The Processionary moth is a defoliating insect that feeds on all species of pine trees and cedars.
This species is distributed throughout the Mediterranean, being present on all of the Iberian Peninsula. Its distribution is limited due to the climate, so that areas with wintry temperatures below -12oC impede its development.
It has been demonstrated that when the feeding activity is very intense it can diminish the growth of some species of pine trees, this being more important in young pine trees with a lower outward appearance than in older trees.
In addition, the forests defoliated by the Processionary moth present a distressing aspect and can become impassable and impede or complicate forestry work because of the urticaria produced by the caterpillars.
MORPHOLOGY AND BIOLOGY
When the pine Processionary is in the moth/butterfly stage, the wingspan in females can reach between 36-49 mm. The forewings are an ash-grey colour with darker veins and margins and three transverse bands. The hindwings are white with grey fringes and a characteristic grey-brown spot in the anal region. They have greyish hairs covering the thorax. The abdomen is cylindrical, stout and its last segments are covered with a tuft of large scales.
The adult males have a wingspan between 31-39 mm and have lots of hairs on the thorax. The abdomen is also very hairy, conical and slightly thinner than the females.
The hindwings are the same as the females, whereas the forewings are a grey colour varying in intensity and in this case, the three transverse bands are much darker and more visible than the females.
Depending on the weather between June and September, the Processionary moth lays the eggs on the pine needles. The number of eggs laid varies between 120 and 300. They are protected by the scales of the abdomen, making it look like a cigarette that covers the needles.
The caterpillars take 30 to 40 days to be born and immediately after hatching they start to feed on the same place they emerged from, establishing a permanent contact with their sisters, something that will endure throughout their larval life. The caterpillars go through 5 larval stages, with social and gregarious behaviour. With each change the larva increases in size, also increasing the size and density of its nests. A recently hatched caterpillar measures around 2.5 mm, growing up to 3 or 4 cm before pupating. The caterpillars develop urticarial hairs as a defence mechanism as of stage 3, which happens around the beginning of winter.
The temperature greatly influences the biological cycle of this insect. When the temperature on the inside of the nest is between 20⁰C and 25⁰C the caterpillars develop normally. With temperatures higher than 30⁰C, the egg laying should happen approximately one month before the temperatures begin to drop below 30⁰C. In the cold areas the egg laying is brought forward compared to the warmer areas.
They also have a lethal inferior threshold; with temperatures lower than 10⁰C on the inside of the nest the colony activity stops, so that when the nights are very cold, the caterpillars come out to feed during the day. Below -12⁰C entire colonies can die. Between 10⁰C and 20⁰C, the caterpillars carry on feeding and sewing the nest, but do not progress in their development.
After the fifth larval stage the caterpillars carry out the burial processions, a behaviour which gives it the common name Processionary. The caterpillars travel in a line, coming down from the nests via the tree trunks, travelling around ten metres on the ground until finding an appropriate place to bury themselves. In this phase of burial, with the caterpillars in the ground, is when the greatest risk of contact with people and pets occurs, at times causing serious symptoms. It is very important to avoid contact with the caterpillars while they travel.
When they find the right place the whole group buries itself. Once they are buried, each caterpillar spins its own silk cocoon. They then pass on to the pre-pupa phase, whose duration varies between 21 and 30 days depending on the temperature. In this case it can occur that for reasons not very well known the pre-pupa enter into diapause, in which they can spend between one and seven years. During the pre-pupa phase, great changes are made in the internal conformation, after moulting, to make way for the chrysalis. The latter are a chestnut-red colour and egg-shaped. Females reach a length of about 20 mm and males a little less than that.
DETECTION AND MONITORING
A minimum of 1 ECONEX G TRAP should be placed per plot and up to 1 trap per 9 hectares. The traps should be hung from the pine trees or on a support for this purpose.
For extensive monitoring the number of traps per surface is increased to 3 traps per hectare, according to the location and uniformity of the plots. On small plots the number of traps should be greatly increased.
We need an ECONEX G TRAP (Code: TA028) and a pheromone diffuser ECONEX THAUMETOPOEA PITYOCAMPA 60 DAYS (Code: VA153) or ECONEX THAUMETOPOEA PITYOCAMPA 200 DAYS (Code: VA331), with a duration in field of 60 and 200 days respectively.
On the inside of the trap the pheromone diffuser is hung from the stopper cap using a paper clip, which is located in the upper part of the trap.
The ECONEX G TRAP has a large capacity and is used for capturing the males of the pine processionary moth (Thaumetopoea pityocampa) through the activation of the trap by placing the ECONEX THAUMETOPOEA PITYOCAMPA pheromone diffuser inside.
The body of the trap is dark brown plastic, slightly rough on the outside and smooth on the inside. The entrance funnels are extended with flaps that limit the field of vision on the inside of the main body of the trap. Attracted by the pheromone diffuser, the male enters the trap and falls into the bag from which it cannot escape.
The lower part of the bag is a dark brown colour, to stop the birds from seeing the captured insects and breaking it to feed themselves.
SYMPTOMS AND DAMAGES
The pine processionary moth produces two types of damage: the first, affecting the plants and causing the loss of pine needles. This is because the caterpillars feed on the pine and cedar needles in winter.
The most significant damage is created from the end of winter to the middle of spring, when the caterpillars are bigger and more voracious.
The larvae from the 3rd to the 5th stage are strongly allergenic. They can even produce severe allergic reactions in people and animals.
In general, the flight of the adult pine processionary moth takes place between the months of June and September.
In spring, observation traps should be placed using 1 or 2 per plot to detect the plague and observe its population levels.
Through tolerance thresholds established in each area, the moment to adopt control measures is later defined.
The plague population, the connection to other pine trees, the level of control needed, etc. An important factor is the size of the pine forest. A larger amount of traps are needed in smaller and irregular forests than on plots with a larger and more uniform surface area.
In this case, the borders around the plots have to be reinforced. It may be necessary to place up to 3 traps per hectare for intensive monitoring purposes.
The diffusers should be stored in their original packaging in a cool, dry place. To preserve the diffusers during large periods of time, they can be stored in the fridge at 4oC for 2 years. In the freezer, at -18oC, they can last up to 4 years.
G TRAP PACKAGING
Corrugated cardboard box with 17 traps.
Measures of the box: 40x60x35 cm (width x length x high).
Weight of box: 9,10 kg.
Nº of boxes per pallet: 20.
Measures of the pallet: 80 x 120 x 190 cm (width x length x high).
Weight of the pallet: 195 kg.
ECONEX CATALOGUE OF PRODUCTS AND SERVICES FOR FOREST PESTS
Catalogue in PDF format with an extension of 94 pages. It is an essential reference work for finding out about the biological behaviour of the main species of forest insects and the solutions of ECONEX to give an effective answer to the problems generated by these through the use of traps and specific attractants.
You can download the catalog by clicking on the image.
TRIPTYCH THAUMETOPOEA PITYOCAMPA – ECONEX G TRAP
Triptych in PDF format that can be downloaded by clicking on the image.
The processionary caterpillars produce two types of damage: the first, which affects the plants, causes the loss of needles, since the caterpillars feed from the end of winter to the middle of the spring of pine and cedar needles.
On the other hand, the caterpillars are strongly allergenic, being able to produce severe allergic outbreaks in people and animals, both in forest areas and in parks and gardens.
The PROCESSIONARYTRAPNEX® L trap is designed to capture caterpillars of pine processionary Thaumetopoea pityocampa, when they descend through the trunk of the trees where they have made nests. The aggregative and social behaviour of this species is used to capture the whole group of larvae when they go to the ground to bury and pupate.
The trap consists of a black PET film of 150 x 25 cm and 0.3 mm in thickness, and of a polyurethane foam bar of rectangular section of 5 x 7 cm x 150 cm in length, crossed in its middle part by a corrugated tube that connects with a polyethylene bag with its lower half opaque.
The black sheet is covered on its inner side by a film of contact glue (without solvents) to facilitate the assembly and to dissuade the processionary caterpillars from climbing up the sheet, forcing them to descend through the tube towards the bag, where they remain retained.
Activation of the trap: Identify trees with active nests of processionary caterpillars, making sure they have not yet descended. Read carefully the instructions included in the trap box. Remove the protective paper from the sheet. Stick the foam bar on the bottom of the sheet, taking care that the bag is approximately in the center. Present the set around the tree and mark the excess foam in the overlapped part. Cut only the excess foam, DO NOT CUT THE SHEET.
Install the trap around the trunk, so that the foam completely surrounds the perimeter of the tree, without holes, sticking the sheet with the overlapped part. The bag should be more or less centered. Secure the overlapping part with staples both on the top and the bottom. Check the foam fit to the trunk looking from below. If there were significant holes, fill with the remaining foam.
The trap is suitable for pine trees with a trunk perimeter less than 130 cm. For trees with a perimeter greater than 110 cm use two or more sheets and foam bars. The sheets must overlap at least 15 cm, ensuring overlapping with staples.
Safety advice: Handle the trap with protective gloves. In case of unprotected handling, wash hands after use. If the caterpillars are inside the trap, handle with extreme care: USE RESPIRATORY PROTECTION MASK. AVOID CONTACT WITH SKIN.
PROCESSIONARYTRAPNEX® L PACKAGING
Corrugated cardboard box with 10 traps, packed in individual boxes.
Measures of the box: 60x80x48 cm (width x length x high).
Weight of the box: 9,5 kg.
No. of boxes per pallet: 8.
Measures of the pallet: 80x120x205 cm (width x length x high).
Weight of the pallet: 86 kg.
TRIPTYCH PROCESSIONARYTRAPNEX® L
Triptych in PDF format that can be downloaded by clicking on the image.
The biological cycle of bats overlaps perfectly with the Processionary moth. The adult moths begin to fly and reproduce between June and September, a period in which the majority of the Chiropteran species have finished bringing up their offspring.
It is in this period of the year when a high depredation of insects happens due to a greater abundance of bats joining the adult population. Those that are born at the beginning of summer and the increased energy requirements of females and the young. The first, recuperating from lactation and the second, investing in their rapid growth, allowing them to survive winter with success.
The trophic resources ingested by the bats depends on the type of habitat, the abundance of species of insects, the seasons, etc. Studies carried out on the diet of Nyctalus leisleri show that an important part of its diet is based on eating lepidopterans (13 – 46%) (Sullivan et al. 1993; Waters et al. 1999). These results are important for our objective. Nyctalus leisleri is a forest species whose presence has been verified on the Mediterranean coast.
The activity of this species begins very early, when night has not yet fallen, coinciding with the hours of activity of the Pine processionary moth (Thaumetopoea pityocampa). The forest character, the type of trophic resources it consumes and the ethology of Nyctalus leisleri increase the probability of capturing the Processionary moths. In the case of Pipistrellus pipistrellus, moths do not constitute a high fraction of their diet, representing approximately between 1 and 5% of its diet (Hoare 1991; Sullivan et al. 1993).
It must be taken into account that the trophic studies of Pipistrellus pipistrellus mentioned, have been carried out in Nordic latitudes where the abundance of Lepidopterans is scarce, existing notable differences regarding the eating behaviour of Mediterranean populations. On the other hand, it also must be taken into account that Pipistrellus pipistrellus is a pervasive species and does not select its prey nor its size. This means they feed on insects that are more abundant in each period of the year (Swift et al. 1985). This characteristic is very important, given that it acts as a regulator on the demography of insect populations.
The majority of the species detected in Spain hunt preferably in forest areas, forest clearings and forest edges. They also visit to a lesser extent fields and urbanised areas, where they can be observed catching their prey around the lights. Generally, their hunting grounds do not tend to be very far from the shelters they use, with the exception of Tadarida teniotis. It is capable of travelling very long distances and hunting at a great height (including 300 m above the ground).
The majority of the bat species can potentially occupy the nests, even though some of them are not in the forest. For example, the fissuricolous and very often anthropophilic Pipstrellus pipistrellus and Pipistrellus kuhlii and the forest bats Hypsugo savill, Nyctalus lasiopterus can install themselves in the nests placed.
Luis Núñez Vázquez – Forest Health Service on the Balearic Islands.
Oscar de Paz y David Almena – Spanish Society for the Preservation and Study of Bats (SECEMU). Department of Zoology and Physical Anthropology. University of Alcalá de Henares (Madrid).
Egoitz Salsamendi, Joxerra Aihartza, Urtzi Goiti y Inazio Garin – Department of Zoology and Animal Cell Biology, University of the Basque Country.
Not all bats spend the day in caves. They tend to use the gaps in the trees to shelter themselves. They also use abandoned mines, buildings, bridges and many other places. In reality, the wide variety of bats reflect the incredible diversity of species that exist. The bats are very opportunistic and have adapted to their environment in creative ways to take advantage of the multitude of shelters available to them. However, human beings frequent the areas where the bats live; modifying or destroying their habitats.
Nests for bats are a real comfortable home for many species of bats. It is a way to provide a valuable refuge for the only species of flying mammals, which is in decline worldwide.
WHY SHOULD I HANG NESTS FOR BATS?
Bats are an important part of our ecosystem. European bats are mainly insectivores and in areas where their populations are very significant, they provide a considerable reduction in plagues of insects.
For example, one bat alone can capture up to 1,200 mosquitos in an hour. However, human activities have caused a drastic reduction in bat populations in the last few years. The bat is a very misinterpreted animal, playing a key role in nature. If it disappears, there will be important changes in the ecosystem.
The lack of suitable shelters for breeding in recent reforestations or young woods significantly influences in the abundance and distribution of the forest species of chiropterans.
With this action specific nests for bats will be installed, with characteristics that allow the reproduction of these species in its interior.
Monitoring the occupancy of the nests also serves to evaluate the forest bat populations.
The position of the nests will depend very much on the area, the latitude, the average temperature, etc. Generally, it is recommended to install the nests in places with 5 to 7 hours of sunlight.
Taking into account that the period of bat occupancy in the boxes (May- September) corresponds to the hottest in the year, it is not advisable to install the nests facing South unless the leaves protect them from exposure to the sun. That being the case, it is possible that the shelters reach non-optimal temperatures for its colonisation.
Maintaining the natural balance in forests through the use of all the biological resources that nature has to offer us, is possible.
The insectivorous birds, whose task in the forest balance, as regulators of plagues is well known. It has been one of the most studied entomophagous animal groups. Some of these birds, like the Woodpeckers build nests with their powerful beaks; Tits, Chickadees, Nuthatches, Redstarts and Old World flycatchers are troglodytes. This means that they use natural gaps found in trees and thick branches to nest and protect themselves from bad weather or predators.
The importance of these birds is clearly reflected, by studying the stomachs of Bluebirds in which large quantities of Tortrix viridiana or Catocala sp. were found, amongst others. Also, Thaumetopoea pityocampa caterpillars (Pine processionary) in their first stages, are very common in insectivores studied from autumn to winter. It has been estimated that the number of insects eaten by a couple of these birds in one year can be up to 5 kg.
These results show the usefulness of these birds in maintaining the biological balance in forests, which justifies the placement of artificial nests in forests. The nests successfully replace the lack of natural holes in trees, achieving a generalised increase in cave-dwelling, insectivorous bird populations. Also, their stability and presence in the forest ecosystem with the resulting benefit that this represents in the fight against harmful insects.
The nests are used during campaigns to protect insectivorous birds, by increasing their populations through the installation of nests.
The use of nests is very generalised amongst Conservationist Societies, Ecological Groups, Universities, Vocational Schools, Town Halls, Education Centres, Summer Camps, Nature Classrooms, Youth Associations and in general anyone who is interested.
There are no fixed rules on the most appropriate position the entrance hole to the nest has to have, given that it depends on a specific location. The East and South orientations are most common. Orientations frequently exposed to very strong winds, storms or any other unfavourable atmospheric conditions should be avoided.
In order to prevent slipping, it is advisable to install them in-between the secondary twigs of a branch or in the crotch of a tree. The height location seems to be irrelevant regarding the birds nesting. Although to avoid being handled by the inquisitive, in public places it is recommended that the nest be installed a minimum of 4 – 5 metres from the ground.
The right time to install the nests is in late autumn, so that the birds can use them for shelter during the winter period. Once they have been familiarised with their presence in the forest, they will be easily accepted for nesting next spring.