Crop Protection最新文献

Parthenocissus semicordata is an excellent vine plant for vertical greening of walls or buildings. A leaf spot disease has been investigated on P. semicordata in the Matoushan National Nature Reserve in Fuzhou city, Jiangxi province, China, since August 2021. The disease incidence was approximately 60–65%, which led to affecting its growth and ornamental value. The pathogen was identified as Colletotrichum siamense based on morphological characteristics and phylogenetic analysis. Pathogenicity tests were conducted by inoculating healthy leaves with spore suspension of C. siamense, and Koch's postulates were confirmed by re-isolation and identification of the pathogen from infected leaves. This is the first known occurrence of C. siamense causing leaf spot on P. semicordata in China. These findings play a crucial role in increasing the knowledge of P. semicordata diseases in China and provide pivotal information for epidemiological studies and control strategies.

Traditional plant protection machinery cannot apply pesticides according to the actual growth demand of crops, which causes a lot of pesticide waste and serious environmental pollution. Based on this, an intelligent variable-rate application system based on 3D LiDAR (light detection and ranging) scanning and PWM (pulse-width modulation) control for maize canopy was developed in this paper. After completing the performance testing, the system was mounted on a lightweight high-clearance self-propelled sprayer by remote controlling with an operating width of 6.0 m, and a ground gap of 2.0 m. And the actual operational performance of the sprayer showed that the prediction error of LiDAR for plant height was within 10%, which illustrated the accuracy of the detection system and the reliability of the variable application based on the plant height change. And the variable-rate system could adjust the spray volume in real-time according to the plant height change. The penetration rate of the upper, middle, and bottom layers maintained a relatively stable state (upper > middle > bottom) at variable-rate application and could reach the normal application level. This study can provide new ideas for efficient pests and diseases control of high stalk crops, especially suitable for small fields, and gives a reference for the structural design of new precise variable-rate application machinery and performance optimization of efficient application technology.

Hirschmanniella mucronata and Meloidogyne graminicola are the main plant-parasitic nematodes found in paddy fields in Thailand causing significant rice production yield losses. Although these nematodes are found widely in fields, an effective management method has not been documented. Here, we examined the nematicidal effects of different cavalcade leaf ages (1-, 2- and 3-month-old), used as aqueous extracts and soil amendments, on H. mucronata and M. graminicola. In vitro tests evidenced maximum mortality of H. mucronata (55.6–60.0%) in 50 mg ml⁻¹ extract from all leaf ages, while mortality (65.9%) and hatchability (67.0%) of M. graminicola second-stage juveniles were observed in 50 mg ml⁻¹ extract from 1-month-old leaves only. Moreover, aqueous extracts of cavalcade showed a repellent effect on both nematodes. Similarly, greenhouse experiments showed a significant reduction of H. mucronata population densities and reproduction of M. graminicola in soil amended with 0.5 and 1.0% (w/w) from each leaf age. LC-QTOF-MS analysis determined that three bioactive compounds, including quercetin, rutin, and kaempferol, are associated with the nematicidal activity of cavalcade against H. mucronata and M. graminicola. The information derived from this study indicates that the leaves of cavalcade are a source of promising phytonematicidals. This is the first study to assess and document its potential for nematicidal activity against H. mucronata and M. graminicola in Thailand. However, further research is needed to evaluate their efficacy under paddy field conditions.

Thymus vulgaris L. is found all over the world and is cultivated in several countries. It is considered an important medicinal plant with anti-inflammatory and aromatic properties. Its cultivation can suffer from infestation by numerous pathogens, which contributes to lower production. Thus, in 2020, a nematological survey in a vegetable growing area in Jaboticabal, São Paulo, Brazil, detected the presence of galls on the root, indicating that it was Meloidogyne spp. To identify the species, a sample with soil and roots was sent to the laboratory. After the analyzes performed, the species was identified as Meloidogyne javanica. This result was based on the morphological characteristics of the adults and the genetic identification. In the morphological part, the following characteristics were found: Perineal region of females low trapezoidal dorsal arch with two lines in laterals, while males have broader basal nodules with a non-raised labial disk, with the head region not separated from the body. Molecular confirmation was performed by genetic sequencing and sequence characterized amplified regions technique (SCAR). This is the first report of T. vulgaris as a host for M. javanica confirmed by Koch's postulate and several lines of evidence. Based on this report, farmers wishing to grow this vegetable should be aware of plants that are also hosts for this species.

The Florida citrus industry has been devastated by huanglongbing (HLB), a fatal citrus disease associated with a bacterium transmitted by the Asian citrus psyllid (ACP). Current management relies primarily on insecticides to reduce vector populations. Growers are interested in options for protecting new plantings including individual protective covers (IPCs), reflective mulch ground cover, and red-dyed kaolin particle films. We tested the efficacy of these tools in reducing ACP densities on young citrus trees against a grower standard control. We also quantified the effects of these treatments on other citrus pests, including citrus leafminer, spider mites, and citrus rust mites, as well as on the incidence and severity of plant pathogens, including huanglongbing and its associated pathogen (Candidatus Liberibacter asiaticus), citrus canker, greasy spot, sooty mold, and melanose. Among these treatments, the IPCs successfully excluded ACP, with no covered trees infected with HLB after two years. Trees in this treatment also showed the lowest densities of citrus leafminer infestation and citrus canker incidence. However, trees under IPCs were susceptible to other issues including sooty mold and spider mites, suggesting that there are trade-offs with using this tool. Trees in the reflective mulch and kaolin treatments did not have reduced infestation of key citrus pests and pathogens compared to the grower standard for key citrus pests and pathogens. Although IPCs cannot solve all citrus ailments, we show that they are a promising tool for protecting young citrus trees from ACP and HLB.

Drosophila suzukii, a significant sweet cherry pest, has traditionally been controlled using broad-spectrum insecticides. Various yeasts are known to attract and stimulate flies to feed on yeast-covered surfaces. We investigated an attract-and-kill formulation based on the yeast Hanseniaspora uvarum and the insecticide spinosad, applied to an 80–100 cm wide canopy strip at 1-m height in six field trials across Italy and Germany to manage D. suzukii infestation in cherry. The attract-and-kill formulation, applied at a dose ranging from 21.6 to 34.9 g per hectare of spinosad, according to the training system, decreased the percentage of D. suzukii infested cherries by 41.74–84.26% and the average number of deposited eggs by 79.51–95.56%. The efficacy was comparable to the conventional application of spinosad alone, which was applied at a dose ranging from 84 to 216 g per hectare. The conventional application decreased the percentage of infested cherries by 53.00–92.00% and reduced the number of deposited eggs by 77.10–92.96%. The attract-and-kill technique led to a reduction of up to 90% of insecticide use by targeting the application on limited section of the cherry tree. The targeted approach not only minimized insecticide quantities per hectare, but also resulted in lower residue levels on treated fruits.

The indiscriminate use of insecticides has directly contributed to the development of resistance in stored product insect pests, raising grave concerns about food contamination from toxic residues. This alarming situation has necessitated the exigency of exploring alternative, eco-friendly pest management strategies. Consequently, this study aimed to exploit paddy husk, an abundant agricultural waste product, for synthesizing silica powders and subsequently to evaluate their insecticidal potential as a seed protectant against the notorious pulse beetle, Callosobruchus chinensis (L.) (Coleoptera: Bruchidae), in chickpea. Amorphous silica gel, Amorphous silica precipitate and diatomaceous earth were individually applied at two different concentrations to chickpea seeds. Mortality assessments of C. chinensis adults were conducted at regular intervals after exposure to treated seeds, immediately and up to six months after storage (MAS). Data on adult emergence of C. chinensis, its damage and weight loss of chickpea seeds were recorded bi-monthly for a storage period of six months. The results revealed that seeds treated with 500 ppm of amorphous silica gel resulted in 100% mortality of C. chinensis adults by fifth day after exposure, even after extended storage periods of four months and six months. Remarkably, no adult emergence, seed damage, weight loss, lowest beetle perforation index and inhibition rate of 100 % pertaining to adult emergence was observed in treated seeds for six months storage period under ambient conditions. The paddy husk silica powders and diatomaceous earth effectively protected the seeds. The findings demonstrated the promising insecticidal potential of amorphous silica gel at 500 ppm against C. chinensis, presenting a viable alternative to conventional synthetic insecticides for controlling stored product insect pests.

Laboratory bioassays were conducted to evaluate the efficacy of thiamethoxam as a grain protectant against Sitophilus oryzae, Tribolium confusum and Rhyzopertha dominica adults. Five concentrations (0.1, 0.5, 1, 2, and 4 ppm) and four commodities (wheat, maize, rice, and barley) were evaluated. Mortality rates were recorded after 7, 14, and 21 d and progeny production was assessed 65 d after exposure. Thiamethoxam was more effective at higher concentrations and S. oryzae was the most susceptible species. Surprisingly, the highest progeny production was recorded for S. oryzae with 154.3 adults/vial, while no progeny production was observed for T. confusum at 2 and 4 ppm in most of the commodities tested. To conclude, thiamethoxam can provide an adequate level of control against major stored-product insect species in wheat, maize, rice and barley.

The use of endophytic entomopathogenic fungi (EEF) represents a promising strategy to boost plant resistance in crops against both biotic and environmental stresses. However, the mechanisms by which this inoculation influences constitutive and herbivore-induced defenses to protect plants against pest insects remain unclear. To address this gap, we investigated whether the inoculation of the EEF Metarhizium robertsii can modulate sugarcane plant defenses and their resistance against the sugarcane borer Diatraea saccharalis. Specifically, we examined the endogenous levels of jasmonic acid (JA) and salicylic acid (SA), as well as the volatile emissions in sugarcane, in the absence and presence of infestation caused by D. saccharalis. We also explored how these inoculations might affect the oviposition preference of D. saccharalis (direct defense) and the chemotaxis of its main natural enemy, the parasitoid Cotesia flavipes (indirect defense), commonly used in biological control programs. Our findings revealed that M. robertsii inoculation alters sugarcane plant chemical traits, affecting their resistance differently against D. saccharalis infestation. In non-infested plants, the inoculation of M. robertsii increased JA and SA phytohormones, suppressed volatile emissions, and reduced egg-laying by D. saccharalis, while exhibiting no effect on C. flavipes attraction. Conversely, in D. saccharalis-infested plants, M. robertsii increased JA content and reduced SA levels, resulting in quantitatively different volatile emissions. These changes increased attraction of C. flavipes compared to infested plants without fungal inoculation. Our results demonstrate that M. robertsii inoculations can enhance sugarcane plants' constitutive defenses against D. saccharalis while improving their herbivore-induced indirect defenses in sugarcane.

Herbicides are pivotal in modern agriculture, efficiently managing weeds and supporting sustainable farming. One of such herbicides is 2,4-dichlorophenoxyacetic acid (2,4-D), a synthetic auxin that targets broad-leaved weeds. It's praised for controlling various weeds with minimal injury to monocot plants. Innovative delivery methods for 2,4-D, like slow release and targeted systems, offer benefits such as extended herbicide release and reduced environmental impact. This review assesses diverse 2,4-D delivery systems: biochar, silica, layered inorganic materials, polymers, and gels, analyzing their benefits and limitations. Success in these systems relies on finding the optimal balance between strong herbicide bonding for high loading efficiency and the controlled release necessary for the desired herbicidal action. Porous materials adapt porosity for this equilibrium, and organic formulations optimize bonding groups. Layered materials, especially hydroxide ones, show potential by attracting 2,4-D anions. Controlled release is critical; Si-based systems achieve pH-controlled release, while polymers rely on hydrolysis modulated by temperature and acidity. Moreover, light-responsive groups offer precise control over 2,4-D distribution via irradiation. These studies highlight how inventive materials and techniques can transform agrochemicals. Ongoing research and development in this field will further enhance the efficiency, sustainability, and safety of herbicide delivery, benefiting agricultural practices and environmental stewardship.