Search Results (21)

Entomopathogenic fungi (EPF) are one of the most environmentally friendly ways to control a plethora of chewing insects such as T. pityocampa, G. mellonella, and A. grisella. Bioassay of EPF on these highly damaging pests is considered important in the face of climate change in order to research alternative solutions that are capable of limiting chemical control, the overuse of which increases insects’ resistance to chemical compounds. In this study, the insecticidal virulence of Metarhizium robertsii isolates, retrieved from forest ecosystems, was tested on second-instar larvae of T. pityocampa, G. mellonella, and A. grisella. Bioassays were carried out in the laboratory, where experimental larvae were sprayed with 2 mL of a six-conidial suspension from each isolate. Mortality was recorded for 144 h after exposure. Mean mortality, lethal concentrations, sporulation percentage, and sporulation time were estimated for each isolate. Metarhizium isolates resulted in the highest mortality (89.2% for G. mellonella and 90.2% for A. grisella). Based on the LC₅₀ estimates determined by the concentration–mortality relationships for the tested fungal isolates, we demonstrated significant virulence on larvae of G. mellonella, A. grisella, and T. pityocampa. Our results indicate that entomopathogenic fungi have the potential to become a very useful tool in reducing chemical applications. Full article

The research on entomopathogenic viruses is of major significance as they could serve as alternatives to chemical pesticides. There are various types of entomopathogenic viruses; among them, Baculoviruses (BVs) are a potential option because they are eco-friendly and target specific. The experiment in question aimed to evaluate the effect of three insect-specific commercial viruses, Cydia pomonella Granulovirus (CpGV), Helicoverpa armigera Nucleopoyhedrovirus (HearNPV), and Phthorimaea operculella Granulovirus (PoG), on the third-instar larvae of Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) and Thaumetopoea pityocampa Schiff (Lepidoptera: Notodontidae). The viruses’ concentrations when tested were 500 ppm, 1000 ppm, 1500 ppm, 3000 ppm, and 6000 ppm, and were applied on the eating medium. Both mortality and larval weight were monitored for 6 days. All three viruses had significant mortality rates on both moths (23.3–83.3% in the highest dose) and larval weights had considerable decreases (70–80% in the highest dose). Generally, noteworthy insecticidal action was recorded after 4 days and in doses higher than 1500 ppm. These results highlight that entomopathogenic viruses may infect species other than their natural host and can be implemented in terms of Integrated Pest Management. Full article

As a social organism, living in a communal structure is one of the most important physical barriers against environmental elements and natural enemies. Thaumetopoea pityocampa (Notodontidae, Thaumetopoeinae) caterpillars are conifer pests that spend most of their larval stage in winter. Although T. pityocampa holds economic and medical significance, the tent construction and foraging behaviour are poorly understood. We observed the tent construction behaviour in autumn (October and November) when third- and fourth-instar T. pityocampa caterpillars build the ‘winter tent’ that can withstand winter conditions. Just before sunset, with no rain and temperatures over 12 °C, tent construction was undertaken by early active individuals, primarily larger male caterpillars. Early active caterpillars emerge from the tent first and spin silk on the tent for expansion and strength. Once temperatures dropped below 12 °C and twilight had passed, the early active caterpillars went out to forage and were later joined by the late active caterpillars, which were predominantly smaller females that had remained inside the tent. Foraging behaviour was continuously monitored for the first to fourth larval instars in the field. Foraging was more frequent in younger instars when environmental temperatures were warmer and became continuous and prolonged in later instar caterpillars as temperatures dropped. The final tent structure built by later instar caterpillars had the thickest layer of silk on the southern side of the tent compared to other orientations to receive maximum solar radiation during the winter. Our study provided additional insights into the collective nest building, foraging and social behaviours observed in Lepidoptera, as well as the roles of individuals within non-eusocial insect colonies. Full article

The larvae of the pine processionary moth are a threat to public health because they produce detachable setae that are about 200 µm long and 6 µm wide, reaching a total number of up to 1 million per mature individual. The setae are intended to be released to protect the larvae from predators but become a public health issue when in contact with humans and warm-blooded animals. Symptoms associated with the setae are typically urticaria and local swelling erythema, although edema of the skin, conjunctivitis or respiratory mucosa may occur. Occupational exposure concerns mainly forest workers but also farmers and gardeners. In the present study, we quantify the exposure to the setae of forest workers in a district of Northern Italy. The pine processionary moth represents a real case of occupational exposure as the urticating setae produced by the larvae caused symptoms in most forest workers directly in contact with the infested trees. In addition, the urticating setae were detected on the body of the chainsaw operators and in the surroundings of the felled trees during the operations. The non-exposed workers of the same agency did not report symptoms, with only one exception, likely linked to a non-occupational exposure. As the risk is not immediately perceived by the workers because direct contact with the larvae is unlikely, a campaign of information to workers and the general population living nearby infested forestry areas about the risk associated with airborne exposure is recommended. This becomes especially important in the areas of recent expansion of the insect, where people are inexperienced. Full article

Entomopathogenic fungi (EPF) consist of a wide range of fungi that can be used as pest control agents, endophytes, and plant growth promoters. In this study of EPF in suburban soils from Achaia, Greece, we used adult beetles as baits for trapping fungal isolates. According to the macroscopic and microscopic traits of the collected isolates, three species corresponded to Beauveria varroae Vuill. (Hypocreales: Cordycipitaceae); Purpureocillium lavendulum Perdomo, Gené, Cano & Guarro (Hypocreales: Ophiocordycipitaceae); and Cordyceps blackwelliae Mongkolsamrit, Noisripoom, Thanakitpipattana, Spatafora & Luangsaard (Hypocreales: Claviceptaceae). Their taxonomic identity was established by ITS-rDNA sequence amplification and sequencing, molecular database comparisons, and phylogenetic analysis. The application of these new EPF species clearly demonstrated remarkable insecticidal action on Thaumetopoea pityocampa (Lepidoptera, Notodontidae) larvae, which increased with the application dose. Our findings are important based on the enhancement of the application of new EPF species as biocontrol agents within the framework of eco-friendly pest management. Full article

Unraveling multiple layers of collective behavior outside the well-known isopteran and hymenopteran societies was a tall order for the scientific community, especially in the case of gregarious juveniles in the order Lepidoptera. Often protected with a solid silk shelter, devoid of reproductive division of labor or conventional forms of parental care, caterpillar aggregations have rarely been considered in terms of economic importance. Of over 60 European communal species, 24 can be associated with voracious feeding habits, and thus be irruptive or pestilential, depending on the extent and severity. This review retrieves 59 cases of biocontrol against Hyphantria cunea (Drury), Euproctis chrysorrhoea (L.), Malacosoma neustria (L.), Thaumetopoea pityocampa (Denis and Schiffermüller), T. processionea (L.) and Yponomeuta malinellus (Zeller) and classifies them in predefined research and application subcategories. The percentage-wise distribution of the utilized or explored biocontrol agents was projected at 35.59% in favor of parasitoids and predators. Falling between fundamental and applicative disciplines, biocontrol, especially in its early days, built a global reputation of being underreported. To provide guidance for future research regarding the group, the functional trait-based concept used in this study is complemented with preliminary outcome assessment. Full article

The pine processionary moth (PPM), Thaumetopoea pityocampa (Denis and Schiffermüller), is one of the most economically important forest defoliators in southern Europe. This pest is a univoltine oligophagous insect species, and the genus Pinus represents its main host. Investigations were carried out in the five-year period 2016–2020 in NW Italy. PPM males were monitored using commercial funnel traps baited with sex pheromone. The infestation index was recorded by counting the number of nests per tree. Temperature and rainfall were automatically recorded by 94 georeferenced meteorological stations. Adult presence was evaluated as the maximum number of captured individuals in a day, total captures during the season, the Julian day at max captures, or at first or last captures. Environmental variables (altitude, cumulative rain, and cumulative degree-days) and biological parameters were summarized using principal component analysis. Our study showed that the analyzed variables contribute to driving and affecting the PPM population dynamics, which also exhibited a year-to-year decrease. Due to the environmental and sanitary importance, all the data collected about the PPM will be useful to develop predictive risk models, as to deploy countermeasures in a timely and cost-effective manner. Full article

Observing phenological changes are important for evaluating the natural regeneration process of forests, especially in Mediterranean areas where the regeneration of coniferous forests depends on seeds and the changes in blossoming time are influenced by climate change. The high temporal resolution of Sentinel-1 data allows the time series analysis of synthetic aperture radar (SAR) data, but it is still unknown how these data could be utilised for better understanding forest phenology and climate-related alternations. This study investigates the phenological cycle of Paphos forest, Cyprus using SAR data from 1992 to 2021, acquired by ERS-1/2, Envisat and Sentinel-1. An average phenological diagram was created for each space mission and a more detailed analysis was performed from October 2014 to November 2021, using the higher temporal resolution of Sentinel-1 data. Meteorological data were used to better understand the drivers of blooming alternations. Using the interquartile range (IQR), outliers were detected and replaced using the Kalman filter imputation. Forecasting trend lines were used to estimate the amplitude of the summer peaks and the annual mean. The observation of the average phenology from each satellite mission showed that there were two main blooming peaks each year: the winter and the summer peak. We argue that the winter peak relates to increased foliage, water content and/or increased soil moisture. The winter peak was followed by a fall in February reaching the lower point around March, due to the act of pine processionary (Thaumetopoea pityocampa). The summer peak should relate to the annual regeneration of needles and the drop of the old ones. A delay in the summer peak—in August 2018—was associated with increased high temperatures in May 2018. Simultaneously, the appearance of one peak instead of two in the ${\sigma }_{VH}$ time series during the period November 2014–October 2015 may be linked to a reduced act of the pine processionary associated with low November temperatures. Furthermore, there was an outlier in February 2016 with very low backscattering coefficients and it was associated with a drought year. Finally, predicting the amplitude of July 2020 returned high relevant Root Mean Square Error (rRMSE). Seven years of time series data are limiting for predicting using trend lines and many parameters need to be taken into consideration, including the increased rainfall between November 2018 and March 2020. Full article

Intensive forest afforestation with native pine species was developed in the 1960s on degraded and deforested lands in the region of the Eastern Rhodopes (south-eastern Bulgaria). Severe damage by wet snow was registered in the coniferous forests of the Rhodopes in March 2015. In the following years, bark beetle attacks were registered on the broken and felled fresh wood. As a result, bark beetle infestation spots appeared in the pine plantations. In the period 2019–2021, damage caused by bark beetles was assessed in the region of State Forestry Kirkovo (the Eastern Rhodopes, south-eastern Bulgaria). An integrated approach using the data of the information system of the Executive Forest Agency (ISEFA), remote sensing data obtained by an “eBee SQ” unmanned aerial vehicle (UAV) equipped with a “Parrot Sequoia” multispectral camera, and subsequent terrestrial observations, was applied. ISEFA data showed that there was no serious damage caused by abiotic and biotic factors in the pine forests of SF Kirkovo until 2014. Snow damage in 2015 affected 513 ha of pine plantations, and bark beetle infestations reached up to 1316 ha in 2016. In 2019, a total of 226.87 ha of pine plantations were captured in three localities—Fotinovo, Kirkovo, and Kremen. The relative share of damage caused by bark beetles was greater in P. sylvestris plantations (15.3–23.0%), compared to damage in P. nigra (2.3%). Four different categories of normalised difference vegetation index (NDVI) were separated in bark beetle infestation spots—living trees, dead trees, grass and shrub vegetation, stones and rocks. The NDVI values in locations with living trees varied between 0.500 (spaces between tree crowns) and 0.700 (central part of the crown projection) (an average of 0.617). In the locations with dead trees, the average values of NDVI of lying trees was 0.273, and in standing trees, NDVI varied between 0.275 (central part of crown projections) and 0.424 (spaces between tree crowns). In the locations with grass and shrub vegetation, stones and rocks, the average NDVI was 0.436 and 0.329, respectively. In the field study, average defoliation of 31.2–32.3% was registered in P. sylvestris plantations, and 47.4% in P. nigra plantations. Defoliations mainly were caused by pine processionary moth (Thaumetopoea pityocampa) and fungal pathogens (Dothistroma septosporum and Lecanosticta acicola). The damage was caused by Ips acuminatus (in P. sylvestris only), and I. sexdentatus, Tomicus piniperda and T. minor (in P. sylvestris and P. nigra). Infestations by other xylophages, such as Phaenops cyanea, Rhagium inquisitor, and Pissodes spp., were also found on pine stems. Full article

The sustainable protection of cedar stands in Chréa National Park can only be accomplished through the stability of the ecosystem. Outbreaks of Thaumetopoea pityocampa are a major threat and are largely attributed to the high population fecundity, changes in the diversity of natural enemies and global interactions within the ecosystem. Egg parasitoids (Hymenoptera) are essential in the biological control of T. pityocampa. To assess the impact of the parasitoids on the populations of the pine processionary moth, egg masses from cedar plantations were collected, reared in a laboratory and checked regularly for the emergence of the egg parasitoids: Trichogramma embryophagum, Baryscapus servadeii and Ooencyrtus pityocampa. Observations showed an inter-annual variation in the abundance of the three parasitoids as a result of the variation in the population density of the processionary moth, and on the underlying effect of temperature. Parasitoids had variable parasitism rates, with yearly averages ranging from 3.86% to 51.14%, dependent on the spatiotemporal distribution of the host populations. The aggregate effect of multiple parasitoid species could optimize control of T. pityocampa in cedar stands. Full article

The pine processionary moth (PPM), namely Thaumetopoea pityocampa or T. wilkinsoni, feeds on pine needles, causing defoliation and promoting tree decline. The production and emission of volatile organic compounds is one of the most effective plant defense mechanisms against herbivory. The present work reviewed available reports on the influence of plant volatiles on PPM behavior. Eighteen volatiles were reported to be detected by the PPM, to inhibit feeding and oviposition, or to reduce attraction to pheromones. High biological activities were reported for limonene or β-pinene enantiomers. Infested pines showed an increased production of bornyl acetate, β-pinene and caryophyllene oxide. Uncovering the volatile cues that influence parasitic PPM behavior provides an important contribution to the establishment of safer pest-management practices to control this pine pest. Full article

The pine processionary moth (PPM) is a dangerous parasitic insect pest of several pine species in the Mediterranean basin, causing defoliation and promoting tree decline. Larvae release urticating hairs that cause strong allergic reactions in humans and animals. Pest management practices implemented by national health authorities include the eradication of nests and application of chemical insecticides. However, commercial pesticides can induce PPM resistance and be harmful to the environment and human health. Essential oils (EOs) are environmentally friendlier alternatives to commercial insecticides. The present review analyses the existing body of work on the biological activity against the PPM and highlights the most successful EOs. A total of nine publications were identified, reporting on the biological activity of 38 EOs extracted from 31 plant species against the PPM. The EOs extracted from Achillea arabica, Citrus aurantium, Lavandula angustifolia, Origanum onites and Thymus vulgaris showed the lowest half maximal lethal concentrations (LC₅₀). O. onites EO components with the highest activities were the monoterpenoid isomers carvacrol and thymol. The use of EOs is a potential ecofriendly alternative for successful PPM pest management, however more extensive studies must be performed to pinpoint highly active and easily accessible EOs and respective volatiles. Full article

The pine processionary moth (PPM), Thaumetopoea pityocampa (Denis and Schiffermüller, 1775) (Lepidoptera, Notodontidae), is considered one of the main insect defoliators of conifers in Southern Europe and North Africa. The species is oligophagous on pines and cedars in Mediterranean countries. This 6-year investigation (2014–2019), carried out in Aosta Valley (NW Italy), on Pinus sylvestris L. aimed to: (i) Monitor the PPM population with pheromone-baited funnel traps; (ii) assess the infestation index (0–5 classes) according to the degree of defoliation; and (iii) apply control strategies, namely Bacillus thuringiensis var. kurstaki (Btk) and mating disruption (MD). In total, 9618 ha were visually monitored and assigned an infestation index. The percentage of woodland stands that were strongly defoliated by PPM (infestation index ≥ 3) increased progressively between 2015 and 2016, affecting from 8% to 19% of the total area monitored; this area decreased to 16% and 13% in 2017 and 2018, respectively, followed by an abrupt decline to 4% in 2019. Both Btk applications and mating disruption significantly reduced the infestation. Where Btk was applied, the rate of larval mortality ranged from 79.47% to 98.43%; conversely, in the control plots, the larval mortality was, on average, 1.56%. The mean number of PPM males captured in traps was significantly lower in the plots where MD was performed, ranging from 8.36 ± 2.37 to 13.47 ± 4.68. The mean number of males captured in the control plots was, on average, 119.16 ± 12.68. The total number of nests recorded per tree was significantly lower in MD plots, ranging from 0.41 ± 0.05 to 0.94 ± 0.14. In the control plots, there were, on average, 4.37 ± 0.76 nests per tree. As already documented for several defoliating forestry insect pests, both Btk and mating disruption proved effective in controlling PPM infestations, and thus, microbial insecticides should be strongly encouraged and adopted by forest managers. Full article

Terpenoids make up the biggest and most diversified class of chemical substances discovered in plants, encompassing over 40,000 individual compounds. In conifers, the production of terpenoids, either as oleoresin or emitted as volatile compounds, play an important role in the physical and chemical defence responses against pathogens and herbivores. In the present work, we examined, for the first time to the best of our knowledge, the terpenic defensive relations of Calabrian pine (Pinus nigra subsp. laricio (Poiret) Maire), facing the attack of the pine processionary moth (Thaumetopoea pityocampa (Denis and Schiffermüller, 1775)), brought about in the open on adult plant individuals growing at two distinct forest sites. Among the volatile terpenoids emitted from pine needles, bornyl acetate [(4,7,7-trimethyl-3-bicyclo[2.2.1]heptanyl) acetate] was the most frequently and selectively associated with the infestation, increasing during the period of most intense trophic activity of the caterpillars (defoliation), and decreasing thereafter. Although further work is needed to clarify whether the observed response reflects defence reactions and/or they are involved in communication among the infested plants and their biotic environment, the present results boost the currently growing interest in the isolation and characterization of plant secondary metabolites that can be used to control pests, pathogens, and weeds. Full article

Global climate change is resulting in a wide range of biotic responses, including changes in diel activity and seasonal phenology patterns, range shifts polewards in each hemisphere and/or to higher elevations, and altered intensity and frequency of interactions between species in ecosystems. Oak (Thaumetopoea processionea) and pine (T. pityocampa) processionary moths (hereafter OPM and PPM, respectively) are thermophilic species that are native to central and southern Europe. The larvae of both species are gregarious and produce large silken ‘nests’ that they use to congregate when not feeding. During outbreaks, processionary caterpillars are capable of stripping foliage from their food plants (oak and pine trees), generating considerable economic damage. Moreover, the third to last instar caterpillars of both species produce copious hairs as a means of defence against natural enemies, including both vertebrate and invertebrate predators, and parasitoids. These hairs contain the toxin thaumetopoein that causes strong allergic reactions when it comes into contact with human skin or other membranes. In response to a warming climate, PPM is expanding its range northwards, while OPM outbreaks are increasing in frequency and intensity, particularly in northern Germany, the Netherlands, and southern U.K., where it was either absent or rare previously. Here, we discuss how warming and escape from co-evolved natural enemies has benefitted both species, and suggest possible strategies for biological control. Full article