Sustainable Management of Medfly without cover sprays

Publication Date

2015

Series Number

Project Number: MT12012

Publisher

Horticulture Innovation Australia Limited

City

Sydney

ISBN

ISBN 0 7341 3599 8

Abstract

- Since the 1960s, dimethoate and fenthion have been used by apple and pear, stone fruit, and mango growers for pre-harvest (cover spray) and post-harvest (dips, flood sprays) control of Mediterranean fruit fly (medfly, Ceratitis capitata). The loss of these insecticides in 2011 and 2015 respectively will make medfly more difficult to control in highly susceptible crops such as summer fruit.

- Several pre-harvest control tactics were developed or tested during the project, including an area-wide approach (AWM). Facets of an AWM program were tested in pome and stone fruit orchards in Jarrahdale in the Perth Hills, and mass trapping was trialled in an area within the Jarrahdale town-site.

- Trapping grids were installed in Jarrahdale and other areas within Perth Hills commercial production areas to determine when and where medfly is abundant, and to assess the efficacy of control measures.

- Monitoring and degree-day modelling showed that medfly survived winter in the adult and immature stages in all Perth Hills areas. A study of the crop phenology provided evidence that suitable hosts are available throughout the year, particularly citrus (lemon, orange, mandarin). Citrus provides shelter and food (e.g. honeydew from scale insects), and females are able to lay eggs into oranges and mandarins in winter when temperatures exceed 10ºC.

- There are two main periods of medfly abundance: summer and autumn. Spring infestation of commercial orchards was attributed to overwintered flies, rather than an influx of adults from nearby areas such as towns. Abundance increases during summer, peaking in late December/January as summer fruits ripen.

- In autumn, medfly adults disperse into surrounding areas to search for suitable over-wintering sites coinciding with ripening of pome fruit. Late autumn baiting is recommended to curb these dispersing adults, coupled with strict orchard hygiene to eliminate overwintering eggs and larvae.

- AWM with bait sprays was highly effective at suppressing medfly (< 1 f/t/d), and was effective with as few as 1-3 growers. New techniques including attract-and-kill devices (MagMED®, Probodelt Conetrap) and the sterile insect technique did not reduce the medfly population below the economic threshold of 1 f/t/d when used alone. However, these techniques were effective when combined with bait spraying. Trap and lure components were identified that growers could use to develop their own mass trapping system, as well as lures to improve monitoring of male medfly.

- The neonicotinoids Samurai Systemic Insecticide™ (clothianidin) and Calypso® (thiacloprid) currently available for use under an APVMA permit, killed medfly eggs and larvae when fruit was treated 7 days after medfly had been allowed to lay eggs. They are both possible replacements for fenthion.

Number of Pages

98

Keywords

Area wide management, mass trapping, lure and kill, Mediterranean fruit fly, sterile insect technique, suppression, bait spraying, cover spraying, clothianidin, thiacloprid, spinetoram, male-targeted trapping, female-targeted trapping

Disciplines

Biosecurity | Entomology | Fruit Science | Horticulture

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