After yesterday's visit to the Upper Mountain Research Station, I was eager to check my spotted wing drosophila (SWD) traps at the Sandhills Research Station today. My first stop at the station was the caneberry breeding plots.
|Caneberry seedling plots at Sandhills Research Station. Photo: HJB|
Raspberries are grown at Sandhills not because they do well here but because most raspberries cannot tolerate high heat. The plots here are intended to screen breeding material for heat tolerance traits that will be used to develop raspberries that can be grown in hot summers. In other words, most raspberries are not happy at the Sandhills.
We began catching SWD adults at the Sandhills on 11 August 2010 and trap captures peaked on 18 August. See trapping data here. Dates are in ordinal days; see here to convert ordinal days into calendar dates. There were no blackberries present at this time, few peaches were remaining, and no larvae were found in fruit. No flies were captured during the month of September, and one fly was caught last week.
SWD and raspberries have a lot in common in terms of temperature tolerance. Both like mild weather and, at least according to current literature for SWD, do not reproduce in hot weather. I suspect that the record heat this summer may have limited SWD's initial spread through North Carolina, but now as fall temperatures cool, we may see more flies and more maggots.
There were a few raspberry plants with fruit, and most of what I observed did not contain visible larvae. I did find one, otherwise perfectly sound fruit, that contained one early instar larva.
|Early instar maggot (center of image), likely spotted wing drosophila, in a red ripe raspberry at the Sandhills Research Station, Jackson Springs, NC. Photo: HJB|
|Ripe and overripe raspberries collected to determine the presence of SWD larvae at the Sandhills Research Station. Photo: HJB|
Sponsored by the Southern Region Small Fruit Consortium, Project 2010 E-01.