Acknowledgement
News
The 1m 3 fumigation chamber used for trials . Photo : P . Wyatt
comprehensive data package showing that this method is effective against all four life stages of Queensland fruit fly ”. The researchers infested nectarines by allowing fruit flies from their captive colony to lay eggs directly into the fruit . The fruit were fumigated after one day ( eggs ) or after allowing the larvae to develop to first , second or third instar maturity .
In total , 30,000 individuals of each life stage were treated with 18g . m3 MeBr , and not a single insect survived . This is the highest level of confidence required by any importing authority , equating to > 99.99 % mortality .
However , this is no use unless the fruit is still good quality . “ Methyl bromide can damage fruit , reducing shelf life ,” Pauline said . “ We conducted fruit quality assessments at different storage times to check whether the doses we were using affected quality or shelf life .
“ The results were excellent , as there were no significant effects of fumigation on colour , rots , firmness , sugars or acids , even at slightly increased times and dosages ”.
As a result , there are three treatment options available for stonefruit growers wishing to export to China from areas not fruit fly-free :
1 . Cold treatment , being 3 ° C for 18 days ( east coast ) or 2.1 ° C for 21 days ( west coast )
2 . MeBr fumigation with 32g . m3 for 2 to 3 hours at 21 ° C followed by cold treatment for 3 to 4 days
3 . MeBr fumigation with 18g . m3 for 5½ hours at 18 ° C
Option 3 is therefore not only a world-first , but has successfully opened the way for Australian stonefruit into China . John Moore ’ s report in this magazine confirms that low dose MeBr fumigation is resulting in fruit arriving in China in excellent condition and getting top price in the big city markets .
Chile is also entering the Chinese market this season , having recently finalised negotiations over entry protocols – just as Australia has . Their fruit will also have to be treated against fruit fly . However , without a protocol that avoids damaging fruit , they may find themselves in the bargain bins .
Looking to the future , fruit fly trials and fruit quality assessments have also been completed for white fleshed peaches . The next step is to repeat the trials on plums , which is happening this season . This should open the way for export of both peaches and plums in the next few years .
Technical officer and fruit fly wrangler Thelma Peek , QDAF . Photo : P . Wyatt
Acknowledgement
This project , SF12016 , was funded by Horticulture Innovation Australia using the summerfruit industry levy and funds from the Australian Government .
20 Australian Stonefruit Grower | December 2016 summerfruit . com . au