Renata Dobosz

Silicon-containing formulations have been investigated as potential complementary tools for managing arthropod pests, including the two-spotted spider mite (Tetranychus urticae Koch). The present study evaluated the effects of different silicon application regimes on spider mite population development and physiological status of sugar beet (Beta vulgaris L. cv. Kujavia) under controlled greenhouse conditions. Plants were treated with one or two foliar applications of a commercial silicon formulation at two dosage levels and artificially infested with adult female spider mites. The population density of developmental stages, leaf infestation level, egg production, and chlorophyll content (SPAD index) were determined. Silicon treatments significantly affected leaf infestation, larval abundance, total motile stages, non-motile stages, and total spider mite population. The most effective treatments reduced the abundance of mobile developmental stages and overall population density compared with untreated controls. Although differences in SPAD values were not statistically significant, no significant effect of the tested silicon-containing formulation on leaf chlorophyll status was detected under the experimental conditions. Multivariate analyses demonstrated differentiation among the experimental treatment combinations, based on the combined set of measured variables, indicating that the treatment combinations differed in their overall plant–mite response. The results indicate that the tested silicon-containing formulation may have potential as a complementary component of integrated pest management programs targeting T. urticae, although its efficacy requires further validation under field conditions.

Specimens of plant parasitic nematode species Heterodera ripae were isolated from the root zone of common nettle (Urtica dioica), a perennial growing near agricultural fields in Winna Góra near Poznań (Wielkopolska region, Poland). The species identity was confirmed by analyses of the structure of the vulval cyst cones, morphology and anatomy of J2, measurements of both developmental stages as well as analyses of the rDNA and mtCOI sequences. Molecular analyses of the Polish H. ripae 28S rDNA sequence revealed that it was the most similar to the H. ripae sequences from South Korea and clustered with them in a phylogenetic tree near a closely related H. ripae from China and H. humuli. Similarly, the mtCOI sequence of the Polish H. ripae population clustered with most H. ripae sequences deriving from Europe and Asia, however it was more distantly related to the sequence from China. Under controlled conditions, H. ripae pathogenicity and potential harmfulness was tested on three plants: common nettle (U. dioica) which served as a control, buckwheat (Fagopyrum esculentum), and sorrel (Rumex acetosa). During the pathogenicity test, H. ripae did not develop new cysts, neither on the roots of F. esculentum nor R. acetosa. At a population of 100–120 nematode eggs and larvae, cysts of the nematode developed on the common nettle’s U. dioica roots, however plants showed no signs of growth inhibition. These numbers may have been too low to lead to plant starvation. It was recommended that soils intended for cultivation of U. dioica as a horticultural crop should be tested for the presence of H. ripae and that plantations of this plant should be monitored for the presence of other herbivorous nematodes, including cyst-forming species.

Among the plant-parasitic nematodes feeding on peppers (Capsicum annuum L.), the most frequently mentioned genera are root-knot nematodes (Meloidogyne), root-lesion nematodes (Pratylenchus), spiral nematodes (Helicotylenchus), and pearl nematodes (Naccobbus aberrans). These nematodes negatively impact pepper plant growth, manifesting as root damage and wilting of the above-ground parts. A study conducted in the intensive pepper cultivation area of Potworów, Poland identified the plant-parasitic nematode genera and species associated with wilting. Soil samples were collected from 26 sites, and 11 genera of plant-parasitic nematodes were found. The most prevalent were Meloidogyne (present in 81% of samples), Pratylenchus (73% of samples), along with Paratylenchus and Quinisulcius (both found in 50% of samples). An average of 55 Quinisulcius capitatus nematodes were found per 100 ml of soil, with the statistical significance of this value being 62.71 for the specific comparison being made in the study. This pilot study confirmed the species Q. capitatus through morphometric, morphological, and genetic analyses (sequencing of the 28S rDNA gene). Subsequently, the abundance of Q. capitatus in pepper crops was assessed under controlled conditions (16/8 hours day/night) by growing peppers in pots inoculated with the nematode. The study revealed an average 23-fold increase in nematode abundance. The observations of wilting symptoms in the pepper plants, concurrent with the rapid increase in Q. capitatus abundance, suggests this nematode is a potential pest for this crop. To our knowledge, this is the first report of Q. capitatus infesting peppers in Poland. These results provide a strong basis for further research into the specific impacts of Q. capitatus on pepper production in Poland.

Previous research strongly associates the body size of poikilotherms with variations in environmental temperature. To investigate this relationship in Meloidogyne hapla , eggs were incubated at 5, 10, 20 (control), 30, 35, and 40°C for durations of 1, 2, 8, or 24 h (10 eggs per Petri dish × 3 dishes, n = 30 eggs per treatment). Following treatment, eggs were maintained at 20°C until hatching into second-stage juveniles (J2), at which point body size traits including body length, width, and mass were evaluated. The findings demonstrate that both incubation temperature and duration are strongly linked to those body size traits of emergent J2. Notably, an incubation temperature of 40°C was consistently associated with a complete absence of embryogenesis across all durations. The most pronounced size reductions occurred at 35°C, corresponding to the minimum J2 dimensions recorded, where length, width, and mass were lower by 5,5%, 11,5%, and 25.4% relative to the control, respectively. Conversely, maximum body length aligned with the 30°C treatment (a 0.85% increase over the control), whereas peak values for width and mass coincided with the 20°C control temperature. These data indicate that while successful egg development aligns with the 20 to 30°C thermal range, morphometric trends vary by specific trait (length vs mass/width), a pattern that corresponds with established literature on the developmental range of M. hapla eggs.

Heterodera schachtii, a nematode primarily feeding on sugar beet and cruciferous plants, e.g., rapeseed, cabbage, broccoli, mustard, and radish, had a significant impact on Camelina sativa (L.) Crantz. The isolation of H. schachtii cysts from C. sativa roots and a known data gap regarding their development on this plant prompted an investigation into their interaction. A pot experiment conducted under controlled conditions in a growth chamber showed that H. schachtii completes its full development cycle in the roots of spring (UP, Smielowska, Borowska, Omega) and winter (Lemka, Maczuga, Luna, Przybrodzka) camelina cultivars at temperatures of 15, 20, and 25 °C. Female nematodes and cysts were most abundant in the Omega cultivar at 20 °C, averaging 9.25 per plant. Nematode feeding did not affect the height or fresh weight of the plants. Plants of the Przybrodzka cultivar had fewer leaves than the control plants. More siliques were observed on the control plants of the UP cultivar kept at 15 °C and those of the UP and Borowska cultivars at 20 °C. Under natural conditions, the number of eggs and larvae in the soil decreased by approximately 50% during the camelina growth cycle for both spring and winter biotypes.

Tetranychus utricae Koch (the two-spotted spider mite, TSSM) is a major pest of sugar beet plants (Beta vulgaris L.), which quickly develops resistance to miticides. Volatile or­ganic compounds (VOCs) have the potential of providing an environmentally friendly al­ternative to currently used insecticides. The main goal of this study was to evaluate the changes in the qualitative and quantitative composition of the VOCs released by sugar beet plants under drought conditions, TSSM infestation, or subjected to combined types of stress. Volatiles were collected over a 2 h period on days 2, 3 and 6 following TSSM feeding and/or drought and, following elution, were analyzed by gas chromatography with mass spectrometric detection. In particular, plants that were subjected to combined abiotic and biotic stress resulted in even higher levels of VOCs being released than from plants subjected to a single stress. Ten key volatiles were identified, namely: (Z)-3-hexenal, (Z)-3-hexen-1-ol, (E)-2-hexen-1-ol, (Z)-3-hexen-1-yl acetate, (Z)-ocimene, linalool, β-pinene, (E)-β-farnesene, β-caryophyllene and benzyl acetate. Of these 10, three were emitted with significantly higher quantities than the other seven: β-pinene, β-caryophyllene and benzyl acetate. This suggests that these three volatiles are potentially the most useful as natural alternatives to synthetic miticides to protect sugar beet crops from TSSM. Fur­ther research is needed to assess this hypothesis and to determine their activity against the mites.

During the observation of a garlic plantation, a sample consisting of plants with symptoms of growth inhibition and the soil surrounding the roots was collected. Phytophagous nematodes were isolated from the soil sample as well as the garlic plant shoots, with an average density of 75 individuals per 100 mL. Microscope slides were prepared from adult individuals and subjected to morphological and morphometric analysis, as well as DNA examination. It was demonstrated that the examined nematodes belong to the species Robustodorus subtenuis. Both the female and male nematodes differed from individuals previously found in the cultivation of Narcissus and Gladiolus. On average, R. subtenuis females have shorter bodies and longer tails, with the averages calculated for the nematode population from the soil being slightly lower than the average values for nematodes from the garlic shoots. Additionally, the females found in the soil had a shorter distance from the lip region to the vulva and a shorter post-vulval sac, the length of which constituted 32 to 45% of the distance from the vulva to the anus. On average, the male bodies were shorter and had longer tails. They were also wider at the level of the anus. The average body length of males isolated from the soil, like that of the females, was lower than the average for individuals isolated from the garlic shoots. Variations in the influence of the host plant on the morphometry of the parasitic nematodes were observed. This is the first report of R. subtenuis colonizing garlic plants in Poland.

Meloidogyne hapla is a serious pest of many cultivated plants. In response to the economic significance of the species, efforts are being made to develop a new method to reduce its harmful effects on crops. The aim of the study was to determin...

Meloidogyne hapla is one of the most important nematode pathogens. It is a sedentary, biotrophic parasite of plants that overwinters in the soil or in diseased roots. The development of M. hapla is temperature dependent. Numerous studies have been performed on the effect of temperature on the development of M. hapla, but only a few of them analyzed the heat shock protein (hsp) genes. The aim of the study was to perform expression profiling of eight hsp genes (Mh-hsp90, Mh-hsp1, Mh-hsp4, Mh-hsp6, Mh-hsp60, Mh-dnj19, Mh-hsp43, and Mh-hsp12.2) at two development stages of M. hapla, i.e., in eggs and second-stage juveniles (J2). The eggs and J2 were incubated under cold stress (5 °C), heat stress (35 °C, 40 °C), and non-stress (10 °C, 20 °C, and 30 °C) conditions. Expression profiling was performed by qPCR. It was demonstrated that only two genes, Mh-hsp60 and Mh-dnj19, have been upregulated by heat and cold stress at both development stages. Heat stress upregulated the expression of more hsp genes than cold stress did. The level of upregulation of most hsp genes was more marked in J2 than in eggs. The obtained results suggest that the Mh-hsp90 and Mh-hsp1 genes can be used as bioindicators of environmental impacts on nematodes of the Meloidogyne genus.

The population dynamics of Tetranychus urticae (two-spotted spider mite – TSSM) are influenced by environmental factors, which were investigated to identify methods limiting the development and harmfulness of this pest. This paper presents findings from a laboratory study on the effect of spraying with water-based extracts of Mentha piperita and Tagetes patula plants on the growth rate of TSSM larvae and nymphs. The time required for the transformation of the larvae into protonymphs was longer for T. patula water- based extracts than extracts from M. piperita. Differences in the time of transformation from the nymphal stage to adult TSSM were also observed depending on the plant waterbased extracts, their concentration, and the host plant on which nymphs were developing. The use of 100 g ∙ l-1 French marigold extract was associated with longer transformation time of nymphs on discs of pea leaves than all tested concentrations of French marigold extract applied to sugar beet leaves. Ten percent of the extracts from peppermint plants had a stronger limiting effect on TSSM nymphs on pea leaves than on bean or sugar beet leaves.