Host preference and influence of the sweetpotato whitefly,Bemisia tabaci (Homoptera: Aleyrodidae) on eggplant (Solanum melongena L.)

Abstract

Three eggplant (Solanum melongena L.) varieties – ‘Dafeng’, ‘Beisite’, and ‘Baiyu’ – were used in this experiment to discover the least susceptible variety among them to sweetpotato whitefly (Bemisia tabaci) infestation. The investigations were carried out after completing one generation of whitefly based on two points of view. Initially, host preference and suitability of whitefly was investigated based on adult feeding, oviposition, and developmental time. Therefore, it was investigated based on growth responses of eggplant. The average developmental time was shortest for the cohort reared in ‘Dafeng’ (21.3 days), while the longest period (23.2 days) was recorded in ‘Baiyu’. In comparison with the control, less significant changes in the six growth parameters, viz. plant height (12.6%), leaf area (12.7%), dry matter (8.2%), absolute growth rate (26.0%), relative growth rate (25.0%), and net assimilation rate (22.2%) were found in ‘Baiyu’ infested by B. tabaci. Adult attraction and oviposition were reduced while developmental time was increased in ‘Baiyu’ compared with the other two varieties. In addition, the reduction percentages of all the six plant-growth parameters of ‘Baiyu’ were comparatively less than other two varieties to whitefly stress. Our research is focused on a shorter development time; higher feeding, oviposition, and the reduction percentage of plant growth indicate that a plant is a suitable host. In view of this, the present findings indicate that ‘Baiyu’ is less susceptible than the other two varieties, ‘Dafeng’ and ‘Beisite’, for whitefly infestation.     

CO2 elevation and soil warming reduce cold hardiness of jack pine under photoperiods of seed origin and latitudes of potential migration

New Forests - Climate change is predicted to cause northward migration of boreal tree species. However, the success of such a migration will be determined by trees’ ability to acclimate to...     

Compressive deformation of wood impregnated with low molecular weight phenol formaldehyde (PF) resin II: effects of processing parameters

To obtain high-strength phenol formaldehyde (PF) resin-impregnated compressed wood at low pressing pressure, the effects of resin content, preheating temperature, pressing temperature, and pressing speed on the compressive deformation of oven-dried low molecular weight PF resin-impregnated wood was investigated. With an increase of PF resin content, the Youngs modulus of the cell wall perpendicular to the fiber direction decreases, and collapse-initiating pressure decreases linearly with the Youngs modulus. This indicates that the occurrence of cell wall collapse is strain-dependent. By increasing preheating temperatures, the collapse-initiating pressure increases due to the increment of the Youngs modulus of the cell wall. An increase in pressing temperature results in the thermal softening of the cell wall and causes collapse at a lower pressure. The wood is compressed effectively despite accelerated resin curing. The pressing speed significantly affects the viscoelastic deformation of the cell wall and the wood is well deformed with decreasing pressing speed, although the differences in density and mechanical properties are relatively small after a pressure-holding period of 30min. In all the parameters examined in this study, the Youngs modulus and bending strength increase with increasing density.     

Livelihood Improvements Through Agroforestry: Evidence from Northern Bangladesh

Agroforestry is one of the most sustainable land management systems practiced around the world due to the socioeconomic benefits that it brings to farmers. In Bangladesh, farmers practice agroforestry, applying indigenous knowledge. The present study was designed to identify the present status, management practices and its role in improving the livelihoods of farmers in northern Bangladesh. Data for the study were collected through quantitative and qualitative methods. A total of 29 tree and 38 agricultural crop species were planted by the102 farmers interviewed. Mangifera indica (relative prevalence 49%) is the most predominant species, followed by Eucalyptus camaldulensis (relative prevalence 35.4%). Farmers of northern Bangladesh plant trees in cropland for fruits (90%), fuel wood (87%) and timber production (79%). Fruit trees were planted with wider spacing while forest and fuel wood species were planted with narrower spacing. Farmer’s livelihoods improved enormously by practicing agroforestry as they have more access to food, fodder and fuel wood which is reflected by greater access to livelihood capitals (except social capital). However, farmers have experienced increased incidences of pests and diseases to the annual crops and trees. Agroforestry practices increases species diversity, ensure economic return and sustain farmer’s livelihoods.