Cranberry Management Calendar - August
- Cranberry Tipworm (any remaining larval stages will finally begin to wind down for the year by month’s end)
- 2nd-Generation Blackheaded Fireworm larvae (this is the generation to really watch out for, particularly if you saw threshold levels–or higher–of 1st-generation larvae and are uncertain as to the effectiveness of any control actions you may have taken earlier in the season)
- All of August: Cranberry Fruitworm larvae
- Late August: Red-headed Flea Beetles (adults) – Large outbreak found in 2009 on August 25th (not spotted on Maine cranberries in previous years). Sweep lightly across the tips to avoid harvesting berries, or do the bulk of the sweeping in areas where you have fewer berries). They are very patchy, often occurring in areas where the vines are lush (so probably fewer berries there as well). High levels of them can impact bud development for the following year. They feed primarily on the undersides of the leaves, consuming the outer surface layers and leaving only the veins behind. They also will gouge the berries. Firm thresholds for this pest have not been quantified, but sweep net counts of 15 per 25 sweeps on average over all acreage is the current rule of thumb. The counts seen in 2009 were in the range of 50 to 100 per 25 sweeps!
- Cranberry Tissue Testing: Tissue samples should be taken during the last two weeks of August or during the first week or two of September. The reason for this is that the concentrations of the 13 required minerals (macronutrients) are stable during this period. Also, the standard values against which the results are compared are based on sampling that was done during this period.