Pathogenic effects of <Emphasis Type="Italic">Xenorhabdus nematophilus</Emphasis> and <Emphasis Type="Italic">Photorhabdus luminescens</Emphasis> (Enterobacteriaceae) against pupae of the Diamondback Moth, <Emphasis Type="Italic">Plutella xylostella</Emphasis> (L.)

The relationship between Xenorhabdus nematophilus and Photorhabdus luminescens, the bacterial symbionts of the entomopathogenic nematodes Steinernema carpocapsae and Heterorhabditis bacteriophora, against the diamondback moth, P. xylostella (L.), pupae showed the pathogenic capability of P. luminescens to be over that of X. nematophilus. They gave 60 and 40?% mortality with LC₅₀ values of 5?×?10⁴ and 5.5?×?10⁵ cells/ml, respectively.The number of bacterial cells influences the rate of killing the pupae of P. xylostella and a direct correlation between mortality of the pupae, percentage of deformed adults and the spraying dose with significant differences were observed. An inverse correlation found between the no. of eggs laid/female, percentage of hatching, adult survival and the spraying dose. These bacterial effects have been attributed to different toxic bacterial enzymes which damage the haemocytes and inhibit activation of the humoral immune system of the insect.     

Direct and admixture toxicity of diatomaceous earth and monoterpenoids against the storage pests <Emphasis Type="Italic">Callosobruchus</Emphasis><Emphasis Type="Italic">maculatus</Emphasis> (F.) and <Emphasis Type="Italic">Sitophilus oryzae</Emphasis> (L.)

We investigated the effects of two commercial diatomaceous earth based insecticides (DE), Protect-It^® and SilicoSec^®, the nano-structured silica product AL06, developed by the section for Urban Plant Ecophysiology at Humboldt University Berlin, and the monoterpenoids, eugenol, and cinnamaldehyde on two stored product pests, Callosobruchus maculatus and Sitophilus oryzae. Protect-It^® was more effective than SilicoSec^® against C. maculatus while the reverse was true for S. oryzae. Generally C. maculatus was more sensitive towards DE and silica treatment than S. oryzae. Mortality rate of both pest species increased when DE’s were applied to food commodities previously treated with a monoterpenoid. In admixture experiments, the toxicity of SilicoSec^® + cinnamaldehyde (LD₅₀ = 42.73 ppm), SilicoSec^® + eugenol (LD₅₀ = 24.30 ppm), and Protect-It^® + eugenol (LD₅₀ = 2.60 ppm) was increased over DE alone against S. oryzae. Both substances showed a synergistic effect considering their co-toxicity coefficient relative to the LD₅₀-value. In contrast, we could not find any synergistic effects in experiments with C. maculatus. Here only Protect-It^® + cinnamaldehyde (LD₅₀ = 20.84 ppm) showed an additive effect while all other combinations of monoterpenoid and DE indicated antagonistic effects. In addition to contact insecticidal effects both monoterpenoids showed a strong fumigant action. The presented results indicate that the natural product DE has great potential to replace synthetic pesticides commonly used in stored product pest management. Efficacy of DE can be improved by adding certain monoterpenoids against certain insect pests.     

Insecticidal properties of <Emphasis Type="Italic">Thymus persicus</Emphasis> essential oil against <Emphasis Type="Italic">Tribolium castaneum</Emphasis> and <Emphasis Type="Italic">Sitophilus oryzae</Emphasis>

Red flour beetle Tribolium castaneum (Herbst) and rice weevil Sitophilus oryzae (L.) are considered to be the major insect pests in storage. Essential oils from aromatic plants are recognized as proper alternatives to fumigants. Thymus persicus (Ronniger ex Rech. f.) is one of these plants that have medicinal properties and is indigenous to Iran. The essential oil was obtained from aerial parts of the plant and analyzed by GC and GC–MS. Carvacrol (44.69%) and thymol (11.05%) were the major constituents of the oil extracted. In this experiment, fumigant toxicity of the essential oil was studied against T. castaneum, S. oryzae at 27 ± 1°C and 60 ± 5% RH in dark condition. The adult insects were exposed to the concentrations of 51.9, 111.1, 207.4 and 370.4 μl/l air to estimate median lethal time (LT₅₀) values. The fumigant toxicity was increased in response to increased essential oil concentrations. The LT₅₀ values at the lowest and the highest concentrations tested were ranged from 28.09 to 13.47 h for T. castaneum, and 3.86 to 2.30 h for S. oryzae. It was found that S. oryzae adults were much more susceptible to the oil than T. castaneum. After 24 h of exposure, the LC₅₀ values (95% fiducial limit) for T. castaneum and S. oryzae were estimated to be 236.9 (186.27–292.81) and 3.34 (2.62–4.28) μl/l air, respectively. These results suggest that T. persicus essential oil merits further study as potential fumigant for the management of these stored-product insects.     

Spatial pattern of beech (<Emphasis Type="Italic">Fagus sylvatica</Emphasis> L.) and oak (<Emphasis Type="Italic">Quercus pubescens</Emphasis> Mill.) seedlings in natural pine (<Emphasis Type="Italic">Pinus sylvestris</Emphasis> L.) woodlands

Spatial pattern of recruitment is an important factor influencing population dynamics of plant communities. The spatial pattern is determined by seed dispersal and by the spatial variability of germination and initial survival. In the process of forest expansion following farmland abandonment, mid- and late-successional species are often dispersed in pioneer forests by birds. This could result in an aggregated spatial pattern of seeds that could influence the dynamics of these species in mixed pioneer forests. In the sub-Mediterranean area, mid- and late-successional species such as Quercus pubescens (downy oak) and Fagus sylvatica (European beech) are expected to replace pioneer Pinus species. Using a point sampling method we demonstrated that beech and oak seedlings (height <2 m) have a clumped distribution in the understorey of pine. This could result from an aggregated dispersal by jays (dispersal effect) or from preferential recruitment in particular habitats (habitat effect). To test these hypotheses we proposed a statistical analysis of spatial patterns of regeneration of beech and oak. Ground cover variables (i.e. cover by rock outcrops, herbs, box shrubs, mosses or pine) did not differ significantly around seedlings as compared with random sample plots. Likewise, clumped seedlings had growth similar to isolated seedlings, thus refuting the hypothesis of preferential location in the most favourable microsites. Aggregated dispersal seems to be involved in the process of regeneration. Since beech and oak seedlings have contrasting ecological demands, we discuss the implication of this pattern for the replacement dynamics of pine by these species.     

Insecticidal efficacy of <Emphasis Type="Italic">Isaria farinosa</Emphasis> in different life stages of <Emphasis Type="Italic">Pissodes punctatus</Emphasis> (Coleoptera: Curculionidae)

The insecticidal activity of an entomopathogenic fungus, Isaria farinosa on pine bark-weevil (Pissodes punctatus) at different life stages underwent laboratory testing. Larvae, pupae and adults of Pissodes punctatus were exposed to a range of concentrations of fungal conidia in suspension for 5 s; mean mortality and LC₅₀ values were calculated. The results showed I. farinosa can effectively infect larvae, pupae and adult pine bark-weevils, and the highest mean mortalities at each life stage can exceed 88%. The mean mortalities increased with higher concentrations of I. farinosa. Larvae were most susceptible with LC₅₀ 1.2 × 10⁶ conidia ml⁻¹ (15 days), pupae (30 days) exhibited the second largest effects, and adults (15 days) with LC₅₀ 1.72 × 10⁶ and 1.99 × 10⁶ conidia ml⁻¹, respectively, at end of the experiments. This suggests that I. farinosa could be a potential bio-control agent against the pine bark-weevil.     

Successful <Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated transformation of <Emphasis Type="Italic">Populus tomentosa</Emphasis> with apple <Emphasis Type="Italic">SPDS</Emphasis> gene

The problem of salinized soils has become one of the most serious constraints to agricultural and forest productivity. With the purpose of enhancing salt stress tolerance of Populus tomentosa, we transformed this tree species with spermidine synthase （SPDS） genes derived from an apple by an Agrobacterium-mediated method. Four transgenic clones were confu＇med by PCR and Southern blot analysis. As well, the expression of introduced SPDS genes was analyzed by real-time quantitative PCR.     

Effectiveness of Neem (<Emphasis Type="Italic">Azadirachta indica</Emphasis>) insecticides against Brassica pod midge (<Emphasis Type="Italic">Dasineura brassicae</Emphasis> Winn<Emphasis Type="Italic">.</Emphasis>)

The efficiency of the botanical insecticide (BI) NeemAzal T/S (containing 1% Azadirachtin A), on the basis of azadirachtin applied in a dose of 20 g a.i. ha⁻¹ against Brassica pod midge (Dasineura brassicae), has been monitored for 4 years. The biological efficiency of BI was compared with the efficiency of some synthetic insecticides. It was ascertained that BI was very efficient in decreasing the number of damaged oilseed rape pods (ranging from 56.5 to 85.9% compared to untreated plants) and its efficiency was comparable with synthetic insecticides based on Chloronicotinyl (Thiacloprid) and Neonicotinoid (Acetamiprid). BI’s efficiency was, in some years, even significantly higher compared to pyrethroid (λ-cyhalothrin). The high biological efficiency of azadirachtin that we ascertained was significantly reflected in increasing potential crop yields. The yield increase of azadirachtin ranged between 9.3 and 19.4% compared to the control sample. Azadirachtin showed the highest yield for the whole time of experimentation, and in some years the yield increase was significantly higher compared to some synthetic agents.     

<Emphasis Type="Italic">Bursaphelenchus mucronatus</Emphasis> (Nematoda: Aphelenchoididae) vectored by <Emphasis Type="Italic">Monochamus </Emphasis><Emphasis Type="Italic">urussovi</Emphasis> (Coleoptera: Cerambycidae) in Hokkaido,Japan

Bursaphelenchus mucronatus Mamiya et Enda has been recovered for the first time from adults of the cerambycid beetle, Monochamus urussovi (Fischer), in Hokkaido, Japan. The nematode was also recovered from the inner bark of Picea jezoensis (Siebold et Zuccarini) Carrière and Abies sachalinensis (Fr Schmidt) Masters infested with M. urussovi larvae. PCR–RFLP analysis indicated that B. mucronatus in Hokkaido is the European type.     

Feeding performance of <Emphasis Type="Italic">Clostera fulgurita</Emphasis> on three clones of <Emphasis Type="Italic">Populus deltoides</Emphasis>

Poplar leaf defoliator, Clostera fulgurita (Walker) larvae were reared on three Populus deltoides clones (PL1, PL5 and PL7) in the laboratory. The nutritional indices were computed for working out the relationship between food consumption and growth rate of 3rd, 4th and 5th instar larvae on three clones. The result showed that the consumption index (CI), approximate digestibility (AD), growth rate (GR), relative growth rate (RGR) and efficiency of conversion of ingested food (ECI) decreased with the increase in the age of the larvae. Efficiency of conversion of digested food (ECD) increased with increase in age of the larvae. GR and RGR varied significantly, indicating that larval development was enhanced on PL1 as compared to PL5 & PL7. The values of AD, ECI and ECD were not affected by the different clones. Feeding and growth indices could be useful to define a defoliation prediction model.     

Antibacterial activity of moso bamboo shoot skin (<Emphasis Type="Italic">Phyllostachys pubescens</Emphasis>) against <Emphasis Type="Italic">Staphylococcus aureus</Emphasis>

This study examined the antibacterial activity of moso bamboo shoot skin (Phyllostachys pubescens). Bamboo shoot skin itself and its dichloromethane extract had antibacterial activity against Staphylococcus aureus. Results suggest the possibility of effective utilization of antibacterial materials from bamboo shoot skins that are mainly discarded at present.     

Variation in the host preferences and responses of <Emphasis Type="Italic">Ascia monuste orseis</Emphasis> Godart (Lepidoptera: Pieridae) to cultivars of collard greens <Emphasis Type="Italic">Brassica oleracea</Emphasis> (L.) var. <Emphasis Type="Italic">acephala</Emphasis>

This work evaluated the preference of Ascia monuste orseis among 29 cultivars of collard greens through free- and no-choice assays using female adults (attractiveness and oviposition) and third-instar larvae (feeding preference), in both laboratory and greenhouse conditions. In free-choice tests with female adults, the L, V, Y, H, A, and Z cultivars produced oviposition non-preference in butterflies. Cultivars R, P, C, and D produced feeding non-preference in third-instar larvae of A. monuste orseis in free- and no-choice tests. Our findings may be useful for genetic improvement focusing on the development of B. oleracea var. acephala cultivars resistant to A. monuste orseis.     

Larval cannibalism and fitness in the stored grain weevils <Emphasis Type="Italic">Sitophilus granarius</Emphasis> and <Emphasis Type="Italic">Sitophilus zeamais</Emphasis>

Resource limitation is an important determinant of life history and behavior while mediating competition and reproduction among organisms. Discreet and closed systems such as grain kernels and seeds impose drastic restrictions to grain beetles that spend their immature stages within a single kernel selected by their mother. This is the case of internally feeding stored grain beetles, such as the grain weevils. Female egg-laying decisions and larval competition largely determine resource limitation for such insects where clustered egg distribution and contest competition with larval interference and cannibalism take place. As the clustered eggs within a grain lead to larval competition and conspecific weevil larvae face each other off during development allowing the emergence of one or two larvae per kernel, we hypothesized that such competition and consequent cannibalism will have fitness consequences for the competing individuals and their offspring. Thus, larvae of the granary weevil (Sitophilus granarius L.) and the maize weevil (Sitophilus zeamais Motsch.) were subjected to larval competition with cannibalism, and lack of it, to assess the potential fitness consequence of cannibalism on these non-carnivorous pest species of stored grains. Larval cannibalism reduced developmental time of maize weevil, but not of granary weevil. However, such condition led to heavier adult weevils of both species exhibiting higher reproductive output generating more and better quality progeny than non-cannibal weevils. These findings indicate direct nutritional benefits of cannibalism to grain weevils favoring their status of key pest species of stored cereal grains.     

Cultivation of <Emphasis Type="Italic">Pleurotus eryngii</Emphasis> on umbrella plant (<Emphasis Type="Italic">Cyperus alternifolius</Emphasis>) substrate

Mycelial growth and mushroom yields of three strains of Pleurotus eryngii produced on wheat bran-supplemented umbrella plant (Cyperus alternifolius) substrate were assessed using surface brightness, bromophenol blue color reactions, ergosterol and glucosamine contents, and water potential as indicators of strain performance. Mycelial growth was 31%–46% greater, depending on strain, on the umbrella plant substrate compared with the mushroom industry standard sugi (Cryptomeria japonica) substrate. Mushroom yields on the first flush were 20%–23% higher, depending on strain, on the plastic bottle-contained umbrella plant substrate. However, yields on the second break were lower from the umbrella plant substrate. Because many growers in Japan only harvest one flush, production of P. eryngii on umbrella plant substrate may offer commercial producers an alternative basal ingredient to diminishing supplies of sugi sawdust.Part of this report was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002.     

Insecticidal activity of synthetic antioxidants,natural phytochemicals,and essential oils against an <Emphasis Type="Italic">Aspergillus</Emphasis> section <Emphasis Type="Italic">Flavi</Emphasis> vector (<Emphasis Type="Italic">Oryzaephilus surinamensis</Emphasis> L.) in microcosm

The purpose of this study is to investigate the insecticidal activity of two benzoic acids 2(3)-tert-butyl-4 hydroxyanisole (BHA) and 2,6-di(tert-butyl)-p-cresol (BHT); two phenolic acids 3-phenyl-2-propenoic acid (CA) and trans-4-hydroxy-3-methoxycinnamic acid (FA); and two essential oils of Eugenia caryophyllata (clove tree) and Thymus vulgaris (thyme) against Oryzaephilus surinamensis (L.) vector carrier of aflatoxigenic fungi on stored peanut. The weight loss of peanut, susceptibility of insects, Aspergillus isolation frequency from insects and peanut, and aflatoxin B₁ analyses from peanut were determined. BHA, BHT, and BHA/BHT mixture were highly effective against O. surinamensis, these chemical agents give 100% mortality at the doses assayed. Essential oil of thyme at 2,000 and 3,000 ppm were highly effective against O. surinamensis, these concentrations gave 100% mortality. No Aspergillus section Flavi contamination was observed in dead insects collected from peanut treated with BHA/BHT mixture. No differences were observed in the fresh weight of pods peanut among treatments with and without chemical agents. All samples of treated peanut pods showed complete inhibition of this toxin after 120 days of storage. Our results indicate that these substances could be evaluated further for the control of pest vectors of aflatoxigenic fungi of stored peanut.     

Comparison of postfire mortality in endemic Corsican black pine (<Emphasis Type="Italic">Pinus nigra</Emphasis> ssp. <Emphasis Type="Italic">laricio</Emphasis>) and its direct competitor (<Emphasis Type="Italic">Pinus pinaster</Emphasis>)

• Introduction   

Laricio pine (Pinus nigra J.F. Arn. ssp. laricio (Poiret) Maire var Corsicana Hyl.) is a form of black pine endemic to Corsica, that may now be under threat due to current fire regimes and competition with maritime pine (Pinus pinaster Aiton).     

Fumigant and repellent activities of essential oil from <Emphasis Type="Italic">Coriandrum sativum</Emphasis> (L.) (Apiaceae) against red flour beetle <Emphasis Type="Italic">Tribolium castaneum</Emphasis> (Herbst) (Coleoptera: Tenebrionidae)

The biological activity of essential oil extracted from coriander, Coriandrum sativum L. (Apiaceae) against eggs, larvae and adults of Tribolium castaneum (Herbst) was investigated in a series of laboratory experiments. Bioassays conducted in air-tight glass chambers showed vapour toxicity and strong repellency on filter paper arena test towards all the stages used. Responses varied significantly (P < 0.001) within insect stages, dosages and exposures. At 12.0 μg/ml dosage, mortality of adults reached 95%, but for 12-, 14- and 16-days larvae, mortalities were 65, 74 and 82%, respectively. On the developmental inhibition, individuals fumigated at the larval stage confirmed that the percentage of larvae reaching to pupal stage and pupae to adult stage, decreased significantly (P < 0.001) with increasing dosage concentration. The oil fumigation yielded 100% mortality for T. castaneum larvae, pupae and adults at 0.08 μg/ml dosage. The oil had fumigant activity against eggs and the toxicity progressively increased with increased exposure times and concentrations. One hundred per cent T. castaneum egg mortalities were obtained with oil fumigation at 20 μg/ml and 96 h exposure period. C. sativum oil also showed highly repellent activity to the adults of T. castaneum, with overall repellency was 90% and at a dosage of 12 μg/ml repellency was 100% in a filter-paper arena test.     

Bioremediation of CCA-treated wood by brown-rot fungi <Emphasis Type="Italic">Fomitopsis palustris</Emphasis>, <Emphasis Type="Italic">Coniophora puteana</Emphasis>, and <Emphasis Type="Italic">Laetiporus sulphureus</Emphasis>

This study evaluated oxalic acid accumulation and bioremediation of chromated copper arsenate (CCA)-treated wood by three brown-rot fungi Fomitopsis palustris, Coniophora puteana, and Laetiporus sulphureus. The fungi were first cultivated in a fermentation broth to accumulate oxalic acid. Bioremediation of CCA-treated wood was then carried out by leaching of heavy metals with oxalic acid over a 10-day fermentation period. Higher amounts of oxalic acid were produced by F. palustris and L. sulphureus compared with C. puteana. After 10-day fermentation, oxalic acid accumulation reached 4.2 g/l and 3.2 g/l for these fungi, respectively. Fomitopsis palustris and L. sulphureus exposed to CCA-treated sawdust for 10 days showed a decrease in arsenic of 100% and 85%, respectively; however, C. puteana remediation removed only 18% arsenic from CCA-treated sawdust. Likewise, chromium removal in F. palustris and L. sulphureus remediation processes was higher than those for C. puteana. This was attributed to low oxalic acid accumulation. These results suggest that F. palustris and L. sulphureus remediation processes can remove inorganic metal compounds via oxalic acid production by increasing the acidity of the substrate and increasing the solubility of the metals.An erratum to this article can be found at     

Fertility variation in endemic populations of Ehrami black pine (<Emphasis Type="Italic">Pinus nigra</Emphasis> Arnold. subsp. <Emphasis Type="Italic">pallasiana</Emphasis> var. <Emphasis Type="Italic">pyramidata</Emphasis>)

Fertility variation and effective number of parents were estimated in the 100 individuals from each of three plantation populations (P1, P2 and P3) of the endangered Pinus nigra. subsp. pallasiana var. pyramidata established in the Isparta–Golcuk district in southern Turkey in 1990. Potential relations between cone yield and growth characters (height, diameter at breast height, diameter at base and crown diameter) were also investigated. Large differences were found among populations and within populations for cone production and growth characters. Mean cone production was eight (ranging from 6.5 in P2 to 9.1 in P1) for the three populations. The 10 most productive individuals for cones produced 32% of the total cones in P1, 39% in P2 and 34% in P3; 21, 16 and 6 individuals, respectively did not produce any cones in the populations. According to the correlation analyses, the relation between cone yield and growth characters changed for the populations, while height, diameter at breast height and crown diameter were positively significantly correlated (r = 0.182, 0.135 and 0.209; p ≤ 0.05) with cone production for the three populations. Fertility variation was 1.81 in total of three populations, ranging from 1.72 in P3 to 3.45 in P1). Effective number of parents was 142 (55.2 of number of parents censused; 29%, P1; 49.8%, P2; 58.3%, P3).     

Leaf-level responses to light in two co-occurring <Emphasis Type="Italic">Quercus</Emphasis> (<Emphasis Type="Italic">Quercus ilex</Emphasis> and <Emphasis Type="Italic">Quercus suber</Emphasis>): leaf structure,chemical composition and photosynthesis

We studied morphological, biochemical and physiological leaf acclimation to incident Photon-Photosynthetic-Flux-Density (PPFD) in Quercus ilex (holm oak) and Quercus suber (cork oak) at Mediterranean evergreen oak woodlands of southern Portugal. Specific leaf area (SLA) decreased exponentially with increasing PPFD in both species. Q. ilex had lower SLA values than Q. suber. Leaf nitrogen, cellulose and lignin concentration (leaf area-based) scaled positively with PPFD. Maximum rate of carboxylation (V_cmax), capacity for maximum photosynthetic electron transport (J_max), rate of triose-P utilization (V_TPU) and the rate of nonphotorespiratory light respiration (Rd) were also positively correlated with PPFD in both Quercus species, when expressed in leaf area but not on leaf mass basis. Q suber showed to have higher photosynthetic potential (V_cmax, J_max^m and V_TPU^m) and a higher nitrogen efficient nitrogen use than Q.ilex. Leaf chlorophyll concentration increased with decreasing PPFD, improving apparent quantum use efficiency (Φ) in both Quercus species. We concluded that, in Q.ilex and Q.suber, leaf structural plasticity is a stronger determinant for leaf acclimation to PPFD than biochemical and physiological plasticity.