Location, reproduction and movement of Neoseiulus californicus (Acari: Phytoseiidae) during the autumn, winter and spring in orchards in the south of France
Field samples and experiments conducted in apple orchards in the south of France showed that Neoseiulus californicus (McGregor) searched for prey on the trees and in the ground cover as late as mid-November 1993, and at least as early in the spring as the end of February 1994. Overwintering females fed, expanded and produced viable eggs within 7.9±0.3 (SE) days given the natural light regime, adequate food and temperatures of 17.0±20.6°C. The first generation of N. californicus developed in the field during March and April 1994. N. californicus nymphs, females and males readily moved over bare ground and through a grass ground cover to trap plants located on stakes 1 m above the ground. In the laboratory, the rate of movement of adult females on 0.5 mm copper wire was a linear function of temperature above a threshold of 11.9±0.9°C. At 25°C they travelled 10 m per h. The migration rate of N. californicus to trap plants on stakes placed in an orchard 13 Apr. increased in 2 weeks from 0.07 to 0.57 predators/trap plant/degree-day, while the migration rate to plants placed directly in the ground cover was 1.45 predators/trap plant/degree-day. The largest population of N. californicus in April occurred on Barley, Hordeum murinum L. This plant produces pollen in April and May, and may be useful in biocontrol programs.
Dispersal of Amblyseius fallacis (Acarina: Phytoseiidae) in an apple ecosystem.
Dispersal of the predatory phytoseiid mite Amblyseius fallacis (Garman) within the ground cover, the air beneath the tree canopy, on the tree trunk and on tree foliage of commercial apple orchards during a growing season is described in relation to environmental factors and densities of A. fallacis and its prey Panonychus ulmi (Koch), Tetranychus urticae Koch, and Aculus schlechtendali (Nalepa) in the aforenamed habitats. Ambulatory and aerial means of dispersal were involved in initial colonization of trees by A. fallacis coming from the orchard ground cover. A mean total of 261°0 (base 12.2°C) since January 1 plus the presence of predators in the ground cover and prey in excess of one P. ulmi equivalent/apple leaf, i.e., the number of P. ulmi + T. urticae + ( A. schlechtendali /15) on an apple leaf, were prerequisites for tree colonization by A. fallacis . Aspects of density independent and dependent dispersal by A. fallacis from trees to sites within and beyond an orchard in response to prey are also reported.
Ignition and burning rates of segregated waste combustion in packed beds.
Recent developments in national recycling and re-use programmes for municipal waste have led to segregation of an increasing proportion of waste to enhance material recovery. Several of the segregated streams contain materials that can not viably be re-used or recycled but can be used for energy recovery. In this study, the combustion of cardboard and waste wood was investigated in a small-scale packed bed reactor in order to provide fundamental data for the design/operation of moving bed furnaces. Key parameters of combustion including the ignition and burning rates were evaluated for various air flowrates and compared to the modelling results. Two successive stages of combustion were identified for both samples: the propagation of ignition front into the bed and combustion of the fuel above the ignition front. The burning rate of cardboard reached a peak of about 300 kg/m(2)h at the air flowrate of 936 kg/m(2)h and decreased at higher air flowrates. For waste wood, both the ignition and burning rates increased in the tested range of the air flowrate up to 702 kg/m(2)h, of which the values were very close to those for the cardboard. The model prediction was in good agreement with the test results for waste wood. However, the burning rate for cardboard was under-predicted due to strongly irregular shapes of the fuel.