The presented studies revealed the usefulness of spruce oil, basil oil, juniper oil and clove oil in monitoring of the occurrence of pea leafminer (Liriomyza huidobrensis Blanchard). While using above mentioned oils on yellow sticky traps, it was found that the number of trapped insects increased significantly. In relation to the control (traps without any addition of aromatic substance), the increase amounted to: 561.33%, 287.95%, 159.74% and 130.77%, respectively.
The fungi that cause sooty blotch grow only on the apple skin, so they use appropriate nutrients which are present on the fruit surface. It has been shown that when the first symptoms of sooty blotch occur a noticeable increase of glucose and fructose content both on the apple skin and in juice is observed. Such increase occurs at pH 4.4. An effect of surface glucose and fructose on the growth of patho- gens responsible for the disease was also confirmed by evaluating the germination of conidia of Phialophora sessilis de Hoog and Peltaster fructicola Jonhson in solution of above mentioned sugars, distilled water and standard d-glucose solutions.