Management of Popillia japonica in container-grown nursery stock in Italy

The Japanese beetle Popillia japonica is an invasive alien species recently introduced and established in Northern Italy. Adult beetles are very polyphagous and feed on vines, fruit trees, forest trees, crops, vegetables, ornamental and wild plant species. Eggs are usually laid by females in moist grassland in the summer, singly or in small clusters. Larvae feed on roots and may be transported in soil of plants for planting grown in containers. Restrictions on movement of plants grown in containers from infested to non-infested areas imposed by phytosanitary regulations have a significant economic impact on the nursery industry. An innovative approach was used to exclude beetle oviposition by weed mulching available for container-grown nursery stocks, and by testing larval survival to the application of chemical (cypermethrin) and organic (Heterorhabditis bacteriophora and Metarhizium brunneum) commercial pesticides registered for European nurseries. The high effectiveness of the method makes it a suitable component of a systems approach strategy for pest risk management, in order to achieve a safe production and trade of nursery plant material in areas infested by the Japanese beetle.

An accreditation program to produce native plant nursery stock free of Phytophthora for use in habitat restoration

Widespread Phytophthora infections have been discovered in nursery stock used in California restoration plantings. In response, nursery Phytophthora best management practices (NPBMPs) designed to exclude Phytophthora from nursery plants were developed to address the need for clean planting stock in restoration projects. A pilot program to implement the systematic use of the NPBMPs, Accreditation to Improve Restoration (AIR), was developed and started in 2018. As of 2020, 13 northern California restoration nurseries have been evaluated and five have met all the program requirements. In 564 tests conducted over four years with a sensitive leachate baiting protocol, no Phytophthora was detected from over 20,000 nursery plants produced in compliance with the NPBMPs. In comparison, Phytophthora was detected in 25% of tests conducted on partially-compliant stock, and in 71% of tests from nurseries following few or no NPBMPs. The AIR pilot program has demonstrated that container stock free of detectable Phytophthora can be reliably produced by adhering to an integrated program of clean nursery production practices. To obtain Phytophthora-free plants for habitat restoration, informed clients were willing to pay increased costs required to produce NPBMP-compliant nursery stock.

Detection and Modeling of Unstructured Roads in Forest Areas Based on Visual-2D Lidar Data Fusion

The detection and recognition of unstructured roads in forest environments are critical for smart forestry technology. Forest roads lack effective reference objects and manual signs and have high degrees of nonlinearity and uncertainty, which pose severe challenges to forest engineering vehicles. This research aims to improve the automation and intelligence of forestry engineering and proposes an unstructured road detection and recognition method based on a combination of image processing and 2D lidar detection. This method uses the “improved SEEDS + Support Vector Machine (SVM)” strategy to quickly classify and recognize the road area in the image. Combined with the remapping of 2D lidar point cloud data on the image, the actual navigation requirements of forest unmanned navigation vehicles were fully considered, and road model construction based on the vehicle coordinate system was achieved. The algorithm was transplanted to a self-built intelligent navigation platform to verify its feasibility and effectiveness. The experimental results show that under low-speed conditions, the system can meet the real-time requirements of processing data at an average of 10 frames/s. For the centerline of the road model, the matching error between the image and lidar is no more than 0.119 m. The algorithm can provide effective support for the identification of unstructured roads in forest areas. This technology has important application value for forestry engineering vehicles in autonomous inspection and spraying, nursery stock harvesting, skidding, and transportation.

Mycosphaerella gibsonii (needle blight of pine).

Mycosphaerella gibsonii is a fungal pathogen causing needle blight, primarily in Pinus species. It causes lesions on needles, first affecting lower needles and then spreading to the upper crown. The disease eventually causes needle necrosis and needle cast, leading to defoliation, stunted growth and host plant death; it is a major obstacle to the production of pine seedlings. M. gibsonii occurs in the tropics and subtropics of South and Central America, the Caribbean, sub-saharan Africa, India, South East Asia and East Asia; the native range is uncertain. Although natural dispersal by wind and water occur locally, international spread is largely due to movement of infected nursery stock. Phytosanitary control measures such as avoiding the planting of infected plants, removal and destruction of all infected pines in nurseries and cleaning between annual production cycles in nurseries can help to reduce the spread of the pathogen. It is listed as an A1 quarantine pest in the EPPO region, and is considered of quarantine significance in South America.

Popillia japonica (Japanese beetle).

The Japanese beetle was first discovered in New Jersey, USA in 1916. It probably entered the USA as grubs with iris bulbs before 1912 when plant materials were first examined. Although not a pest in Japan, extensive, well-watered, turf, and a lack of parasites, allowed populations to rapidly build up and spread steadily west to the Mississippi River. The loss of the chlorinated hydrocarbon insecticides, and the end of the Federal quarantine on nursery stock, has allowed beetles to move into western states at a rapid rate. Beetles are pests of quarantine concern in the western USA and Europe. P. japonica was found on Terceira Island, Azores, Portugal in the 1980s. Again, extensive turf allowed establishment of beetles, population explosions, the infestation of that island, and subsequently of three more of the Azorean Islands. Beetles have moved considerably outside of the climatic conditions in their native Japan.

Mycosphaerella gibsonii (needle blight of pine).

Mycosphaerella gibsonii is a fungal pathogen causing needle blight, primarily in Pinus species. It causes lesions on needles, first affecting lower needles and then spreading to the upper crown. The disease eventually causes needle necrosis and needle cast, leading to defoliation, stunted growth and host plant death; it is a major obstacle to the production of pine seedlings. M. gibsonii occurs in the tropics and subtropics of South and Central America, the Caribbean, sub-saharan Africa, India, South East Asia and East Asia; the native range is uncertain. Although natural dispersal by wind and water occur locally, international spread is largely due to movement of infected nursery stock. Phytosanitary control measures such as avoiding the planting of infected plants, removal and destruction of all infected pines in nurseries and cleaning between annual production cycles in nurseries can help to reduce the spread of the pathogen. It is listed as an A1 quarantine pest in the EPPO region, and is considered of quarantine significance in South America.

Phytophthora alni species complex (alder Phytophthora).

The alder Phytophthora species complex of oomycetes encompasses the hybrid P. ×alni and its two parental species, P. uniformis and P. × multiformis (Brasier et al., 1999; Husson et al., 2015). It emerged in the early 1990s and is associated with severe decline of alder trees on river banks of Europe. The main pathogen involved, P. ×alni, was previously unreported. Its pattern of occurrence suggests an invasive species, but one that arose from several hybridization events in different places rather than spreading from a central origin. The population structure of P. uniformis, one of the parental species, suggests that it is introduced in Europe and native in North America (Aguayo et al., 2013); the origin of the second parent, P. × multiformis, remains unknown. Long-range spread is mainly through planting of infected nursery stock, followed by downstream spread in river water by motile zoospores. The pathogen was on the EPPO alert list from 1996 to 2001.

Phytophthora alni species complex (alder phytophthora).

The alder Phytophthora species complex of oomycetes encompasses the hybrid P. ×alni and its two parental species, P. uniformis and P. ×multiformis (Brasier et al., 1999; Husson et al., 2015). It emerged in the early 1990s and is associated with severe decline of alder trees on river banks of Europe. The main pathogen involved, P. ×alni, was previously unreported. Its pattern of occurrence suggests an invasive species, but one that arose from several hybridization events in different places rather than spreading from a central origin. The population structure of P. uniformis, one of the parental species, suggests that it is introduced in Europe and native in North America (Aguayo et al., 2013); the origin of the second parent, P. ×multiformis, remains unknown. Long-range spread is mainly through planting of infected nursery stock, followed by downstream spread in river water by motile zoospores. The pathogen was on the EPPO alert list from 1996 to 2001.

Dreyfusia nordmannianae (silver fir adelges).

Several conifer aphids of the family Adelgidae were probably introduced on nursery stock from Asia to Europe in the nineteenth century on imported fir (Abies spp.) and most of them were unknown before reaching Europe (Kenis et al., 2007). D. nordmannianae was introduced in Europe in the 1840s on imported Nordmann fir (Abies nordmanniana) and moved onto a new host, the European silver fir, Abies alba, where it has since caused important damage on young silver fir trees and Nordmann fir plantations (Bejer, 1981; Nierhaus-Wunderwald and Forster, 1999; Kenis et al., 2007).

Plum pox virus (Sharka).

Plum pox virus disease (Sharka) is one of the most destructive diseases of stone fruits. The causal agent, Plum pox virus (PPV) is easily transmitted by many aphid species in a non-persistent manner, by manmade grafting (nursery trade), and has a very wide host range among Prunus species. Infected plants may not show symptoms for several months and symptoms are often transient in appearance. The disease symptoms are often mistaken for other maladies and the virus can become established before the first recognition of the disease. Although spread is difficult to control within a local area because of aphid vectors, the long distance spread can be controlled by strict quarantine regulations and use of virus-free certified nursery stock.