Phytoparasitica最新文献

The invasive fall armyworm (FAW), Spodoptera frugiperda (J.E. Smith), poses a significant global threat with serious economic implications. Global concern heightened following the first major outbreak in Africa in 2016. Our research, which confirmed the presence of FAW in Indonesia in 2015 through re-examined samples from a maize field in Lampung region of Indonesia, supports the hypothesis that the invasion pattern does not follow the predicted west-to-east chronological timeline. Historical records and reidentification suggest that FAW may have been established in Indonesia, Africa, and Australia as early as nineteenth century, suggesting its potential presence in these regions much earlier than previously thought. The spread of FAW could be linked to the movement of people and plants such as maize or Para grass (Brachiaria mutica), at least at the end of the nineteenth century. This underscores the importance of rigorous identification methods for accurately tracking invasive species like FAW. Analyzing these historical records alongside the genetic structure of populations in Southeast Asia, particularly in Indonesia, is crucial for future research aimed at developing effective management strategies to mitigate the impact on the global agriculture.

Apple scar skin viroid (ASSVd) and other apple viruses [apple chlorotic leaf spot virus (ACLSV), apple stem-pitting virus (ASPV), and apple stem grooving virus (ASGV)] can cause significant economic losses to the apple industry. We used ASSVd- and ASGV-infected Malus pumila ‘Spy 227’ and ACLSV-, ASPV-, and ASGV-infected M. pumila ‘Gala’ apple as the plant materials for virus elimination experiments. We evaluated the viral elimination effectiveness of electrotherapy at different electric current intensities and treatment durations on in vitro plants of these two apple cultivars. Furthermore, the effect of cold therapy (4 °C) combined with ribavirin (25 μg/mL) at different treatment durations on two apple varieties was investigated. The effects of electric current intensity and treatment duration on shoot tip survival differed between ‘Spy 227’ and ‘Gala’, and shoot tip mortality after electrotherapy was related to the self-tolerance of apple plants. During cold therapy combined with ribavirin, in vitro Spy 227 plants started to die after 50 d of treatment and the death rate increased with the extension of treatment time. The cold tolerance of in vitro Gala was lower than that of Spy 227. The Quantitative reverse-transcription PCR (qRT-PCR) and RT-PCR were used to detect the viroid and viruses in regenerated plants. The results showed that electrotherapy did not inhibit ASSVd, ACLSV, ASGV, or ASPV. Moreover, cold therapy combined with ribavirin had no eliminating effect on ASSVd, but the elimination rate of ASGV under treatment periods of 80 d and 95 d was 60.4% and 60.1%, respectively. Considering the impact of ASSVd on apple plant health, additional research is needed to develop methods to manage this viroid effectively.

Mal secco disease of citrus is caused by the mitosporic ascomycete fungus Plenodomus tracheiphilus (formerly Phoma tracheiphila [Petri]). Mal secco is a highly destructive vascular disease of lemon and other citrus which is presently confined to the Mediterranean basin and has a marked economic impact on the citrus industry. The fungal pathogen infects the host tree by penetrating through wounds in the roots or canopy. Infection spreads quickly into the main branches and trunk and tree mortality usually ensues. The most typical symptoms are veinal chlorosis, leaf wilt, red discoloration of the xylem and dieback of twigs and branches. Current accepted control of the disease is mainly by sanitation of infected wood, and copper application during the winter to prevent germinating spores from infecting the plant. No effective chemical control for this disease has been reported. We present a drip-irrigation protocol to protect trees and control the disease in which we apply 250 g/ha of the triazole fungicide flutriafol five times a year. Progression of disease symptoms in the treated trees was inhibited by up to 81% compared to the untreated control, thereby significantly shortening the sanitation process and making it less costly than in untreated trees. Moreover, disease symptoms became less severe as the duration of treatment increased. We have treated orchards for 3 years, and present an effective commercial protocol for the growers which will help them control Mal secco disease.

Resistance against aphids is an integrated pest management tactic that enhances the economic and environmental sustainability of cereal production. The aim of our study was to assess the degree of antibiosis against Metopolophium dirhodum (Walker) (Hemiptera: Aphididae), one of the most important cereal aphids in temperate regions, in two lines of small grain cereals bred in the Crop Research Institute (CRI) of Prague: spring wheat, Triticum aestivum L. cv. ‘Rufia’, and germplasm of durum wheat, Triticum turgidum ssp. durum (Desf.) van Slageren ‘TTD40363’, under controlled laboratory conditions. Resistant spring wheat cultivar (‘Libertina’) and highly susceptible spring barley (Hordeum vulgare L. cv. ‘Sebastian’) were used for reference. The responses of M. dirhodum to each line and population growth projections were determined according to the age-stage, two-sex life table theory. We found that Rufia was susceptible and TTD40363 was rather resistant to M. dirhodum. The projected population sizes after 35 days were ~ 41,000 individuals in spring wheat Rufia and ~ 12,000 in durum wheat TTD40363, which is within the range delimited by the reference cultivars (4,000 in the highly resistant spring wheat Libertina and 77,500 in highly susceptible spring barley Sebastian). This study provides new data on small grain cereal resistance to aphids. An age-stage, two-sex life table approach was used to assess resistance to aphids on durum wheat and barley for the first time.

The recent surge in sweet potato (Ipomoea batatas) cultivation in Europe prompted an investigation into associated entomofauna within Portugal's southwestern region, known for its longstanding sweet potato production. This study aimed to assess entomofauna associated with this culture.

Insect sampling was conducted by leaf and sweep net across three regional sites during 2018 and 2019 revealing the presence of Empoasca fabalis. Histological examination of sweet potato leaves affected by E. fabalis feeding unveiled significant damage, including the emergence of whitish spots (termed “stipples”) and subsequent necrotic spots. Comparative analysis between infested and undamaged control leaves revealed significant damage, involving mesophyll cell content deprivation and cellular disruption. This study describes, for the first time, the histological nature of the necrotic damage and suggests that E. fabalis primarily acts as a stippler on sweet potatoes, mainly targeting mesophyll cells with limited consumption of vascular tissue. The invasive behaviour and wide host range of E. fabalis pose a threat to sweet potato cultivation. These findings emphasize the need for monitoring to address the potential impact of E. fabalis on Europe’s agricultural ecosystem and native vegetation.

In addition, six other Auchenorrhyncha species were identified during this study, including four crucial vectors of plant diseases: Laodelphax striatellus, Psammotettix alienus, Anaceratagallia glabra, Austroagallia sinuata, together with Empoasca solani and E. alsiosa. These results emphasise the importance of managing these insects in sweet potato cultivation.

Silicon (Si) enhances plant resistance against herbivores and improves crop yield. This study investigated the effect of foliar application of silicic acid (SA), an important available form of Si, on the population growth of aphids (Lipaphis erysimi), gas exchange parameters and yield of rapeseed. The first experiment with treatments of foliar spray of 0.4% SA and a control, revealed a significant reduction in L. erysimi population growth in the 0.4% SA treatment (235.60 aphids/ plant) compared to the control (311.16 aphids/ plant). Additionally, the 0.4% SA treatment significantly enhanced rapeseed yield, with 68.28 siliqua per plant, 15.16 seeds per siliqua and 3.73 g yield per plant, compared to the control with 56.08 siliqua per plant, 13.08 seeds per siliqua and 3.26 g yield per plant. The second experiment with treatments of 0.4% SA alone, aphid alone, 0.4% SA + aphid and a control, showed no significant changes in gas exchange parameters for 0.4% SA and the control. However, 0.4% SA + aphid and aphid alone treatments significantly reduced the gas exchange parameters. Notably, 0.4% SA + aphid exhibited a lesser reduction in photosynthetic rate and stomatal conductance compared to aphid alone treatment, indicating the role of SA in enhancing gas exchange parameters during L. erysimi infestation in rapeseed. These findings suggest the beneficial application of SA in rapeseed to reduce aphid infestation, increase gas exchange parameters and improve yield.

Tea mosquito bug (TMB), Helopeltis theivora is a most serious pest on cocoa worldwide that inflicts huge economic losses under epidemic situations. Laboratory colonies are necessary to perform year-round research to develop suitable management strategies for this pest. This study aimed to establish a population of TMB on suitable cocoa-feeding substrates under laboratory conditions. We used green cocoa pods and tender shoots as a food substrate and compared the biological parameters of H. theivora between them. The adult females preferred to lay more eggs on pods (32.20 ± 1.86 eggs/female) either singly or in a small group, and low fecundity was observed on shoots (20.75 ± 1.16 eggs/female). Meanwhile, egg hatching was highest on pods (92.48 ± 2.91%) than on shoots (74.08 ± 3.73%). This pest consists of five nymphal instars and the total nymphal duration was 13.53 ± 1.26 and 14.73 ± 0.85 days on pods and shoots, respectively. In addition, the per cent survival of H. theivora was highest on pods (78.66 ± 3.46) and lowest on shoots (51.85 ± 2.33). Significant differences were recorded in adult longevity and the mean life span of males and females were 13.17 ± 1.58 and 16.63 ± 1.64 days on pods; 11.10 ± 1.41 and 14.36 ± 1.53 days on shoots, respectively. Further, females lived longer than males in both substrates. Although, TMB will survive both on pods and tender shoots; rearing on pods could be more suitable and reliable to establish a sizable population of H. theivora under laboratory conditions.

Bedellia somnulentella Zeller, 1847 (Lepidoptera: Bedelliidae), microlepidoptera leafminer of plants of the Convolvulaceae family, has Ipomoea batatas as its main commercial host. The distribution of this insect is cosmopolitan, with importance in different regions of the world. The aim was to report the occurrence of B. somnulentella in the Atlantic Forest, as well as its host plant and a predator, in the state of Minas Gerais, Brazil. Distimake dissectus var. edentatus (Convolvulaceae) plants was damaged in the Atlantic Forest biome in the municipality of Viçosa, Minas Gerais state, Brazil. Agelaia vicina Saussure, 1854 (Hymenoptera: Vespidae) fed on B. somnulentella caterpillars and pupae. The record of this insect on D. dissectus var. edentatus expands the number of its hosts in the Atlantic Forest. The record of the predator A. vicina increases the number of enemies and reinforces the importance of Vespidae to reducing populations of the leaf miner B. somnulentella in the field.

Amrasca biguttula biguttula Ishida is the major biotic constraint in okra cultivation that cause considerable economic loss. Screening of okra (Abelmoschus esculentus) genotypes is important to develop leafhopper-resistant high-yielding cultivars for improving crop yield. To categorize leafhopper-resistant okra genotypes, we used a comprehensive collection of morphological and biochemical parameters with multivariate analysis in this study. Plant morphological and biochemical parameters were estimated by collection of leaves from different okra genotypes with three replicates during peak leafhopper infestation period and assay were performed based on specific standard protocols. Completely randomized block design was deployed and significant variations in plant morphometrics, biochemicals, and leafhopper population were recorded from each genotype screened. In the present study the morphological parameter viz., the shortest plant height was observed in resistant genotype AE 23 (17.21 cm) and the tallest plant height was recorded in the susceptible genotype AE 26 (63.22 cm) followed by Pusa Sawani (63.07 cm). The maximum leaf area of 132.24 cm² was recorded in AE 15 genotype. Biochemical data reveals that, protein content was highest in susceptible genotype AE26 (11.01 mg/g), followed by Pusa Sawani (10.72 mg/g), and the lowest in the resistant genotype AE65 (4.72 mg/g) followed by AE27 (5.54 mg/g). While phenol, OD phenol, surface wax content were maximum in identified moderately resistant genotypes. The Kaiser Criterion or eigenvalue is greater than one for the first four principal components with the cumulative percentage of variance of 78.48 percent. Principal component analysis simplified the understanding of the interactions among leafhopper and biophysical and biochemical characteristics. The genotypes AE65, AE23, AE 27, No.315, and AE4 expressed resistance in terms of higher total phenol, ortho dihydroxy phenols, tissue toughness, and surface wax contents. Our visual observations on the growth and development of okra genotypes under leafhopper pressure were represented by principal component analysis which makes it reliable. Therefore, the identified jassid-resistant okra genotypes could be further utilized as a source of appropriate donor parents in the breeding of leafhopper-resistant okra varieties.

The efficiency of pistachio nuts was investigated on the multiplication of Ectomyelois ceratoniae (Zeller) (Lep: Pyralidae) by rearing a cohort of 61 eggs individually at 26 ± 1 ℃, 60 ± 10% RH, and 16:8 h L:D. The age-stage two-sex life table theory and bootstrapping were used to analyze the data. The survival probability from a newly born egg to larva, pupa, and male and female adults was 0.77, 0.52, and 0.26 and 0.24, respectively. The total immature duration of males (45.33 d) was significantly shorter than that of females (49.47 d). The mean female fecundity was 98.08 eggs/fertile female (n = 12) and 78.46 eggs/all females (n = 15), respectively. The life expectancy of a newborn E. ceratoniae was 34.83 d, and the reproductive value was 79.63 at age 49 d of the female. Female moths had slightly longer longevity (7.82 d) compared with males (7.58 d). The population parameters R₀, r, and λ were 19.29 offspring, 0.0548 d⁻¹, and 1.0563 d⁻¹, respectively. When eggs are harvested and the discard age is 62 d, the maximum harvest rate is 0.9481. Therefore, for a daily harvest of 10,000 eggs, the daily recruits of 547 eggs, 421 larvae, 287 pupae, 134 females, and 143 males are required in a stable stage structure rearing system. Each larva damaged and fed upon 2 gr. of raw pistachio to complete its development. Consequently, about 842 gr. pistachio nuts must be provided daily to meet the larval feeding demand, which imposes a cost of about $10 (local retail price) to the rearing system as nutritional provision.