Use of Stem Implanted Bioherbicide Capsules to Manage an Infestation of Parkinsonia aculeata in Northern Australia.

Victor J. Galea

doi:10.3390/plants10091909

Abstract

An infestation of parkinsonia (Parkinsonia aculeata) located on Alexandria Station, Northern Territory, Australia, was successfully treated with a bioherbicide using stem-implanted capsules. The bioherbicide (Di-Bak Parkinsonia®), containing three endemic endophytic fungi (Lasiodiplodia pseudotheobromae, Macrophomina phaseolina and Neoscytalidium novaehollandiae), is the first Australian registered woody weed bioherbicide. The product was effectively administered to the plant stems using a mechanical device, resulting in the subsequent development of a dieback event. After a period of establishment, it progressed through an adjacent untreated population, resulting in a significant decline in infestation vigour and preventing recruitment from the seedbank. This is the first report of large-scale management of parkinsonia by this method.

Highlights

Parkinsonia (Parkinsonia aculeata L.), known as Mexican palo, Jerusalem thorn, blue palo verde, horse bean tree, sessaban and Barbados flower fence [1], is a thorny shrub that can grow into a small tree with a natural range from the southern USA through to Argentina [2]
Parkinsonia populations are greatest in northern Australia (Queensland, Northern Territory and Western Australia), with only a few scattered infestations reported in New South Wales and even fewer in South Australia
The first detailed examination of parkinsonia dieback across northern Australia [6] resulted in the identification of 41 fungal species from

Summary

Introduction

Parkinsonia (Parkinsonia aculeata L.), known as Mexican palo, Jerusalem thorn, blue palo verde, horse bean tree, sessaban and Barbados flower fence [1], is a thorny shrub that can grow into a small tree with a natural range from the southern USA through to Argentina [2]. Parkinsonia is thought to have been introduced in Australia in the 1860s [3], quickly spreading through its utility as an ornamental shade tree and, by 1906, was considered a weed [4]. Significance (WoNS) in recognition of it being a major weed threat. This classification identifies parkinsonia for implementation of strategic action plans (at various jurisdictional levels) and as a priority species for management programs and targeted research, as it produces impenetrable thickets which impact grazing systems [5] and natural riparian zones. Dieback of parkinsonia is a documented phenomenon leading to plant mortality, and sometimes entire populations are affected [5]. The first detailed examination of parkinsonia dieback across northern Australia [6] resulted in the identification of 41 fungal species from

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