This paper briefly presents the aims, requirements and results of partial least squares regression analysis (PLSR), and its potential utility in ecological studies. This statistical technique is particularly well suited to analyzing a large array of related predictor variables (i.e. not truly independent), with a sample size not large enough compared to the number of independent variables, and in cases in which an attempt is made to approach complex phenomena or syndromes that must be defined as a combination of several variables obtained independently. A simulation experiment is carried out to compare this technique with multiple regression (MR) and with a combination of principal component analysis and multiple regression (PCA+MR), varying the number of predictor variables and sample sizes. PLSR models explained a similar amount of variance to those results obtained by MR and PCA+MR. However, PLSR was more reliable than other techniques when identifying relevant variables and their magnitudes of influence, especially in cases of small sample size and low tolerance. Finally, we present one example of PLSR to illustrate its application and interpretation in ecology.

https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1600-0706.2008.16881.x

Partial least squares regression as an alternative to current regression methods used in ecology

Wild boar are now present on all continents except Antarctica and can greatly affect community structure and ecosystem function. Their destructive feeding habits, primarily rooting disturbance, can reduce plant cover, diversity, and regeneration. Furthermore, predation and habitat destruction by boar can greatly affect animal communities. Effects of wild boar on fungi and aquatic communities are scarcely studied, and soil properties and processes seem more resistant to disturbance. Wild boar also affect humans’ economy as they cause crop damage and transmit diseases to livestock and wildlife. In this review, we found that most of the published literature examines boar effects in their introduced range and little is available from the native distribution. Because most of the research describes direct effects of wild boar on plant communities and predation on some animal communities, less is known about indirect effects on ecosystem function. Finally, predictive research and information on ecosystem recovery after wild boar removal are scarce. We identified research gaps and urge the need to lower wild boar densities. Identifying commonalities among wild boar impacts on native ecosystems across its introduced range will help in the design of management strategies.

Impact of wild boar (Sus scrofa) in its introduced and native range: a review

For many leaf-feeding herbivores, synchrony in phenology with their host plant is crucial as development outside a narrow phenological time window has severe fitness consequences. In this review, we link mechanisms, adaptation, and population dynamics within a single conceptual framework, needed for a full understanding of the causes and consequences of this synchrony. The physiological mechanisms underlying herbivore and plant phenology are affected by environmental cues, such as photoperiod and temperature, although not necessarily in the same way. That these different mechanisms lead to synchrony, even if there is spatial and temporal variation in plant phenology, is a result of the strong natural selection acting on the mechanism underlying herbivore phenology. Synchrony has a major impact on the population densities of leaf-feeding Lepidoptera, and years with a high synchrony may lead to outbreaks. Global climate change leads to a disruption of the synchrony between herbivores and their host plants, which may have major impacts for population viability if natural selection is insufficient to restore synchrony.

Phenology of forest caterpillars and their host trees: the importance of synchrony.

Climate Change and Agriculture in the United States: Effects and Adaptation

https://www.fs.fed.us/rm/pubs_other/rmrs_2012_regniere_j001.pdf

Effects of temperature on development, survival and reproduction of insects: experimental design, data analysis and modeling.

Multicoloured Asian lady beetle (Harmonia axyridis [Pallas], Coleoptera, Coccinellidae) - invasive beneficial species.

In 2009, three Slovenian strains of entomopathogenic nematodes) and commercial product Entonem (active ingredient S. feltiae), were tested under laboratory conditions for their activity against adult cereal leaf beetles (Oulema melanopus). The nematode strains were tested at four different doses (250, 500, 1000, and 2000 infective juveniles/adult) and at three temperatures (15, 20, and 25 oC). Steinernema carpocapsae strain C101 was the most effective and showed itself to be a good alternative to chemical insecticides, and appears to have the highest potential for controlling overwintered cereal leaf beetles under field conditions. In our bioassay the temperature had the greatest influence on the efficacy of the entomopathogenic nematode strains; both S. feltiae treatments (strain B30 and Entonem) proved to work better at the lowest temperature, however the strain H. bacteriophora D54 had its best efficacy at the highest temperature in the experiment. Several species (S. feltiae and S. carpocapsae) have been efficient at lower suspension concentrations, which enables their economical usage against the cereal leaf beetle in integrated cereal production in the future.

/pdf/activity-of-entomopathogenic-nematodes-rhabditida-against-1th6hkbgki.pdf

Activity of entomopathogenic nematodes (Rhabditida) against cereal leaf beetle (Oulema melanopus [L.], Coleoptera, Chrysomelidae) adults under laboratory conditions.

Spraying parameters are important factors when spraying wheat heads against fusarium head blight (FHB) to control the deoxynivalenol level in the grain and to obtain high and quality yields. In 2019 and 2020, field trials were conducted in order to establish the effect of the spraying pressure (2 bar, 4 bar, and 6 bar) of special nozzles with a variable flow rate Agrotop VR 1.5 on the head fungicide coverage, yield parameters, and the deoxynivalenol (DON) value in the grain. The coverage of the front and rear sides of wheat heads increased with the increase of spraying pressure from 2 to 6 bar. In 2019, when the infection with FHB was more severe, no significant differences appeared in the yield and the hectoliter weight at a lower spraying pressure, while the DON value at this pressure approached the maximum permissible level. In that year, the DON value exponentially fell with the increase of spraying pressure. In 2019, the thousand grain weight was higher at the spraying pressure of 6 bar than at the pressures of 2 and 4 bar. The results show that also a lower spraying pressure (2 bar) and a volume application rate (117 L/ha) below the recommended one suffice to retain the DON value in the grain below the maximum permissible level, even in years with more severe infection.

https://www.mdpi.com/2073-4395/11/1/43/pdf

The Influence of the Spraying Pressure of an Injector Asymmetric Double Nozzle with Variable Flow on Head Fungicide Coverage, Yield, Grain Quality, and Deoxynivalenol Content in Winter Wheat

/pdf/controlling-the-western-corn-rootworm-with-the-help-of-4czrvjc32s.pdf

Controlling the western corn rootworm with the help of cellulose pearls

IZVLECEK V kmetijskih ekosistemih lahko talni skodljivci povzrocijo veliko gospodarsko skodo. Za njihovo zatiranje se najveckrat uporabi kemicna fitofarmacevtska sredstva, ki pa imajo lahko tudi negativne vplive na okolje. Raziskovalci zato preucujejo druge možnosti zatiranja tako nadzemskih kot tudi talnih skodljivih organizmov v kmetijstvu. Gibanje organizmov je povezano z zaznavanjem kemicnih dražljajev iz okolja. Studije so v zadnjih letih pokazale, da se proti kemicnim dražljajem lahko gibajo tudi naravni sovražniki skodljivcev (entomopatogene ogorcice). Govorimo o t.i. neposredni obrambi rastlin pred skodljivimi organizmi. Rastlina, ki jo je napadel herbivor, zacne v okolico sproscati kemicne signale, ki na naravne sovražnike povzrocitelja delujejo privabilno. Doslej je bilo identificiranih le nekaj kljucnih spojin, ki so odgovorne za posredovanje v tako imenovanih multitroficnih interakcijah in le nekaj genov ter biokemicnih poti, ki so odgovorne za proizvodnjo hlapljivih organskih snovi (HOS). Mnoge spojine ostajajo se vedno neznane, toda identifikacija le-teh ima velik potencial za uporabo pri varstvu rastlin. Napredki v razumevanju rastlinskih emisij in njihove vloge pri signaliziranju predstavljajo enega izmed novih nacinov manipulacije rastlinskih eksudatov, s katerimi bi izboljsali naravne obrambne lastnosti rastlin. Kljucne besede : entomopatogene ogorcice, talni skodljivci, HOS, neposredna rastlinska obramba ABSTRACT In agricultural ecosystems, soil pests can cause great economic damage. Pesticides are often used for their control, but they may also have negative effects on the environment. Researchers are therefore exploring other options for suppressing both above-ground and soil-dwelling organisms in agriculture. The movement of organisms is associated with the detection of chemical stimuli from the environment. Studies have shown in recent years that natural enemies (entomopathogenic nematodes) of pests can also move against chemical stimuli. The term is known as an indirect plant defense. The plant that has been attacked by the herbivor starts to release chemical signals to the environment, which act on the natural enemies of the pests. To date, only a few key compounds have been identified that are responsible for mediation in so-called multitrophic interactions and only a few genes and biochemical pathways that are responsible for the production of volatile organic compounds (VOCs). Many compounds remain unknown, but their identification has great potential for use in plant protection. Progress in understanding plant emissions and their role in signaling is one of the new ways to manipulate plant exudates to improve the natural defenses of plants. Key words: entomopathogenic nematodes, soil-dwelling pests, VOCs, indirect plant defense

/pdf/multitroficne-interakcije-med-rastlinami-talnimi-skodljivimi-8g5duccla9.pdf

Multitrofične interakcije med rastlinami, talnimi škodljivimi žuželkami ter entomopatogenimi ogorčicami / Multitrophic interaction between plants, underground pests and entomopathogenic nematodes

Stanislav Trdan

Papers

Multicoloured Asian lady beetle (Harmonia axyridis [Pallas], Coleoptera, Coccinellidae) - invasive beneficial species.

Activity of entomopathogenic nematodes (Rhabditida) against cereal leaf beetle (Oulema melanopus [L.], Coleoptera, Chrysomelidae) adults under laboratory conditions.

The Influence of the Spraying Pressure of an Injector Asymmetric Double Nozzle with Variable Flow on Head Fungicide Coverage, Yield, Grain Quality, and Deoxynivalenol Content in Winter Wheat

Controlling the western corn rootworm with the help of cellulose pearls

Multitrofične interakcije med rastlinami, talnimi škodljivimi žuželkami ter entomopatogenimi ogorčicami / Multitrophic interaction between plants, underground pests and entomopathogenic nematodes