Please note unless something pressing is happening in the MA cranberry world next week, the next IPM message will be out on July 10.
Unfortunately, two new sites in MA have been identified with Cranberry False Blossom Disease (CFBD). Now is a good time to see the distinct aberrant bloom (club shaped and upright), but it can be hard to detect without close inspection – not visually obvious from the shore! See this fact sheet from NJ for more info. If you find uprights that you suspect are infected with CFBD, PLEASE let us know so we can accurately assess the spread and status of the disease in our state.
Scout for blunt-nosed leafhoppers, which vector the disease. There is currently no known treatment for CFBD, and plants are not thought to recover. The only management strategy is to manage the blunt-nosed leafhoppers and prevent spread of the disease.
Cranberry fruitworm moths are flying and will continue to fly for the next month. Some of the super hybrids have some sized-up berries that are perfect for egg laying. Time your Altacor (or other chlorantraniliprole e.g. Osaria, Turazi) based on % Out-of-Bloom (OOB).
Percent out-of-bloom
(pinheads + fruit) ÷ (flower pods + open flowers + pinheads + fruit)
If you have 40-50% OOB on a super hybrid, it is likely time to spray. If you see enough pinheads starting to size up on the Ben Lear or Stevens, then it is time to treat those as well. With Early Black and certainly with Howes, berries do not size up quickly and you can drag your feet several days longer before applying management for eggs. Moths will fly around to find the bigger berries and preferentially lay on those.
Be sure to check the label of the chlorantraniliprole product you are using. Altacor eVo has a very low-rate range (1.5-2.2 oz) compared to regular Altacor. Other generic products are generally similar to the high rate of the older Altacor (3-4.5 oz). In all cases, use the highest rate allowed by the label for chemigation for good efficacy. A 10–14-day interval is recommended between sprays to get the longest coverage time.
We continue to hear from growers that they are seeing a lot of variability in the field - with some beds getting their 1st/2nd fungicide spray this week while other are already being treated for fruit worm.
We have had a few sites, mostly new plantings, showing heat stress from last week’s dry and windy conditions. Be sure to irrigate tender new growth more when there are a low dew point and low humidity. The 2” of rain that we got earlier this week was very much needed, but all cranberry growing areas are still in a “Significant Drought”.