Plagues and diseases

Infestation of pine trees in Javea and surroundings   

Infestation of pine trees in Javea and surroundings  

The pines in the Costa Blanca have had a lot to endure in the last year. In addition to the drought and pine processionary caterpillar, they are also affected by beetles such as Tomicus destruens that have caused many trees to be lost.   Now we also see that the pine trees in Javea and the surrounding area look brown and dehydrated at the top (photo 1),it is mainly the young needles that dry out as we can see in the picture below.   Commissioned by BIO JARDINSOSTENIBLE S.L.U. the entomologist Silvia Hellingman has examined over 50 samples from different locations to investigate what is happening with the coniferous trees.     Diagnosis   In all samples and on the spot observations we have found several aphids and scale lice (Diaspididae) (Photo 2,3).   The insects feed on the juices of the needles. By sucking the juices the needles dry out, which gives a sad appearance to the trees.     The cause of the many and different pests is due to the climatic conditions. We are dealing with an exceptionally warm winter, as a result of which insects that usually overwinter as an egg become more active with all its consequences.   In addition to lice, also many egg packages from the pine processionary caterpillar were found, as well as the nests left by the young caterpillars to settle elsewhere in the trees (Photo 4). These spots are also brown coloured, this phenomenon in combination with the needles affected by the leaf and scales ensure that the pine trees look bad.     Fungi due to stress   Mildew spores were also found in some samples. If the trees are in poor condition due to, for example, periods of long drought, they become susceptible to fungi.   Fungi can be transmitted to the pine trees by numerous insects.     Bacteria Candidatus Phytoplasma pini   Recently there was an article in the local media about the damage to the coniferous trees in Javea in which the bacterium Candidatus Phytoplasma pini was named as causative.    It could be possible; bacteria on plants are often transmitted by insects by, for example, aphids, leaf fleas or cicadas.   The impairment as we saw, however, does not match the symptoms of the infection by the Candidatus bacterium.   In Spain, this phenomenon is called Escoba de brujas. (Picture 5).   It will have to be further investigated, but it is very unlikely that there is a bacterial infestation here, although due to the climate change, more and more plagues are manifesting which may or may not be transmitted by insects.     Nature reacts quickly   In all locations there are many larvae of various species Ichneumonidae (Syrphidae) present. These are natural enemies of the aphids and there are also species that focus on young pine processionary caterpillars.   The first larvae of ladybirds have been observed in various affected trees, these larvae feed on different types of leaf and fungus lice. In addition, we found many parasitized leaf and scale lice. This is the work of the zealous parasitic wasps.   The parasitic wasps deposited their eggs in the aphids. The larvae eats the aphid from the inside out. On the attached photo we can see the exit holes of the parasitic wasps (Photo 6). The parasitic wasps have flown out of the dead louse. They mate and search for new aphids to parasitize them.   In addition to the beneficial insects, the insects that suppose a thread to the pine trees are eaten by many birds.     Conclusion   The dry and warm autumn and winter have ensured that the insects that would normally be in winter rest have affected the pine trees.   Fortunately, there are many natural enemies present that provide a significant reduction of the pests. Because of the current cold period, the pest pressure will naturally decrease.   We will continue to monitor the development of the damage in the pines and we will of course report new developments.     Research and photos: Silvia Hellingman   Text: BIO JARDINSOSTENIBLE S.L.U. / Silvia Hellingman...

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When predictions comes true; Xylella Fastidiosa

When predictions comes true; Xylella Fastidiosa

There will be a before and after. After causing havoc in the cultivation of olive trees in Italy and infecting numerous almond trees in the Balearic Islands, the bacterial infection Xylella Fastidiosa has reached the Iberian Peninsula and is very likely to have arrived to stay forever.   A few days ago the first outbreak of this infection was confirmed in the town of Guadalest, in the province of Alicante. Although not contagious for humans, it causes serious damage to some very important cultivations in our country, such as: olive trees, citrus trees, grapevines, almond trees, peach trees, as well as numerous ornamental plants.   Xylella Fastidiosa is a bacteria that is transmitted by insects known as Chicharritas or Saltahojas (Cicadélidos). These feed on the Xylem - the plant tissue that drives the sap and holds the plant - infecting the tree. The bacteria produces the drying of leaves and branches, and if the necessary measures are not taken on time, finally, the tree will die. Although there is no preventive treatment or known cure, promising news comes from Italy, where a treatment is being developed in conjunction with the University of Foggia and the Council of Research in Agriculture and analysis of agrarian economy in Caserta, Italy. Infections are often latent and have no symptoms, making it difficult to detect the pest in the area. Once the infection is detected and confirmed, the eradication protocol is activated or the containment measures are applied instead. The eradication program of the Ministry of Agriculture and Health requires the elimination and destruction of all infected plants as well as those with symptoms and host plants in the area. Where eradication is no longer possible because of the extent of the infection, the competent official body may apply containment measures in that area.   Below you can find the link to the list of host plants of the strains of Xylella fastidiosa present in Europe: Http://ec.europa.eu/food/plant/plant_health_biosecurity/legislation/emergency_measures/xylella-fastidiosa/susceptible_en.htm.   In the fight against Xylella fastidiosa it is necessary to promote collaboration between the Ministry of Agriculture, the different Autonomous Communities and the working groups of experts at national and international level to reinforce the strategy to combat the spreading of the infection.   If you detect signs of infection with Xylella fastidiosa in plants or trees in your area do not hesitate and contact the Department of Plant Protection of the Ministry of Agriculture or notify our company, Jardin Sostenible, by sending an email to info@biocontrole.es or call +34 965 875 045.  One of our specialists will come and check the affected plant on site....

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