Seasonal dynamics of three lepidopteran stored grain pests in Slovenia

In the period 2004-2006 seasonal dynamics of Mediterranean flour moth (Ephestia kuehniella), Indianmeal moth (Plodia interpunctella) and Angoumois grain moth (Sitotroga cerealella) was studied in the mills and grain warehouses in central Slovenia. For this purpose pheromone traps were used from April until December, and the males of all three lepidopteran pests were counted in two week intervals. The three insect pests under investigation developed two peaks in capture per year that might represent two distinct generations per year. In the maize open air storage Ephestia kuehniella was the most numerous, while Plodia interpunctella was more frequent in the closed storage in mills and warehouses, Sitotroga cerealella was slightly less common in these latter closed warehouses. Keywords: Monitoring, Lepidoptera, Stored grain pest, Pheromones, Sloveni

Glucosinolates in plant protection strategies: A review

This review discusses the importance of glucosinolates in plant protection. The Brassicaceae, which are cultivated worldwide, use glucosinolates and their decomposition products to defend themselves against attacks by harmful organisms. The glucosinolate content varies among individual plant species, plant organs and developmental stages. The glucosinolate content in plants is also affected by biotic and abiotic factors, while the type or quantity of glucosinolate determines the susceptibility of the plants to insect pests. These facts can pose a problem when implementing this knowledge in cultivation of the Brassicaceae, especially in regions with moderate climates where Brassicaceae crops are exposed to attacks by a large number of harmful organisms. Under these circumstances, it is essential to research new, or to improve the existing environmentally acceptable methods of protecting Brassicaceae plants against economically important pests

Effect of spraying speed on head coverage of winter wheat with fungicide, occurrence of Fusarium head blight and deoxynivalenol, yield and grain quality

The effect of spraying speed (5, 8.5 or 12 km/h) on deposition quality of fungicide on a winter wheat head, yield, grain quality, occurrence of Fusarium head blight (FHB) and deoxynivalenol (DON) content in grains was investigated in 2011 and 2012. Asymmetric double flat fan air-injector nozzles were used in the trial at a spraying pressure of 5.0 bars. A prothiconazole + tebuconazole fungicide mixture was used for spraying. An increase of spraying speed significantly lowered coverage values at the front and rear parts of a wheat head. At all three spraying speeds, the rear part of a wheat head reached a better coverage value. The effect of spraying speed was significant in 2011, when the 5 km/h spraying speed generated a significantly higher grain yield and a significantly higher thousand-grain weight in comparison with the other treatments. In both trial years, the lowest grain yield occurred on the unsprayed control. In 2011 and 2012, the latter also reached the lowest hectolitre weight and thousand-grain weight. In both trial years, the unsprayed control had a significantly higher DONcontent than the other treatments. In 2012, the DONcontent on the unsprayed control exceeded the allowed maximum level. The spraying speed did not affect the DON content in the grains. The effect of spraying speed was also noted in the FHB incidence. A significantly lower FHB incidence occurred at the 5 and 8.5 km/h spraying speeds

QUANTITY OF GLUCOSINOLATES IN 10 CABBAGE GENOTYPES AND THEIR IMPACT ON THE FEEDING OF MAMESTRA BRASSICAE CATERPILLARS

Abstract -In 2011, we studied the glucosinolate content in 5 cultivars and 5 cabbage hybrids grown outdoors in order to study their influence on the feeding of cabbage moth caterpillars (Mamestra brassicae). The selected genotypes were categorized into three groups, early (the growth period from 55 to 70 days), mid-early (80-90 days) and mid-late (110-140 days), while the samples of cabbage for glucosinolate analysis were taken at five intervals, during which we also assessed genotypes for the extent of damage caused by caterpillars. We found that the feeding of caterpillars affected primarily the mid-early and mid-late genotypes of cabbage, and that the glucosinolate content among the different cabbage genotypes varies. The highest content of the analyzed glucosinolates was established in mid-late genotypes. Glucobrassicin was the only glucosinolate found in all cabbage genotypes, yet its antixenotic effect (r=0.20) was very low. We found that sinalbin negatively affects the feeding of cabbage moth caterpillars in mid-early cabbage genotypes (r=-0.34), while the same effect of sinigrin on the extent of damage can be observed in mid-late genotypes (r=-0.27). We have established a strong or moderate correlation between the gluconapin (r=0.87) and progoitrin (r=0.66) contents in mid-late genotypes and the extent of damage caused by caterpillars. Our research proves that different cabbage genotypes are responsible for different susceptibilities to damage by the cabbage moth, and that one of the factors of natural resistance of cabbage are also glucosinolates. Despite this, due to their variability in cabbage we cannot precisely determine the set of genotypes that would ensure a higher cabbage yield as a result of less damage caused by the cabbage moth. Thus, we need to identify in more detail the reasons for the time and quantum variability of glucosinolates in Brassicaceae

Native and non-native egg parasitoids associated with brown marmorated stink bug (Halyomorpha halys [stål, 1855]; hemiptera: Pentatomidae) in western slovenia

Halyomorpha halys (Hemiptera: Pentatomidae), native to East Asia, has become a globally invasive pest, as a serious threat to agricultural production and a notorious nuisance pest in urban areas. Considerable efforts have been made so far to develop effective pest control measures to prevent crop damage. Biological control of this invasive stink bug by egg parasitoids has proven to be the most environmentally sustainable long-term solution. Knowledge of the native egg parasitoid fauna is of key importance when implementing a biological control program. Therefore, the main objective of our study was to detect egg parasitoid species associated with H. halys in the Goriška region (Western Slovenia) and to evaluate their impact on the pest population under field conditions. In the years 2019 and 2020, around 4600 H. halys eggs were collected in the wild and more than 3400 sentinel eggs were exposed to detect parasitoids in the field. Five egg-parasitoid species emerged from H. halys eggs: Anastatus bifasciatus (Hymenoptera: Eupelmidae), Telenomus sp., Trissolcus basalis, Trissolcus mitsukurii (Hymenoptera: Scelionidae) and Ooencyrtus telenomicida (Hymenoptera: Encyrtidae), all of them are new records for Slovenia. The native species, An. bifasciatus, dominated in urban and suburban areas, while non-native Tr. mitsukurii prevailed in agricultural areas. Overall parasitism rates of naturally laid eggs by the parasitoid species complex in 2019 and 2020 was 3.0 and 14.4%, respectively. Rapid recruitment of native parasitoids, early detection of an effective alien parasitoid species and increasing overall parasitism rates are very encouraging results, which need to be followed and verified in future research

Head and leaf fungicide deposit on winter wheat, deoxynivalenol content and yield parameters as affected by different nozzle types

In 2014 and 2015, we studied the effect of fungicide spraying with 11 different nozzles on the quality and quantity of head and leaf fungicide deposit, the percentage of Fusarium head blight (FHB) incidence, FHB index, the DON content, yield and grain quality parameters. The best quality and quantity of fungicide deposit on the front and rear head sides was achieved with the TeeJet Turbo FloodJet TF VP2 nozzle (FLOOD) and the Albuz AVI-TWIN 110-03 nozzle (AVI). In comparison with the majority of treatments, the FHB incidence and the FHB index was the highest on the unsprayed control. The FHB index was higher using the Lechler IDK 120-03 nozzle (IDK) than with the other nozzle types. In all the treatments, the DON content in the grain was less than 50 μg/kg. At this very low level of infection this is not surprising. The grain yield was the smallest on the unsprayed control. Better fungicide coverage of wheat heads with the FLOOD and AVI nozzles did not result in a statistically higher yield or better grain quality parameters. Negative correlations were confirmed between yield and variables as DON content, FHB incidence and FHB index and also between falling number and variables as fungicide coverage, FHB incidence and FHB index. Positive correlations were determined between DON content and FHB incidence, between hectolitre weight and variables as spray deposit and coverage and between protein content and variables as spray deposit and coverage

Development of high-throughput methods to screen disease caused by Rhizoctonia solani AG 2-1 in oilseed rape

Background: Rhizoctonia solani (Kühn) is a soil-borne, necrotrophic fungus causing damping off, root rot and stem canker in many cultivated plants worldwide. Oilseed rape (OSR, Brassica napus) is the primary host for anastomosis group (AG) 2-1 of R. solani causing pre- and post-emergence damping-off resulting in death of seedlings and impaired crop establishment. Presently, there are no known resistant OSR genotypes and the main methods for disease control are fungicide seed treatments and cultural practices. The identification of sources of resistance for crop breeding is essential for sustainable management of the disease. However, a high-throughput, reliable screening method for resistance traits is required. The aim of this work was to develop a low cost, rapid screening method for disease phenotyping and identification of resistance traits. Results: Four growth systems were developed and tested: (1) nutrient media plates, (2) compost trays, (3) light expanded clay aggregate (LECA) trays, and (4) a hydroponic pouch and wick system. Seedlings were inoculated with virulent AG 2-1 to cause damping-off disease and grown for a period of 4–10 days. Visual disease assessments were carried out or disease was estimated through image analysis using ImageJ. Conclusion: Inoculation of LECA was the most suitable method for phenotyping disease caused by R. solani AG 2-1 as it enabled the detection of differences in disease severity among OSR genotypes within a short time period whilst allowing measurements to be conducted on whole plants. This system is expected to facilitate identification of resistant germplasm

Efectividad de las vallas electrificadas con electrodos de cobre en el control de las babosas (Arion spp.) bajo corriente continua y voltaje eléctrico

Terrestrial slugs of the genus Arion are native to Europe, where they represent an important agricultural pest. This study determined the effectiveness of electrified fencing on barrier crossing by slugs. The fences were placed in glass insectariums. DC (direct current) voltages (2, 4, 6, 8 and 10 V) applied across the fence were tested together with limiting electric current values (0.1, 0.01 and 0.001 mA). Four categories of behavior were identified for slugs in the presence of an electrified fence: the animals (1) were stationary, (2) were moving but avoided the electrodes, (3) touched the electrodes and/or attempted unsuccessfully to cross the electrified fence and (4) succeeded in crossing the electrified fence. The effect of the applied voltages and the limiting current values on slug movement was highly significant. Forty-one percent of slugs crossed the fence at the lowest applied voltage, whereas only 1% of slugs succeeded in crossing at the highest voltage. The lowest limiting current values resulted in the most frequent fence crossings. For larger voltages and limiting currents, the frequency of slug crossings was effectively zero at fence regions positioned on the glass walls of the insectariums. In conclusion, this method of slug prevention may be highly effective, environmentally friendly and may result in deterrence, not death, of terrestrial slugs, a ubiquitous pest responsible for significant economic damage in agriculture.Las babosas terrestres del género Arion son nativas de Europa, donde representan una importante plaga agrícola. En este trabajo se determinó la eficacia de usar barreras electrificadas para impedir el paso de las babosas. Se colocaron vallas electrificadas en insectarios de vidrio y se aplicaron voltajes de CC (2, 4, 6, 8 y 10 V), limitados por diferentes valores de corriente eléctrica (0,1, 0,01 y 0,001 mA). Se identificaron cuatro diferentes respuestas de comportamiento de las babosas: (1) se quedaron quietas, (2) se movieron evitando los electrodos, (3) tocaron los electrodos e/o intentaron, sin éxito, cruzar la valla y (4) lograron cruzar la valla electrificada. El efecto de los voltajes aplicados y de los valores de corriente limitantes en el movimiento de las babosas fue muy significativo. El 41% de las babosas cruzó la valla con el menor voltaje aplicado, mientras que sólo el 1% de las babosas logró cruzar con el voltaje más alto. Los valores más bajos de corriente dieron lugar a los cruces más intensos de la valla. Para tensiones y corrientes más altas la frecuencia de los cruces de las babosas fue prácticamente cero en las zonas de la valla colocada en las paredes de vidrio de la insectarios. En conclusión, este método de control de las babosas puede ser muy eficaz, respetuoso con el medio ambiente y producir disuasión, no la muerte, de las babosas terrestres, una plaga responsable de importantes pérdidas económicas en la agricultura