Monitoring and Management of the Pine Processionary Moth in the North-Western Italian Alps

Abstract

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.

Latest Developments in Insect Sex Pheromone Research and Its Application in Agricultural Pest Management

“…However, the timing of application is always critical. In MD trials conducted in Aosta Valley (NW Italy) in 2016–2017, the number of males collected was significantly lower in the plots where MD was performed in comparison to control plots [ 199 ]. In addition, the total number of nests recorded per tree was significantly lower in MD plots.…”

“…In addition, the total number of nests recorded per tree was significantly lower in MD plots. The technique appears to be the most appropriate control strategy for the processionary moth, and address that repeated annual applications of MD could dramatically reduce population densities below the economic injury level [ 199 ].…”

Morphometric characterization of the pine processionary, Thaumetopoea pityocampa in the Tlemcen area, Algeria

“…The value of this ratio is 1.96 in the Sebdou station is in favor of the males. When the sex ratio is in favor of males, the potential of the Thaumetopoea pityocampa population is low (Ferracini et al, 2020;Questienne and Miermont, 1978). These results can be explained by the primordial action of climatic factors on the biology of the pine processionary, in particular that of the minimum temperatures in January and the annual sunstroke.…”

“…These results can be explained by the primordial action of climatic factors on the biology of the pine processionary, in particular that of the minimum temperatures in January and the annual sunstroke. Ferracini et al (2020) has suggested over the years that the gradations of this pest were primarily linked to climatic factors. The aforementioned author notes that high or low temperatures can cause significant physiological disturbances, which can go as far as stopping feeding.…”

Recent Advances in the Monitoring, Assessment and Management of Forest Pathogens and Pests

“…Bacillus thuringiensis var. kurstaki (Btk), combined with mating disruption, are reported to be effective in controlling Thaumetopoea pityocampa Denis et Schiffermüller [27], a harmful insect for forest, urban and peri-urban pines, that needs to be kept under control because its larvae also cause public health problems for humans and pets. Finally, the use of Btk can also be integrated with other biological products, as proposed by Ruiu et al [28].…”