Cây Cảnh - Bonsai
BLACKSPOT
Posted On
June 8, 2017
at 9:38 am
by lovetadmin / 50 Comments
BLACKSPOT ON ROSE PLANT
CAUSAL ORGANISM:
Diplocarpon rosae: This disease may also be called leaf spot, leaf blotch, star sooty mold and several other names. It is the most important disease of outdoor roses on a world wide basis. The fungus has probably been widely distributed with the cultivated rose and no really complete resistance is believed to exist.
SYMPTOMS:
Small black spots of 2 mm diameter can be found on upper leaf surfaces as well as immature canes. These spots are black and sooty enlarging to 12 mm with generally circular appearance but having a feathery edge. Further development involves the appearance of yellow margins around the spot and a yellow condition that can extend into the entire leaf. Late in the growing season defoliation can occur along with purple red, raised irregular blotches on immature wood.
DISEASE CYCLE:
The fungus usually over winters on infected leaves and canes as a mycelial mat rarely producing the perfect or sexual stage. As temperatures rise in the spring the fungus produces conidia which are moved by air currents or splashing water to new developing and expanding leaves which are very susceptible. Conidia germinate under conditions of free moister and need free water conditions for at least seven hours in order for infection to occur. The fungus is considered an obligate parasite producing haustoria in the host cell. As the infection develops, the leaf spot expands taking on the characteristic black appearance and producing conidia as secondary inoculum. Usually the lower and inside areas of the plant are more likely to be infected because these areas have longer time periods when free water is available on leaf surfaces allowing the germination and penetration of the fungus. Several cycles of infection and production of secondary inoculum can occur throughout a growing season.
CONTROL:
Dormant pruning, removal of attached leaves and cleaning up old leaves under the bushes can do much to reduce the over wintering inoculum. A well aerated site will do much to reduce disease incidence by preventing the occurrence of free water on the foliage for long time periods. Pruning to allow air movement and watering without wetting the foliage could also be important means of prevention. Some roses may be more resistant than others, but specialized races of the fungus quickly arise. When conditions are favorable in early spring, protectant sprays can be used on a one week interval or after periods of rain to prevent infection. Surfactants may allow the active materials to spread more evenly on plant surfaces and persist longer during periods of precipitation.



REFERENCES:
Horst, R. K. 1983. Compendium of Rose Diseases. The American Phytopathological Society, St. Paul, Minnesota. Pp.7-11 and Color Plates 8-11.
Hi, for all time i used to check web site posts here early in the morning, because i like
to find out more and more.
Excellent site you’ve got here.. It’s difficult to find good quality writing like yours these days. I really appreciate individuals like you! Take care!!
I was wondering if you ever considered changing the page
layout of your site? Its very well written;
I love what youve got to say. But maybe you could a little more in the way of content so people could connect with it better.
Youve got an awful lot of text for only having one or 2 images.
Maybe you could space it out better?
60 mg prednisone daily buy prednisone without prescription 54 prednisone
When someone writes an paragraph he/she maintains the
plan of a user in his/her mind that how a user can know it.
So that’s why this article is great. Thanks!
Good post. I learn something totally new and challenging on websites I stumbleupon on a daily basis. It will always be exciting to read content from other authors and use a little something from other web sites.
ivermectin/pyrantel stromectol uk ivermectin purchase online
I’m impressed, I have to admit. Seldom do I come across a blog that’s equally educative and amusing, and let me tell you, you’ve hit the nail on the head. The issue is something that too few men and women are speaking intelligently about. I’m very happy that I found this in my search for something regarding this.
viagra cialis voucher cialis index cialis with effexor
It’s hard to find well-informed people about this subject, but you sound like you know what you’re talking about! Thanks
prednisone 20mg prices prednisone prescription drug
What’s Taking place i am new to this, I stumbled upon this I’ve found It positively
helpful and it has aided me out loads. I’m hoping to give a contribution & assist other customers like
its helped me. Good job.
best online drugstore prices of viagra at walmart cause of ed
cialis with effexor cialis 20 mg best price cialis advertisement
ivermectin for guinea pig ivermectin merck stromectol and herbs
cialis buy paypal cialis 20 mg best price cialis price canada
cheap pills online treat ed vitamins for ed
prednisone 10 mg over the counter buy prednisone buy prednisone online without a script
herbal ed vacuum therapy for ed how to get prescription drugs without doctor
Very good post! We are linking to this great post on our site. Keep up the good writing.
best male ed pills ed drugs list non prescription ed drugs
Having read this I believed it was rather informative. I appreciate you finding the time and energy to put this content together. I once again find myself personally spending a lot of time both reading and leaving comments. But so what, it was still worthwhile!
free turnitin is designed to bring you the additional help you require in finishing your next academy article. We compare the most suitable educational authors, Impact of Employee Retention on Business is a location where you can acquire skilled benefits from talented writers. We persevere to create all our customers comfortable! Money-back promise, Professional essay writers from the US 6+ years of knowledge Entrusted college essay service.
best online canadian pharmacy canadian online drugstore prescription drugs canada buy online
best otc ed pills what are ed drugs best ed pills at gnc
how much ivermectin paste to give a dog for mange ivermectin where to buy ivermectin injections
Greetings! Very helpful advice in this particular article! It is the little changes that make the most significant changes. Many thanks for sharing!
buy canadian drugs how can i order prescription drugs without a doctor ed prescription drugs
Nice post. I learn something totally new and challenging on blogs I stumbleupon everyday. It’s always useful to read through content from other writers and use something from other web sites.
non prescription erection pills ed medications medication for ed dysfunction
I do not even know how I ended up here, but I thought this post was good.
I do not know who you are but certainly you are going to a famous
blogger if you are not already 😉 Cheers!
Wonderful article! We will be linking to this particularly great content on our website. Keep up the good writing.
cat antibiotics without pet prescription buy prescription drugs online prescription drugs without prior prescription
Simply want to say your article is as astonishing. The clearness in your
put up is just spectacular and that i can suppose you’re a professional on this
subject. Well along with your permission let me to grab
your RSS feed to stay updated with approaching
post. Thanks 1,000,000 and please keep up the gratifying work.
I could not resist commenting. Very well written!
stromectol 3 mg tablets price stromectol for sale buy stromectol online
order generic modafinil 200mg modafinil 200mg for sale
brand provigil buy provigil pill buy provigil without prescription
highest rated canadian pharmacies buying from canadian online pharmacies prescription drugs without doctor approval
erythromycin pregnancy https://erythromycinn.com/#
best ed pill pills for ed ed meds online without doctor prescription
Hey there, I think your website might be having
browser compatibility issues. When I look at your blog site
in Firefox, it looks fine but when opening in Internet Explorer, it has some overlapping.
I just wanted to give you a quick heads up! Other then that, great blog!
provigil medication
purchase modafinil for sale provigil 100mg tablet
stromectol 3 mg tablets price stromectol 3 mg tablets price stromectol for sale
provigil 100mg pill order modafinil 200mg without prescription
buy provigil pills order modafinil pill buy provigil 200mg without prescription
We promise and deliver you entirely counterfeit free and unique substance for all assignments. We offer Finance Assignment Help all around the globe, so regardless of where you are, you will get assistance from the best experts.
cialis 20 mg price where to buy liquid cialis generic tadalafil 20mg india