Egyptian Journal of Biology

Host preferences of aphidophagous hoverflies from field distribution of their larvae

2015-02-26T16:51:20+00:00

The patterns of occurrences among aphid colonies of the larvae of two species of highly polyphagous predatory hoverflies, Episyrphus balteatus (de Geer) and Syrphus ribesii (L.) (Diptera: Syrphidae), were assessed in three areas (Nottingham, Cardiff (UK) and the Czech Republic); in the last two sites, larvae of other syrphid species were also identified. The two syrphid species showed considerable diet overlap, their larvae using many of the same aphids as food, but with significant exceptions. Together with information from the literature, even for these very generalist species there was a consistent pattern of preference among aphid species. Most other species showed restricted preferences. Larvae were more frequent on developed aphid colonies than on colonies that were younger or had almost disappeared.

Keywords: food specificity; niche breadth; predatory insects; aphids; Syrphidae.

Alterations of blood indices associated with low-dose administration of methomyl insecticide for short times to albino rats

2015-02-26T16:51:20+00:00

The study aimed to investigate haematological and biochemical alterations associated with short-term intraperitoneal sublethal (1/10 LD₅₀, 2 mg/kg body weight) methomyl administration to male albino rats over two and five days, and also the effects of a two-week recovery period. Methomyl administration over five but not two days decreased mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. A number of blood biochemical parameters increased (serum glucose, cholesterol, triglycerides, urea, uric acid, creatinine) or decreased (globulin); a recovery period returned many entirely or nearly to control levels. Enzyme activities (ALP, ALT, AST) and bilirubin levels increased following methomyl treatment, but again returned to control levels following a recovery period. We conclude that short low doses of methomyl can harm the blood, kidney and liver of rats.

Keywords: methomyl insecticide; hematology and biochemical alternations; male rats.

Geometric morphometric analysis of the molars in three species of the genus Mus (Mus) (Rodentia, Muridae) based on the outline method

2015-02-26T16:51:20+00:00

The relatively new technique of outline-based geometric morphometrics was applied in a study of the variation in the shape of the upper and lower molars among 122 mice, belonging to one species from Iran (Mus musculus) and two species from Europe (Mus macedonicus, Mus spicilegus). Differentiation of specimens based on molar shape was highly dependent on the details of the shape information. Among molars, the second upper and first lower molars are better at separating the species. This method provides a useful way to distinguish species based on the outline of their molars.

Keywords: shape variation; upper and lower molars; mice; Iran; Europe.

Trichoderma-mediated enhancement of nutrient uptake and reduction in incidence of Rhizoctonia solani in tomato

2015-02-26T16:51:20+00:00

Trichoderma harzianum is a naturally occurring filamentous fungus which solubilizes mineral nutrients and inorganic fertilizers, increasing availability and uptake of nutrients to the plant. Rhizoctonia solani is a major problem for seedlings, causing damping-off and in mature plants causing foot and root rot in the tomato crop, reducing nutrient uptake. The aim of this study is to evaluate the effect of Trichoderma harzianum (BHU-51), Trichoderma harzianum (BHU-105) and their consortium Trichoderma harzianum (BHU-51+BHU-105) on management of R. solani and nutrient levels in the plants.
The application of Trichoderma as a seed treatment significantly decreased the incidence of damping-off and increased the vigour index of the plants. The maximum reduction in disease incidence was recorded for the consortium (BHU-51+BHU-105) treatments. The mineral content in treated plants was also higher than untreated pathogen-inoculated controls. Field trials also showed that the consortium produced better results in terms of shoot length, chlorophyll content and yield than the control.
The application of Trichoderma in consortium form increased mineral nutrient uptake, reduced disease incidence and obtained a greater yield with reduced chemical pesticide loads, benefitting farmers and consumers.

Keywords: Trichoderma; Rhizoctonia solani; nutrient uptake; damping-off; disease management.

Socio-economic determinants of the quality of Irvingia gabonensis harvested by rural dwellers in Sagbama Local Government Area of Bayelsa State, Nigeria

2015-02-26T16:51:20+00:00

The study was carried out to assess the socio-economic determinants of the quantity of Irvingia gabonensis (ogbono) harvested by rural dwellers in Sagbama Local Government Areas of Bayelsa State. A total of sixty respondents were randomly selected from twelve rural communities of the study area. Data were collected using a structured questionnaire and personal interview. Descriptive statistics, multiple regression analysis and a willingness-to-accept compensation model were used in the assessment. The majority of the respondents were female (63%). Household size was a significant predictor in determining the quantity of Irvingia gabonensis harvested from the forest. Injuries from knife cuts while opening or picking the fruits, and attacks by wild animals, were the major problems encountered by harvesters. Policies should allow some access to sustainable harvested non-timber forest products, and harvesters should recognize the importance of controls on the levels of harvesting.

Keywords: Non-timber forest product; household size; harvesting constraints; over-exploitation

Effect of plant-growth-promoting rhizobacteria inoculation on plant growth, productivity and economics of Basmati rice

2015-02-26T16:51:20+00:00

A field experiment was conducted in a wet season (Kharif) to study the effects of plant growth-promoting rhizobacteria(PGPR) inoculation on agronomic traits and productivity of Basmati rice (cv. ‘Pusa Basmati 1401’) in a randomized block with twelve treatments. We evaluated one bacterial (Providencia sp. PW5) and one cyanobacterial strain (Anabaena sp. CR3), and also a Multani mitti (Fuller’s earth)-based blue-green algal biofertilizer (a composite culture of Anabaena, Nostoc, Tolypothrix and Aulosira sp.). Plant growth, yield attributes, yield and net return of rice were significantly improved due to the rhizobacterial inoculation. The highest responses were recorded from combined inocula of bacteria and cyanobacteria together with compost.

Keywords: Bacterial inoculants; BGA; cyanobacterial inoculants, PGPR; yield attributes.

The stimulating impact of elevated temperatures on growth and productivity of Parthenium hysterophorus L.

2015-02-26T16:51:20+00:00

Invasive alien weeds pose a great threat to biodiversity by suppressing the native flora and causing negative impacts on crop yields. Parthenium hysterophorus is an exotic weed that causes nuisance and health hazard to mankind and animals, and is a danger to the environment. Experiments were conducted during summer and winter to understand the impact of different temperature conditions on the growth of Parthenium. Pot studies conducted at 22-300°C temperature conditions were considered as control. During summer at 35-450°C, various growth parameters significantly increased in comparison to the 7-150°C temperature regime in winter. Different biochemical constituents were also higher in the leaves during summer than in winter season. The present investigation clearly indicates that growth and productivity of Parthenium was directly proportional to the increase in atmospheric temperature, indicating the possibility of the influence of rising temperature on its invasiveness.

Keywords: Climate change

Total lipid accumulation and fatty acid profiles of microalga Spirulina under different nitrogen and phosphorus concentrations

2015-02-26T16:51:20+00:00

Nutrient limitation in terms of nitrogen and phosphorus increased lipid accumulation under depleted growth in Spirulina strains. Nitrogen limitation was found more effective than phosphorus in accumulating lipid. The fatty acid profile was variable: palmitic (48%), linolenic (21%) and linoleic acids (15%) were the most prevalent types. It was interesting that nitrogen limitation was more effective in increasing total lipid content, whereas phosphorus limitation had more effect on the fatty acid profile. Fatty acid ratios were different under the two conditions of nutrient limitation, with γ -linolenic acid being accumulated in higher quantities under nitrogen than phosphorus limitation.

Gastro-intestinal helminths of pigeons (Columba livia) in Gujarat, India

2015-02-26T16:51:20+00:00

A study was conducted to assess the prevalence of helmith parasites of domestic wild and zoo pigeons in Gujarat, India by faecal sampling and postmortem examination. Qualitative examination of 78 faecal samples revealed 71 (91%) with parasitic infections of nematodes (85%), cestodes (31%) and Eimeria sp (77%). There were 200-1600 nematode eggs per gram during the monsoon season, which was high compared to the 200-1000 eggs per gram in winter and summer. In post-mortems 85% had parasitic infections, of nematodes (75%), cestodes (69%) and Eimeria sp (58%). Two species of nematodes (Ascaridia columbae and Capillaria obsignata) and five species of three genera of cestodes (Raillietina echinobothridia, R. tetragona, R. cesticillus, Cotugnia digonophora and Hymenolepis sp) were identified. Despite their parasitic infections, not a single pigeon revealed any alarming clinical signs.

Effect of source and methods of zinc application on corn productivity, nitrogen and zinc concentrations and uptake by high quality protein corn (Zea mays)

2015-02-26T16:51:20+00:00

Results of a field study conducted at the Indian Agricultural Research Institute, New Delhi, India showed that the combined application of soil + foliar (in two sprays at tasseling and initiation of flowering) produced significantly more grain and stover yields than either soil or foliar applications alone. Application of Zn-coated urea was better than soil application of Zn sulphate with regard to grain and stover yields. The combined application also recorded the highest Zn concentration in corn grain as well as in stover, with the treatments falling in the following order: combined ˃ foliar ˃ soil through Zn-coated urea ˃ soil. This is an important finding for the agronomic biofortification of Zn in corn.

Keywords: Crude protein; foliar application of zinc, zinc biofortification, zinc-coated urea, zinc sulphate

Effect of insecticides on foraging behaviour and pollination role of Apis mellifera L. (Hymenoptera: Apidae) on toria (Brassica campestris var. toria) crop

2015-02-26T16:51:20+00:00

The effects of insecticide application on foraging and pollination by honeybees in toria (Brassica campestris var. toria) cultivar RSPT-1 were studied at Jammu (India).Under field conditions the application of betacylfluthrin, betacyfluthrin + imidacloprid and carbaryl resulted in 100% bee mortality within one hour of spraying. After 48 hours, 100% mortality was recorded in all the treatments except malathion (94%). The post-spraying effects of the insecticides were much higher during the first hour after treatment, but after 48 hr there was 100% mortality in all treatments except imidacloprid (43%). Residual effects after spraying were high for flowers sprayed with imidacloprid (76% mortality), demeton-o-methyl, carbaryl, and ethiprole, moderate for betacyfluthrin (49%), betacyfluthrin + imidacloprid, and profenophos, and low for malathion (12%). The residual effect decreases with time and after 96 hours of spraying, the residual effect was reduced in almost all the insecticides. The number of foraging bees were greatly reduced in all treatments 24 hr after spraying, compared to levels before spraying, recovering considerably after 3 days, and normal after 7 days. Open pollination resulted in 1.80 times more yield compared to caged condition and crop pollinated by bees alone. This study suggests that both protective application of insecticides and use of honeybees for pollination are essential for maximum crop yields.

Biocidal spectrum of a rice field cyanobacterium Nostoc sp.

2015-02-26T16:51:20+00:00

The antimicrobial efficacy of hexane, dichloromethane and ethyl acetate extracts of a rice-field cyanobacterium, Nostoc sp., were evaluated against cyanobacteria and phytopathogenic fungi. The maximum production of biocidal compounds was observed in cultures grown for 20 days under optimized conditions (phosphate =1.4 mg/l; light intensity ≈ 3000-4000 lux). Fractionation of the extracts showed six spots on silica-gel-coated plates. Hexane extract was the most potent biocide, showing marked (35-42%) reduction in the growth of fungi, but no negative influences on seed germination or seedling growth of wheat, rice and mung bean, emphasizing its suitability for use in agriculture.

Keywords: Antifungal; extract; inhibition zone; metabolite; Pythium debaryanum; Rhizoctonia solani

Dragonflies and damselflies of the St Katherine Protectorate

2015-02-26T16:51:20+00:00

The indigenous Bedouin tribes of South Sinai (Egypt) irrigate small gardens for agricultural purposes and this has been shown to boost the biodiversity of plants, birds and insects, including dragonflies (Odonata). The gardens offer water-related resources normally in short supply in arid regions. There is very little information available on the dragonflies and damselflies of the Sinai. We assess the importance of Bedouin gardens to Odonata by recording them in the gardens and in unmanaged habitat in the St Katherine Protectorate. The gardens are widely utilised by Odonata: ten species were recorded in total, all observed in the gardens at least once.