- 3.2.1 Probability of entry
- 3.2.2 Probability of establishment
- 3.2.3 Probability of spread
- 3.2.4 Economic consequences
- 3.2.5 Overall assessment of risk
3.2 Dasineura mali
The data sheet for this pest was drafted by scientists of Landcare Research New Zealand Limited, not by New Zealand MAF as cited in the draft IRA. New Zealand requests that AFFA change the way this datasheet and other relevant datasheets are cited.
3.2.1 Probability of entry
In establishing the risk of Dasineura mali entering Australia on apple fruit from New Zealand, AFFA has concluded that pupae or larvae present in the calyx of the apple would not be detected during packhouse or on-arrival inspection. Larvae feed inside the leaf rolls caused by infestation of developing leaves. Contamination of fruit with pupae or larvae can occur when mature larvae are exiting the leaf rolls trying to reach the soil for pupation, and are caught in the stem or calyx of the fruit (Smith et al. 1995). These mature larvae are an orange colour and are up to 4mm long (Smith et al. 1999b). New Zealand considers that both mature larvae and cocoons would be easy to detect at standard pre-export or on-arrival inspection. As such, it is unlikely that the pest would escape detection and enter Australia on apple fruit.
| New Zealand believes that the pest would be detected during inspection, and that the risk of entry is low. |
3.2.2 Probability of establishment
The risk of establishment has been assessed by AFFA as moderate (i.e., an even probability of occurring). However, New Zealand believes that a more accurate assessment is that the probability of establishment is very low.
Apple is the only recorded host of D. mali. Reproduction of the pest requires a breeding pair to establish during the 3 -4 day life of the adult. As most of the apple fruit exported to Australia will be imported into urban environments it is very unlikely that a larva from a discarded apple could pupate, find a mate, and find an apple tree to lay on within the short life of the adult. As an example of this, apple leaf curling midge has never established in California despite importation of apple fruit from New Zealand (and other states of the USA) for over 20 years.
| New Zealand believes the probability of establishment is very low. |
3.2.3 Probability of spread
AFFA has concluded that the risk of spread is moderate despite the limited host range, the availability of natural enemies (Tomkins et al. 2000) and the limited flying capability of the adults. New Zealand believes that the probability of spread has been over-estimated.
| New Zealand believes that the probability of spread is low. |
3.2.4 Economic consequences
In the assessment of economic consequences, AFFA has reported that a majority of growers in Nelson ranked D. mali as the most serious pest on their property. In reality, 33% of growers ranked D. mali as the most serious pest and a further 17% of growers ranked the pest as equal with mites as the most serious pest on the property (Smith and Chapman, 1995). This survey was completed in the 1994-95 season and included 30 growers from a small region in Nelson and is not necessarily indicative of the pest status in other regions of New Zealand. Biological control using the natural predator Platygaster demades is now being used and has proved to be an effective control agent.
New Zealand considers that the conclusion reached by AFFA in the assessment of economic impact is inconsistent with the definition on p46 of the draft IRA "...serious effect on economic stability, societal values or social wellbeing would be limited to a given geographic region". The impact is more likely to be a minor effect on production only, and "to be minor to directly affected parties. The impact is unlikely to be recognised at any other level", i.e., very low.
| New Zealand considers that the economic consequences of this pest would be very low. |
3.2.5 Overall assessment of risk
| The risk of entry, establishment and spread of D. mali would be more accurately described as very low and the economic consequences as low giving an unrestricted risk estimate of negligible. This is below the ALOP specified by AFFA and no risk management measures should be required for this pest. |
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