Last minute alert: Laura McDermott will be hosting “office hours” for berry growers every Thursday beginning April 16 (today!). Starting at 12:30 PM, there will be a short (10 min) presentation, then time for Q&A. Join by clicking this link : https://cornell.zoom.us/j/103904012, or you can call 1-646-518-9805, meeting ID: 103 904 012

In Western NY and across the Northeast, cooler weather has slowed bud development on berry crops. Near Lake Ontario, blueberry buds (at green tip) and new strawberry leaves have not progressed much since April 6.

In a protected site in Wyoming County, however, early varieties were at tight cluster. With cold weather predicted for most of the next week, growers have a bit of a reprieve in the race against pest and disease development. However, there is still plenty to do:

Blueberries: finish pruning if you haven’t yet, being sure to take out any galls of blueberry gall wasp. Consider going back and taking out even more canes than usual – research in Michigan is showing that SWD pressure is lower (and control is better) where bushes are pruned 25% harder than traditionally. This is not infection weather, but next week looks like it will be, so be ready to get out there with those mummyberry and anthracnose sprays. This is also the time to get nitrogen fertilizer on blueberries. For greatest efficiency, apply half of the fertilizer at bud break (or now), and half at petal fall, though this isn’t as important on heavy soils. For rates, refer to this table from the Highbush Blueberry Production Guide:

Age of plants (years)	Urea	Ammonium sulfate	Actual Nitrogen
8	145	310	65
7	120	260	55
6	100	215	45
5	80	170	35
4	60	130	27
3	45	95	20
2	35	75	15

 

There is still time, though the window is closing, to get preemergent herbicides out. See last week’s post for recommended products.

Strawberries: I spotted some active strawberry aphids this week, so they are hatching and moving about. Still plenty of two-spot mites around as well. They will slow down with this cold, but be ready for things to move fast when it warms up again. Natural enemies can handle low populations, and I see huge differences between fields. Do your own scouting – you might not need to spray at all! Get a simple jewelers loupe to help you see and identify the insects. Strawberries should not be fertilized in the spring, unless you are using plasticulture and fertigating at very controlled rates.

Raspberries: Buds are breaking and new shoots emerging from the soil. For blackberry and black raspberry growers – this is the best time to prune, as it is easy to see winter damage and prune it out. It is probably too late for lime sulfur, but copper or hydrogen peroxide products (as well as other fungicides) could still be used against cane blights. Be very careful with herbicides at this point, as new emerging canes are already getting burned. It’s time to get fertilizer on – see last week’s post for recommended rates.

Announcements:

• Cornell and NYS experts are hard at work on recommendations for pick-your-own operations in light of COVID-19. Stay tuned – we will post more information through this blog when it is available.
• There is now a 2ee label for use of Verdepryn 100 SL in blueberries against blueberry stem gall wasp. Verdepryn (cyclaniliprole)  is a diamide that has recently come on the market and is currently labeled for use on blueberries in NY (but not on Long Island) for quite a number of insect pests including cranberry fruitworm, Japanese beetle, spotted wing drosophila and blueberry maggot.  It also has some efficacy against blueberry stem gall wasp Hemadas nubilipennis, which is an emerging problem in highbush blueberry plantings in NY and other areas.  Although blueberry stem gall wasp has been around in NY at low incidence for many years, it is becoming more problematic throughout the eastern USA.  One of the reasons for this is likely the increased insecticide use for spotted wing drosophila that has occurred in the past 8 years.  Until this 2ee, we did not have any insecticides labeled in NY for blueberries that included blueberry stem gall wasp.  The only recourse growers had was removing galled stems while pruning.  For low pressure situations, this is relatively effective.  Under high pressure situations, however, recent research by Michigan State University entomologists has shown the benefits of also applying insecticides post-bloom targeting this pest.  They achieved best results with two post-bloom sprays, 7-10 days apart.  See the label for other information and restrictions.