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The effect of Quassia extract on eggs and larvae of the apple sawfly Hoplocampa testudinea was studied. The efficacy of this extract is mainly due to an oral toxicity to the neonate sawfly larvae. The main active ingredients, Quassin and Neoquassin, were tested separately. Wheras Quassin has a considerable efficacy also on older larvae, Neoquassin is less efficient in this case. While Quassin and Neoquassin are found in different Quassia sources in varying relations to each other and have different efficacy, they have to be considered separately in the definition of extract quality by the content of active ingredients. These findings mean, that the “egg maturity” is not important for application date. Nevertheless, the application must take place before the larvae hatch. It was shown that low rates of Quassin (4-6 g/ha) can show very good results in the field, in other cases the rates necessary for good efficacy are much higher. This corresponds to farmers experience. Several factors as application technique and the condition of the blossom must be taken in consideration and will be object of further studies. The side effects of Quassin, Neoquassin and Quassia extract on Aphelinus mali and other beneficial arthropods were tested. Quassia is harmless to all organisms tested.

This study investigates the possibilities to treat oligo-asthenozoospermia, a cause of sterility, by assisted conjugation. After completing acrosome reaction, normal motile spermatozoa are microinjected into mouse oocytes. After 2 hours of incubation time in medium with lactate and albumins, spermatozoa are put into dibutyryl 3',5'-guanosine monophosphate (dbcGMP) and imidazole for the completion of an acrosome reaction. One motile spermatozoon each was injected microsurgically into the perivitelline space of an oocyte. The survival rate of the oocytes after injection was around 85%. The oocytes with two pronuclei and a second polar body were considered as fertilized. Of those injected oocytes 21.5% were fertilized with acrosome reacted spermatozoa, whereas only 5.6% were fertilized with spermatozoa without dbcGMP treatment. Thus, motile and acrosome reacted spermatozoa essentially fertilize oocytes at microinjection into the perivitelline space very well. This technique may become a hopeful procedure to treat human oligo-asthenozoospermia in an IVF/ET-programme.