Psila rosae

The antennal olfactory receptor system in several phytophagous insects is very sensitive in the detection of the green odour components. In the Colorado beetle Leptinotarsa decemlineata, the threshold of response for trans-2-hexen-1-ol is circa 10b molecules per ml of air (17). In comparison, at 760 mm Hg and 20 C, 1 ml of air contains about 1019 molecules. The insects tested i.e., the migratory locust Locusta migratoria, the carrot fly Psila rosae (18), the cereal aphid Sitobion avenae (19), the Colorado beetle L. decemlineata (17), Leptinotarsa... 

Prunus dulcis var. dulc. See Almond Prunus persica. See Peach Prunus salicina. See Plum, Japanese Pseudococcidae. See Mealybugs Pseudomonas blight, pear and, 170 Pseudomonas marginalis, 418 Psila rosae. See Carrot rust flies Psyllas, pear. See Pear psyllas Psyllids. Buxus and, 51 Pumpkin, 213... 

Guerin, P. M., E. Stadler, and H. R. Buser, Identification of host plant attractants for the carrot fly, Psila rosae, J. Chem. Ecol., 9, 843-861 (1983). 

A mixture of volatiles from carrot Daucus carota, Apiaceae) is responsible for oviposition by females of the carrot fly Psila rosae). Among these are the phenylpropanoids. E-methyleugenol, -asarone, a prenylated coumarin, osthol (31), bergapten (18), xanthotoxin (19), and an acetylenic compound, falcarindiol (Harbome, 1986). No single component of the mixture is responsible for the behavior of the fly. 

To solve the problem of non-polar chemicals in water, Blaney (1975) used a suspension of leaf surface waxes in a 50 mM NaCl solution. Since our attempts to use this technique gave unclear results in the carrot rust fly, Psila rosae, we tested additional methods. The most promising results were obtained using 10 7o methanol extracts of leaf surfaces in a 100 mM NaCl solution as represented in Fig. 1.4 (StSdler, unpublished). We found no indication of damage or stimulation by methanol in different fly species. These results are in agreement with those of Dethier (1951) the 50% behavioral rejection threshold for methanol is about 5 to 10 molar for the blowfly, Phormia regina, and the cricket, Gryllus assimilis. 

Stadler, E. (1977) Host selection and chemoreception in the carrot rust fly (Psila rosae F., Dipt, Psilidae) Extraction and isolation of oviposition stimulants and their perception by the female. Colloques Internationaux CNRS, Comportement des insectes et milieu trophique, 265, 357-72. 

Jones, O. T. and Coaker, T. H. (1979) Responses of carrot fly larvae, Psila rosae, to the ordorous and contact-chemostimulatory metabolites of host and non-host plants. Physiol. Ent., 4, 353-60. 

More detailed information on turning rates and movements can be obtained by providing a surface on the petri dish that will record and retain the larval tracks. Jones and Coaker (1977) utilized a thin layer of agar coated with talc over which larvae of the carrot fly, Psila rosae, crawled. Larval tracks were evident in the talc field, and permanent records of larval movement were made by photographing the plates. Time-lapse photography also has been used to provide a permanent track of movement in relatively small arenas (Bell Tobin 1981), and more modem video equipment provides greater flexibility for such recording. 

Jones, O.T. T.H. Coaker. 1977. Oriented responses of carrot fly larvae, Psila rosae, to plant odours, carbon dioxide and carrot root volatiles. Physiol. Entomol. 2 189-197. 

---