Impact of cereal aphids feeding on yield of spring wheat in central Saudi Arabia

الملخص EN

-A two-sea son field experiment was conducted in Gassim Region to evaluate yield losse s in wheat , cv .

Ye corah Rojo , due to feeding of cere al aphids Oil folia ge ami ea rs.

Caged plot s were an ificially col on ized with D.

ill , 20 and 40 aphids/stem .

Ca ged e ars were col onized with the same aphid den sities at three growth sta ges.

Losses ill grain weight a nd grain number at 10 aphids/stern infe station level amounted up 10 27.0% and 20.2%, in 19R7IRR seaso n.

and 12 .7% and lJ.3% in llJHHlRlJ season .

re spectively .

When aphids fed o n de veloping cars .

the 10 aphids/cur level resulted in gra in weight and gr ain number reductions am ounting up 10 35.5% and 37,lI'X, .

13.0 'X, and 13,4% and lJ.O'X, and 4.7'}'o when infes ta tio ns, were started at head emergence , head flowering or head maturity .

resp ectively.

Infestations starling at head eme rge nce were more damaging th an those s tarting later .

It is recommended that tr eatments should be started at levels below 10 aphids per ste rn or ear (at head eme rge nce)