Die Bekämpfung der Fichtengallenlaus Adelges laricis Vall. : Anlage und Auswertung eines Versuches

Birmensdorf

1961

S. 325-342

3 Abb., 6 Tab., 11 Lit. Ang.

Artikel aus einer ZeitschriftUnselbständiges Werk

200157567

A study was made to show the influence of certain insecticides and methods of application an the control of overwriting larvae of Agelges laricis Vall. The insecticedes used had mineral oil, BHC and organic phosphate as active ingedients and were applied by spraying and miting with portable equipment. A new experimental method was employed which allowed the application of the different insexcticides to trees within a small area. The individual tree is the sample unit and replications of treatments can be made within the same surface area by the method used. In this method, all trees not being given the particular treatment were completely covered by polyethylene sacks. In this way, six different treatments and a check were repeated three times in each of the two seperate areas about 100 meters apart. The evaluation of the effectiveness of the treatment is based on counts of 40 larvae per tree. Four twigs per tree were selected at randomand the first ten larvae abserved on each twig were included in the sample. We distinguished anly between living and dead larvae. The interpretation of results was done by an analysis of variance with a two-way layout, after a modification of the proportions p of survived insects by the equation: y=< sin √p. The result show that we abtained the best control by spraying or misting of mineral oils. The effectiveness of lindane mist was also good. A 100% kill of the larve was realized when sprayed with 4% Paramaag-winter, 89,5% with a mit of concentrated mineral oil and 85,5% with lindane mist at a concentration of 6%. Treatments of 0,15% Hexamul, 0,1% Rogor (=dimethoate) 40 spray and 12% Rogor mist were not enough effective. The effectiveness of mist soutions applid by portable equipment suitable for use under forest conditions enables us to hope that control of Drayfusia (=Adelges) species in silver fir can be accomplished in a similar manner.