EVALUATION OF WATER QUALITY OF A MOUNTAINOUS STREAM (PELION, CENTRAL GREECE) USING BENTHIC MACROINVERTEBRATES

Biotic indices are commonly used in biomonitoring programs to assess the quality of surface waters. In the present study, a number of biotic indices based on benthic macroinvertebrates have been applied in assessing the water quality of a mountainous stream (Pelion, Central Greece). Samplings were done in summer and autumn 2012 in two sampling sites (Karamani, Servanates) using two sampling methods: (a) a standard pond net and (b) the Surber method. Invertebrate identification was performed to the family level. The Biological Monitoring Working Party (BMWP) score, the Average Score Per Taxa (ASPT), the Lincoln Quality Index, as well as the Iberian BMWP, and the Iberian ASPT were applied to the benthic macroinvertebrate samples to assess the water quality of each site. According to ASPT, IASPT and LQI, the biological water quality of both sampling sites was very good, regardless of the season and the sampling method used, with the exceptions of the summer samplings in Servanates with both sampling methods, and in Karamani with Surber, for which a good water quality was assessed with LQI and IASPT, respectively. In contrast, the BMWP and IBMWP scores for the sampling site Servanates were low, corresponding to fair water quality, but this effect was attributed to the particular hydrological conditions of this site. The sampling method did not significantly affect the sampling efficiency and, consequently, the results of the water quality evaluation

Insecticidal effect of six entomopathogenic nematode strains against Lasioderma serricorne (F.) (Coleoptera: Anobiidae) and Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae)

The insecticidal effect of Heterorhabditis bacteriophora Poinar (Nematoda: Heterorhabditidae), Heterorhabditis megidis Poinar, Jackson and Klein (Nematoda: Heterorhabditidae) and two strains of Steinernema carpocapsae Weiser (Nematoda: Steinernematidae) and Steinernema feltiae Filipjev (Nematoda: Steinernematidae) against the cigarette beetle, Lasioderma serricorne (Fabricius) (Coleoptera: Anobiidae) and the confused flour beetle, Tribolium confusum Jacquelin du Val (Coleoptera: Tenebrionidae) was examined under laboratory conditions. The nematodes were applied at the following doses: 0 (control), 100, 1000, 5000,10,000 and 20,000 infective juveniles (IJs) per ml, corresponding to 0, 10, 100, 500,1000, and 2000 Us per in sect, and their infectivity was tested at 27 degrees C and 70% r.h. after 4 and 8 days of exposure. Adult emergence and progeny production was evaluated 4 and 8 weeks after the initiation of the bioassays. In the case of L serricorne adults, one strain of S. carpocapsae caused 15.6 and 58.9% mortality after 4 and 8 days exposure, respectively, in semolina treated with 20,000 Us per ml. On the other hand, larval mortality of serricorne did not exceed 19% in all treatments tested. Similarly, larval mortality of T. confusum was low, reaching 15.2 and 22.4% after 4 and 8 days exposure, respectively, at the highest dose tested. This is the first report on the effect of entomopathogenic nematodes against the cigarette beetle L serricorne. Further experimental work is required to optimize the conditions under which these entomopathogenic nematodes could be used for the effective control of stored-product pests. (c) 2012 Elsevier Ltd. All rights reserved

Comparison of two pirimiphos-methyl formulations against major stored-product insect species

The insecticidal effect of two pirimiphos-methyl formulations [emulsifiable concentrate (EC) and capsule suspension (CS)] was evaluated in laboratory bioassays against adults of Sitophilus granarius, S. oryzae, Rhyzopertha dominica, Tribolium confusum, Oryzaephilus surinamensis, Prostephanus truncatus and Liposcelis entomophila. Pirimiphos-methyl was applied at five dose rates, 0.5, 1, 2, 3 and 4 ppm, and, depending on the natural mortality level, insect mortality was assessed after 1, 2, 7, 14 and 21 d of exposure. After the final mortality count, all individuals were removed and progeny production was evaluated after an additional period of 65 d. In another series of laboratory bioassays, the insecticidal efficacy of these two pirimiphos-methyl formulations was evaluated against S. granarius, T confusum and R. dominica at three temperatures (20, 25 and 30 degrees C) and two relative humidity (r.h.) levels (55 and 75%). Pirimiphos-methyl was applied at two dose rates, 2 and 4 ppm, and mortality of beetles was measured after 7,14 and 21 d of exposure. In all cases, Sitophilus species were highly susceptible to both pirimiphosmethyl formulations, since complete (100%) mortality was noted with doses >= 1 ppm after 7 d of exposure. In contrast, R. dominica and P. truncatus were the least susceptible to pirimiphos-methyl, as mortality did not exceed 82 and 57%, respectively, for any of the dose rates or formulations tested. Progeny production was in most cases suppressed by pirimiphos-methyl, with the exception of R. dominica. Moreover, in most of the combinations tested, there was no significant and consistent effect of temperature and r.h. on S. granarius, T. confusum and R. dominica mortality. (C) 2013 Published by Elsevier Ltd

Response of local and commercial tomato cultivars and rootstocks to Meloidogyne javanica infestation

Fifty two local Greek tomato (Solanum lycopersicum) cultivars and accessions and ten commercial nematode-resistant tomato cultivars and rootstocks were evaluated under controlled environmental conditions for resistance against the root-knot nematode Meloidogyne javanica. All tested local tomato cultivars and accessions were susceptible to M. javanica. Conversely, the commercial root-knot nematode-resistant tomato cultivars significantly reduced galling and egg mass production of M. javanica. Depending on the inoculum level (200 or 400 second stage juveniles (J2) per plant), the tested tomato rootstocks showed a different response to M. javanica. When plants were inoculated with 200 M. javanica J2 a significantly lower number of galls and egg masses was recorded for all tested rootstocks in comparison to that of the control 6 weeks after inoculation. Plant inoculation with 400 M. javanica J2 resulted in reduced root galling on the non-grafted rootstock Multifort 6 weeks after inoculation, whereas a significantly lower gall index was recorded for all non-grafted rootstocks and the grafted rootstocks Multifort and Unifort 12 weeks after inoculation

First report of Candidatus phytoplasma mali in Greece and correlation with small apple fruit disorder occurring in the orchards of the pelion mountain

The apple producing area of the Pelion Mountain suffers the last six years from the extensive phenomenon of small fruiting. Small fruit may appear in few or even all trees of the orchards as well as on few or several branches of each tree. Recovery phenomena and reappearance of the symptoms were observed. Malus xdomestica 'Starking Delicious', widely cultivated at Pelion Mountain, showed high susceptibility. Preliminary studies on the aetiology of this phenomenon were focused to physiological abnormalities in small fruits and to pathogen detection. In small fruits, a high concentration of Mn is observed. The basic colour is not modified, but anthocyanids in the phloem are reduced. Soluble solids and dry mass is decreased, but no difference in pH and acidity is measured. Small apples also show inability in reaching maturation, as they are harder and remain on the tree for many weeks after harvest. Injections with oxytetracycline in a small number of trees were carried out; in the next year a remission of the symptoms in 60% of cases was observed. In September 2005, PCR diagnostic tests for Candidatus Phytoplasma mali in symptomatic trees were performed revealing high presence of the pathogen in the region; out of the 131 trees tested, 43 were positive. The high detection rate of Candidatus Phytoplasma mali in symptomatic trees reveals the high correlation of the presence of the pathogen with small fruit disorder

Larvicidal activity of spinosad and its impact on oviposition preferences of the West Nile vector Culex pipiens biotype molestus – A comparison with a chitin synthesis inhibitor

In the present study, the larvicidal activity of ageing aqueous suspensions of spinosad against larvae of Culex pipiens biotype molestus, as well as their effect on the oviposition preferences of adult gravid females were evaluated in laboratory bioassays. Spinosad was applied at its label dose and the aqueous stock suspensions were stored for various ageing intervals up to 38 days. Untreated distilled water and diflubenzuron served as negative and positive control, respectively. Stock suspensions were taken after 0, 2, 6, 8, 16, 30 and 38 days of storage for diflubenzuron and after 0, 2, 6, 8, 20 and 27 days for spinosad, and were used for the bioassays. Furthermore, the effect of spinosad on the oviposition response of Cx. p. biotype molestus gravid females was investigated in two-choice oviposition preference bioassays. Spinosad was evaluated at half of its label dose and at its label dose, whereas diflubenzuron and distilled water served as positive and negative control, respectively. Results showed that both insecticides were found highly effective for the control of Cx. p. biotype molestus larvae, for ageing intervals up to 27 and 38 days for spinosad and diflubenzuron, respectively. Spinosad acted immediately after the preparation of the insecticidal solution (LT50 = 1.5 h), whereas for aged samples, LT50 values increased with the increase of the ageing interval (LT50 = 5 days for the 27 days old sample). For diflubenzuron, ageing time increased its insecticidal activity, as for aged diflubenzuron-treated solutions, lower LT50 values were achieved. In the oviposition preference bioassays, significantly fewer egg rafts were laid in water treated with spinosad at its label dose compared to control. However, this was not the case for water treated with spinosad at half of its label dose. Oviposition Activity Index (OAI) values were always comprised between −0.3 and 0.3, showing no relevant oviposition deterrence or attraction. The results of the present study contribute to our understanding of the effect of ageing on insecticidal solutions widely used in urban areas to control Cx. p. biotype molestus. Although an important vector of high public health importance, Cx. p. biotype molestus has been scarcely studied as target of environmentally and toxicologically reduced risk insecticides, such as spinosad

Investigation on the apple proliferation epidemics in the orchards of the Pelion Mountain and preliminary observations on possible phytoplasma vectors

The apple producing region in the Pelion Mountain (Magnesia prefecture, Thessaly, Greece) is suffering for more than 10 years from the apple proliferation disease. The orchards are basically planted with cv 'Starking Delicious', are grafted on seedling rootstocks and are older than 40 years. The presence of the 'Candidams Phytoplasma mali' was proven by PCR/RFLP analyses as well as by sequencing. 'Ca. P. pyri' was also detected in at least three different orchards. First attempts to identify the vectors were carried out by monitoring the insect populations in 8 different orchards, one species of psyllids morphologically identified as Cacopsylla pulchella (Low) was the most present insect in the orchards all along the two-month monitoring (May/June). Cacopsylla mali (Schmidberger) was also present in the orchards but in lower numbers. The monitoring is continued and still in progress

Effect of different diet composition on the fat profile of two different black soldier fly larvae populations

Black soldier fly larvae (Hermetia illucens; BSFL) can transform organic wastes into nutritional biomass useful in animal feeding. The aim of this work was to study the effect of five diets (meat, fruit, vegetable substrates, a mix of them and control) on the profile of fatty acids (FAs) and sterols of BSFL. For a more exhaustive characterization of the nutritional properties, the profile of esterified FAs in the sn-2 position of the triglycerides, the most absorbed lipid component during animal digestion was evaluated. The dietary effect was estimated on two different Hermetia illucens populations (Greek − UTH and Italian − UNIPI). The diet affected all the lipid fractions examined. Regardless of diet, the fat was characterized mainly of lauric acid and other saturated FAs, which were found to be synthesized by the larvae, as it was not present in any of the five substrates. In general, UTH larvae contained a higher level of lipids (7.38 vs 2.48 g/100 g of larvae; P < 0.001) and saturated FAs (49.71 vs 36.10 g/100 g of Total Lipids; P < 0.001) and a lower percentage of monounsaturated FAs (14.74 vs 26.70 g/100 g of Total Lipids), C18:3n-3 (0.67 vs 1.13 g/100 g of Total Lipids; P < 0.001), and C18:2c9t11 (2.02 vs 2.80 g/100 g of Total Lipids; P < 0.001). Irrespective of the populations, BSFL reared on control and fruit substrates showed higher level of lipids (8.06 and 5.61 g/100 g of larvae, respectively), and saturated FA (38.99 and 71.19 g/100 g of Total Lipids, respectively), while the presence of meat increased the level of C20:4n-6, C20:5n-3 and C22:5n-3 (0.70, 0.13 and 0.45 g/100 g of Total Lipids, respectively). The results confirmed that BSFL accumulate phytosterols in their lipid fraction. The sterol profile was strongly influenced by the substrate on which the larvae were reared, with higher levels of cholesterol in the larvae of the meat group (38.55 mg/100 g of Total Lipids) and of stigmasterol and campesterol (9.04 and 15.23 mg/100 g of Total Lipids, respectively) in those of the vegetable group. The sterol content between the two populations was significantly different, with a higher percentage in UTH larvae (113.28 vs 34.03 mg/100 g of Total Lipids; P < 0.001). Finally, BSFLs showed a high plasticity of the lipid profile depending on both the substrate and the metabolism linked to the different populations. This variability allows the nutritional characteristics of the BSFL to be shaped by modifying the substrate, to adapt it to the technological and feeding needs to which the larvae are destined