This spring ’s overcast and coolheaded weather condition has favour the fungus Botrytis cinerea , which causes a gray mold on many greenhouse ornamentals . recognize the problem is n’t difficult . Common disease symptoms admit leaf spots and blight and stem canker ( shape 1 ) . Botrytis ’ call card include the turgid masses of hoar conidiospore or spores that are produced . It is this grey-haired conidial fuzz that render this disease the name “ gray-haired mold . ” An infection that commence as a small leafage spot that ’s barely detectable can quickly expand into a enceinte area . peak petals that drop on the leaf assist as a food base for Botrytis , allow the pathogen to easily infect folio . pee and gamey relative humidness are the central gadget driver for Botrytis .
While there are strategies to prevent the ramp up of this disease , many growers are now having to triage to prevent further losses . Fungicides can define going but beneficial reportage is involve and short intervals between applications may be require to decelerate the disease . When fungicides use a similar mode of activity againstBotrytis , they will have the same FRAC code . The FRAC computer code can be found on the fungicide label . To insure that theBotrytispathogen does not become insubordinate to antimycotic , use a spray program that include several type of fungicides that have unlike FRAC codes .
The “ A ” and “ B ” Team table shows the results of many years of testing fungicide production and number the product name , FRAC code and dynamic ingredient . The products number in the A Team are especially effective against Botrytis . The B Team products also limit disease , but may not be as in force as the A Team products and are recommend for use when disease pressure is not severe and for use in alternating programs . Always alternate among fungicide products with active ingredients that have different mode of action ( FRAC codes ) to delay the development of fungicide resistance in the Botrytis pathogen .
When disease atmospheric pressure is high , count tank - premix and a cut clip between applications . Here is an example of a course of study that could be used to twist back an outbreak :
Do not apply fungicides that admit the alive ingredient fludioxonil to geraniums .
- Not recommend when disease pressure is gamy .
- The FRAC code is an alphamerical code assigned by the Fungicide Resistance Action Committee and is based on the mode of action mechanism of the active ingredient .
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