F1 hybrids were produced by crossing, in artificial conditions, female Barbus barbus and male B. meridionalis. Results from the genetic study describing enzymatic patterns produced after electrophoresis of experimental F1 hybrids confirmed a great part of the original interpretation of patterns observed in the natural population. Morphological studies which examined denticle length on the last hard ray of the dorsal fin (well developed in B. barbus and absent in B. meridionalis), showed that F1 hybrids' values were not exactly intermediate between the parental values. Up to two years old, experimental hybrids displayed identical growth rates and sexual dimorphism of length (in favour of the females) as B. barbus growing in the same conditions. At this age, in female hybrids, the ovaries matured and produced fertilizable ovules: in male hybrids, the testicles were morphologically normal but no sperm was produced. If this sterility is confirmed in the reciprocal cross (male B. barbus × female B. meridionalis), the phenomenon would be an essential feature in understanding this hybridization.

Laboratory-reared tsetse, Glossina pallidipes were inoculated with the tsetse virus by microinjection into the haemocoel, and feeding through micropipettes. The inoculated tsetse were reared on rabbits for 45 days, and feeding, flight and mating activities recorded. The tsetse were dissected and the conditions of the salivary glands and gonads noted. In males, tsetse were examined under a compound microscope and the presence of spermatozoa noted. F1 pupae were allowed to emerge, dissected, and the salivary glands examined for hypertrophy, and the gonads for sterility.

There was no reduction in the activity of inoculated tsetse. Infection level was 23.5% in the treated adults. All infected ♂♂ were sterile while ♀♀ were fertile. There was no significant difference in the maternal age at larviposition, F1 pupal weight, or incubation period of F1 pupae, between treated and untreated tsetse.

A high proportion of F1 adults (65%) were infected, with category four hypertrophied salivary glands. All males with enlarged glands were sterile. The evidence obtained shows that the tsetse virus may be used in biological control of G. pallidipes.