The Phasmatid control operation in the Central Highlands of Victoria I. History, biology and control methods.  F.G. Neumann and J.E. Harris.  January 1972.  23 pp. (unpubl.)

SUMMARY

This report summarises the control history of Didymuria violescens in southeastern Australia and the available data on its bio-ecology relevant to control prescriptions. Current and future control methods are also discussed.

The problem of phasmatid control in the Central Highlands of Victoria appears to be unique and a study of the control histories in forests other than E. regnans contributed little to its solution. With low persistence contact insecticides such as malathion, the “timing” of the spray application is of paramount importance. On the basis of experimental data and from post-spraying egg surveys it seems clear that spraying in the Central Highlands should commence during the first week of January and be completed no later than the first week of February during peak years.

In view of the sensitivity of E. regnans to defoliation, the feeding stages of phasmatid plagues must be controlled quickly. This can currently only be achieved by spraying forest with insecticide from the air. With presence spraying efficiency, indications are that a minimum of three sprayings at two-year intervals within the prescribed control period will be required in many localities to reduce plagues to non-detectable levels.

To increase the right of phasmatid control in dense forests of E. regnans, a number of non-chemical procedures are proposed as suitable adjuncts to spraying. These include heavy thinning or priority clear felling of worst affected stands and the replacement of susceptible vegetation on ridge tops with conifers.

Also published:

Neuman, F.G., Harris, J.A. and Wood, C.H.. (1977)  The phasmatid problem in mountain ash forests of the Central Highlands of Victoria.  For. Comm. Vic., Bull. 25, 43 pp.