Cercospora /Pseudocercosporella
While the fungiCercosporaorPseudocercosporellathat make ashen spot can severely affect turnip , rutabaga , canola , leaf mustard , radish , horseradish root , and hybrids of turnip and mustard , they are much less likely to affect kale , collards , Brassica oleracea italica , or cauliflower .
This is a cool conditions disease and is most potential to strike at 55 to 65 F.
The disease has been a particular problem on canola flora in Europe with pod losses of up to 15 % .
White spot (Pseudocercosporella capsellae) infecting a turnip leaf. Cropped. Photo courtesy of Gerald Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.orgvia CC 3.0.
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ethnical intervention are the best way to check this disease , and the word below will walk you through the symptom , spirit cycle , and mastery measures of white spot disease on cruciferous plant .
What You’ll Learn
Symptoms
whitened spot disease gets its name from the orbitual white-hot spots that are scatter over the leaves , stems , or pod of infected plant . aged muscae volitantes may develop dark borders , and the midpoint may fall out . Such lesions look like shot holes .
In add-on to turning yellow , leaves that are sternly affected wry out and wither , although they remain attached to the plant .
Lesions on the radical are trivial with a distinct bound between tissue paper that is diseased or salubrious . The lesion start out brown and then wrick ash - gray to white . Large numbers of tiny obscure speck manakin in the lesion , which are know as gray stem .
White spot (Pseudocercosporella capsellae) infecting a turnip leaf. Cropped. Photo courtesy of Gerald Holmes, California Polytechnic State University at San Luis Obispo, Bugwood.orgvia CC 3.0.
Infected seed seedcase set out out with small brown spots . They then expand and become grayish - whitened with disconsolate point inside .
Cool Moist Conditions Favor Disease Development
The remains of infected plants are a significant reference of spores to spread the disease . The wind can diffuse the sexual spore recollective distances in the fall if the conditions is moist following rain or dew and the temperature are 55 to 65 F.
pelting or splashing water spread asexual spore in the late dip that can cause disease the next springtime .
The fungus can winter in volunteer crop plant or in susceptible locoweed like wild table mustard , barbaric radish , and shepherd ’s bag .
Cultural Controls
bar is the good bet to control lily-white spot of crucifers . Purge susceptible weeds and any volunteer crucifer that are growing near your crop .
At the end of the season , remove the plant life detritus or plow it profoundly into the territory .
splay your harvest and avoid growing any genus Brassica in the immediatel sphere for three year .
Do n’t plant cole crops in or near an area that was infected during the late season .
Promoting in force grunge drainage will also help to protect against this infection .
Liquid Copper Treatment
you’re able to apply liquid copper ( a solution certfified organic ) to your cole harvest to control white spot fungus .
BONIDE ® Liquid Copper Fungicide via Arbico Organics
Spray all the plant as soon as you see the disease . Be sure and spray the tops and seat of the leaves , and spray again every 7 - 10 days .
Fungicide Treatment
As soon as you see the white-hot speckle symptoms , you may apply the fungicide Benlate to the plants . This antifungal agent is a 50 % result of the compound benomyl . Benlate can be toxic to some crucifers , specially cabbage .
White Spot Fungi Infects Some Crucifers and Not Others
While these fungi do not typically infect kale , collards , Brassica oleracea botrytis or Brassica oleracea italica , they do affect a range of cruciferous vegetables . They have been severe pathogen of canola oil in Europe .
White spot fungi opt coolheaded temperatures and oftentimes overwinter on volunteer crucifer , susceptible weeds , or in plant tissue paper .
While limpid copper is an option , prevention is usually the good way to verify this disease .
If you are still trying to place a picky disease on your cole crops , you might try on one of our other guide such as :
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About
Helga George , Ph.D.
