Pest Update 2 September 2017

Friday, September 1, 2017

Spotted Wing Drosophilia (SWD) counts have been steadily climbing in all traps, whether located in or outside of the crop.  As can be expected, captures remain higher for traps located along the field borders.  However, we have been observing sustained captures and gradual increases in trap numbers located within the crops, over the past few weeks. To date, we have observed adult SWD emerge from blueberries, raspberries and blackberries. Although up-to-date GDD calculations suggest that temperatures are average (if not slightly below) for this time of year, we do know that this is when SWD populations will spike and one can easily see trap captures go from double digits to over a 1000. Monitoring the crop with traps and fruit collection and testing for infestations is critical at this time.  (Dr. Deb Moreau, Entomologist, AAFC)

Strawberry aphid is the main vector of strawberry virus diseases in Nova Scotia.  Strawberry aphid monitoring began in early spring and will continue into the fall as part of a provincial funding program with HNS and Perennia.  Populations have remained low throughout the summer in managed strawberry fields across the province.  With that said, we typically see a "blip" in September of increased numbers, so be sure to continue to protect next years fields. 

The large raspberry aphid is the primary vector in NS of bramble viruses that are responsible for decline in cane vigor and decreased fruit quality.  Monitoring activities have found them in commercial fields and at field edges in wild bramble.  Their size makes them easy to scout with the naked eye.  They can be found at the tips and undersides of newly expanded leaves where tissue is supple.  Given the prevalence of wild bramble that are potential sources of virus, it is important to monitor and protect fields if you have a confirmed population of aphids.

Large raspberry aphid.
Potato leafhopper was first found in early July and has now been found throughout the Annapolis Valley and the south shore (Erika Bent, APM Agricultural Pest Monitoring Consulting Ltd).  Adults (see photo) and nymphs are present in apple orchards, strawberry and raspberry fields.  Feeding by the leafhoppers results in yellowing and crinkled leaves (see photo) and they are able to transmit aster yellows and green petal in strawberry.  Nymphs and adults can be found by looking on the undersides of the leaves; nymphs walk sideways when disturbed.

Potato leaf hopper adult on strawberries.
Potato leaf hopper damage in strawberries
(photo credits: Erika Bent).
Sharp-nosed leafhopper is able to transmit stunt in highbush blueberries.  Erika Bent (APM Agricultural Pest Monitoring Consulting Ltd.) has been finding adults on yellow sticky traps throughout the Annapolis Valley over the past couple weeks.  Controlling the leafhopper will help reduce the spread of stunt, but not eliminate it.  Infected plants should be removed and destroyed.