Wheat Curl Mite and the Wheat Streak Mosaic Virus (WSMV) - Centre for Environmental Stress and Adaptation Research (CESAR) | Grains Research & Development Corporation (GRDC) | Australian Crop Pest | WSMV | Wheat Mite Control

Management

Wheat Streak Mosaic Virus (WSMV) is primarily spread by the Wheat Curl Mite (WCM), Aceria tosichella, although low levels of transmission can also occur through infected wheat seed. WCM typically colonise the youngest tissue of a wheat plant and acquire WSMV when feeding on infected plants. Chemical control of mites is believed to be largely ineffective as they predominantly live (and are protected) within leaf whorls. Also, research from abroad has shown pesticide usage to be ineffective as mites are difficult to target and develop resistance to pesticides rapidly.

Infected volunteer wheat and alternate host plants provide both an effective “green bridge” refuge for WCM outside growing periods, and a potential source of re-infestation and spread of WSMV to successive wheat crops. Additionally, WCM has a large dispersal potential facilitated by wind. As a result, WCM survival and dispersal are the key factors influencing the spread of WSMV. Despite efforts to develop mite resistant wheat cultivars, primary management of WSMV focuses on reducing numbers of WCM through the control of volunteer wheat and alternate plant hosts.

Current control strategies in Australia:

• Break the disease cycle. Control of over-summering volunteer wheat/cereals and grasses within fields, on field boundaries, roadsides and around storage areas reduces the numbers of mites that can invade autumn sown crops. Already this has proven to be an effective control strategy in Australia.

• When possible delay sowing in autumn until temperatures are too low for mite activity (temperatures between 24 °C and 27 °C are optimal for WCM population survival and growth). In many cases this may not be a viable option, e.g. grazing wheat.

Current control strategies in Australia:

Australian Wheat Streak Mosaic Cycle