This book contains 20 chapters about the impact, environmental fate, modes of action, efficacy, and non-target effects of insecticides. The chapters are divided into 7 parts. Part 1 covers the ...non-target effects of insecticides, whereas part 2 is dedicated to integrated methods for pest control, in which insecticides are an important element for diminishing the populations of insect pests. Part 3 includes chapters about the non-chemical alternatives to insecticides, such as metabolic stress and plant extracts. Insecticides and human health are the main topic of part 4, and the interactions between insecticides and environment are discussed in part 5. Part 6 includes the chapters about insecticides against pests of urban areas, forests and farm animals, whereas biotechnology and other advances in pest control are discussed in part 7.
In a laboratory experiment, we studied the insecticidal effects of invasive alien plants on the rice weevil. The research was carried out in two parts. In the first part, we studied the insecticidal ...properties of seven different plant species, namely, Bohemian knotweed (Fallopia × bohemica), Japanese knotweed (Fallopia japonica), false indigo-bush (Amorpha fruticosa), tree of heaven (Ailanthus altissima), staghorn sumac (Rhus typhina), Canada goldenrod (Solidago canadensis), and giant goldenrod (Solidago gigantea). Mixtures of powders and wheat were prepared in two different concentrations, namely, 2.5 w% and 1.25 w%. The experiment was performed at temperatures 20 °C and 25 °C and at two humidity levels, 55% R.h. and 75% R.h. Very low mortality (below 8%) was found when using combinations with the higher relative humidity. No significant differences were observed between the effects of these concentrations. In the second part of the experiment, Norway spruce wood ash and diatomaceous earth (product SilicoSec®) were added to the powder obtained by milling leaves of four different invasive plant species (Canada goldenrod, staghorn sumac, tree of heaven, false indigo). In the independent application, wheat was added to the powder at a concentration 2.5 w%. In the treatments that involved mixtures of powder and wood ash/diatomaceous earth, we applied 1.25 w% plant powder and 1.25 w% wood ash or 1.25 w% plant powder and 450 ppm of a SilicoSec® preparation. The positive control was carried out as two separate treatments with 2.5 w% wood ash of Norway spruce and 900 ppm of the SilicoSec® product, while untreated wheat represented the negative control. The experiment was performed at two temperatures (20 °C and 25 °C) and two R.h. values (55 and 75% R.h.). The mortality of beetles was recorded on the 7th, 14th, and 21st day after the start of the experiment. Higher mortality rates of rice weevil adults were found at the higher relative humidity, and an important factor of mortality was also the day of exposure, as a higher mortality was found when the exposure of individuals to the tested substances was for a longer time period. After 21 days at 25 °C and 55% R.h., the combinations in which the lower concentration of Norway spruce wood ash was added to the powder of invasive alien plants achieved more than 90% mortality of beetles. By adding the plant powder of invasive alien plants to wood ash, we achieved a greater insecticidal efficacy of invasive plants and lower concentrations of wood ash. Nevertheless, the results of our research do not indicate any great usefulness of the plant powder of invasive plants in suppressing the rice weevil. Additional studies should primarily focus on the insecticidal efficacy of powder from the genus Solidago, which in our study, displayed the greatest insecticidal potential among the tested invasive plants.
In a laboratory study we investigated the contact and barrier efficacy of different natural substances (wood ash, sawdust, hydrated lime, and diatomaceous earth) against slugs of the genus Arion, an ...important agricultural pest. Natural substances were tested individually and in combination with each other. The experiment was carried out in plastic petri dishes and in glass insectaria. Moistened tampons and fresh leaves of lettuce were placed into both experimental arenas. The slugs were starved for 48 hours prior to the experiment. Six categories of behaviour were identified for slugs in the presence of the natural substances: (1) slug survived the experiment, (2) slug died during the experiment, (3) slug crossed the barrier, (4) slug did not cross the barrier, (5) slug fed on the lettuce, and (6) slug did not feed on the lettuce. The effect of different treatments (natural substances) was significant. The results of our study have shown that hydrated lime had the best contact efficacy on slugs (the mortality of slugs was 100%), both individually and in combination with other substances. The treatments with hydrated lime also proved to be the most efficient barrier preventing slugs from feeding on lettuce. Hydrated lime shows great potential in Arion control in our investigation; however, further research is needed to investigate the practical value (how to avoid the problem when the substance becomes wet), safety and economics of hydrated lime used in this way.
The wood ash from seven plant species (sessile oak, European beech, European hornbeam, silver fir, European spruce, common alder, and Spanish chestnut) was tested against Spanish slug (Arion ...vulgaris) as an environmentally acceptable alternative to chemical bait pellets. We carried out laboratory and semi-field experiments to assess the contact and barrier efficacy of selected wood ash. To demonstrate the contact efficacy, slugs were rolled in the wood ash. Geochemical analysis of wood ash was carried out as well. The highest concentrations of chemical compounds SiO2, Al2O3, Fe2O3, MgO and MnO and elements Ba, Co, Cs, Ga, Cu, Pb and Zn were identified in the most effective ashes (beech, oak, fir, and spruce) compared to the ineffective ashes (hornbeam, chestnut, black ader). The concentration of cobalt was comparably higher, while the concentration of molybdenum was comparably lower in the four most effective wood ashes. The results of our studies revealed that the wood ash of oak and spruce have great contact efficacy. The oak and beech wood ash showed the strongest barrier efficacy against slugs. In the semi-field trials, only 10% of the plants treated with oak wood ash were damaged by slugs. The oak wood ash is an efficient alternative for slug control, however, further studies and biotechnical enhancement are needed.
The effect of wireworm-damaged lettuce roots on the antioxidative defense system (ascorbate-glutathione cycle, photosynthetic pigments) and movement of insect/slug parasitic nematodes towards ...determined root exudates was studied in a glasshouse experiment. Lettuce seedlings were grown in a substrate soil in the absence/presence of wireworms (Elateridae). The ascorbate-glutathione system and photosynthetic pigments were analyzed by HPLC, while volatile organic compounds (VOC) emitted by lettuce roots were investigated by GC-MS. Herbivore-induced root compounds, namely 2,4-nonadienal, glutathione, and ascorbic acid, were selected for a chemotaxis assay with nematodes
,
,
,
, and
. Root pests had a negative effect on the content of photosynthetic pigments in the leaves of infested plants, indicating that they reacted to the presence of reactive oxygen species (ROS). Using lettuce as a model plant, we recognized the ascorbate-glutathione system as a redox hub in defense response against wireworms and analyzed its role in root-exudate-mediated chemotaxis of nematodes. Infected plants also demonstrated increased levels of volatile 2,4-nonadienal. Entomopathogenic nematodes (EPNs,
,
, and
) proved to be more mobile than parasitic nematodes
and
towards chemotaxis compounds. Among them, 2,4-nonadienal repelled all tested nematodes. Most exudates that are involved in belowground tritrophic interactions remain unknown, but an increasing effort is being made in this field of research. Understanding more of these complex interactions would not only allow a better understanding of the rhizosphere but could also offer ecologically sound alternatives in the pest management of agricultural systems.
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Whiteflies (Aleyrodidae) is small group of insects (Insecta) that comprises around 1500 species from 160 genera. Whiteflies damage important cultivated and ornamental plants by sucking plants juice. ...Most of the species are from tropical area, in our region they are the most common in greenhouses. Because worldwide transport, whiteflies become invasive all around the world. The identification of whiteflies species in adult stage is problematic. Morphological differentiation of pupae is one of the better methods for determining identity of species, but it may vary depending on the host plant on which they develop which can lead to misidentifications and erroneous naming of new species. The application of genetic diagnostics under the umbrella of classical taxonomy was imperative for successful development and delivery of the biological control program, phylogenetics and plans for biological control. The most common modern techniques for whiteflies determination are computer programs for photography analysis, molecular methods with DNA isolation and sequencing.
The western corn rootworm (WCR),
LeConte (Coleoptera, Chrysomelidae), is an important insect pest of maize in North America and Central and Eastern Europe. In Central Europe, the larvae emerge in May ...and its three instars feed intensively on maize roots in June, causing plant lodging that leads to a loss of economic yield. A three-year field experiment (2016-2018) was conducted to compare the effectiveness i) of soil-applied granular insecticide based on the active ingredient tefluthrin, ii) of maize seeds dressed with thiacloprid, and iii) entomopathogenic nematodes
Poinar (Rhabditida: Heterorhabditidae, product Dianem) against WCR larvae. An additional treatment with alcohol ethoxylate (i.e., soil conditioner) mixed with entomopathogenic nematodes was performed in 2017 and 2018 to check for any increase of entomopathogenic nematodes' effectiveness. Field tests were carried out in two fields infested naturally with a WCR pest population, one in Bučečovci (Eastern Slovenia) and the other in Šmartno pri Cerkljah (northern Slovenia), exhibiting dissimilar pedo-climatic conditions and soil pest densities. The treatments were performed in five replicates per experiment in each year. The efficacy of the treatments was very similar at both locations, despite the approximately five-fold lower WCR soil pest densities in northern than in eastern Slovenia, as well as being constant over time. The largest number of WCR beetles was observed in the negative control, followed by that of beetles subjected to thiacloprid treatment (insignificant decrease taking into account the entire three-year dataset). Treatments with tefluthrin (44.1 ± 11.7%),
(46.2 ± 7.4%), and
+ alcohol ethoxylate (49.2 ± 1.8%) significantly decreased the numbers of emerging beetles. Treatments of thiacloprid,
, and
alcohol ethoxylate additionally led to significantly increased maize plant weights. Furthermore, entomopathogenic nematodes were able to persist in maize fields for almost five months at both experimental locations in silty and sandy loam soils. It was concluded that the control of WCR larvae in maize using the entomopathogenic nematode
is as effective as a tefluthrin treatment, and could thus offer a sustainable
biological control management option in Europe.
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Four types of nozzles were tested on large-scale trials with a 40 m2 plot unit size. The Avi Twin 110-01 (80 L ha−1), 110-02 (160 L ha−1), 110-03 (240 L ha−1), and 110-04 (320 L ha−1) symmetric ...double fan injector nozzles were tested during the 2020/2021 and 2021/2022 growing seasons. This study aimed to evaluate the performance of spray nozzles with regard to deoxynivalenol (DON) accumulation in durum wheat grains. Artificial inoculation with Fusarium spp. was performed after durum heads were protected with fungicide. The percentage of heads covered with fungicide droplets, grain yield, yield-related traits, technological quality parameters, and concentrations of DON were determined. Compared to the control (without fungicide treatment), the Avi Twin 04 nozzle caused a reduction of 45.0% in the DON concentration on average across both growing seasons. This positively corresponded to the percentage of heads covered with fungicide droplets, which was highest when this nozzle was utilized. In both trial years, the DON reduction caused by the 110-04 twin nozzle was higher than that caused by the 110-01 nozzle. Treatment with the 110-04 nozzle more effectively improved the grain yield, 1000-kernel weight, and test weight compared to treatment with the 110-01 nozzle and the untreated control. The differences in technological quality were less pronounced when different spray nozzles were used.
The use of aeration, which refers to cooling of a grain mass using low-volume airflow rates with ambient air, is an under-utilized component of management programs. A model simulation study was ...conducted for the country of Slovenia by examining historical weather data for 10 selected sites to determine if sufficient cooling hours <15 °C were available in August and September to cool stored wheat. The weather data were then coupled with a degree-day model to determine if a generation of Sitophilus oryzae (L.), the rice weevil, could be produced in the absence of aeration, using a start date of 1 August. The weather data for September was used to classify Slovenia into different risk zones, depending on the number hours <15 °C. Three sites from each zone, from warmest to coolest, Portorož, Novo Mesto, and Lesce, were further examined using a web-based aeration model and insect population growth model for S. oryzae developed by Texas A&M University Beaumont TX for cooling stored rough rice, to predict bin temperatures and population growth from 1 August to 30 November. The results show that, for most of Slovenia, in the absence of aeration, a complete generation of S. oryzae could occur based on an infestation beginning 1 August. The use of aeration immediately cooled stored wheat in the three selected sites, resulting in a dramatic decrease in predicted populations of S. oryzae in aerated wheat compared to unaerated wheat. The results show that the use of aeration may be expanded in Slovenia for management of stored commodities, and it could help alleviate dependence on insecticides for insect pest management after harvest.
In plants, apical dominance prevents the development of lateral shoots. It can be overwhelmed by apical bud defoliation, allowing numerous lateral buds to develop into more lateral branches carrying ...more fruits and possibly increasing seed yield. This study tested this hypothesis on five hemp (Cannabis sativa L.) cultivars in a 2-year field experiment. In comparison to the intact ones, the defoliated plants developed several lateral shoots. The hemp seed yield was significantly influenced by the year of production, the apical bud removal, and the cultivar. The average two-year seed yield of the defoliated plants (715 ± 47 kg/ha) was significantly higher than the yield of the intact plants (568 ± 35 kg/ha). Absolutely the greatest effect of apical bud removal on the seed yield was observed for the cultivar 'Novosadska konoplja', where increase was 225 kg/ha (25%); a slightly smaller difference occurred for the cultivar 'Uniko-B' (183 kg; 30%), followed by 'Juso-11' (140 kg/ha; 27%) and 'Bialobrzeskie' (128 kg/ha; 29). Cultivar 'Beniko' presented the smallest difference with apical bud removal - 58 kg/ha (15%) yield increase We maintain that hemp producers can achieve a larger seed yield not only by selecting an appropriate cultivar and row distance but also by removing apical buds.
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