Why Did the Cause of Pierce’s Disease in Grapevines Spread to Europe Only in 2013?

Greenhouse gases have, according to measurements, increased the Earth's average temperature by nearly 1.5 degrees Celsius per year. As a result of this change, harmful pathogens may spread to regions where they have not previously been found. This applies to both alien invasive species and so-called newcomer species, which are spreading to new areas without human intervention.

Eduardo Moralejo and his colleagues have published a study examining the phylogenetics, epidemiology, and history of Xylella fastidiosa, a North American bacterium spread by insect vectors that causes Pierce’s disease in grapevine. Their research provided insight into why European vineyards have, until now, avoided this pathogen.

Before this study, it was a mystery why the export of American grapevines to France in the late 19th century to combat phylloxera did not lead to the spread of X. fastidiosa at that time. Phylogenetic analysis revealed that the most recent common ancestors of the bacterial populations lived around 1875. This timing aligns with the first epidemic caused by the bacterium in the U.S. and its subsequent spread to the southeastern United States.

Moralejo and his team also showed that continental Europe's climatic conditions were too cool from the 19th century until the early 1990s for Pierce’s disease to develop into an epidemic. Consequently, the pathogen could not establish itself or spread from the plants imported into Europe at that time, even if they had been infected.

However, the situation has changed due to global warming. As a result, the risk of epidemics has been increasing for over three decades. It remains to be seen when this bacterium will be found beyond the limited areas of Europe’s southernmost regions, where it was first detected in 2013.

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Preventing future fires in Hawaii is possible, but the question remains: Are animal activists and politicians prepared for the necessary measures?

Hawaiian researchers Daniel Rubinoff and Samuel M. ‘Ohukani‘ōhi‘a Gon III reported in the journal Science that the fire that devastated the city of Lahaina, Hawaii, has killed more people than any other U.S. wildfire in the past 100 years. According to them, the underlying causes of the wildfire were land-use mistakes that led to the proliferation of easily ignitable invasive species and a lack of control over feral goat grazing.

Therefore, the removal of invasive species, the restoration of native plants, and better management of feral goat populations are essential measures to prevent similar wildfires in the future. The latter is crucial because feral goats have played a significant role in the disappearance of Hawaii's native dry forest ecosystem.

Goats were originally introduced to Maui as a gift to King Kamehameha I in 1789. However, the problem arose when these goats escaped into the wild and became feral. As a result, they have consumed native plants and stripped the bark from native trees. This, coupled with previous fires and the decline of Maui's plantation industry, has created a cycle in which wildfires continue to increase, allowing invasive species to spread.

One potential solution to prevent wildfires, according to researchers, could be the intensive grazing of cattle, which would reduce the quantity of invasive species that serve as fuel. However, this solution would negatively impact reforestation efforts, carbon sequestration, and lead to erosion and increased flood risks during winter rains. It would also result in barren landscapes and fail to support Hawaii's native biota, which is a critical Hawaiian biocultural resource.

Instead, it would be better to restore native Hawaiian dry forests, which burn more slowly than invasive shrubby grasslands. This, in turn, would require the widespread eradication of goats.

It remains uncertain whether the wildfires witnessed this year will indeed prompt the envisioned changes in Hawaiian conservation practices. There could be resistance from animal rights activists opposing large-scale goat eradication operations, and politicians might be reluctant to allocate funding for these essential changes, considering the economic sacrifices involved.

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A popular hobby risks ecological balance, private property and human health in Finland

A popular hobby risks ecological balance, private property and human health in Finland

Ticks carry bacteria and viruses with them. The bacteria are causing Lyme borreliosis, which is a serious disease but can be treated with antibiotics. In contrast, some viruses may cause Tick-borne encephalitis (TBE), which is a serious tick-borne disease in Europe that can only be avoided by vaccinations.

Today it was informed that the number of TBE cases has increased considerably in Sweden and Finland due to the climatic change and and COVID-19 pandemic, the latter of which has brought people for outdoor activities. At least in Finland one of the main causes was not mentioned. That is the dramatically increased number of white-tailed and also roe deer, both of which act as hosts to ticks, and therefore enable higher population sizes of disease causing agents.

Deer populations also cause major damage to young forests by eating hardwoods and pines, which result in direct losses to forest owners as well as directs forest owners to plant spruces, which in Central Europe have been attacked seriously by beetles, and the same has been predicted to happen also in Nordic countries if the climates continue warming as predicted.

Hunting is, however, a popular hobby in Finland, and people involved are bringing huge amounts of food to the deer in wintertime, which increases considerably their population sizes. That maximizes the amount of animals for hunting but also their effect on the spread of tick-borne diseases and forest damages. 

For anyone looking from the side, it should be imperative to end the feeding of deer due to the vast problems they cause. And the common sense says, that white tailed deer should be removed from the country due to its nature as an alien invasive species. It simply is not sustainable to jeopardize ecological balance with an aggressively reproducing alien animal, put the health of lay people at risk nor damage their properties because of a hobby - no matter how enjoyable that may be.

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