The use of tracers to estimate the exposure of beneficial insects to direct pesticide spraying in cereals

A fluorescent spray tracer was used to measure the profile of spray deposits through winter-wheat crop canopies and upon beneficial insects, placed in fixed positions which approximated to their natural distributions. Tracer deposition profiles were recorded on a series of occasions between G.S. 47 to G.S. 90. Deposition levels declined through the canopy on each occasion but the proportion of the spray reaching the ground varied between growth stages. Deposition rates upon insects followed the same trends but insects on the aerial parts of the plant received a higher volume of tracer per unit area than the part of the crop that they were placed upon. Insects placed on the ground received a dose equivalent to their ground area. For a given distribution of insects, these data permit direct spray exposure to be estimated. The general application of the method to a wide range of crops, to the calculation of risk indices, to the standardisation of field tests and to the development of selective spray placement methods are discussed.     

SEM observations on petals and fruits of some Turkish endemic Bupleurum L. (Umbelliferae) species

Petal and fruit surface sculpturing are reported for seven endemic Bupleurum species in Turkey. Considerable differences in the dorsal surface of petals were observed, but major structural similarities were found in the ventral surface of petals. Significant taxonomic differences between species were determined on the surfaces of the fruits. These microstructural surface features are evaluated as possible consistent parameters in the delimitation of species of Bupleurum. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 441–449.