2002 The Rhododendron

• Date: 22nd January 2016
• author: Kathy Wilson

An excerpt from an article by Kathy Wilson on lace bug from this journal.

With the ongoing “lacebug on rhododendrons” discussions that inevitably occur amongst Society members and horticulturists, some information from Mount Tomah Botanic Gardens’ Procedures and Plans may be of interest, and perhaps even offer some hope, for the management of this very clever, but very damaging, insect.

Over the last 15 or so years many changes have been implemented, and are ongoing, in the management practices for rhododendron lacebug at MTBG. These changes have been brought about by many factors including pesticide resistance, a greater awareness of the unacceptable aspects – both to humans and the environment – of the use of upper range S-rated chemicals, and changes in the range of new products available.

Initially the rhododendrons, some 1,800 specimens, were “preventively”sprayed with a systemic – up to an S7, such as Lebaycid®; an S6 – Folimat®; an S7; or Metasystox® – which was de-registered six or seven years ago. These are no longer considered best options due to their toxicity to operators, and the inconvenience of withholding periods required before re-opening areas to the public after spraying. The toxicity effects to bees and other insects are also taken into account. Products containing pyrethrum are also not favoured as pyrethrums kill all insects. The marketing of the “natural” qualities of pyrethrums has masked the fact that it kills all insects, the “beneficials” as well as the targeted “problem” insect...

CONTENTS
President’s Report · Dr Allan Kerr Grant......................................................3
Annual Report 2001–2002 · Barry Stagoll....................................................5
Life membership · Bill McClure..................................................................8
My Edinburgh rhododendron experience · Gillian Brown.........................10
Management of lace bug at Mt Tomah Botanic Gardens · Kathy Wilson.....13
More on Australian hybrids · Ken Gillanders..............................................15
Adelaide, Spring 2001 · Tania Thomas and Rosemary Thomson..................17
When is a rhododendron an azalea? · Peter Valder.......................................18
Vireya species regenerated · Brian Clancy...................................................22
The case for deadheading · Barry Davidson................................................25
Emu Valley Fairyland · Maurice Kupsch.....................................................29
Emu Valley revisited · Terry Shadbolt..........................................................31
Dr John Layton Rouse OAM · Bob Withers and Graham Snell..................34
The species collection at the N.R.G. · Barry Stagoll...................................38
The Whibley hybrids · Allan Kerr Grant.....................................................39
Some musings about lilies · Michael Hammer............................................41
Woodbank Nursery, we thank you · Barry Davidson..................................56
Tolerant and tough vireyas · Allan Kerr Grant and John Schutz...................61
Rhododendron wentianum · Lyn Craven........................................................64
Rhododendrons on a tropical mountain · M.S.Viraraghavan.......................66
New Registrations 2001–2002 · Ken Gillanders.........................................72
Report by the Treasurer · Neil Webster......................................................75
Branch Information...................................................................................79