Occurrence and control of borers in Hunter Valley vineyards

Abstract

Occurrence and control of borers in Hunter Valley vineyards

Summary

The lamiine cerambycid, fig longicorn A. vastator, has been known to attack vineyards in the Hunter Valley through most of this century (Froggatt 1919). The Hunter Valley of New South Wales is an important wine producing region and threats to the economic viability of its vineyards are viewed with concern. In the Lower Hunter Valley, an outbreak of A. vastator is causing serious damage to vineyards. The current infestation, known in this area since 1985 has, in 1993, spread to many vineyards in the Pokolbin district with up to 70% of vines infested in some vineyards.

Extensive research funded by the Hunter Valley Vineyard Association and the Grape and Wine Research & Development Corporation (formerly G&WR Council) was conducted on this pest problem between 1989-1993.

Ecological study demonstrated that the life cycle of this univoltine cerambycid pest species presented only a narrow window of opportunity to achieve successful control. The I-III larval instars are present in a relatively exposed position on the surface of, and just under, the bark where they are best able to be contacted by insecticide sprays. Initially the development of chemical control recommendations was restricted to insecticides currently registered for use in grapes in NSW. Reasons for this are given in the report. To this extent, azinphos methyl, chlorpyrifos and methidathion applied to barked areas of grapevines were found to provide field control against young larvae of A. vastator. A management strategy for this pest, based on these components, was prepared and growers were advised of this information. An Agnote, which is regularly updated, was produced and provided to each grower experiencing this pest problem.

The difficulty of studying borer pests because of their inaccessibility in woody hosts has resulted in few effective control programs that prevent serious economic loss from being developed. This is reflected in the large number of topics that were considered in this study. Many avenues of approach were investigated, with a number proving fruitless. However, it is considered that the control strategy developed in this program offers an effective and practical approach to dealing with this problem providing the advice is followed. Unfortunately, this relies on a heavy usage of organophosphate insecticide. The spraying demands and concerns over the frequent use of these chemicals are causing a problem for a number of growers and alternatives are being investigated. Further study into the side effects of these insecticides on beneficial pest mite populations can also be justified.

Progress in this project has been reported to Hunter Valley growers at biannual viticultural seminars conducted by the Hunter Valley Vineyard Association in Spring 1989, Spring 1990, Autumn and Spring 1991, Autumn and Spring 1992 and to meetings of the Technical Committee, HVVA and to the HVVAAGM.