This paper develops a deterministic and a stochastic population size model based on power-law kinetics for the black-margined pecan aphid. The deterministic model in current use incorporates cumulative-size dependency, but its solution is symmetric. The analogous stochastic model incorporates the prolific reproductive capacity of the aphid. These models are generalized in this paper to include ...

Two faba bean, Vicia faba L., cultivars, Gazira2 and Misr1, representing cultivars moderately resistant and susceptible to aphids, were analyzed for peroxidase (POD) and polyphenol oxidase (PPO) activities induced by cowpea aphid, Aphis craccivora Koch. infestation. Two tissue types (whole plant [WP] and detached leaf [DL]), two infestation status (infested and uninfested), and three aphid infe...

The evolution of reproductive isolation without geographic isolation (sympatric speciation) has recently gained strong theoretical and empirical supports. It is now widely admitted that many host-specific phytophagous insect species have arisen through shifting and adapting to new plants. The pea aphid Acyrthosiphon pisum has received considerable attention in this context and is now considered...

In this paper, capillary zone electrophoresis method was used for the determination of vitamin C and nicotinic acid content in black bean. 20 mmol/L borax solution and 20% acetonitrile concentration, 20kV voltage, 254 nm UV detection wavelength was chosen for electrophoretic analysis. Measured vitamin C and nicotinic acid content in black bean were 0.333 mg/g (RSD = 3.9%) (n = 5), 0.482 mg/g (R...

The present study was carried out at Wadi El Natrun district, El-Behera Governorate during season 2019–2020. In a field study, the effect of two planting dates and three rates nitrogen fertilizer on population Legume aphid, Aphis craccivora (Koch) (Homoptera: Aphididae), in faba bean (Vicia faba, L.)were investigated. results show that higher occurrence aphid recorded early date than recommende...

Common bean (Phaseolus vulgaris) production and storage are limited by numerous constraints. Insect pests often the most destructive. However, resource-constrained smallholders in sub-Saharan Africa (SSA) do little to manage pests. Where farmers use a control strategy, it typically relies on chemical pesticides, which have adverse effects wildlife, crop pollinators, natural enemies, mammals, de...

The aim of this study was to determine the effects water extracts tarragon (Artemisia dracunculus L.) on feeding intensity, mortality, and weight gain selected pests, i.e., adult pea leaf weevils (Sitona lineatus L.), nymphs, wingless females black bean aphids (Aphis fabae Scop.), L2 L4 larvae Colorado potato beetle (Leptinotarsa decemlineata Say). In addition, effect voracity non-target organi...

Seasonal occurrence of aphids and aphidophagous insects was monitored for six years (2006 2011) from full leaf expansion in May to leaf fall in October variety pecan trees that were not treated with insecticides. Aphid outbreaks occurred two times per season, once in the spring and again in the late summer. Yellow pecan and blackmargined aphids exceeded the recommended treatment thresholds one ...