A broad range of benzophenone hydrazone derivatives was prepared and tested against selected chewing insect pests, allowing the analysis of structure-activity relationships. Good activity was found only when the aromatic rings were substituted at the 4-positions with an halogen atom and a triflate or perhaloalkoxy group. In contrast, a number of substituents on the hydrazone part led to active compounds, the best results being achieved with acyl-type substituents. The excellent laboratory and greenhouse activity of the best representatives was confirmed in semi-field trials against Spodoptera littoralis.

from both ExpF-based treatments were almost identical.Not all xylem-mobile molecules behave in the same way and this is illustrated by a comparison between ExpF and¯uquinconazole when both were mixed with Adj1. Fluquinconazole was recovered only in very small quantities, the single greatest recovery being 0.17% over a 24 h period. These recoveries are considerably less than those already described for ExpF when mixed with the same adjuvant. That recovery in guttation¯uid is not solely related to the level of uptake into the plant is supported by data from other experiments (Harris RI unpublished) where the uptakes of both¯uquinconazole and ExpF were very similar when mixed with Adj1 (60 and 69%, respectively, 24 h after application).Using ExpF as a model compound it should be possible to investigate the behaviour of other formulation systems on target crops. A speci®c example of the use of this system is the evaluation of encapsulated formulations. It is possible to prepare capsules with a range of properties, one of these being ease of capsule breakdown, resulting in the release of the encapsulated compound. This can be monitored using arti®cial surfaces, but there is now the possibility of doing studies in vivo using the model described above.Information about the loss of fungicide, insecticide and herbicide molecules in guttation¯uid can also help explain biological performance against target species. For example, the activity of ExpF against Erysiphe graminis DC f sp tritici Marchal, (the causal organism of powdery mildew of wheat) was enhanced when mixed with Adj2 but not Adj1 (Moss, N A pers. comm.). From the results discussed above it is possible that a biologically signi®cant proportion of the applied dose of ExpF, when mixed with Adj1, was lost through guttation, resulting in an inferior performance compared with the mixture with Adj2. Life-cycle studies showed ExpF to be more effective as a protectant than curative fungicide and that the early stages of pathogen development were most affected. A formulation optimising surface retention rather than foliar uptake would, therefore, be more appropriate. Synthesis and insecticidal activity of 4-perhaloalkoxy (or thioalkyl) benzophenonehydrazone derivativesDieter Dürr, Laurenz Gsell, Roger G Hall, Friedrich Karrer, Alfons Pascual* and Alfred Rindlisbacher Novartis Crop Protection AG, PO Box, 4002 Basel, Switzerland Abstract: Benzophenonehydrazone derivatives containing a mesylate or tri¯ate substituent are known to exhibit insecticidal activity. In the present study, such substituents have been replaced by perhaloalkoxy groups. High levels of activity against lepidopteran pests were observed in greenhouse trials. For optimum activity, the substituents should be relatively small. In semi-®eld trials, however, none of the compounds tested showed suf®cient persistence to warrant further development.

Die Synthese einiger symmetrischer und unsymmetrischer Cyanine mit dem Benz‐l,3‐dithiylium‐, dem 5‐Äthoxy‐benz‐l,3‐dithiylium‐, dem 4,5‐Dihydro‐l, 3‐dithiylium‐ und dem Benz‐l,3‐oxathiylium‐Ring als Endglied wird beschrieben. Die Beziehungen zwischen Konstitution und Farbe werden kurz erörtert. In allen Reihen zeigen die Hemicyanine mit Dimethylaminostyrylgruppen kräftige positive Ab‐weichungen vom Mittelwert auf.

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