How can do artificial infection to wheat by loose smut Ustilago tritici disease and when
Use cold water spray by dissolving the old leaf infection collected from the field. Or use the infected soil from the same field. Receive pure culture of fungi from national collection center, grow it shortly in the laboratory and spray on wheat crop.
Loose smut being extetnaly and internally seed borne disease of what was first fungus in the history of phytopathology used for experimentation. Inoculate seeds directly with spore mass and sow it. The fungus will produce symptoms late
I am in confuse, whether above mentioned methodology would cause disease in sprayed crop in same season or cause disease for next crop period?
Dear RP Mainali
i think in next season because this season you get the spores and make the inoculation by spray in same season t.symptoms become visible in the next season that i undestood them
It is well established that loose smut is occurring through flowers, and it is well known also that infected pikes appear befoer healthy ones. In this case you have to collect fungal teliospores from one year to infect spikes just after their appearance and you have to inoculate this spikes early in the morning when the flowers are opened.
Loose smut is carried internally in the seed, so you need to infect during flowering. High humidity and moderate temperature (16-22°C) favor infection. You may want to clear embryos after harvest to get an idea of the percent infection. This can be quite a bit of work, consider sending to a lab that specializes in it. This protocol is for barley (Hordeum vulgare), but works for wheat.
From: International Rules for Seed Testing, Annex to Chapter 7
7-013a: Detection of Ustilago nuda on Hordeum vulgare (Barley)
NaOH and lactic acid are corrosive, wear gloves and clean up spills promptly.
Prepare 5% (w/v) NaOH by dissolving 50g in 1000ml distilled water with stir bar.
Lacto-glycerol is 1:1:1 glycerol (glycerine): lactic acid: water.
Decide how many seed you need to look at. Some references say 400-500 seed (resolution to 0.25-0.20%), ISTA uses 2000-4000 seed.
Place seed in large excess of 5% NaOH, maintain at RT (20°C) for 24hr.
Wash in warm water to separate embryos, use set of screens to catch endosperm and chaff, collect embryos in 1mm mesh sieve.
Transfer embryos to 1:1 water: glycerol for further separation from endosperm.
Transfer embryos to 50ml lacto-glycerol in 250-500ml beaker.
In fume hood: Clear embryos by boiling in lacto-glycerol for 5 min. Clear other items from hood, wear lab coat, gloves, goggles.
Transfer embryos to fresh glycerol for examination. Scutellum becomes more transparent after soaking in glycerol for 1-2 hrs.
Examine embryos at 16-25X, look for golden brown mycelium approximately 3µm thick. May find few short strands, or complete invasion of scutellum tissues.
I wonder why you did not use Vercon in www.vercon.sci.eg it is an expert system to answer these type of questions. It is in Arabic and only can be used in Egypt and other country if it has the similar environment. I developed these systems more than 10 years ago. It works like an online expert. There is a problem in English version. I think if you google translate, it may work properly.
try to use this link. Add information about your farm then run the expert system
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