Endophytic Beauveria bassiana activates expression of defence genes in grapevine and prevents infections by grapevine downy mildew Plasmopara viticola

Fungal entomopathogens like Beauveria bassiana (Ascomycota: Hypocreales) are known as antagonists of insects with multiple functional and ecological roles, and have attracted increased attention as biocontrol agents in integrated pest management programmes. For some crop plants, it has been proven that endophytic B. bassiana, besides its entomopathogenic habit, can provide protection against plant pathogens or limit their damaging effects. However, for grapevine, limited knowledge is available on the influence of endophytic B. bassiana on fungal pathogens and about the mechanisms underlying putative protection effects. This study assessed the protective potential of endophytic B. bassiana against grapevine downy mildew Plasmopara viticola in greenhouse experiments. Three and seven days after a B. bassiana treatment, potted grapevine plants were inoculated with P. viticola and the evolving disease severity was assessed. Disease severity was significantly reduced in B. bassiana-treated plants compared to control plants, depending on the age of leaves. Furthermore, a microarray and an RT-qPCR analysis were performed to work out fundamental aspects of genes involved in the interaction between grapevine and B. bassiana. The results indicate an up-regulation of diverse defence-related genes in grapevine as a response to endophytic establishment of B. bassiana. Thus, endophytic establishment of an entomopathogenic fungus such as B. bassiana in grapevine plants would represent an alternative and sustainable plant protection strategy, with the potential for reducing pesticide applications in viticulture.     

Virulence of select entomopathogenic fungi to the brown marmorated stink bug, Halyomorpha halys (Stål) (Heteroptera: Pentatomidae)

The brown marmorated stink bug. Halyomorpha halys, (BMSB) is an exotic pest causing damage to fruits and vegetables. They also transmit diseases. Integrated pest management strategies are lacking for this invasive. For the first time, information is presented on the virulence of several entomopathogenic fungi against BMSB. Three Beauveria bassiana and two Metarhizium anispoliae isolates were bioassayed against adult BMSB. One B. bassiana isolate was the active ingredient in BotaniGard^® which produced 85 and 100% mortality in 9 and 12 days post treatment, respectively. Experimental isolates ERL 1170 and ERL 1540 were also efficacious. Metarhizium anispoliae isolates produced lower mortalities than the B. bassiana isolates. Data presented showed the potential for management of BMSB with entomopathogenic fungi. Copyright © 2012 Society of Chemical Industry     

Insecticidal efficacy of beauveria bassiana,diatomaceous earth and fenitrothion against rhyzopertha dominica and tribolium castaneum on stored wheat

Bioassays were conducted in stored grains to evaluate the combined use of the entomopathogenic fungus Beauveria bassiana, diatomaceous earth (DE) and fenitrothion against adults of Rhyzopertha dominica and Tribolium castaneum. The insecticide agents were applied to wheat as follows: the fungus at 1 × 10⁸ conidia/kg of wheat, DE at 3 g/kg of wheat and fenitrothion at a rate of 0.15 ml/kg of wheat (25% of field dose rate). Surviving insects and progeny production were monitored at thirty-day intervals until four months. For both insect species, significantly less progeny was produced on wheat treated with fenitrothion and DE + B. bassiana formulations in comparison with controls. The effect of insecticides on the grain damage, germination power of wheat and bulk density was also evaluated. After four months, B. bassiana mixed with DE reduced the damaged insect grains by 50% in comparison with both fenitrothion and control treatments. Trials using DE caused a reduction in bulk density while there were no significant differences for germination testing between treatments.     

Systemic action of novel neonicotinoid insecticide IPP‐10 and its effect on the feeding behaviour of Rhopalosiphum padi on wheat

BACKGROUND: IPP‐10 is a novel neonicotinoid insecticide recently developed in China and has good activity against sucking insects. Studies were carried out to investigate the activity of IPP‐10 against Rhopalosiphum padi L. RESULTS: The results demonstrated that IPP‐10 had both contact and systemic activity, including acropetal and basipetal translocation in wheat vascular bundles. Starved R. padi were allowed to stay on wheat treated with a sublethal dose of IPP‐10. The results of studying their feeding behaviour from an electrical penetration graph (EPG) revealed a decrease in total time and bout duration of xylem and phloem ingestion, but the total time and bout duration of phloem salivation were significantly prolonged. The frequency (7.03 ± 0.49 Hz) of the xylem ingestion waveform produced by aphids on wheat treated with IPP‐10 was significantly lower than that of blank control aphids (8.20 ± 0.30 Hz). Consequently, aphids born on wheat treated with IPP‐10 were obviously lighter and less fecund than the control aphids. CONCLUSION: These tests indicated that IPP‐10 had both contact and systemic activity, with sublethal effects resulting in reduction in R. padi feeding behaviour, growth rate and fecundity. Copyright © 2010 Society of Chemical Industry     

Pathogenicity of <Emphasis Type="Italic">Beauveria bassiana</Emphasis> and <Emphasis Type="Italic">Metarhizium anisopliae</Emphasis> against <Emphasis Type="Italic">Galleria mellonella</Emphasis>

The greater wax moth Galleria mellonella L. (Lepidoptera: Pyralidae) is occasionally found in beehives and is a major pest of stored wax. Entomopathogenic fungi have recently received attention as possible biocontrol elements for certain insect pests. In this study, 90 isolates of Beauveria bassiana and 15 isolates of Metarhizium anisopliae were screened for proteases and lipases production. The results showed significant variations in the enzymatic action between the isolates. In the bioassay, the selected isolates evinced high virulence against the 4th instar of the G. mellonella larvae. The isolates BbaAUMC3076, BbaAUMC3263 and ManAUMC3085 realized 100% mortality at concentrations of 5.5 × 10⁶ conidia ml⁻¹, 5.86 × 10⁵ conidia ml⁻¹, and 4.8 × 10⁶ conidia ml⁻¹, respectively. Strong enzymatic activities in vitro did not necessarily indicate high virulence against the tested insect pest. The cuticle of the infected larvae became dark and black-spotted, indicating direct attack of fungus on the defense system of the insects. The LC₅₀ values were 1.43 × 10³, 1.04 × 10⁵ and 5.06 × 10⁴ for Bba3263AUMC, Bba3076AUMC and Man3085AUMC, respectively, and their slopes were determined by computerized probit analysis program as 0.738 ± 0.008, 0.635 ± 0.007 and 1.120 ± 0.024, respectively.     

Effect of <Emphasis Type="Italic">Beauveria bassiana</Emphasis> mixed with diatomaceous earth on mortality,mycosis and sporulation of <Emphasis Type="Italic">Rhyzopertha dominica</Emphasis> on stored wheat

A laboratory assay was designed to determine the insecticidal efficacy of Beauveria bassiana (Balsamo) Vuillemin (Hyphomycetes: Moniliales) and diatomaceous earth (Diafil 610) against Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae). The fungus B. bassiana was applied at 2.23 × 10⁷, 2.23 × 10⁸ and 2.23 × 10⁹ conidia kg⁻¹ of wheat individually as well as mixed with 200 and 400 ppm of Diafil 610. The conditions for the trials were 30 ± 2^oC with 55% r.h. and the counts for mortality were made after 8, 16 and 24 d. All the dead adults were removed after each count and the vials were kept for the next 60 d to assess the emergence of the F₁ generation. The findings from these studies proved that the extended exposure interval and the highest combined dose rate of the entomopathogenic fungus and the diatomaceous earth gave the maximum mortality of the beetles. The emergence of the progeny was also highly suppressed where the maximum dose rate of the synergized treatments was applied. The rate of mycosis and sporulation in the cadavers of R. dominica was maximum where the low dose rates of B. bassiana were applied.     

Sublethal effects of four insecticides on the reproduction and wing formation of brown planthopper, Nilaparvata lugens

BACKGROUND: The brown planthopper (BPH), Nilaparvata lugens Stål, is a major rice pest in many parts of Asia. Neonicotinoids such as imidacloprid and dinotefuran are widely used for control of this pest, and resistance to these insecticides has developed in recent years. This pest has also been widely exposed to triazophos and fenvalerate, although these insecticides are not used for the control of the pest directly. Here, the effects of sublethal doses of these four insecticides on the reproduction and wing formation in BPH were examined. RESULTS: Imidacloprid and dinotefuran reduced the fecundity of BPH to 68.8% and 52.4% in macropterous families, and to 57.9% and 43.1% in brachypterous families, when compared with the untreated controls. By contrast, triazophos and fenvalerate increased fecundity. In both macropterous and brachypterous families, sublethal doses of imidacloprid and dinotefuran showed significant induction of macropterous adults. CONCLUSION: Imidacloprid and dinotefuran could reduce the fecundity of BPH to a significant extent, demonstrating further activity against this pest in addition to their direct toxicity. The significant induction of macropterous adults by sublethal doses of imidacloprid and dinotefuran is of importance in the management of this pest, particularly in the areas of predicting the size of emigrating populations and the numbers of insects likely to occur in newly colonized areas. Copyright © 2008 Society of Chemical Industry     

Development of an integrated pest management programme for cotton. Part 1: Establishing and utililizing natural enemies

The strategy for the control of cotton pests, notably Helicoverpa spp., in Australia is insecticide-dependent with limited consideration of the role of beneficial insects. A programme for the development of an integrated pest management (IPM) approach commenced in cotton fields at Norwood near Moree in New South Wales in 1992. In this approach, an alternative crop, lucerne (Medicago sativa), was used in an interplant system plus spraying of cotton with a supplementary food (Envirofeast®), which served to attract and retain predators in treated plots. The predator complex consisted of predatory beetles, bugs, lacewings and spiders. The deployment of these two components, interplants and predator retention, reduced the number of Helicoverpa spp. eggs, very small and small larvae (first, second and third stages), medium and large larvae (fourth and fifth stages) and resulted in a cotton yield (2.72 bales ha^?1) that was significantly higher (p < 0.01) than the yield from the untreated control plot (0.59 bales ha -1 ). However, the yield from the interplants and food sprayed plot was significantly lower (p < 0.01) than in the insecticide-managed plot (7.12 bales ha^?1). Whenever the ratio of predators to Helicoverpa spp. (pests) per metre row of cotton was S 0.5, Helicoverpa pest numbers were maintained below the economic damage threshold. Though not successful in suppressing Helicoverpa spp. numbers, to avoid significant yield loss, further improvement could be made by introducing other potential components to the IPM strategy.     

PGPR and entomopathogenic fungus bioformulation for the synchronous management of leaffolder pest and sheath blight disease of rice

BACKGROUND: The biological control of plant pests and diseases using a single organism has been reported to give inconsistent and poor performance. To improve the efficacy, bioformulations were developed possessing mixtures of bioagents. RESULTS: Bioformulations combining Pseudomonas fluorescens Migula strains Pf1 and AH1 and Beauveria bassiana (Balsamo) Vuill. isolate B2 were developed and tested for their efficacy against leaffolder pest and sheath blight disease on rice under glasshouse and field conditions. The combination of Pf1, AH1 and B2 effectively reduced the incidence of leaffolder insect and sheath blight disease on rice compared with other treatments. An in vitro assay of leaffolder preference to rice leaf tissues treated with Pf1 + AH1 + B2 biformulation showed variation from normal growth and development of leaffolder larvae. Plants treated with the Pf1 + AH1 + B2 combination showed a greater accumulation of enzymes, lipoxygenase and chitinase activity against leaffolder insect compared with other treatments. Similarly, the plants showed a higher accumulation of defence enzymes, peroxidase and polyphenol oxidase activity against sheath blight pathogen in Pf1 + AH1 + B2 treatment compared with the untreated control. The bioformulation mixture attracted the natural enemy population of leaffolder under field conditions. In addition, a significant increase in rice grain yield was observed in Pf1 + AH1 + B2 treatment compared with the untreated control. CONCLUSION: The combination of P. fluorescens strains and B. bassiana isolate effectively reduced the incidence of leaffolder insect and sheath blight disease on rice plants and showed the possibility of controlling both pest and disease using a single bioformulation. Copyright © 2010 Society of Chemical Industry     

In vitro effects of flutriafol and azoxystrobin on Beauvaria bassiana and its efficacy against Tetranychus urticae

BACKGROUND: Testing the compatibility of chemical pesticides and fungal biocontrol agents is necessary if these two agents are to be applied together in the integrated management of plant pests and diseases. In this study, the fungicides azoxystrobin (a strobilurin) and flutriafol (a triazole) were tested in vitro for their effects on germination of conidia and mycelial growth of Beauveria bassiana (Bals.) Vuill. and in bioassay for their effect on fungal activity against Tetranychus urticae Koch. The fungicides were tested at three different concentrations [recommended rate for field use (1 × X) and the dilutions 10^?1× X and 10^?2× X]. RESULTS: Flutriafol inhibited growth of mycelia and germination of the fungal conidia at all concentrations tested in vitro, and also reduced the efficacy of B. bassiana in bioassays against mites. The inhibitive effect of azoxystrobin in vitro varied with the concentration applied. A significant effect was observed at 1 × X and 10^?1× X concentrations on both the germination of conidia and mycelia growth. At 10^?2× X concentration, azoxystrobin showed little effect on B. bassiana. However, when this fungicide was tested in bioassays, none of the concentrations reduced B. bassiana activity against mites. CONCLUSION: Azoxystrobin was most compatible with B. bassiana, while flutriafol was the most harmful. Further studies are required to confirm the negative effect of flutriafol on B. bassiana activity. Copyright © 2010 Society of Chemical Industry     

Novel use of nanostructured alumina as an insecticide

BACKGROUND: The worldwide need to produce an inexpensive and abundant food supply for a growing population is a great challenge that is further complicated by concerns about risks to environmental stability and human health triggered by the use of pesticides. The result is the ongoing development of alternative pest control strategies, and new, lower‐risk insecticidal molecules. Among the recent technological advances in agricultural science, nanotechnology shows considerable promise, although its development for use in crop protection is in its initial stages. RESULTS: This study reports for the first time the insecticidal effect of nanostructured alumina. Two species were used as model organisms, Sitophilus oryzae L. and Rhyzopertha dominica (F.), which are major insect pests in stored food supplies throughout the world. Both species experienced significant mortality after 3 days of continuous exposure to treated wheat. Nine days after treatment, the median lethal doses (LD₅₀) observed ranged from 127 to 235 mg kg^?1. CONCLUSION: Comparison of these results with recommended rates for commercial insecticidal dusts suggests that inorganic nanostructured alumina may provide a cheap and reliable alternative for control of insect pests. This study expands the frontiers for nanoparticle‐based technologies in pest management. Further research is needed to identify its mode of action and its non‐target toxicity, and to determine the potential of other nanostructured materials as pest control options for insects. Copyright © 2010 Society of Chemical Industry     

两株虫生真菌对草地贪夜蛾的致病力及高毒力菌株与卵寄生蜂的相容性

为有效防控新入侵我国的重大农业害虫草地贪夜蛾 Spodoptera frugiperda,采用浸叶法测定球孢白僵菌 Beauveria bassiana菌株Bb1237、 Bb201017、 Bb20091317及金龟子绿僵菌 Metarhiziumanisopliae菌株Ma189和莱氏绿僵菌 M. rileyi菌株MrCDTLJ1对草地贪夜蛾3龄幼虫的致病力,筛选对草地贪夜蛾3龄幼虫有较强致病力的菌株,并测定该菌株对草地贪夜蛾3龄幼虫的致病力和对其天敌的致死率。结果显示,球孢白僵菌Bb20091317和莱氏绿僵菌MrCDTLJ1对草地贪夜蛾3龄幼虫的累计校正死亡率显著高于其他菌株,分别为95.59%和97.06%,致死中时LT₅₀分别为3.42 d和5.72 d, LC₅₀分别为7.05×10⁶个/mL和2.25×10⁵个/mL。2种菌在高浓度1×10⁸个/mL下对草地贪夜蛾天敌夜蛾黑卵蜂 Telenomus remus和玉米螟赤眼蜂 Trichogramma ostriniae成蜂的致死率也仅介于15%~20%之间。表明球孢白僵菌Bb20091317和莱氏绿僵菌MrCDTLJ1不仅对草地贪夜蛾有高致病力,同时与夜蛾黑卵蜂和玉米螟赤眼蜂有较好的相容性。     

Biological traits and prey consumption of <Emphasis Type="Italic">Anthocoris minki</Emphasis> fed on <Emphasis Type="Italic">Agonoscena pistaciae</Emphasis> and <Emphasis Type="Italic">Brachycaudus (Thuleaphis) amygdalinus</Emphasis>

The predatory insect Anthocoris minki Dohrn (Heteroptera: Anthocoridae) is an indigenous Anthocoris species for the biological control of pests in pistachio orchards. The pistachio psylla Agonoscena pistaciae Burckhardt and Lauterer (Homoptera: Psyllidae) is an important insect pest in pistachio trees in Turkey. Similarly, Brachycaudus (Thuleaphis) amygdalinus (Schouteden) (Hemiptera: Aphididae) is a pest of almond trees that is considered as alternative prey for A. minki when pistachio psylla are not available in early spring on pistachio trees. The development time, survival percentage of immature stages, longevity, fecundity, prey consumption, and life table parameters of A. minki fed on A. pistaciae and B. amygdalinus nymphs were determined at 25 ± 1°C, 70 ± 5% r.h., and a 16 h:8 h (L:D) photoperiod under laboratory conditions. The nymphal survival rate was significantly higher when nymphs were fed on A. pistaciae (an average of 96.7%) than on B. amygdalinus (an average of 71.4%). The development time of A. minki was significantly shorter when nymphs were fed on B. amygdalinus (10.3 days) as opposed to A. pistaciae (11.0 days). No significant differences among prey species were found for longevity and fecundity. The total female longevity and fecundity of A. minki was 38.0 days and 247.2 eggs, respectively, when nymphs were fed on A. pistaciae; and 35.4 days and 233.0 eggs, respectively, when nymphs were fed on B. amygdalinus. On average, 104.4 A. pistaciae and 77.7 B. amygdalinus nymphs were consumed during the nymphal development time for A. minki. Adults of A. minki consumed significantly more psyllids than aphids throughout their life span. The greater difference did not significantly inpact the longevity and fecundity of A. minki. Females of A. minki consumed an average of 631.0 A. pistaciae and an average of 273.3 B. amygdalinus nymphs, while female predators consumed significantly more prey than males. The intrinsic rate of increase (r _m ) of A. minki fed on A. pistaciae (0.174) was significantly greater than those fed on B. amygdalinus (0.148). The successful development and reproduction of both A. pistaciae and B. amygdalinus indicates that they are suitable prey for A. minki.     

Species composition,toxigenic potential and pathogenicity of Fusarium graminearum species complex isolates from southern Brazilian rice

This study aimed to assess the extent and distribution of Fusarium graminearum species complex (FGSC) diversity in rice seeds produced in southern Brazil. Four species and two trichothecene genotypes were detected among 89 FGSC isolates, based on a multilocus genotyping assay: F. asiaticum (69·6%) with the nivalenol (NIV) genotype, F. graminearum (14·6%) with the 15‐acetyldeoxynivalenol (ADON) genotype, and F. cortaderiae (14·6%) and F. meridionale (1·1%), both with the NIV genotype. Seven selected F. asiaticum isolates from rice produced NIV in rice‐based substrate in vitro, at levels ranging from 4·7 to 84·1 μg g^?1. Similarly, two F. graminearum isolates from rice produced mainly 15‐ADON (c. 15–41 μg g^?1) and a smaller amount of 3‐ADON (c. 6–12 μg g^?1). One F. meridionale and two F. cortaderiae isolates did not produce detectable levels of trichothecenes. Two F. asiaticum isolates from rice and two from wheat (from a previous study), and one F. graminearum isolate from wheat, were pathogenic to both crops at various levels of aggressiveness based on measures of disease severity in wheat spikes and rice kernel infection in a greenhouse assay. Fusarium asiaticum and the reference F. graminearum isolate from wheat produced NIV, and deoxynivalenol and acetylates, respectively, in the kernels of inoculated wheat heads. No trichothecene was produced in kernels from inoculated rice panicles by any of the isolates. These findings constitute the first report of FGSC composition in rice outside Asia, and confirm the dominance of F. asiaticum in rice agroecosystems.     

Field evaluation of entomofungal pathogens against cowpea aphid,Aphis craccivora Koch,and their effect on two coccinellid predators

The present study was carried out to assess the field efficacy of 10 isolates of entomofungal pathogens on management of cowpea aphid, Aphis craccivora. All the tested isolates showed suppressive effect on aphid population. Two-year pooled data revealed lower incidence of 19.37–40.81 aphids/plant in the entomofungal pathogen treated plots compared to higher incidence of 88.07 aphids/plant in untreated control. Among the 10 isolates tested, Vl-8 isolate of Lecanicillium lecanii, Ma-6 isolate of Metarhizium anisopliae and Bb-5a isolate of Beauveria bassiana showed 78.01%, 77.42% and 76.91% reduction of aphid population, respectively, over control and were on par with each other. Significantly higher yields were recorded in the plots treated with Bb-5a, Ma-6 and Vl-8 isolates (1252, 1225 and 1208 kg/ha, respectively) compared to untreated control (916 kg/ha). The predatory coccinellid populations of Cheilomenes sexmaculata and Micromus timidus in entomofungal treated and untreated control plots were almost similar and found statistically non-significant, indicating the safety of fungal pathogens to these coccinellid predators.     

Mortality of Isaria farinosa and Beauveria bassiana on sunn pests Eurygaster integriceps and Eurygaster austriaca

The effects of Isaria farinosa (Holm.) and Beauveria bassiana (Balsamo) on adult stages of sunn pests Eurygaster integriceps Puton and Eurygaster austriaca (Schrk.) were investigated at 27±1°C, 95% r.h. and 16L:8D in the laboratory. Two concentrations, 1×10⁶ and 1×10⁸ conidia ml^-1, were used. Mortality of inoculated and non-inoculated adults was counted at 6, 9 and 12 days after treatment. Beauveria bassiana caused higher mortality of both species than I. farinosa. Neither caused significantly high mortality at 1×10⁶ conidia ml^-1. Both were more pathogenic at 1×10⁸ conidia ml^-1 and caused more than 85% mortality 12 days post treatment. Both were more pathogenic to E. austriaca.     

Winter wheat pests and their natural enemies under organic farming system in Slovakia: Effect of ploughing and previous crop

Organic farming system of winter wheat was investigated in Solvakia over three years, 1995–1997. The system was carried out on a small scale (four plots of 50 m²). Neither pesticides nor inorganic fertilisers were applied. Effect of two treatments, ploughing and previous crop, on the community of pests and natural enemies was surveyed. There were two types of ploughing (shallow and deep) made in autumn before sowing. As previous crops, silage-maize and alfalfa were used each season. The effect of all factors was analysed by multivariate method, redundancy analysis (RDA) and Monte Carlo permutation to assess statistical significance. During three years, 37 taxons of pests and 27 taxons of natural enemies were recorded. The results of RDA showed that the community of insects (pests and natural enemies) was mainly influenced by temporal variation. The highest abundance of all insects was observed in 1996. The effect of the two treatments on the community of pests and natural enemies was less obvious. Pests were found to be significantly more influenced by ploughingthan by previous crop. Most of pests occurred more abundantly on plots with shallow ploughing and on plots after maize. Abundance of natural enemies were, however, significantly affected by previous crop. Majority of them were more abundant on plots after maize than after alfalfa. Ploughing had only marginally significant effect on natural enemies that were more abundant on shallow ploughed plots. Both ploughing and previous crop had only negligible effect on species diversity of natural enemies.     

Green peach aphid,Myzus persicae (Hemiptera: Aphididae), reproduction during exposure to sublethal concentrations of imidacloprid and azadirachtin

BACKGROUND: Resurgence of insect pests following insecticide applications is often attributed to natural enemy disturbance, but hormesis could be an alternative or additional mechanism. Green peach aphid, Myzus persicae (Sulzer), is an important insect pest of many crops worldwide that may be exposed to sublethal insecticide concentrations over time. Here, the hypothesis that exposure to low concentrations of imidacloprid and azadirachtin can induce hormetic responses in M. persicae is tested in the laboratory. RESULTS: When insects were exposed to potato leaf discs dipped in sublethal concentrations of insecticide, almost all measured endpoints—adult longevity, F1 production, F1 survival and F2 production—were affected, and a statistically significant (P < 0.05) stimulatory response was recorded for F2 production following exposure to imidacloprid. No other measures for hormesis were statistically significant, but other trends of hormetic response were consistently observed. CONCLUSIONS: Given that variable distribution and degradation of insecticides in the field would result in a wide range of concentrations over time and space, these laboratory experiments suggest that exposure to sublethal concentrations of imidacloprid and azadirachtin could stimulate reproduction in M. persicae. Copyright © 2008 Society of Chemical Industry     

Winter wheat pests and their natural enemies under organic farming system in Slovakia: Effect of ploughing and previous crop

Organic farming system of winter wheat was investigated in Solvakia over three years, 1995–1997. The system was carried out on a small scale (four plots of 50 m²). Neither pesticides nor inorganic fertilisers were applied. Effect of two treatments, ploughing and previous crop, on the community of pests and natural enemies was surveyed. There were two types of ploughing (shallow and deep) made in autumn before sowing. As previous crops, silage-maize and alfalfa were used each season. The effect of all factors was analysed by multivariate method, redundancy analysis (RDA) and Monte Carlo permutation to assess statistical significance. During three years, 37 taxons of pests and 27 taxons of natural enemies were recorded. The results of RDA showed that the community of insects (pests and natural enemies) was mainly influenced by temporal variation. The highest abundance of all insects was observed in 1996. The effect of the two treatments on the community of pests and natural enemies was less obvious. Pests were found to be significantly more influenced by ploughingthan by previous crop. Most of pests occurred more abundantly on plots with shallow ploughing and on plots after maize. Abundance of natural enemies were, however, significantly affected by previous crop. Majority of them were more abundant on plots after maize than after alfalfa. Ploughing had only marginally significant effect on natural enemies that were more abundant on shallow ploughed plots. Both ploughing and previous crop had only negligible effect on species diversity of natural enemies.     

Designer repellents: combining olfactory, visual or taste cues with a secondary repellent to deter free-ranging house sparrows from feeding

BACKGROUND: Repellents may prevent bird pests from eating crops or protect non‐target birds from eating harmful substances. The feeding behaviour of free‐ranging house sparrows (Passer domesticus) presented with wheat treated with the secondary repellent anthraquinone (AQ), paired with visual and/or olfactory and taste cues, was recorded in a series of trials. The aim was to determine the suitability of repellent combinations for preventing birds from consuming pest baits. RESULTS: Anthraquinone significantly reduced wheat consumption. The addition of cinnamon oil did not reduce consumption further, but the addition of either a blue colour or d‐pulegone enhanced repellency. Green wheat was consumed more than blue wheat. In a multichoice test, the sparrows did not differentiate between low and high concentrations of AQ on blue‐dyed wheat. With treatments on separate tables, the higher concentration was more repellent. Additional olfactory/gustatory cues palatable to pest mammals did not make the AQ‐treated wheat more or less acceptable to sparrows. AQ‐treated blue wheat with/without cinnamon oil was more repellent than green wheat with cinnamon oil, a colour/odour combination typically used for pest baits in New Zealand. CONCLUSIONS: These data demonstrate the potential of combining the secondary repellent AQ with additional salient cues for modifying the feeding behaviour of sparrows. Copyright © 2011 Society of Chemical Industry