Laboratory evaluation of natural pyrethrins, pymetrozine and triflumuron as alternatives to controlCeratitis capitata adults

Three insecticides, pyrethrins + piperonil butoxide (PBO), pymetrozine and triflumuron, were tested as potential alternatives for controlling the Mediterranean fruit flyCeratitis capitata (Wiedemann) (Diptera: Tephritidae). The compounds were administered to adult flies in the laboratory by different uptake methods at the recommended rates currently used in fruit crops in Spain. Pyrethrins + PBO (80 + 320 ppm a.i.) exhibited a comparable knock-down effect to malathion (1,500 ppm a.i.) in the laboratory, irrespective of the method of application used. After these results were obtained, the number of concentrations tested was increased to carry out a dose-response analysis. Pymetrozine (300 ppm a.i.) and triflumuron (150 ppm a.i.) did not kill adults at the concentrations tested. However, pymetrozine diminished the fecundity, especially when adults were fed the insecticide; egg hatch was decreased by 59.3% compared with controls. Further experiments showed that increased period of ingestion and higher concentrations had a clear effect in reducing both fecundity and fertility. The possible use of pyrethrins + PBO and pymetrozine to reduce populations ofC. capitata is discussed. http://www.phytoparasitica.org posting July 22, 2006. Corresponding author     

Effects of extracts of toxic fescue given orally to rats.

Fresh fescue (Festuca arundinacea) was obtained from farms where toxicity was encountered in cattle grazing the fescue. The fescue was dried in a forced draft oven at 60 degrees C and then ground. The dry ground fescue was extracted with ether and then re-extracted with either 1% sodium bicarbonate (NaHCO3), sodium hydroxide or hydrochloric acid. The residual ether was evaporated and the residue resuspended in ethyl alcohol diluted with water 1% (control) and 1 mL of the above extracts of fescue were given daily to rats, via stomach tube, beginning the seventh day after breeding. Two of the seven rats given the 1% NaHCO3 fraction of the extract of fescue gave birth to live young. One of these litters contained only five pups, with one being stillborn. Three of the seven rats aborted, one gave birth to seven stillborn pups and one female died during birth. All females fed the 1% NaHCO3 and the other extracts of the fescue gave birth to normal litters. Rats fed the ether extract which was re-extracted with 1% NaHCO3, acidified and re-extracted with ether, dried and resuspended in 1% NaHCO3 produced similar reproductive problems as those rats given the ether extract of fescue which was re-extracted only once with 1% NaHCO3. Therefore, it appears that the toxic entity(s) of fescue can be extracted and that infertility/abortion/still-birth ratio of rats may be used as a bioassay.     

Fungicides for the control of Mycogone perniciosa (Magn.), the cause of wet bubble on the cultivated mushroom

Two formulations of chlorothalonil (as Daconil 2787) were compared for their activity against Mycogone perniciosa Magn. on the cultivated mushroom Agaricus bisporus (Lange) Imbach. At the same does rates, the flowable formulation was more toxic than the wettable powder to both pathogen and host, but more marketable mushrooms were obtained from diseased plots treated with the flowable formulation at each dose rate (1.0, 0.5 and 0.1 g ai m^?2). Levels of disease control were related to dose rates, making it impracticable to lessen toxicity to mushrooms by reducing the dose rate. Fluotrimazole was less active than chlorothalonil against M. perniciosa and was more toxic to mushrooms.