Phytophthora fragariae

Phytophthora fragariae is a fungus-like (oomycete) plant pathogen that causes red stele, otherwise known as Lanarkshire disease, in strawberries.

The pathogen is spread via zoospores swimming through water present in the soil, released from sporangia.

[1] The oomycete does not infect tomato, apple, potato, turnip, cauliflower, chickweed, groundsel, or corn spurry.

[citation needed] The Phytophthora pathogens in strawberry and raspberry are similar in many ways morphologically, culturally, and molecularly, but are different in growth.

Due to the infection, the stele of the root turns a wine to brick red, and starts to decay and die from the tip upwards.

The most dependable way to determine if a plant has P. fragariae is the presence of microscopic oospores.

[citation needed] The symptoms on the above-ground parts of the plant generally do not begin to show until late spring and early summer.

Overall, the plant ceases to grow, or is stunted in growth, and shows a decline in runner development.

In some cases, not frequently, the plant will merely wilt and die before visible symptoms are able to develop above the ground.

This brings about the opportunity for secondary fungi and oomycetes to mask the original Phytophthora pathogen.

Also, using PCR with primers DC1 and DC5 in the second round was also found to yield favorable results to detect P. fragariae var.

The zoospores swim through the water in the soil to find roots where they encyst and form germination tubes to infect the plant.

[8] Goode 1956 discovered that early in the infection process the zoospores recognize not only the target – the root – but particular parts of its surface and adhere there.

[4] There are three main components of the environment that affect the effectiveness, speed, and ability of P. fragariae to infect: soil moisture, temperature, and pH.

In fact, there is a direct correlation between the soil moisture and the percentage of roots that were infected with P. fragariae.

However, as you approach the lower and higher ends of the temperature range, the disease develops and spreads more slowly.

In contrast, soils with a lower pH are better suited for the mycelium and more mature parts of the oomycete.

These chemicals, when applied in late autumn just before the infection of new roots, have been proven to be effective against var.

Some strains with phenylamide resistance have been found and have proven to be problematic in Germany and North America.

Due to the importance of water in germination and infection, good drainage can help reduce the proliferation of the disease.

Some information suggests that after a severe outbreak farmers could see yields as low as 1 metric ton per hectare (0.40 long ton/acre; 0.45 short ton/acre).

This disease can wipe out entire plantations in only a few years, effectively ruining a starting raspberry farm.

The countries it affects most are the U.S., China, Belgium, France, Germany, Italy, Netherlands, Russia, Switzerland, Norway, Finland, and the UK.