The egg parasitoids ofThaumetopoea pityocampa in the atlas Mountains near Marrakech (Morocco)

Studies were performed on 25 egg batches ofThaumetopoea pityocampa (Den. & Schiff.) collected onPinus pinaster Ait. on 29. XI. 1995, in the Atlas Mountains of Morocco near Marrakech at 1400-1800 m above sea level. All the egg masses had been deposited in the autumn of 1995 and were exposed to the parasitoids throughout the developmental period of the host. In 1996, the egg batches, kept singly in test tubes, were observed almost daily. Emerged parasitoids were recorded and separated. The final analyses were made in November 1996 based on the meconia and remains of the emerged or the dead parasitoids in the eggs. In all cases, oviposition occurred from the base to the tip of the needles, distances varying up to 62 mm from the base. The mean number of eggs per batch was 175 (range 34-245), the number of egg-rows varied between 6 and 11, and a 1-cm egg-row contained a mean of 9 eggs. Caterpillars hatched from 72. 7% of the eggs; total mortality of the eggs was thus 27. 3%. The impact of egg parasitoids was 21. 4%. Most of the parasitized eggs were attacked byBaryscapus servadeii (Dom.) followed byOoencyrtus pityocampae (Mercet). Males (1. 5%) were found only in B. servadeii. The emergence rate ofO. pityocampae was much higher in the year of host oviposition than in the following year. B. servadeii emerged in equal numbers before and after hibernation, and in the subsequent year in equal numbers in spring and autumn. The high rate of emergence ofB. servadeii in April-May is discussed in relation to the embryonic development ofThaumetopoea bonjeani (Powel) until the end of winter, as an alternative host ofB. servadeii in the Atlas region.     

Effects of defoliation caused by the processionary moth on growth of Crimean pines in western Turkey

An outbreak of the pine processionary moth (PPM), Thaumetopoea wilkinsoni Tams (Lepidoptera: Thaumetopoeidae), began in spring 1998 and lasted 6 years in a Crimean pine (Pinus nigra Arnold) plantation in western Turkey. The effects of PPM on the radial, height and volume growth of Crimean pine trees were investigated by examining the increment losses for three defoliation intensities (groups). PPM activity in Crimean pine stand was assessed through radial increment analysis of cores extracted at breast height. In 2004, increment cores were collected from moderate and high defoliation and low defoliation dominant or co-dominant trees. Based on the sample, annual radial growth indices from 1998 to 2004 were calculated. Growth functions were defined as the cumulative sum of radial, height and volume increment graphically compared between Crimean pine defoliation group sample trees. The sample trees are the same subspecies and varieties. After the defoliations, radial, height and volume growth of low defoliation group trees was found to be significantly greater than that of the other affected groups. During the 1998–2004 period the total radial growth of low, moderately affected and highly affected trees was, respectively, 49, 33 and 31 mm; the total height growth was 3.1, 1.8 and 1.0 m; and the total volume growth was 50, 14 and 10 dm³.     

Identification by meconia of two egg parasitoids ofThaumetopoea wilkinsoni

Baryscapus servadeii (Dom.) andOoencyrtus pityocampae (Mercet) were the most frequent egg parasitoids ofThaumetopoea wilkinsoni Tams (Lep.: Thaumetopoeidae) in the Mountains of Lahav, Israel. Their meconia, remaining in the eggs, differ in structure and can be used to determine the annual rate of parasitism without collecting emergent adults. InB. servadeii, diapausing insects can be discriminated from non-diapausing ones by their meconia.     

Effect of different hosts onThaumetopoea pityocampa populations in northeast Portugal

A study was carried out at the Natural Park of Montesinho, NE Portugal, in order to evaluate the effect of different pine species (Pinus pinaster Ait.,P. nigra Arn. andP. sylvestris L.) onThaumetopoea pityocampa populations. The structure of the egg batches, the impact of the egg parasitoids on natural mortality of the pest and the species of parasitoids present, as well as their emergence dynamics, were analyzed. The length of the egg batches varied among pine species with the longest ones onP. nigra. The mean number of eggs per batch differed betweenP. sylvestris and the two other hosts studied, with fewer eggs per batch on the first. No differences were found in the size of eggs among pine species. The egg mortality varied between 25.8% and 33.0%, with no differences among hosts. Parasitism was the main cause of death.Baryscapus servadeii (Mercet.) was the most abundant parasitoid species, followed byOoencyrtus pityocampae (Dom.) andTrichogramma embryophagum Htg.B. servadeii dominated in the egg batches collected fromP. pinaster andP. nigra, whereasO. pityocampae was most frequent onP. sylvestris. The emergence ofB. servadeii started in the middle of March and continued until August, with the emergence peak at the end of May. The emergence ofO. pityocampae started at the end of April and continued throughout September, with maximum values in June. http://www.phytoparasitica.org posting Sept. 20, 2006.     

Environmental persistence of<Emphasis Type="Italic">Bacillus thuringiensis</Emphasis> products tested under natural conditions against<Emphasis Type="Italic">Thaumetopoea wilkinsoni</Emphasis>

Information on persistence ofBacillus thuringiensis (Bt) is needed to improve the microbial pest management programs against the pine processionary mothThaumetopoea wilkinsoni in pine forests in Israel. The persistence of the microbe under natural conditions of rain and sunlight was evaluated and is documented here for the first time. Pine saplings were sprayed with three commercialBt products, Foray 48B, Delfin WG and Dipel DF, all used at 32,000 IU mg⁻¹ in a formulation with 1% (w/v) of condensed milk. In experiments conducted in November and December of 2004, the saplings were either exposed to rain and sunlight or were sheltered to avoid these environmental factors. The lowest rainfall recorded in the 8-day experiments was 16.5 mm (test 2) and the heaviest was 71.1 mm (test 1). Solar irradiation ranged from 9.4 to 10.9 MJ m⁻². The minimum temperature was close to 10°C and the maximum was less than 23°C. Needles of the treated saplings and their controls were sampled after 0, 1, 5 and 8 days, and were fed to 1 ^st or 2 ^nd instar larvae. Dipel DF persisted better than Delfin WG and still retained its initial activity of 80–100% mortality on day 8 at low rainfall (test 2). Dripping ofBt from upper to lower branches was quantified with the larval bioassays. The milk formulation proved to be an effective rain-fasting adjuvant. http://www.phytoparasitica.org posting May 4, 2007.     

Effects of pine processionary caterpillar Thaumetopoea pityocampa contact in dogs: 41 cases (2002-2006)

The pine processionary caterpillar, Thaumetopoea pityocampa, is considered an emerging pine pest in Mediterranean countries, with high medical relevance. In recent years, adverse reactions reports in humans following contact with T. pityocampa have been increasingly reported. Dogs living in pinewood areas are also frequently exposed to the caterpillar. This work consisted on a retrospective study of 41 cases of lepidopterism. All dogs presented drooling, dysphagia, submandibular lymphadenomegaly and clinical signs of pain. The animals were distributed in three groups, according to the time span from exposure to the caterpillar until presentation: up to 2 h (group 1), 2-5 h (group 2) and more than 5 h (group 3). All animals from groups 2 (n = 5) and 3 (n = 9), and eight dogs from group 1 (n = 27) developed lingual necrosis. Lepidopterism coursed through a predictable clinical pattern. The evolution was mainly dependent on the time span between exposure to the caterpillar and medical intervention, which should take place earlier than 2 h from exposure.     

Determining the edge effect of pine processionary moth (Thaumetopoea pityocampa) in its horizontal distribution in the stand

Pine processionary moth is one of the most important forest pests in the Mediterranean Basin. There is need to explore its distribution behaviour to undertake effective control and determine the edge effect of its horizontal distribution in the stand. Five trial sites damaged by the insect were selected and traps installed in all trees in the sites. The number of nests and larvae was counted and diameter increment cores were taken. The distance to the edge of the stand revealed that there was no statistical difference in the number of nests and larvae up to 25 m while there was a statistically significant difference(0.5%)at [25 m. There was a 2-fold difference in the density of nests between 0 and 25 m and [25 meters, and a 3.8-fold difference in the number of larvae. The effect of pine processionary moth on tree diameter was not significant between trees at the edge of the stand and those in the stand.     

Impact of defoliation by the pine processionary moth (<Emphasis Type="Italic">Thaumetopoea pityocampa</Emphasis>) on radial,height and volume growth of calabrian pine (<Emphasis Type="Italic">Pinus brutia</Emphasis>) trees in Turkey

An outbreak of the pine processionary moth (PPM),Thaumetopoea pityocampa Schiff. (Lepidoptera: Thaumetopoeidae), began in spring 1998 and lasted 5 years in aPinus brutia Ten. (Calabrian pine) stand. Tree volume and volume elements increments were examined throughout a PPM outbreak cycle from 1981 to 2003, for an even aged, pure, undisturbed, young Calabrian pine stand. Tree ring chronologies of ‘control’ Calabrian pine, which was not defoliated by PPM during the period of 1998–2003, were used to estimate potential growth characteristics in the ‘host’ Calabrian pine (moderate and high defoliation groups) for current and past outbreaks. Increment cores were collected from 70 host and 78 control dominant or co-dominant trees and annual radial growth indices from 1981–2003 were calculated for each defoliation group in a 41 point sampling. Growth functions were defined as the cumulative sum of radial, height, and volume increment, and graphically compared between host Calabrian pine (3 moderate and one high), four control Calabrian pine and one host Crimean pine (Pinus nigra Arnold) sample trees. At least three severe outbreak periods were identified (from 1981–86; 1992–97; and 1998–2003), much of the study area being severely affected by PPM. Tree ring evidence suggests that large scale (in 1981, 1992, 1998) and partial (in 1988) outbreaks occurred in the study area. Negative inflections of host radial growth curves relative to control height and volume indicated PPM activity. The periodic average diameter growth reductions (in %) in 1981, 1988, 1992 and 1998, respectively, were 0, 13, 5 and 0 for control, 12, 8, 7 and 2 for moderate, and 18, 5, 0 and 7 for high defoliation groups. Outbreaks appear to be associated with dry winter and spring weather prior to the autumn and winter in which feeding occurs. http://www.phytoparasitica.org posting Sept. 28, 2004.     

A comparative evaluation of Origanum onites essential oil and its four major components as larvicides against the pine processionary moth, Thaumetopoea wilkinsoni Tams

The pine processionary moth (PPM), Thaumetopoea wilkinsoni Tams. (Lepidoptera: Thaumatopoeidae), is an important forest pest in the Mediterranean area, and urticating hairs of the caterpillars of this species cause allergic reactions on skin of humans and animals. In the present study, the larvicidal activities of Turkish oregano (Origanum onites L.) essential oil and its four major components, carvacrol, gamma-terpinene, terpinen-4-ol and thymol, were evaluated against fourth/fifth-instar larvae of PPM under laboratory conditions. The essential oil was larvicidal to PPM with an LD(50) value of 3800 microL L(-1) when 0.1 mL was applied per larva. Carvacrol was the most toxic component found in the essential oil (LD(50) = 3100 microL L(-1)), followed by thymol (LD(50) = 5500 microL L(-1)). The other two components, gamma-terpinene and terpinen-4-ol, were less effective. The results showed that Turkish oregano essential oil and its two components, carvacrol and thymol, could be potential alternatives to synthetic insecticides for the control of PPM.     

Is the expansion of the pine processionary moth,due to global warming,impacting the endangered Spanish moon moth through an induced change in food quality?

Recent climate change is known to affect the distribution of a number of insect species, resulting in a modification of their range boundaries. In newly colonized areas, novel interactions become apparent between expanding and endemic species sharing the same host. The pine processionary moth is a highly damaging pine defoliator, extending its range northwards and upwards in response to winter warming. Its expansion in the Alps has resulted in an invasion into the range of the Spanish moon moth, a red listed species developing on Scots pine. Pine processionary moth larvae develop during winter, preceding those of the moon moth, which hatch in late spring. Using pine trees planted in a clonal design, we experimentally tested the effect of previous winter defoliation by pine processionary moth larvae upon the survival and development of moon moth larvae. Feeding on foliage of heavily defoliated trees (>50%) resulted in a significant increase in the development time of moon moth larvae and a decrease in relative growth rate compared to feeding on foliage of undefoliated trees. Dry weight of pupae also decreased when larvae were fed with foliage of defoliated trees, and might, therefore, affect imago performances. However, lower defoliation degrees did not result in significant differences in larval performances compared to the control. Because a high degree of defoliation by pine processionary moth is to be expected during the colonization phase, its arrival in subalpine pine stands might affect the populations of the endangered moon moth.