Rhinocyllus conicus, a weevil introduced for biological control of exotic weeds, has had major nontarget ecological effects on native thistles. Some practitioners have argued that this is an isolated case. We report, however, that another Eurasian weevil (Larinus planus), currently being distributed in North America for the control of Canada thistle (Cirsium arvense), is significantly reducing ...

Controversy exists over estimation of ecological risk in biological control. At present, the risk to the rare, federally listed Pitcher’s thistle (Cirsium pitcheri) in North America from Rhinocyllus conicus, a biological control weevil now feeding on many native thistles, is unknown. We hypothesized that quantification of host specificity and potential phenological overlap between insect and pl...

Agromyzidae is a large and cosmopolitan fly family with approximately 2,500 known species. Here we present 22 new records of agromyzid-host plant associations. Plants were sampled from 2002 to 2005 in São Paulo state, Brazil. A total of eight agromyzid species were reared from 18 Asteraceae host species. The genus Melanagromyza Hendel was the commonest. This is the first detailed study reportin...

High biodiversity is known to increase many ecosystem functions, but studies investigating biodiversity effects have more rarely looked at multi-trophic interactions. We studied a tri-trophic system composed of Centaurea jacea (brown knapweed), its flower head-infesting tephritid fruit flies and their hymenopteran parasitoids, in a grassland biodiversity experiment. We aimed to disentangle the ...

This study was done to evaluate the effect of different planting arrangements (square, lozenge and rectangular) and various concentrations of potassium sulfate (K2SO4) fertilizer (0, 100, 200 and 300 kg/ha) on yield and essential oils quantitative of Calendula officinalis L., a medicinal and ornamental plant. The experiment was done as a factorial in randomized completely blocks design (R.C.B.D...

Cistus ladanifer has been used in ruminants feeding systems, but there is no information about the seasonal variation chemical composition and nutritional value of each morphological fraction during its growth cycle. This study characterized fractions C. (leaves, stems, flower buds, flowers, seed heads) throughout year composition, vitro digestibility, antioxidant activity. The leaves were more...