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The rice root-knot nematode (RRKN), Meloidogyne graminicola Golden and Birchfield 1965, is a dangerous crop pest that affects rice production on a global scale. The largest rice-producing countries struggle with the impacts of RRKN infestation, namely, underdeveloped plants and a reduction in rice grain that can reach up to 70% of crop yield. In addition, the shift to strategies of sustainable pest management is leading to a withdrawal of some of the most effective pesticides, given the dangers they pose to the environment and human health. Volatile metabolites produced by plants can offer safer alternatives. The present study characterized the nematicidal activity of volatile phytochemicals against the RRKN and compared the most active with commercial nematicides concerning their safety to the environment and human health. Rice plants were used to grow large numbers of RRKNs for direct-contact bioassays. Mortality induced by the volatiles was followed for four days on RRKN second-stage juveniles. Of the 18 volatiles tested, carvacrol, eugenol, geraniol, and methyl salicylate showed the highest mortalities (100%) and were compared to traditional nematicides using (eco)toxicological parameters reported on freely available databases. While methyl salicylate had a faster activity, carvacrol had more lasting effects. When compared to synthetic nematicides, these volatile phytochemicals were reported to have higher thresholds of toxicity and beneficial ecotoxicological parameters. Ultimately, finding safer alternatives to traditional pesticides can lower the use of damaging chemicals in farming and leverage the transition to agricultural practices with a lower impact on biodiversity. [ABSTRACT FROM AUTHOR]

Pines are the most economically important trees in the world and, together with eucalyptus, they dominate commercial forests. But the success of a relatively small number of widely planted species, such as Pinus pinaster, the maritime pine, comes at a price. Pines are attractive to damaging pathogens and insect pests, including the pinewood nematode (PWN), Bursaphelenchus xylophilus, the causal agent of pine wilt disease (PWD). Originally described in Japan, PWD has caused widespread destruction to forests in countries such as China, Taiwan, Portugal, Spain and the United States. PWN causes irreparable damage to the vascular system of its pine hosts, leading to mortality within 3 months. Pine sawyer beetles (Monochamus spp.) are key vectors of PWD, introducing the PWN to healthy trees during feeding. Other organisms contribute to PWD spread and development, including bacteria, fungi and bark beetles. Control measures include tree felling to prevent vector transmission of PWN, insecticide treatments, trapping of Monochamus spp. and tree breeding for plant resistance. The PWN is a quarantine pathogen and subject to regular legislation and phytosanitary measures aimed at restricting movement and preventing introduction to new areas. Current research is investigating the use of biopesticides against PWN and Monochamus spp. This review examines the biology, epidemiology, impact and management of PWD through published research, grey literature and interviews with people directly involved in the management of the disease in Portugal. [ABSTRACT FROM AUTHOR]

Numerous plastic products are used in agriculture, including containers, packaging, tunnels, drip irrigation tubing, and mulches. Large amounts of plastics are used as mulches on the soil surface for vegetable and fruit production (tomato, cucumber, watermelon, strawberry, and vine) to reduce weed competition, increase water and fertilizer use efficiency, and enhance crop yield. Portugal uses around 4500 t/year of polyethylene to cover approximately 23,000 ha of agricultural land, and only a small amount is recovered for recycling or secondary uses because of issues of contamination with the soil, vegetation, pesticides, and fertilizers. Cleaning and decontaminating polyethylene mulch are costly, and commercial technology is often not accessible or economical. Most plastic mulch is composed of polyethylene that degrades slowly and produces a large quantity of residues in the soil, with a negative impact on the environment. In the present study, the effects of long-term cultivation of blueberry using green 100% high-density polyethylene mulch in the south Portugal were evaluated for soil chemical and biological changes. High-density green plastic mulch did not contaminate the topsoil with di(2-ethylhexyl) phthalate, and heavy metals, buttotal nitrogen, organic carbon concentrations, electric conductivity, and microbial activity were significantly reduced in the planting row compared with the bare soil without mulching. Furthermore, the presence of plastic mulch did not negatively affect the presence of nematodes, and the number of Rhabditida (bacterial feeders) increased in the planting and covered row. [ABSTRACT FROM AUTHOR]

Climate change is prompting a shift of tropical pests to locations with a previously lower probability of invasion. This is the case for root-knot nematodes, Meloidogyne sp., particularly of the tropical group. Among them, M. ethiopica is now considered a threat to European food security. The development of novel sustainable nematicides can be based on in vitro bioassays of highly active phytochemicals, e.g., volatiles from essential oils. However, a steady supply of nematodes is often very difficult and dependent on environmental conditions. In the present study, an in vitro co-culture system of M. ethiopica parasitizing hairy roots of Solanum lycopersicum was established, for the first time, to easily obtain populations of second-stage juveniles (J2). These were then used to screen the nematicidal activity of 10 volatile compounds characteristic of essential oils. Finally, information on the most successful compounds was reviewed to predict their environmental dispersion and ecotoxicological hazards. The M. ethiopica population obtained from the co-culture was morphologically similar to reported populations in natural conditions and could be accurately used in direct-contact bioassays. The aldehydes citral and citronellal induced complete mortality of the tested J2, at 1 mg/mL, while compounds from other chemical groups were not as successful. In comparison to commonly used commercial nematicides, citral and citronellal were less likely to accumulate in the water environmental compartment and have lower reported toxicities compared to aquatic organisms and to mammals. Overall, in vitro co-cultures showed the potential to expedite the screening and discovery of bioactive compounds as a contribution to the development of sustainable biopesticides, as well as to lower the impacts of modern farming on agroecosystems. [ABSTRACT FROM AUTHOR]

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Esteya vermicola is a potential biological agent of the pinewood nematode (PWN), Bursaphelenchus xylophilus, due to its high infectivity. However, knowledge of E. vermicola colonization in the host pine tree is less known. To reveal the distribution pattern of E. vermicola inside the pine tree and the interactions between fungus and PWN, biocontrol tests were conducted on 10 years old Pinus densiflora. A green fluorescence protein (GFP)‐tagged E. vermicola was used to observe the fungal hyphae. Real‐time TaqMan PCR quantification was applied to quantify the fungal hyphae in host tree. The results suggest that inoculation with the fungus significantly improved the survival rate of tested trees. Besides, the number of PWN extracted from fungal inoculated tested trees significantly decreased. Moreover, the fungal hyphae and lunate conidia grown in tested trees were observed with the GFP‐tagged E. vermicola. The real‐time quantification of E. vermicola illustrated the differential distribution of E. vermicola in wilted, wilting and healthy pine trees. Additionally, the promotion of fungal hyphal dispersion by B. xylophilus was found in the pine trees artificially infected with PWN. This study reveals the distribution of E. vermicola and PWN during biocontrol of pine wilt disease and provides direct evidence of the effectiveness of this fungus to control PWN. The migration of PWN infected by E. vermicola was supposed to improve the fungal extension in host pine tree. [ABSTRACT FROM AUTHOR]

Background The pinewood nematode ( PWN) Bursaphelenchus xylophilus is an important conifer disease worldwide. It is the direct cause of the death of millions of pines in south-east Asia (mainly Japan, China and Korea) and has been established in Portugal since 1999. The phasing out of methyl bromide has created an urgent need for alternative treatment of wood packaging materials. The effect of sulfuryl fluoride ( SF), a broad-spectrum fumigant used to control insects, was tested in Pinus pinaster boards naturally infested by PWN. Results Boards were fumigated for 24 h at three different temperatures (15, 20 and 30 °C) with dosage ranges of 3169-4407, 1901-4051 and 1385-2141 gh m−3 respectively. Treated wood was sampled for nematode identification and counting, before treatment and after 24 h, 72 h and 21 days. No survival was found in the 15 °C and 30 °C treatments, while at 20 °C the mortality ranged from 94.06 to 100%. Some reasons for the survival at 20 °C are presented. Conclusion Results confirm SF to be an effective quarantine treatment for PWN at 15 and 30 °C. Further studies are needed to obtain the most effective dosage at 20 °C, and to determine the toxicity of SF fumigation on B. xylophilus at other temperatures, especially at 25 °C. © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Ambrosia beetles, including Platypus cylindrus, commonly act as vectors of Ophiostomatales. In an investigation of fungi associated with P. cylindrus, several species of Ophiostomatales were identified, including two species of Ophiostoma s. str. These two species were characterized based on comparisons of DNA sequences of the internal transcribed spacer regions including the 5.8S gene of rDNA and β‐tubulin gene. Two distinct clades were discernable in the phylogenetic trees, supported by high bootstrap values. One clade included the species Ophiostoma tsotsi, reported herein for the first time in Tunisia, and the species Ophiostoma quercus. [ABSTRACT FROM AUTHOR]