We’ve been working on an Oregon Specialty Crop Block Grant project revolving around SWD Integrated Pest Management strategies. Part of this work involves intensive fruit sampling of marketable fruit at the highest risk locations in blackberry and blueberry fields. High risk locations include field edges, particularly those that are next to wild habitat that is conducive to overwintering SWD. It also includes fruit that is most protected from the elements (inside canopy, shaded locations) on the bush. Normally this sampling effort is very effective at identifying if SWD infected the fruit well before it is harvested which means management tools can be implemented, leaving little opportunity for the infestation to make it to the processing facility.
We’ve just had a handful of very hot days which have damaged blackberry fruit. Heat damaged fruit brings in a whole other concern of other insect invasion, specifically other fruit and vinegar flies that play a decomposing role for compromised fruit. The soft, sunburned fruit that remains will either come off with the machine harvester or it will be stuck on the plant, unwilling to release. If the fruit does release from the plants, it will be sorted out at the processing line before the rest goes into a higher grade.
While normally not a concern, it does bring up a potential conundrum worth mentioning. Are there going to be fruit sampling tests collected at the processor dock which are going to mistakenly identify larvae in fruit as SWD when in reality it is not since all drosophila larvae are visually identical? Should the different drosophila species matter anyway considering a contaminant is a contaminant? Should standard SWD testing protocols at the processor focus on the sorted product versus the incoming load which includes the compromised berries destined for sort out anyways?
These other drosophila species do not pose a risk to the remaining marketable fruit, so maybe that is the message? Either way, it should make us think.
Your input is always welcome so chime in below:
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