OUR LAND/LA VERDAD DE MURCIA NEWSPAPER

ECONEX NEWS

OUR LAND/LA VERDAD DE MURCIA NEWSPAPER

05.11.14 – PEPA GARCÍA

The ‘Mediterranean Pine Shoot Beetle’ swallows up forests

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Entomologists and specialists in forest health still remember with dread the pest that devastated forests in the Region of Murcia between 1994 and 1996. And that was two decades ago. It was an invasion by the ‘Mediterranean Pine Shoot Beetle’ (Tomicus destruens), which destroyed 40,000 hectares of pine forest in the Region of Murcia and caused mass mortality to the Aleppo pine (Pinus halepensis). Millions of specimens fell at the hands of this small beetle that destroyed pines, young and old alike. They were undeniably weakened by the extreme drought that affected the Levante (Spanish East Coast) from 1992 to 1994 and turned the water year of 1993 to 1994 into one of the driest up to now, making it the hottest summer of the 20th century. “It was the largest Mediterranean Pine Shoot Beetle invasion known to Southern Europe” observes Diego Gallego, a biologist specialised in this type of Coleoptera. He began researching this species to develop his thesis, then went on to collaborate with the Environment Agency and the Department of Zoology and Physical Anthropology at the University of Murcia. It was a line of investigation that led him to develop the first traps for this endemic species, capable of having a destructive effect on the region’s forests (mostly Aleppo pine trees).

Now history is repeating itself, although experts are confident that after experience between 1994 and 1996 about the pest was gained, together with the best skills and knowledge, they could keep it at bay. Or at least not let it reach the devastating proportions as it had done in the past. <>, explained the Environment Agency.

In fact, in June 2008 the network of Permanent Forestry Monitoring Stations (Estaciones de Seguimiento Forestal Permanente – ESFP) started working in the region. They are a sub-division of the Forest Health Unit with 20 stations spread out all over the region (Jumilla, Mazarrón, Murcia, Espuña, Lorca, Zarcilla, Caravaca, Moratalla, Abarán and Yecla).

It is precisely this network that has allowed for the detection of the invasion, considering that the count has gone from collecting 10 samples of ‘Orthotomicus Erosus’ per trap to 500 samples per trap being collected.

In this instance, explains the Environmental Department, the marks on the dead pinewood correspond to trees that have dried up from lack of water and attacks in their environment by another species of perforating coleopteran (Orthotomicus erosus). << It is an anomaly, because this insect does not usually cause such a high mortality rate in trees>> explains Gallego, but given the extreme weakness of the Aleppo pine trees, they have already detected attacks in ‘Pinus pinaster’ or Cluster pine trees in Sierra Espuña.

«The drought, last year’s high temperatures from autumn to spring and other circumstances that have escaped us, have predisposed the trees to being attacked by ‘Orthotomicus erosus’, causing mass mortality during the summer», comments Gallego. It is a pest that is usually followed by the most aggressive borer (‘Tomicus destruens’). The problem, warns Diego Gallego, is that the top of the tree remains inert until autumn when the pine starts to move the sap again, for which the top of the tree demands water, but doesn’t receive it because it’s dead. Which means it dries up and we see this happening.

The first interventions

The treatment for this less lethal species of beetle and for the aggressive ‘Tomicus destruens’ is the same, explains the Environmental Department. Although their life cycle, warns Gallego is different, the egg laying period of Tomicus destruens takes place from October (they usually continue until the beginning of April). Damage caused by Tomicus destruens will show its effect on pine forests the following spring.

Regional exploration

To try to tackle this worrying threat, the Environmental Department has installed traps (1 trap every 9 hectares). They have also started to explore on a regional scale to assess the potential damage that the pest could cause. The report could be finished in approximately two weeks and will provide the exact amount of forest hectares that have been affected.

<> explains the Environmental Department. One form of defence used is the release of resin, which drowns its invaders. However, while the rain resists in watering our mountains and providing them with enough humidity to revitalise the trees, the Environmental teams have already chopped down trees in the areas most affected, such as Los Cuadros (Murcia and Santomera). Also, at the beginning of January they will continue cutting down the trees that have died (as much from the drought as from ‘Orthotomicus’). So, when spring arrives, any new marks can be distinguished on the dead pine trees, which would be the result of the most aggressive ‘pine weevil’ (‘Tomicus destruens’) and therefore, the focal point for this second threatening pest.

The main focal points

At the moment, the area most affected by ‘Orthotomicus’ (although signs of some isolated attacks from the first ‘Tomicus’ have already appeared) is in Coto Cuadros, in which four hectares of Aleppo pine trees have been cut down by the Environmental Department. In addition, the specialists explain, Librilla (around the Algeciras reservoir and Castellar) has also suffered a severe attack. Marks have been detected in the forests of Cartagena, Fortuna, Totana, Murcia, Mazarrón, some in Lorca and some isolated cases in Pliego and Cieza. In fact, the Ministry of Environment have assured that the areas of Sierra de la Pila, Sierra Espuña and El Valle-Carascoy have hardly been affected. And from Cieza upwards there are no signs of the pest because the land conditions and humidity are different.

They even venture to predict that in the areas where there are no extensive marks on the affected pine trees, the ‘Orthotomicus erosus’ effect will be like the work carried through to thin out the forests periodically.

Diego Gallego, who has collaborated with the Regional Government «offering technical advice» until a couple of years ago now works in the company Econex. The company specialises in selling traps which monitor forest pests, as well as fighting them off when they turn into an invasion. This collaboration came about through his research work at the University of Murcia, which has finally allowed these products to be sold, because up until a few years ago they were inexistent. For this reason, it has been confirmed by the Local Authorities in the Valencian Region and Murcia that there has been a great demand for traps and attractants.

These are measures that will help <> assures Gallego, claiming that the actions of the Environmental Department, who began to take measures last September were correct. He acknowledges the fact that the increase in mass trapping is a costly measure for public funds, apart from the fact that staff are required to dispose of the infected material, as well as monitoring the traps and taking the captured insects away periodically.

Pest specialists hope that the climate will change and that the rain will help to fight the new pest, but at the same time recognising that if the mortality rate is very high then much of the area would have to be chopped down. However, they would have to reconsider the restoration of these areas with other species of trees. Although currently, the reforestation projects are not carried out just with ‘Pinus halepensis’, the species most sensitive to attacks by these beetles. Instead, the pine forest (30%) is combined with other woodland and scrub species to create diversified forests.

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