Aphid bio­type re­vealed

The Weekly Advertiser Horsham - - Ag LIfe -

Aus­tralian sci­en­tists have con­firmed the Rus­sian wheat aphid, now es­tab­lished through­out parts of the na­tion’s south-eastern crop­ping re­gions, is a sin­gle bio­type.

This new knowl­edge, achieved through re­search in­vest­ments by the Grains Re­search and De­vel­op­ment Cor­po­ra­tion, will un­der­pin on­go­ing and fu­ture re­search ef­forts aimed at com­bat­ing the ce­real crop pest first de­tected in South Aus­tralia in 2016.

Now present in ar­eas of South Aus­tralia, Vic­to­ria, Tas­ma­nia and south­ern New South Wales, Rus­sian wheat aphid has been the fo­cus of GRDC re­search, which is pro­vid­ing the Aus­tralian grains industry with greater un­der­stand­ing of the pest and its po­ten­tial im­pact.

En­to­mol­o­gists Maarten van Helden and Greg Baker from the South Aus­tralian Re­search and De­vel­op­ment In­sti­tute have led ex­per­i­ments to iden­tify the bio­type of the aphid in Aus­tralia and pos­si­ble ori­gin of the in­cur­sion.

Their work has con­cluded the aphids in Aus­tralia be­long to a sin­gle bio­type, or have the same ge­netic make-up, named RWAAU1.

Dr van Helden said the vir­u­lence pro­file of RWAAU1 was al­most iden­ti­cal to the Amer­i­can RWA1 bio­type, which sug­gested the ori­gin of the in­cur­sion in Aus­tralia was ei­ther from the United States or from the same ori­gin as the orig­i­nal RWA1 first de­tected in Colorado in the States in 1986.

“Not only does this in­for­ma­tion help to iden­tify the most likely geo­graph­i­cal ori­gin of the aphid, and the pos­si­ble in­cur­sion path­way, but it also en­ables iden­ti­fi­ca­tion of the plant re­sis­tance genes – among the many ex­ist­ing over­seas – that could be used by breed­ers to de­velop new re­sis­tant ce­real va­ri­eties,” Dr van Helden said.

“While it is still im­por­tant to know where, when and how this aphid has ar­rived in Aus­tralia to avoid other in­cur­sions, it is even more im­por­tant to know what aphid bio­types have ap­peared in Aus­tralia, to be able to po­ten­tially de­velop sus­tain­able man­age­ment strate­gies, which in­clude plant re­sis­tance as one tool.”

In ad­di­tion to ex­per­i­ments to de­ter­mine aphid bio­type, the GRDC has been in­vest­ing in re­search to con­firm sus­cep­ti­bil­ity of com­mer­cial wheat and bar­ley cul­ti­vars to Rus­sian wheat aphid; as­sess­ing po­ten­tial sources of plant re­sis­tance; Rus­sian wheat aphid bi­ol­ogy, ecol­ogy and eco­nomic thresh­olds un­der Aus­tralian con­di­tions; an in­ves­ti­ga­tion into al­ter­nate hosts for Rus­sian wheat aphid; tri­als look­ing at in­sec­ti­cide ef­fi­cacy; and de­vel­op­ment of prac­ti­cal re­sources.

IN­SIGHT: Ex­per­i­ments to iden­tify the bio­type of the aphid present in Aus­tralia and pos­si­ble ori­gin of the in­cur­sion have been led by SARDI en­to­mol­o­gists Maarten van Helden, pic­tured, and Greg Baker.

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