Pesticides and Phytomedicine / Pesticidi i fitomedicina

Botryosphaeriaceae fungi on apple fruit – identification and sensitivity to fungicides and essential oils in vitro

Milica Milošević — 2025-05-09

Apple production suffers significant economic losses and fruit quality reduction
due to fungal pathogens, particularly ones that cause postharvest fruit rot, such as
Botryosphaeriaceae fungi. Isolates used in this study were obtained from symptomatic
apples and, based on morphological characteristics and sequence analysis of two genes
(EF 1-α and β-tubulin), they were identified as Diplodia seriata and Botryosphaeria dothidea.
Pathogenicity tests on healthy apple fruits revealed that D. seriata was more aggressive
than B. dothidea, with significantly higher average values of lesion diameter and depth.
Fungicide sensitivity tests showed that D. seriata was more sensitive to the combination
fluopyram + tebuconazole (EC50=0.00023 μg a.i. ml-1), while B. dothidea exhibited higher
sensitivity to pyraclostrobin (EC50=0.025 μg a.i. ml-1). With 98.44% and 97.56% percent
growth inhibition (PGI) rate of D. seriata and B. dothidea (respectively) at 10 μg a.i. ml-1, the
tested combination of fungicides surpassed pyraclostrobin in inhibition potential. Four
essential oils (thyme, rosemary, lavender and lemongrass) were also tested for antifungal
activity using the fumigant macrodilution method. Thyme oil demonstrated the highest
antifungal potential, completely inhibiting the mycelial growth of both species at
0.05 μl ml–¹ of air. Strong inhibition potential was also shown by lemongrass oil with
100% inhibition of D. seriata and B. dothidea mycelial growth at 0.07 and 0.09 μl ml–¹ of air,
respectively. Rosemary oil showed a moderate inhibition potential, while lavender oil was
the least effective. These findings highlight the inhibiting potential of fungicides against
D. seriata and B. dothidea, but they also indicate that thyme and lemongrass essential
oils could be used as viable alternatives. Further research is needed to determine their
effectiveness in in vivo assays and potential impact on fruit quality and the environment.

Natural and semi-synthetic insecticides protect onion from wireworms Agriotes spp. larvae (wireworm) damage

Mirjana Prijović — 2025-05-09

Wireworms, the larval stage of click beetles (Elateridae: Agriotes spp.), pose a
significant threat to global agriculture, particularly to root vegetables, such as onion.
Their subterranean lifestyle, as well as the withdrawal of some traditional synthetic
insecticides, make them challenging to control. Therefore, this research aimed to
compare the effects of natural, semi-synthetic and synthetic insecticides in controlling
wireworm damage in an onion field.
A field trial for testing the effects of different insecticidal treatments on plant
density, wireworm damage (%) and total onion yield, was conducted at the Institute
for Vegetable Crops (Smederevska Palanka, Serbia) in 2024. The experiment consisted
of six treatments: an untreated control, three natural insecticides (two formulations
of spinosad a.i. - granular and liquid, and Beauveria bassiana ATCC 74040 2.3×107
conidiospores/ml), a semi-synthetic insecticide (a.i. spinetoram) and a synthetic
insecticide (a.i. tefluthrin). The insecticides were applied during planting, following
their label application rates per hectare. Assessments were conducted 20 and 42 days
after treatment (DAT) to determine plant density. Wireworm damage was specifically
evaluated 42 DAT, and yield was calculated by weighing the harvested onion bulbs. The
results showed that the granular spinosad formulation, applied in furrows at planting,
significantly increased plant density 20 DAT, while its liquid formulation, applied as
a soil treatment during planting, resulted in the lowest density. Spinetoram showed
the highest plant density 42 DAT and the highest percentage of wireworm damage
(15%) of all insecticides tested. The control had the highest percentage of damaged
plants and the lowest yield. Onion yield was at the maximum after treatment with
spinetoram, whereas the lowest yield was achieved after treatment with the granular
spinosad formulation.
Field trials show that natural and semi-synthetic insecticides can effectively
control wireworms, ensuring adequate crop protection and viable yields. This
study supports developing and adopting environmentally conscious soil pest
management.

Analytical approach for simultaneous determination of azoxystrobin, prothioconazole and trifloxystrobin in plant protection products

Sanja Lazić — 2025-05-09

IIn this study, an isocratic reversed-phase high-performance liquid chromatographic (RP-HPLC) method with diode array detection (DAD) was developed and validated for simultaneous determination of azoxystrobin, trifloxystrobin and prothioconazole in plant-protection products. Chromatographic separation of the active substances was achieved using 0.1% acetic acid and acetonitrile (30:70 v/v) at a flow rate of 0.52 ml/min on a Zorbax Eclipse XDB-C18 (50 mm × 4.6 mm × 1.8 μm) and UV detection at 210 nm. Validation was done by
evaluating the linearity and precision of the method, repeatability of injections, accuracy, and limits of detection and quantification (LOD and LOQ). Under the conditions, correlation coefficients of linearity were 0.996-0.997, the precision of method, expressed as relative standard deviation, was lower than the modified Horwitz values, the accuracy of all individual substances was within the range of 94.61-107.35%, while repeatability of the injectons was satisfied with RSD of 0.94-1.35%. LOD and LOQ were 0.0063 mg/ml and 0.019 mg/ml for azoxystrobin, 0.0051 mg/ml and 0.015 mg/ml for prothioconazole and 0.0051 mg/ml and 0.015 mg/ml for trifloxystrobin, respectively. A simple, precise, accurate, and fast analytical method for simultaneous determination of the fungicides azoxystrobin, prothioconazole and trifloxystrobin can be proficiently used for their detection and quantification in formulated products. The developed and validated method was applied to real samples, confirming the method's applicability.