In Marin County, recent rains led to foliar infections on Pacific madrone, denuding leaves. These plants now have healthy new growth. What happened?

Pacific madrone foliar infections associated with rains are common throughout the West Coast. Typically, the spotted and necrotic leaves are ultimately substituted with healthy foliage and the plant fully recovers.

Other than for copper-based sprays, what control methods are available for cypress canker?

There are several  products that have been tested for controlling cypress canker. The following paper maybe the most useful one to compare products. Della Rocca, G., Di Lonardo, V., Danti, R. 2011. Newly-assessed fungicides for the control of cypress canker caused by Seiridium cardinale. Phytopathologia Mediterranea. 50 (1), pp. 65-73. The most effective active ingredients […]

Which trees give off the most oxygen?

Assignment levels of oxygen emission are not precise and different methods can give different results. That said, it is well documented that oxygen release is proportional to the overall leaf mass, also known technically as Leaf Area Index. There is general agreement that: Pines are at the bottom of the list in terms of oxygen […]

If reforesting an area impacted by SOD with local acorns, what can be done to prevent spreading the pathogen during planting?

Take the following precautions when using local acorns for oak reforestation projects in areas impacted by SOD to help minimize pathogen spread. Place acorns in a 10% dilution of bleach for 10 minutes then rinse twice with tap water. Make sure volunteers’ shoes are free of soil, mud, and organic material. Be sure tools being […]

How long can Phytophthora ramorum survive in wood chip mulch?

Survival of P. ramorum (SOD pathogen) in wood chips depends on a few factors: Were the chips allowed to become wet? What size are the chips? Is green waste present? What time of year was the wood chipped? Where in California are the chips located? Chips that are piled wet or tarped and include infected […]

How long can Phytophthora ramorum survive in soil moved from an infested area?

Survival of P. ramorum (SOD pathogen) in dead hosts or non-plant substrates is extremely variable and strongly affected by climatic factors. Although a comprehensive study on this topic has not conducted, extrapolating from several studies we can say the following: Soil becomes more infectious from late winter to early summer in the presence of rainfall, […]

When will the 2016 SOD Blitz and training sessions be held?

SOD Blitzes include a training session for blitz volunteers on SOD and proper sampling, followed by time in the field  for collecting and marking sample locations. All necessary collection materials are provided to volunteers during the training session for use either the same day of the training or the day after. All samples are to […]

What can cause leaf tip scorch on redwood trees?

Leaf tip scorch symptoms on redwood trees are found from the lower to upper canopy and include healthy leaves interspersed with brown and grey leaves or portions of leaves. Grey leaves typically have black margins into the healthy tissue. Such symptoms are typically caused by a fungus called Pestalotiopsis funerea. They are commonly associated with […]

What are the modifications required for drone canopy leaf sampling?

Make sure the prop blades are protected. Modify the tail to include a collection device.  A very sharp blade at a sharp angle allows twigs to be cut off and often to remain caught in the space between the blade and tail. Learn how to drive the drone using the camera. For more on drones […]

Does phosphonate act as a vaccine, keeping trees from getting SOD?

Phosphonate is only intended to be used on trees that do NOT have sudden oak death (SOD). Once a tree is infected, it is of no use. It helps to boost the tree’s own immunity system against the pathogen. So, if a tree is very susceptible to P. ramorum (the pathogen that causes SOD), then […]

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