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LinkedInOrange rust emerging again in blackberry
This article is to share some information regarding orange rust in blackberries on the Central Coast. Apparently, this fungus was detected last year and it continues to spread. Previously only seen in some local plantings of Chester blackberries it has now been found on several occasions in proprietary blackberry plantings. Orange rust is a tough disease to deal with, so it is worth being able to identify and knowing what steps one needs to take to mitigate its spread.
Orange rust is caused by two fungi, Arthuriomyces and Gymnoconia which are distinguished by the shape of their spores and life cycle length. Their growth is favored by cooler temperatures and high humidity. While it is not common that orange rust infected plants die outright, their ability to produce fruit is severely compromised.
As readers can clearly see in the photos below, orange rust is hard to miss in the field. From further away, infected canes have a spindly appearance and on approaching one will see the upper leaf margins of both primocane and floricane framed with the distinctive orange of the fungal infection on the underside of the leaves.
Of all the rust fungi that we deal with in caneberries on the Central Coast, orange rust is unique in that it grows systemically in the plant, meaning that the most important management tool for growers dealing with an infestation of orange is a shovel. There is no effective fungicide for orange rust. Infected plants should be removed entirely, meaning all canes, leaves and the roots. This is best done before the pathogen spores are ready to be spread by rain and wind in mid-April through May.
Orange rust on blackberry- note relative spindliness of infected leaves compared to those not infected in background
Underside of leaf infected with orange rust
Comments:
First, YES, your berries are safe if they are washed.
Secondly, I doubt the disease that your Ollalieberries have is orange rust, it almost certainly is stem and cane rust, which is Kuehneola uredinis. I know this because trailing blackberries (or dewberries if you want to be exact) don't get orange rust. Anyway, enjoy your berries!
It's hard to tell with a picture, but I suspect the rust you are seeing is either yellow or late leaf rust, both of which are common on raspberries. I am guessing that these also occur on black raspberry.
Could you look closely at those small black bugs? I suspect those might be masses of teliospores, which are overwintering stages of the rust. If you send me some pictures I will tell for sure.
Mark
Dig out the plants, and get as much of the roots as possible.
Mark
We pulled our blackberries plants all out because of the rust invading our plants over the last three years. Should these infected plants go into the garbage instead of the greenwaste recycle?
How many years should we waite before we plant blackberries in the same place. We don't have an alternate spot.
We live in Corralitos Ca.
Thanks,
Scott
Nothing I find in the literature points to long term survival in the soil. Given that this fungus survives either as mycelium in living plant parts or teliospores of undefined duration, if you gave the spot a year or two between the time of plant removal and the time of putting new ones you should be ok. This would give you time for the roots containing mycelium to break down and probably a lot of teliospores to die.
A couple of things going on here. The rust your Ollalies are infested with is actually leaf & cane rust (Keuhneola uredinis), and this will definitely migrate to your Boysens. Be careful there.
The Triple Crowns very likely won't take it up though, but watch those closely for the orange rust depicted in this article.
Mark
I don't think that would be the case. Orange rust is a a fungus, so one is consuming something that has a lot of the components of a mushroom.
Mark
Sounds like you are confronting a case of sunburn, but without any pictures or anything it's hard for me to tell. That or a lack of water. Has the sun exposure been long?
Mark
I answered you directly, but what you have (thanks for the pictures) is cane and stem rust and not orange rust. Stem and cane rust is quite common on trailing blackberry varieties like Ollalie and Boysens so your situation is not unusual. Refer to the UC IPM guidelines for more direction on how to manage it. Thanks for checking in!
Posted by Judy J on June 6, 2013 at 6:18 PM