Onion yellow dwarf virus (OYDV), an aphid-borne potyvirus is one of the major viral pathogens of garlic causing significant yield losses worldwide. It is found almost everywhere in the world where Allium species is grown. The aim of this study was to test the presence of OYDV infection in garlic from Ethiopia. The presence of the virus was tested by Reverse transcription polymerase chain reaction (RT-PCR). The direct sequencing of the PCR product produced a sequence of 296 bp. Sequence analysis showed 89.27% sequence homology with an isolate from Australia (HQ258894) and 89.29% with an isolate from Spain (JX429964). A phylogenetic tree constructed with MEGA 7.0 revealed high levels of homology with various isolates of OYDV from all over the world and thus further confirmed the identity of the virus.

Characterisation of two-spotted spider mite ( Tetranychus urticae Koch , Acari: Tetranychidae) response to aqueous extracts from selected plant species. Aqueous extracts from four plant species of known insecticidal activity on arthropods were tested against two-spotted spider mite females to describe their mode of action on the spider mite. The extracts effects on: (a) the mite establishment on host plant; (b) initiation of feeding (probing behaviour); (c) initiation of permanent feeding and (d) the mite mortality (a toxic effect) was measured using various experimental techniques. The highest toxic action was shown by NeemAzal-T/S (an extract from Azadirachta indica; production of Trifolio-M GmbH company) and repellent by water extract from Allium sativum and Urtica dioica. NeemAzal T/S also shown a strong activity as a feeding suppresant for T. urticae.