for Leaf Rust, Stem Rust, and Stripe Rust of Wheat Caused by Puccinia triticina, Puccinia graminis, and Puccinia striiformis, Respectively." August 28,2006. 

The coffee trees in the world are subject to a large number of diseases (2-4, 8, 73, 92) lists range up to 60 and more, and yet the disease possibilities do not always disturb plantation owners. Occasionally, as where the leaf rust attacks, or where koleroga (black rot) is serious, growers are on the lookout for diseases and are anxious about their future. There are local places where diseases are apparently more benign than in others, and this tends to dull the worry about disease losses in a country. 

Rust, Oriental Rust, Leaf Disease, Leaf Rust... 

Mayne, Thomas, and others (38, 60, 81) have observed in the Orient that active defoliation from coffee leaf rust will leave unhealed places at the points where unseasonably dropped leaves were attached to stems. Into the leaf traces left exposed Colletotrichum and similar weakly parasitic organisms will enter and cause dieback. Many gross observations in the western tropics on chronic deterioration, paralleling... 

In India some of the early work was toward refinement of spraying to control leaf rust and the researchers started their studies with strong Bordeaux sprays. Munro and Sandararaman showed (46) that uncontrolled leaf disease reduced the coffee harvest very seriously, but that although 10-10-50 Bordeaux materially controlled the disease it depressed the fruit crop. With Bordeaux of formulas 5-5-50 or 2 -2 -50, the crop increase was one half to one third more than that produced under 10-10-50 Bordeaux or under no spray. 

Similar results had been reported previously for an elicitor isolated from intercellular washing fluids of leaf rust infected wheat leaves which induced browning and chlorosis (128,129). The reactivity of wheat cultivars... 

Escape Shorter crop growth period and/or early ripening to be able to avoid the critical infestation period, or to have enough yield before the infestation becomes too severe (potato/late blight onion/downy mildew carrot/carrot fly) One or more monofactorial and multifactorial, durable resistance traits against pest and disease affecting yield and/or quality (scab/apple, late blight/potato, lettuce/downy mildew, yellow and brown leaf rust/wheat) weed competition by an allelochemical ability... 

Southerton, S. G., and Deverall, B. J., 1990, Histochemical and chemical evidence for lignin accumulation during expression of resistance to leaf rust fungi in wheat. Physiol. Mol. Plant Pathol. 36 483-494. 

Foliar sprays require application during the growing season. An alternative would be seed treatment with a long-term systemic fungicide that could be applied at planting. Such a material is currently being tested. Triadimenol (Baytan), (8-(4-Chlorophenoxy)-a-(l, 1-dime-thylethyl)-lH-l,2,4-triazole-l-ethanol), when applied as a seed treatment, will provide control of powdery mildew on wheat into mid-season. In most years, this would preclude the need for foliar sprays for powdery mildew control, but does not provide a solution for control of Septoria leaf blotch or late season leaf rust. 

James, W.C. and C.S. Shih. 1973. Relationship between Incidence and Severity of Powdery Mildew and Leaf Rust on Winter Wheat. Phytopathology 63 183-187. 

These compoimds have been tested in vivo against wheat leaf rust, Puc-cinia recondite, at a fixed dose of 0.001 M. The following equation represents the best QSAR model for the antifungal activity (D = log[a/(100 - a)] - log Mw where, a is the percentage inhibition and Mw is the molecular weight of the tested compound) of these compoimds. 

Triphenyltin hydroxide (Fentin) and triphenyltin acetate (Brestan) are used to combat potato blight, leaf spot on celery and sugar beet, rice blast, and coffee leaf rust. Tricyclo-hexyltin hydroxide (Plictran), bis(trineophyltin) oxide (Vendex or Torque), and 1-tricyclohexylstannyl-l,2,4-triazole (Peropal) have also been used for the contol of mites on apples, pears, and citrus fruits. 

Table IV. Control of wheat powdery mildew and leaf rust with para-chloro...

The compound RH-124 (triazbutil, 66), 4- -butyl-1,2,4-triazole is a systemic fungicide for the control of wheat leaf rust, which is caused by Puccinia recondita tritici (Meyer et al., 1970). In foliar, seed and soil applications this active material was superior to benomyl, triarimol or oxycarboxin against leaf rust, though the duration of effectiveness inside the wheat plant was relatively short (Rowell, 1976). 

P. viticola downy mildew grape leaf P. recondita leaf rust wheat leaf... 

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