Asier Labaka_Elia Hermoso de Mendoza_Arrate Etxebeste
Pine processionary caterpillar
Elia Hermoso de Mendoza
• Scots pine (Pinus sylvestris L.) has a wide
distribution in Europe and Asia.
• Important in economic and ecological terms.
• In the study:
– They Investigate the impact of PPC on natural
populations of Scots pine in southern Spain
– Evaluate the consequences for forest regeneration
and thereby prescribe appropriate guidelines to
prevent the potential devastation of the pest.
Biological cycle of Scots pines
April (year 0). year 1 year 2
Flowering Female Cones develop
and strobili are
May of year 1 to January
22 months seed dispersion
Biological cycle of processionary
in mid-summer. September autumn and winter
Eggs laid and hatch
in the canopy of the trees
In the nest ---protected cold
In Trevenque area Studying Biological cycle
National Park of Sierra Nevada
Why?? of Scots PPC (2)
In 98´- 99´had a heavy
Grow native Pinus defoliation by PPC
Silvestris (pine processionary
Defoliation January and Larvae are in a mature
2.2.1.- On juvenile Scot pine
They observed the survival of the
- Estimating of porcentage of defoliation suffered
during the period of plague activity.
- And divide the new growth by initial growth.
2.2.3. On adult Scot pine
Observed parts of the
pine as: flowers
Two process: seeds.
1) Estimated the percentage of damage suffered
during the period of plague.
Measured of diametre, lengh and the
number of seeds and the average weight.
2) Choose 10 pines completily defoliated and
10 with low or no defoliation. They measured
Results and discussions
• PPC drastically reduces the growth and
the reproduction of Scots pine.
• Juvenile defoliated trees:
– Grow 50% less than other trees
– Have 50% fewer seeds
– Have 40% lighter seeds
• Scots pine have lower rate of growth in
southern Spain, so the PPC afection is
• Also the global warming is reducing the
days with frost so larval survival of PPC
Conclusion and guidelines
• The effect of global warming on Scots pines because of the
PPC will have a negative effect in southern Spain.
necessary to control.
• Biological controls have limited effect and are
expensivemethods based on self-perpetuating
characteristics of the system.
• Short term the increased tree diversity and
community complexity in adjacent reforested
pine stands could greatly reduce the spread of
• Long-term reforestation programmes helping
both the spread towards adjacent areas as well
as the migration of Scots pine in altitude will be
valuable for preventing attack by PPC.
• This task may be achieved with techniques
already developed in situ using shrubs as nurse
plants to increase seedling survival
minimizing the ecological impact of reforestation on
these protected high-mountain ecosystems.