Plant Protection Science - In Press
Occurrence of the white cochineal Parlatoria blanchardi in the fur of the black rat and potential risks for its spread to the date palm standsOriginal Paper
MLIK Randa, Yasmina KHERBOUCHE, Salim MEDDOUR, Abdallah AOUADI, Makhlouf SEKOUR, Khawaja G. RASOOL, Abdulrahman Saad ALDAWOOD
The parasitic interactions between arthropods and animals differ according to the parasite and host. For the first time, these interactions between the date palm scale (Parlatoria blanchardi) and the black rats (Rattus rattus) were recorded. P. blanchardi was found among the ectoparasites that black rats carried, enabling us to investigate for a year whether R. rattus may serve as a contributor to guarantee the survival of P. blanchardi. This allowed us to record a prevalence rate of P. blanchardi on R. rattus equal to 5.79% during the year, unlike in the five months was 100%. Furthermore, the mean intensity was 3.39 during the year and 2.54 during the five months. Statistics revealed that there was a very highly significant difference (chi-squared = 62.067, df = 24, p = 3.244e-05) between the three age classes of P. blanchardi recorded in different age categories of R. rattus. In addition, the age classes of rats differ significantly in terms of P. blanchardi numbers (chi-squared = 18.246, df = 3, p = < 0.001). The results of the Negative Binomial Mixed Model indicated a significant positive effect of Temperature (GLMM: z = 3.13, p < 0.01) and sex (Male) (GLMM: z = 2.22, p < 0.001) on insect abundance. One potential new reservoir for date palm scale survival could be the black rat.
Azadirachtin as a sustainable tool for zero pesticide residue production: Residue dissipation in open-field tomato productionOriginal Paper
Tahseen Chikte, Michal Kumšta, Václav Psota, Tomáš Kopta
The growing demand for vegetables free from pesticide residues has fuelled the search for sustainable pest management solutions. This study assessed the efficacy of azadirachtin, a neem-derived biopesticide, in achieving no detectable pesticide residues in tomato production under open-field conditions. The experiment from April to September 2024 included systematic application and residue analysis with Liquid chromatography-mass spectrometry (LC-MS). The results showed that azadirachtin degraded rapidly, with residual levels in leaves, green fruits, and matured fruits falling below detection thresholds (0.01 mg. kg-1) after 8-10 days following treatment. The statistical analysis revealed strong time-dependent residue dissipation, with little systemic buildup in fruit tissues. The findings indicate that azadirachtin is a feasible, environmentally friendly alternative to synthetic pesticides, consistent with food safety requirements and customer preferences for pesticide residue-free fruit. Future research should examine ecological factors affecting degradation rates to optimize its application in diverse agro-climatic conditions.
Flavonoids as bio-insecticides: Harnessing plant metabolites as a biochemical shield against insectsReview
Thamaraikannan Sivakumar, Sunilkumar Devanathan, Parthasarathi Ganesan, Kavithamani Duraisamy, Murugan Marimuthu, Vellaikumar Sampathrajan, Karthikeyan Adhimoolam, Senthil Natesan
The global decline in crop production threatens food security, particularly as the human population grows. Among the many environmental challenges affecting agriculture, biotic stress caused by insect pests is a major factor in yield reduction. Traditionally, synthetic pesticides have been used to manage insect infestations; however, their excessive and indiscriminate application raises serious concerns regarding environmental pollution, human health risks, and the development of pesticide-resistant pest populations. In response, natural plant-derived compounds, particularly flavonoids, have emerged as promising bioinsecticides due to their potent insecticidal properties. Flavonoids, a diverse group of secondary metabolites found abundantly in plants, exhibit strong insecticidal activity by disrupting insect digestion, interfering with nutrient absorption, and inhibiting growth and metamorphosis. These bioactive compounds act through multiple mechanisms, reducing the likelihood of resistance development while offering an eco-friendly alternative to conventional chemical pesticides. Additionally, flavonoids contribute to integrated pest management strategies by enhancing plant defense responses and synergizing with other bioinsecticides. Despite their potential, research on flavonoid-based insect control remains limited, particularly regarding their formulation, stability, and large-scale applicability. More studies are needed to explore their interactions with insect physiology, optimize delivery methods, and assess their environmental impact. Advancing flavonoid-based bioinsecticides can contribute significantly to sustainable pest management in modern agriculture, reducing dependence on synthetic pesticides while preserving ecosystem balance.
A Green Approach: Effects of organic weed control on weed diversity and phenology
Sarwan Kumar, S. S. Rana, Gaytri Hetta, Navjot Rana, Graciela Dolores Avila-Quezada, Ahmed Z. Dewidar, Mohamed A. Mattar
A long-term experiment in the maize-pea cropping system was conducted in Palampur from October 2019 to September 2021 as part of the All India Coordinated Research Project on Weed Management (AICRP-WM). Ten methods for managing weeds. namely, T1-hoeing, T2-raised stale seedbed + hoeing, T2-stale seed bed + hoeing, T5-stale seed bed + mulch, T6-raised stale seed bed + mulch, T4-mulch 5t ha-1, T7: Intercropping fenugreek in rabi season and soybeans in kharif season . A randomized complete block design with three replications was used to assess T8-crop rotation (soybean, mustard, and maize-peas alternately), T9-intensive cropping (additional crops of mustard in the fall and buckwheat in the summer), and T10-chemical check (pendimethalin in rabi season and atrazine in kharif season). The weed flora consisted of eight weed species during kharif 2020, fourteen during kharif 2021, and thirteen during rabi season 2019–20 and 2020–21. The species composition of weeds changed significantly in the second year compared to the first. In contrast to the chemical check, the organic weed control treatments showed a variety of weed flora, according to diversity and phytosociological study. Long periods of germination/emergence, blooming, and fruiting were found in phenological research. Rabi weeds appeared between October and January and between May and August. They flowered and produced fruits or seeds in March and September, respectively, and matured in April and September. Crop rotation followed by Raised stale seed bed (RSSB)+ hoeing + earthing up resulted in a much greater yield; however, in the second year, chemical check was comparable to this treatment. Additionally, crop rotation increased profitability over time.
Bionomics of wheat seed gall nematode Anguina triticiOriginal Paper
Manish Kumar, Matiyar Rahaman Khan, Ajay Singh Sindhu, Arti Kumari, Swathi Karthika, Bharat Gawade, Ashish Kumar Singh, Vishal Singh Somvanshi, Anil Sirohi
The wheat seed gall nematode Anguina tritici is a scientifically interesting nematode due to its aerial parasitic behavior, and ability to survive for years under desiccated conditions in seed galls. However, Anguina’s life cycle and its correlation with host-plant growth and environment are poorly understood. Here, we conducted a microplot study in IARI, New Delhi, India to examine the effects of early and late sowing dates of wheat on the life cycle of the wheat seed gall nematode by using the growing degree days (GDD). The study confirmed the presence of juvenile stages in the soft, undifferentiated floral mass and the upper one-third part of the stem. During the early stage of floral differentiation, the plant ovary develops into milky grains, while the galls (false ovules) become fully green. An increase in size and gonad cell development was observed when nematode J2s entered the floral tissue. The count of adult females in galls marginally surpasses that of adult males, and the female:male ratio ranged from 1.46:1 to 1.48:1. After GDD and cGDD (cumulative growing degree day) calculation we found that nematode completed its life cycle in 90 to 140 days, depending on the wheat sowing dates and change in temperature. The study also showed that nematode development was in-sync with the growth and development of wheat plants. The information developed from the study such as the cumulative GDD and it’s correlation with Anguina’s life cycle, presence of nematode in stem, flower and gall, it’s migration from collar to flower, presence of various stages of nematode in different plant tissues, and it’s undergoing the anhydrobiotic process in seed galls may be used to determine the best time to intervene and manage nematode infestations.
New data on pathotype distribution of Plasmopara halstedii in one of the most important Italian areas dedicated to sunflower cultivationShort Communication
Andrea Del Gatto, Mauro Dal Pra', Ilaria Alberti
Downy mildew of sunflower is caused by the oomycete Plasmopara halstedii Novot. Italy has seen an increase in mildew infections in parallel with the spread of the crop. In the present situation there is a substantial lack of information that can help farmers and researchers in the control of the disease. The most relevant one seems to be the pathogenetic variability of P. halstedii. To overcome the problem, we conducted a preliminary test to collect the first data about this variability.
Interaction of seaweed metabolites with plants to enhance protection against biotic and abiotic stressesReview
Bibi Aida, Deepak Kasote, Jisun Lee
Abiotic and biotic stresses such as pathogens, pests, temperature extremes, and salinity have a significant impact on the nutritional value, growth, and yield of economically important food crops. Traditional reliance on chemical fertilizers and pesticides led to substantial risks to the environment and health, making it necessary to search for ecological alternatives. Scientists have found that seaweeds are an essential reservoir of primary and secondary metabolites. Certain metabolites or molecules present in a large number of seaweed extracts can act as elicitors, functioning as pathogen-associated molecular patterns (PAMPS) and activating plant defense mechanisms via the induced systemic resistance (ISR) and systemic acquired resistance (SAR) pathways, even in the absence of biotic stress. Seaweed-derived metabolites have emerged as promising biostimulants, offering a natural means to enhance plant resilience and productivity. This review analyzes various seaweed extracts and their metabolites, such as polysaccharides, phenolic compounds, and fatty acids, emphasizing their biological effects on crops subjected to biotic and abiotic stresses. Additionally, it discusses the mechanisms of action of seaweed extracts and their specific metabolites, along with the biochemical, physiological, and molecular pathways that contribute to enhancing plant defense mechanisms.
Attenuating strategies of the insecticidal effect and life history traits of Chaitophorus leucomelas (Koch, 1854) (Insecta: Aphididae): Case of the aqueous extracts of Asteraceae dittrichia viscosa and a synthetic product of the Neonicotinoids /Pyrethroids familyOriginal Paper
Fatma Zohra TCHAKER, Zahr-Eddine DJAZOULI, İsmail KARACA
Methods used to control natural enemies; insects in particular, have been mainly chemical. Given the irritations associated with the use of pesticides, a search for alternatives is required, particularly through the use of plant extracts. The present study focused on comparing the insecticidal power of aqueous extracts of Dittrichia viscosa in combination with a bio-adjuvant Silene fuscata and a synthetic pesticide Thiamethoxam/ Lambda-cyhalothrin on the abundance, biochemical life traits and demographic parameters of the winter phenotype of Chaitophorus leucomelas. Two extracts were prepared through the maceration process: aqueous extracts of the whole plant D. viscosa and aqueous extract ratio of D. viscosa and S. fuscata (1:1). As for the chemical product, two concentrations were used: the prescribed dose (4 mL/L) and half of that dose (2 mL/L). Abundance, fecundity, demographic parameters, as well as the energy balance (lipid-glucidic biomarkers) of C. leucomelas were considered variables to assess the effectiveness of different approaches. The results show a strong effect of the aqueous extracts of D. viscosa on the abundance, with a well pronounced insecticidal activity under the effect of the aqueous extract ratio. Lipid and carbohydrate energy biomarkers of sexuparae undergo strong changes depending on the products used, with a very significant disturbing action of the synthetic product compared to aqueous extracts. The fecundity shows a remarkable disturbance under the action of the active ingredient compared to aqueous extracts. The results also confirm that the products applied cause a disturbance in the growth rate (rm) and reproduction (R0) of C. leucomelas females, with the chemical treatment having the strongest effect. The full dose of the active ingredient causes remarkable disturbances on the multiplication rate (λ) and the mean generation time (T) of the sexuparae compared to the other applied molecules. Some stability is reported for the doubling time (DT) of treated females compared to the control ones. Overall, the extracts induce a significant toxic effect with a minor disruptive impact on the biochemical life traits and demographic parameters of the pest, compared to the synthetic product.
Allelopathic potential of Turnera subulata leaf extract on choisum via untargeted metabolomicsOriginal Paper
Nor Atirah Mohd Aridi, Nornasuha Yusoff, Muhd Arif Shaffiq Sahrir, Kamalrul Azlan Azizan
Allelopathic plants release phytotoxic compounds that contribute to their invasiveness by suppressing nearby species. However, it remains unclear that exact mechanism of action (MOA) underlie the allelopathy. This study explores the allelopathic mechanisms of T. subulata on the recipient indicator plant choisum using metabolomics approach. Briefly, T. subulata leaf aqueous extracts (LAE) at different concentrations (0, 0.1, 1, 10, 50, and 100 mg/mL) were sprayed at 100 mL/m2 on choisum seedlings at the two to three leaves stage. After 21 days, the Soil Plant Analysis Development (SPAD) values and photosynthetic pigments of exposed choisum were measured, and their metabolites were subjected to gas chromatography-mass spectrometer (GC-MS) analysis. The results revealed a 25% decrease in SPAD, a reduction of 65% (chl a) and 71% (chl b), and 45% reduction in stomatal length at 100 mg/mL. A total of 11 significant metabolites (P < 0.05) with variable important for projection score exceeding 1 (VIP > 1) were selected as important biomarkers. These metabolites were identified as amino acids, carbohydrates, and fatty acids. The findings reveal the allelopathic potential of T. subulata and provide insights into the response of choisum in response to the allelopathic activity of T. subulata LAE.
Isolation and characterization of pathogenic and endophytic fungi associated with avocado plants showing dieback symptoms in IndonesiaOriginal Paper
Riska Amril, Tri Budiyanti, Jumjunidang Jumjunidang, Sri Hadiati, Raden Heru Praptana, Mizu Istianto, Nurmansyah Nurmansyah, Herwita Idris
Avocado (Persea americana Mill) is a high value fruit crop in Indonesia. This exotic commodity is affected by dieback disease, an unrecorded disease that threatens production. The objectives of the present study were to characterize the pathogen and endophytic fungi associated with dieback disease of avocado plants. Fungal isolates were collected from branches of avocado showing dieback symptom in Standard and Instrument Tropical Fruit Applied Institute (SITFAI) experimental orchards during 2022–2023. A total of 17 fungal isolates selected from 73 fungal isolates recovered from three location were characterized morphologically, molecularly, phylogenetically, and by pathogenicity tests. Identification of fungal species were done on morphological characteristic and molecular analysis obtained from internal transcribed spacer (ITS), 28S region of ribosomal DNA, and trans elongation factor 1 (TEF1). The fungal isolates were tested for their pathogenicity to avocado local variety test with two stages. First step was mechanical inoculation of all the fungal isolates with one avocado seedling and three slashed stems as replication. Second step was mechanical inoculation of four selected isolates (the isolate caused necrosis symptom to avocado seedling) to avocado local variety seedling with three seedlings and three slashed stems as replications. The result revealed that fungal species such as Neofusicoccum parvum, Colletotrichum tropicale, C. fruticola, Neopestalotiopsis sp. Pestalotiopsis sp., Pseudofusicoccum ardesiacum, Nigrospora sphaerica, Nemania bipapillata, Neoroussoella leucaenae, Penicillium citrinum, Lasiodiplodia theobromae, L. krabiensis, Lasiodiplodia sp. were obtained from avocado plant showing dieback symptom. The most frequently genus isolated were fast growing, Botryspaeriaceae (58,9%), followed by Penicilium spp. (20.5%), Pestalotiopsis spp. (15.1%) and Colletotrichum spp. (5.4%). Artificial inoculation of a L. theobromae isolate induced necrosis symptom on local avocado seedling.
Biological activity of Paenibacillus polymyxa GT2 isolate from soil in Japan against anthracnose caused by Colletotrichum orbiculare in cucumberOriginal Paper
Abdul Wali Haqyar, Masatoshi Ino, Naoto Kimura, Takumi Okido, Junichi Kihara, Makoto Ueno
Cucumber anthracnose is a destructive fungal disease caused by Colletotrichum orbiculare. Common control strategies include the use of chemical fungicides. However, this may lead to the development of pathogen resistance over time. Therefore, it is necessary to identify natural compounds or microorganisms for developing new chemicals and the biological control of fungal pathogens. Isolate GT2, a bacterial isolate from soil samples collected in Shimane Prefecture, significantly inhibited the in vitro mycelial growth and conidial germination of C. orbiculare, indicating a fungicidal effect against this pathogen. Furthermore, anthracnose lesion formation was significantly suppressed without phytotoxicity when cucumber leaves were pretreated with a cell culture suspension of the isolate GT2 before inoculation with C. orbiculare. Bioautography detection of the culture filtrate (CF) of isolate GT2 using thin-layer chromatography showed that the inhibitory compound against C. orbiculare growth had an Rf of 0.38. The effective compound in GT2-CF was the ethyl acetate insoluble, heat-stable at less than 121 °C, and a molecular weight of more than 1000 Da. Sequence analysis of the 16S rDNA region of GT2 indicated that it shares 99% similarity with the bacterium Paenibacillus polymyxa. In conclusion, the Paenibacillus polymyxa isolate GT2 demonstrated potential for developing a new fungicide and biological agent against anthracnose disease caused by C. orbiculare.