Russian wheat aphid causes greater reduction in phloem transport capacity of barley leaves than bird cherry-oat aphid.

The effects of feeding by the Russian wheat aphid (RWA). Dutraplu.s nom! Mordvilko and the Bird cherry-oat aphid (BC A). Rhopaloppluan pad, L on the transport capacity of barley Holdeum vulgare L leaves were investigated and compated with a view to i-elan ng these effects to the visible symptoms shown by the respective infested plants RWA causes extensive chlorosis and neciosis on an infested plant whereas I3CA causes no obseivable symptoms Our results using the xenobiotic. phloem mobile Bum ophole. 5, 6 carboxyBurn escei n chacetate (5. 6-CFDA) ievealed striking ch fletences in damage to the transpol t of assimilates thiough the phloem by these two aphids The result clearly suggests that short-term feeding by RWA causes a reduction in tiansport of assimikites and a mole severe reduction oi pei haps even permanent cessation of transport during long-term feed111,2. In contrast. feechntz by BCA does not lead to a !milked dect ease in transport do ring short-term feeding period. howevei, a !eduction in the uanspoit was recorded donne long-term feeding activities These iesults perhaps suggest that damage to ti ansport capacities of the barley leaves appeals lobe partly responsible for the observed symptoms in RWIA-infested plants and the lack of them during BCA in symptoms such as 'eduction ol cessation in transport of assionlates to growing tissues may lead to such observable symptoms